Appendix — Raytheon Co. v. Roper Corp.

Supreme Court brief1984

Ask Donna

What actually matters in this document.

Text

Office - Supreme Court. US

FILED

s 83-2128 _——

ALEXANDER \. STEVAS,

CLERK

No. -

In the

Supreme Court of the United States.

OcTOBER TERM, 1983.

RAYTHEON COMPANY,

PETITIONER,

ROPER CORPORATION,

RESPONDENT.

Appendix A.

ROBERT A. CESARI,

MARTIN J. O’DONNELL,

STEVEN J. HENRY,

CESARI AND MCKENNA,

312 Union Wharf East,

Boston, Massachusetts 02109.

(617) 523-8100

Counsel for Petitioner

Of Counsel:

JOsEPH D. PANNONE,

WILLIAM R. CLARK,

141 Spring Street,

Lexington, Massachusetts 02173.

(617) 862-6600

BATEMAN & SLADE. INC ~ BOSTON, MASSACHUSETTS

PETITION FOR WRIT OF CERTIORARI TO THE

UNITED STATES COURT OF APPEALS

FOR THE FEDERAL CIRCUIT

APPENDIX

VOLUME A

Torrey U.S. Patent 4,028,520 (the Patent in Suit)............Al

Highlighted Portions of Torrey Patent....eeeeseeecceseceveeecAl4

Tingley U.S. Patent 3,430,023. .ccccccccccccvcscccevecscscccce Al7

Boehm U.S. Patent 3,440,386. .cccrcccccccccccccccccccsccscccsces AZZ

French Patent 1,249,130 (Miwag Mikrowellen A.G.).......2++-2- A3Z

Peranslation of French Patent 1,249, 130. scccscccccsccsessesces AZT

VOLUME B

Opinion of U.S. District Court, Jan. 20, L9B3.cccccscsccsccceebd

Opinion of U.S. Court of Appeals, Dec. 30, 1983..........2....B43

Order of U.S. Court of Appeals Denying Rehearing

Mar. he eo ihe eee a’ eee ohe ew ebb eae een eee

Roper Exhibit No. Css eek ek dW hee PERSE EOS OEKSLE EERO NSS

Raytheon Exhibit NO. BJT. ccccccccccccccccccccsccccscccccsccecbID

Roper's Pre-Trial Brief (Selected PartsS)....ccceeeecceeeeeee +Bl6

Roper's Answer to Raytheon's Request for Admission No. 23....B80

Deposition Transcript of R. D. Triplett (Selected Parts).....B8l

Stenographic Transcript of Trial (Selected Parts)............B82

EDITOR'S NOTE

THE FOLLOWING PAGES WERE POOR

HARD COPY AT THE TIME OF FILMING.

IF AND WHEN A BETTER COPY CAN BE

OBTAINED, A NEW FICHE WILL BE

ISSUED.

United States Patent «1% me 11) 4,028,520

Torrey {45) June 7, 1977

($4) AIR FLOW SYSTEM FOR COMMON Attorney, Agent, or Firm—Leydig, Voit, Osann, Mayer

CAVITY MICROWAVE OVEN

[75] Inventor: Samaer H. Torrey, West Lafayete,

ind.

[73] Assignee: Roper Corporstion, Kankakee, Ml.

[22] Filed: Feb. 26, 1976

(21) Appl. No.: 661,524

v8 fas 219/10.55 B; 219/10.55 F

J SS | een HOSB 9/06

(58) Field of Search .............. 219/10.55 B, 10.55 F,

219/10.55 R, 126/273 R, 19 R, 343/731, 732,

741, 772, 879

{56) References Ched

UNITED STATES PATENTS

oO "eee 219/10.58 B

Fa eee . 219/10.58 F

3.172.987 3/196S3 Frezmayer ................... 219/10.58 B

ee 9 MEE A ccrtnrtaahownseiiatiinsrcnsiien 126273 KR

3.470.942 10/1969 Fuksdaetal .............. 219/10.55 B

3.626.135 12/197) Fitzmayer .................. 219/10.55 F

3.962.561 6/1976 Phantenaz 2200000000000... 126/19 R

Pnmary Examiner—Arthur T. Gnmiey

& Hoh, Lid.

{$7} ABSTRACT

A combined microwave-thermal] range having an oven

cavity with a thermal heating element for baking and

self-cleaning purposes, the botiom wall of the oven

cavity having an mlet opening and the top wall having

a vent opening. A microwave module mounted in space

provided under the botiom wall of the cavity includes a

microwave power supply housing enclosing a magne-

tron and blower. The module has an associated wave-

guide secured to the top of the housing and extending

cantilever-fashion close to the botiom wall of the cav-

Ry, with the outlet of the waveguide in alinement with

the central opening couples microwave energy from

the waveguide to the cavity. Blower air passes from the

blower inlet through the magnetron and waveguide and

into the cavity for ventilaung the same. The blower

inlet is located at a level below the bottom wall of the

cavity so that, when the blower and magnetron are

turned off and the thermal element is turned on, air

passing through the blower, power supply housing and

waveguide flows upwardly by natural convection into

the opening mm the botiom wal] of the cavity with final

escape through the vent at the top of the cavity.

7 Claims, 16 Drawing Figures

U.S. Patent june 7, 1977 Sheet 1 of 5 4,028,520

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AIR FLOW SYSTEM FOR COMMON CAVITY ine 2-2 2 FG.1.

MICROWAVE OVEN = “FAG. 2a shows the relation berween the antenna and

BACKGROUND OF THE INVENTION ns ee i Os ee FG

For » number of years oven cavites have been em —_ FIG. 3's 8 front view of the oven of FIG. J with the

tures present precuca! problems where operated im 10 Sonmiructed in accorance sith Ue present mvenuon

threr_ modes namely microweve, thermal and self. — FIG. 3 5 8 vervical seccion taken the micro-

40 2 level, on the order of 900" F., capable of producing Song tine $8 in FIG. 2. ===

“thermal decomposition of the a00 on the cavity mr- —_ FAG. 6 is a transverse section taken through the mod-

faces, a slightly positive preascre is created causing 35 tle looking along the line 6—4 in FIG. 5.

back-up volauiit decomposition = }. Go is a fragment taken along line 6o-—¢0 in FIG

products into the waveguide where condensation wakes SS

; j = $36. 7 is 2 crom sectional view the hollow

place. resulting in an accumulstion. or build up. of : ctor ad through —

FAG. 7s ip a profile view of the antenna in FIG. 7.

characteristics of the waveguide. Such accumulation és Pepa test ere ad een Lene

" : = 7. *

invention to provide 8 Common cavity oven which » : - .

scaled againn excape of microwave energy when oper-= 200 WH senain preferred embodiments, .& will be

: understood that we do not intend to be hmited to the

aied in the microwave mode but which nevertheless has : -

ee co . 35 parucular embodiments shown and that we intend, on

good ventilauion charactersucs when opersied m the the contrary, to Shea sew ' =e

_ thermal and self<clean modes, msuring a well defined stent consi eaek 3 Sele Ser anit and

and unidirectional ventilation path regardless of the scope of the 2 ded cia} rns

operating temperature and which prevents backflow of

the air and volatile products of decompotition into the 40 DETAILED DISCLOSURE

inlet opening regardless of the lemperature achieved = “Turning to FIGS. 1 and 3 there is shown a typical free

within the Cavity. : Wanding electric range to which the presest mvenuon

h is 2 more specific object to provide # venUlaton = hay been applied. The range hat an oven cavity 20

sytem which is capable of resisting Suto igniuon pres ing 8 top wal] 21, a boniom wail 22, aide walls 23,

sures of the products of decomposition and m which 4; 34 and a back wall 25. AH of the wails are of “aand-

enidirecuona) flow of ventilaung air & assured even mM = wich” construction formed of sheew of meu

the presence of severe soil. with insulation, preferably m the form of giss woo! m

and the tike which have been resomed to in prior struc- Chaving a gasket 31 which provides continuous gnd

tures in order to insure ageing backflow of conumi- “unbroken engagement with a land wirface 32 ov. the

nated air, : - Fange body. The gasket ie of the ype intended for

i i a general object to provide = ventilating system $5 shielding agains escape of thermal and microwave

for a common cavity oven usable m all three modes of = energy, and its effect be use of 8

operstion end which is safe m afi three of the modes pontinonan Shakes pine eo saveaenad eoberbare

become apparent upon reading the arusched detalied «= perature self-cleaning. Consequently, 2 latch is used

Sescripuien and upon reference t the drawings i= having a latching contro! 34, with the mode of oper-

=. = SSS SS tion being selectable by a mode switch 35 at the top of

FIG. I is a perspective view ofa free runnding electric = the range. Within the oven cavity is a grid-type shelf 46

range of conventional design but incorporsung # 45 formed of metallic conductors im spaced paraliel rela-

source of microwsve energy and hsving provision for = Gon and extending horizontally over the entire area of

use of thermal and microwave energy simultaneouslyim — the Cavity. The shelf preferably has no central crossbar

a common oven cavity. - extending perpendicularly to the conductor. Metallic

4,0°° «nn

supports are used at the respective ends of the shelf,

however. we employ mo means to assure positive

grounding of the supports We have found with our

feed sysiem that arcing does not occur im the oven in

spite of intermittent meta! to metal contact, therefore.

Below the oven cavity 20, and of generally conform-

ing shape. is a storage space having s closure 40 form-

ing 8 portion of s drawer 41 mounted upon slides 42

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‘Specifically. the Dange seats an

land 112 chich b Seemed in the plate 301 and which

Burrounds the opening 100, the land serving as a dam wo

keakage of oven spills into the hollow conduc:

socket receiving the circular lower end 113 of the con-

ductor Such socket is defined by an annular mount

116 made of pressed metal and whuch is spot welded or

> otherwise securely fastened to the top wall 93 of the

waveguide At the root of the socket ws 2 resilient con.

ductive gasket 117 which may, for example, be formed

of metal gauze

For clamping the hollow conductor against the gause

in the socket /15, s pair of clamping screws 12! are

provided which *xtend through registenng openings in

the Marge 111, with the threaded ups of the screws

being received in tapped openings 122 in the mounting

member 116.

The screws 121 are not, however, relied upon to keep

the Mange 111 ughuy seated against the land Prefer.

ab!) three sddiuonal screws 123 project through regu.

tering openings im the Dange to engage tapped boiles

4p 124 w the land

Spaced sbove the flange 111 is # mounting mng 125

which i supporied upon short pedestals 126. The

mounung ring 125 w secured by screws 127 which

telescope through the Oange and imto reguienng

45 “apped holes in the land

Thus im assembling the device the flange us seated on

the land and the screws 121 are wghtened in the

threaded holes 122 to seat the conductor 110, at m

lower end, firmly against the socket 115 im the wave-

guide The screws 123 are then ughtened in place to

Goubly insure that the Dange 111 = wmumately seated

against the land Finally, the screws 127 are inserted

Mo the mountng nng. and ughtened

Because of the canulever extension of the waveguide

$2 wpor the housing $1, the waveguide occupies «

nominal posivon from which it may be resiliently de-

flected without strain or damage w the module, for

example, when the screws 121 are turned to draw the

holiow conductor down into contact with the gasket

@ 117, the end of the waveguide os simultaneously drawn

upwardly Unrough s smal! angie, resilenuy twersting the

module, un! Opposiuon to turning of the screws ind).

cates that the hollow conductor 110 ms fully boriomed

Seating of the hollow conductor to provide a tight yom!

at both ends sw assured. notwithstanding dumensiwonal

variauons, under producuon-line condiuions, between

the bottom 22 of the cavity and the plane of the sup-

ports 44 in the storage space

46c-"

In accordance with the present invention (FIG. 7) an

antenna & mounted for rotation coaxially im the hollow

conductor 110, the antenna being coupled at ms lower

end to 8 motor and drive ain mounted upon the wave-

guide As will be discussed im greater detail, the an-

tenna. indicaicé at 130 has 2 straight shank poruon 131

which is coaxially arranged in the conductor 110, 8

“wansitional” poruon 132 which s upwardly angled

and « radial arm portion 133. In the preferred embodi-

ment the antenna is formed by first and second abrupt

bends 134, 135. The lower end of the antenna, indi-

cated at 136 gs keyed for reception im s rotatable mount

137 journaled im the bottom wall of the waveguide To

serve as & bearing for the upper end of the antennas, and

to shield the upper end of the hollow conductor from

food spills or other foreign matier, is a ceramic duc 140

supported within the amounting ring 125 on the posu

126 and having # central opening 141. The antenna

held captive in Use central opening by 8 snap ring 142

whoch @ in interfenng relauon with the underside of the

dmac

ht is one of the features of the present construcuon

that the entire antenna and hollow conductor assembly

may be convenienUy removed, when service becomes

necessary, from the inside of the oven cavity By un-

actewing the screws 127, the mounting ring 125, disc

140, and the antenna itself may be drawn clear of the

conductor Next, unscrewing the screws 121 frees the

lower end of the conductor 110 from its seat on the

waveguide, and unscrewing the screws 123 permit

separauon of the conductor Mange 111 from the land

112 on the botiom wal! of the oven so that the conduc-

tor may be ified clear The cunductor assembly may be

reinstalled by simply reversing the procedure

For the purpose of rotating the mount 137, s small,

clock-type dnving motor 150 wu provided having inter-

na) gear reduction The motor is mounted on the top

side of & motor mounting Mange 151 which extends

from the side of the waveguide Pinned to the motor

shaft oa first gear 152 located on the underside of the

waveguide and which meshes with « second gear 153

which pinned to # shaft 154 forming 8 part of the

mount 137. The shaft = journaled in 8 bearing 155 of

plastic or the like which occupies an opening 156 in the

bottom of the waveguide, the opening being sufficiently

smal! so that negligible leakage occurs The motor gear

reduction, and the ratio of gears 152, 153, in such that

the antenns rotates at 2 low speed which may, for ex-

ample, be on the order of 5 to 10 revolutions per min-

ule, in any event providing 8 period of rotauon which os

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in accordance with one of the features of the ren. The mode selector switch 35 is used having « firm

tion al passages are provided between the power gup- = contact 181 for thermal heal, s second contact 182

ply howsing so that » portion of air from the blower 80, = which energizes the , and « third, or dual

and which cool the magnetron, flows through the 55 contact 183 which turns on both of the energy sources

waveguide and hollow conductor for ventilating the 8=— As indicated im the figure, the blower motor 84 and

Cavity when the blower is on. for final venting from the §=—s antenna motor 150 are turned on whenever the magne

sop of the cavity, with the same an peth being utilized §=—swon is turned on but are off at al! other times. A fourth

to set up flow of convecied ait during thermal cooking, or “se!f<ciean™ posivon 184 is also provided, with the

that Wustrated in FIG 9, parucularily as regerds the

safety features which are effective in the self-clean

mode

mitt

" ROTARY ANTENNA

The preferred form of antenna 130 disclosed im FIG

Je, rotated at a relauvely slow speed on the order of a

few revoluuons per minute, has been found to be highly

effecuve in bringing about an equalued dutnibuuvon of

microwave energy throughout the cavity with relative

freedom from the hot spots which usually characterze

microwave cookery The antenna is distinguished by s

of the bollow conductor for radiation of a guided wave

im the cavity which seu up a plurality of radiation pat-

terns

in understanding the operation of the antenna ft will.

first of all, be appreciated that microwave energy &

Girectl) propagated from the waveguide into the cavny

independently of antenna action, the resulting wave

been referred to as the “imertial™ wave. In addition.

microwave energy which is coupled to the lower end of

the antenna is guided along the antenna for radiation

therefrom in the form of a “guided” wave Where an L

shaped or T shaped antenna & employed having an

abrup! 90° bend, it is found that the bend consututes s

mar discontinuity which actually prevents microwave

caergy from being converted to # guided wave. How-

ever, where the antenna, at point of exi, s bent on

more gradual basis, that is, is bent over # transitional

region of at least the radius of the hollow conductor

through which it projects into the cavity, the propor-

tion of energy in the guided wave, as compared to the

inerual wave, is increased and, in addition, the guided

wave controls the patiern of radiation within the Cavity

The increased number of radiation patierns, with con-

tinuous sweeping, inherently produces fewer hot spots

than either the simpler, stationary mode patterns

achieved using. for example, an antenna of the conven-

tional monopole type, of 8 Conventional antenna in

combination with auxiliary surring means

In the preferred form of the invention, illustrated in

FIG 7a, the antenna has two concentrated bends 134,

135 to define its three portions The radial arm poruon

133 has s length which is preferably greater than the

transitional poruon to improve radiation patierns and-

for facilitate impedance matching while maintaining 8

low profile. In practical cases the total redial length of

the antenna may be on the order of 2.0 to 5.0 inches

It is one of the features of the antenna that the bends

134, 135 are so related to one another that the antenna

bes in the plane of the lower heating element 28. Al-

though the antenna illustrated in FIG. 7e can be em-

ployed with conventionally formed U shaped heating

elements whose surfaces are remote from the antenna.

for those cases where the antenna Up overlies a heater

surface, the preferred heater shape, as shown in FIG

2c, is circumferentially distributed about the antenna

path at a substannally constant radius so that the effect

of the heating element 28 upon the radiated energy

temains substanually constant throughout the rot-

tonal cycle.

Moreover, by spacing the radia! portion 133 of the

antenna, and the heaung element 28, at the same rela-

tively close spacing to the adjacent (botiom) wal! 22,

there 6 minimum encroachment upon the space within

the cavity, in other words, a high degree of compact-

ness is achieved In a practical case, the spacing of the

heating element and antenna from the adjacent wal! u

on the order of one and one-half inch. By keeping the

antenna within the confines of the bottom heanng ele-

ment, and with the latier distributed as shown in FIG

2c, the antenna self does not take up any addivonal

space within the cavity, making the utilization of space

much more efficient than where a stirring device or

conventional type of rotating antenna is employed

h will be understood, however, that the invention s

not limited to the exact profile Dlustrated in FIG. 7e

and, if desired, the wighty higher profile, Diustrated in

FIG. 10, may be used In ths embodiment, in which

corresponding reference numerals are used with add:-

tion of subscript ¢ to indicate corresponding paru of

the device, the included angle ¢ at the first bend 134<

is increased and the included angle at the second bend

135c is decreased Preferably the angle @ should be

kept within the range of 105° to 165°, while the m-

cluded angle at the second bend should be approxi-

mately (270° - @) to provide a low profile.

While it is preferred to form the antenna with con-

centrated bends, the antenna may be gradually bent or

smoothly “faired” over the length of the transitional

ruon as indicated m FIG. 11, which corresponds to

ric 7a, the same numerals being employed with addi-

tion of subscript b. Thus it will be noted that ty transi-

tional portional 132d has a length at le»<: = radius r of

the hollow conductor between the point 134) denoting

Ue en of the shank and the poir: 135) denoting the

beginning of the radial arm 133.

The invention is not. however, limited to the embodi-

ments illustrated in FIGS. 10 and 11 but includes the

dogieg configuration set forth m FIGS. 12 and 13

where corresponding elements are denoted by the same

reference numerals with addition of subscripts ¢ and d.

respectively. Thus referring to FIG. 12 the antenna has

@ straight shank portion 131c which is coaxially ar-

ranged in the hollow conductor, with a bend 134

which is substantially less than 90° to produce an in-

cluded angle a which preferably lies within the range of

95° to 165°, the angled portion 132 being preferably at

beast equal in length to the radius of the hollow conduc-

tor The structure of FIG 13 corresponds to that of

FIG i2 except that the concentrated bend 134¢ has

been replaced by a gradual bend two define an angled

poruon 132d having the same effective length

in each of the illustrated embodiments of FIGS. 10 -

13 the use of an obtuse angle o to define a transitional

portion 132 of dogleg configuration results in efficient

guidance of energy from the shank to the radiating

poruons of the antenna with minimum electrical dis-

conunuity thereby to convo! the ratio between the

energy in the guided wave and that in the directly emit-

ted, or inertia] wave, with the guided wave being effec-

Uvel) superimposed upon the inerial wave and swept

continuously throughout the cavity for unproved en-

ergy distribution in the cavity with relative freedom

from hot and cold spots Thus the distribution is to be

disunguished from that using 8 conventional monopole

which tends to concentrate energy im a radial ring con-

centnc with the monopole and the various types of

“mushroom” antenna configurations which tend to

Gistnbute energy about the penphery while leaving a

relatively large “hollow” energy region at the center of

the cavity It is found that using 8 rotated antenna of

the above-described design the usual meta) grid type of

shelf employed in conventional electric ranges is effec-

uvely penetrated It is one of the observed benefits of

the invention, that arcing between metallic conductors

placed within the oven cavity does not occur. Special

precautions such as proper microwave grounding or

insulated standoffs are not needed for metal grid

shelves, shelve supports, or heating elements. This,

while not fully understood, is attributed to the uniform

energy distribution within the cavity.

ht is one of the observed benefits of the present inven-

Bon that a larger percentage of energy reaches the

foodstuff along a direct radiation path than in conven-

tonal microwave ovens. Thus, using an electrically

transparent vessel to contain the foodstuff, with the

vessel supported in a generally central position, micro-

wave energy received from the waveguide and from the

rotauing antenna creates even internal heat within the

foodstuff, free of hot or cold spots as described Such

energy transfer ts more uniform than that which occurs

by reason of unccntrolied muluple reflection against

All

the walls of the cavity, thereby reducing the ume it

takes to completely cook the foodstuff.

While it is preferred to use electrically transparent

cooking vessels, another of the observed benefits of the

described antenna is the fact that the cooking patiern

does not seriously degrade when cooking with metallic

utensils, nor do metallic cooking utensils cause adverse

operating conditions harmful to magnetron operating

life. Evidently the secondary reflections which occur

also produce 8 more uniform energy distribution than

that which occurs from conventional monopole or stir-

rer type microwave energy distribution systems.

Conventional sources of waveguide energy are highly

sensitive to the dimensions and proportions of the cav-

ity in which the energy is utilized Thus, starting with a

cavity of 2 certain dimension it has been necessary in

the past to “tailor™ the antenna and waveguide to the

cavity and to make other adjustments including the

position of point of feed im order to create a desired

modal pattern. It is found, by contrast, that the present

design of module and its associated antenna is largely

independent of the size and dimensional! proportions of

the cavity so that the module and antenna assembly

may be utilized by the manufacturers of different types.

sizes and designs of oven cavities, free standing. built-

in, and portable as well, on an O.E.. basis, and with

the only modification of the basic range structure being

the provision of seating for the housing at a proper leve!

and the use of a hollow conductor and clamping screws

of appropriate length accommodated to the thickness

of the lower insulated wall of the cavity. As a result

almost any design of thermal oven may be modified to

include microwave energy at a relatively smal) incre-

ment in cost, greatly expanding the market for micro-

wave devices and mdeed expanding the market for

ranges in general.

While the above discussion has emphasized conver-

sion of an electric range to microwave usage, it will be

understood that the present microwave module is also

applicable to conversion of gas ranges, although the

latter will, of course, require a greater degree of modifi-

cation Consequently, the term “thermal element” will

be understood as not being. necessarily, limited to an

electric heating element. The term “storage space™ has

been used for convenience to apply to any available

space adjacent the regular oven cavity.

Although it is preferred to seat the microwave power

supply housing in a remote position in the storage

space, it is conceivable that in a range design providing

a wide oven having a limited front-to-back dumension,

im may be more convenient to mount the microwave

housing along the side of the storage space with some

sacrifice in the width, but not length, of the drawer.

Consequently, the term “back” used in connection

with storage space shal) be considered to be a relative

term including both of the positions. The term “hollow

conductor” which has been applied to the hollow tube

110 is also a general term applying to means defining

any opening of passage between « waveguide and an

oven cavity and the length of which depends upon the

thickness of any insulating layer which may be pro-

vided. The term “waveguide” shal) be considered to

cover any conductor of wave energy from the magne-

tron for discharging microwave energy into, or which

energizes an antenna im a shielded oven cavity. Thus

the term waveguide as used herein includes a coaxial

transmission line. The term “magnetron” refers to any

source of high intensity microwave energy.

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duces a field which is so uniform and a result which is =

&© predictable, that “formula cookery”, based upon the be

conventional cookbook instructions, is possible for the ——

first time. Specifically, in the case of pastry and similar 3~

baked goods. the foodstuff, im normal! quantity, i sub- =—

jected to microwaves for a period of five minutes, after — gm

which baking is completed using thermal energy at the — at te

temperature, and im just one-half of the time, given in — ang

the conventional cookbook In the case of other foods. # &

both types of energy are applied from the beginning of = 3

the cycle and the total cooking time is reduced to one- = — 2

Quarter of that given in the cookbook. = focated st ale w the dott

_ 4. in a combined microws —— Sof 3 i SS. utned on alt i thermally con-

1 ea Se — -suficienth; constricted to tha! air is Convected im the

mm the cavi pe ee ee eg peg peers

=a eer ae jevel for = US pee ae ete

=m wall of dc cocker bowing an tet opeeing. wanes = ~ Pination 3 iene yak Pega

S Schaiag S Secliy Osan at tea Sap ak Oe aoang- 5s sertangcer Gd toy tal 5 tomes epee & door an-

~ tictowave pown’ supply including a Blower and amag- closing end sealing the from surface of the cavity

~ Biron having cooling fins, the biower having a blower agains! passage of ax and microwave energy, 8 thermal

~ inlet for drawing in cooling ait and an outlet for tupply- element im the cavity, the walk of the cavity being

ing such sir under slight % the cooling fing.a = insulated, the botiom wall of the cavity having an mici

waveguide having an miei connected t the 3 opening. means defining a cavity ait yeni 21 the top of

and extending under the bottom wall of the cavity to the cavity, 5 microwave supply having a housing

terminate at an Ovllet, means for connecting the ancluding a and blower, the blower having 5

outlet magnetron ;

~ of the waveguide to the inlet opening of the cavity for ‘blower nie! and arranged to draw m cooling ai from

_ sonducuon of microwave energy into the cavity. means outside the housing for supplying under slight pressure

wavrtguide and into tht cavity fot ventilating the cavity — netron and extending the housing and under the

when Ue and blower are turned on. the = Boriom wall of the cavity. the waveguide having an

_ Blower miet being located st 2 lever below the botiom 40 outlet alined with the opening in Ux bottom wall of the

wall of the cavity so that when the blower and magne- cavity, a hollow open-ended conductor ¢

tron are turned off and the thermal element is turned = through the opening for coupling the outie of the

on ait is thermally convected from the blower inlet = Waveguide to the Cavity. means for securing the upper

through the ai passages into the waveguide and mip ~~ end of the boliow conductor to the boriom wall of the

the cavity for exiting through the cavity ai vent not- 45 cavity and the lower end of the conductor w the wave-

the auto ignition pressure which exists im = guile for conduction of microwave energy mto the

the cavity under high temperature self-cleaning condi- _— cavity. the wall of the waveguide having 2 pattern of

tions. the convention path of the air being sufficiendy = small openings communicating with the housing so that

consiricted 50 thal ait & convecied in the seH-cleaning =—s'8 portion of the pressurized sit from the blower and

OES SES Wee NE ee ee 30 magnetron passes through the waveguide and holiow

ing an explotive reaction with the products of decom- tonduttot into the caviiy for ventilating the cavity

position, when the magnetron and blower ate turned on, the

2. ln s combined microwave-thermal range, the com- housing having 3 relatively large vent opening through

bination comprising a frame having walls defining 2 = which i i

rectangular oven cavity and a lower space, a door en- 55 internal pressure im the housing thereby

closing and sealing the from surface of the cavity i the pattern

agains! passage of ait and microwave energy. a thermal

eiemem in the cavity, control means for operation of — Jevel, the blower mie: and large

range

for food preparation and ai a high temperature level for 60 that when the biower and magnetron are turned off and

a seif-cieaning mode, the walls of the Cavity being insu- the thermal element is turned on flow of air through the

ducharge of st least a portion of the air into che housing = reclangwiar oven cavity and 2 lower space. a door ¢-

Al3

-—. 9

_gonvecied db rma men wed antes Be Fad aeaget bo ox fom ts

bination comprising 5 frame having walls defining 5 _ the escape of microwsve energy theretyough.

rectungular oven cavity and a lnwer space of conform- §-—-'7«. The combination as claimed m claim 6 m which

amg shape, a door enclosing and sealing the front sur- 35 the openings im the wall of the waveguide and the vent

face of the cavity againt! passage Of aif and microwave | ~ Opening are tuifficiently limited im total area as to lnmit

£hetgy. a thermal ciement in the cavity. comrol means — the flow of air for mictowave cookery to within the

for operstion of the thermal clement withm 9 normal — Sp tale tap poco phgdereed tater

Scat ies plata! a neieeenge babel rE sponte oman wae meow sss

to 2

iamperature level for a ee eee

the cavity being insulated. the bonom wall of the ceviry =

having a7 inte: opening. means defining 8 cevny a = : == = == ==

bs)

re)

While the operation and easy replacement of the

microwave system will be apparent from the foregoing.

the following summary is offered With the mode

switch 35 in the “combined” mode, the heating ele-

ments establish a temperature set by the thermostat

186, and the magnetron, blower motor 84 and antenna

motor 350 are al) energized, with the wave from the

antenna being swept throughout the cavity for equal-

ized distribution of microwave energy, as will be de-

ascribed. A portion of the blower air feeding through air

passages 161, and thence through the waveguide and

hollow conductor, is discharged under the antenna

supporting disc 140 into the cavity for eventual escape

through the vent 162 at the top of the cavity. The bulk

of the pressurized cooling air is discharged directly

from the housing through the oper.ings 87, 89 and, via

opening 88, mto the guard 170 which surrounds the

waveguide and antenna motor 60 that all of the micro-

wave components are kept at 8 safely low temperawre

regardless of the thermal temperature achieved in the

_Savmy._ — : a

— Because of the fact that afl of the niet openings for

=the convected ay are well below the level of the boriom

wall of the cavity, the convection pressure differential

~% sufficiently great to insure upward flow through the

—tytiem even in the face of pressute developed by ~ ‘Ruto

ignivon™ sears ee eres

wmio the wave-

$62, without reliance upon the usual gap m the door

_gasket free of possibility of back-up oF explosion.

In the event that servicing of the module is required,

the hollow conductor assembly which communicates

with the front end of the waveguide is loosened and

retracted upwardly as previously described Unscrew-

ing of the screws 121 frees the front end of the wave-

guide from the oven structure Subsequent removal of

screws 1740, 17Sc which secure the trough 170 and

screws 59 which hold the housing in seated position,

permits the module to be pulled forwardly through the

drawer opening Electrica) disconnection of the power

supply module may be facilitated by a simple multi-

prong plug and socket In a typical service call a new

module 1s slipped in place by simply reversing the pro-

cedure.

ROTARY ANTENNA

The preferred form of antenna 130 disclosed in FIG

Ja, rotated at a relatively slow speed on the order of a

few revolutions per minute, has been found to be highly

effective in bringing about an equalized distribution of

microwave energy throughout the cavity with relative

freedom from the hot spots which usually characterize

microwave cookery. The antenna is distinguished by a

straight shank portion 131 and a radially extending arm

portion 133 which is arranged approximately perpen-

dicularly with respect to the shank, with an angied

transitional portion 132 in between, the angled poruon

bearing an obtuse angle with respect to both the shank

and the arm and having a length of at least the radius r

of the b2Ulow conductor for radiation of a guided wave

in the cavity which sets up a plurality of radiation pat-

terns.

In understanding the operation of the antenna it will.

first of all. be appreciated that microwave energy b

directly propagated from the waveguide into the cavny

Al4

independently of antenna action, the resulting wave

been referred to as the “mertal™ wave In addition.

microwave energy which is coupled to the lower end of

the antenna is guided along the antenna for radiation

therefrom in the form of a “guided” wave Where an L

shaped or T shaped antenna s employed having an

abrupt 90° bend, it is found that the bend constitutes a

major discontinuity which actually prevents microwave

energy from being converted to a guided wave. How-

ever, where the antenna, at point of ex, & bent on a

more gradua) basis. that ss, is bent over @ transitiona!

region of at least the radius of the hollow conductor

through which it projects into the cavity, the propor-

ton of energy in the guided wave, as compared to the

imerua) wave, is increased and, in addition, the guided

wave controls the pattern of radiation within the cavity.

The increased number of radiation patterns, with con-

tinuous sweeping. inherently produces fewer hot spots

than either the simpler, stauonary mode patterns

achieved using. for example, an antenna of the conven-

ona) monopole type, or & Convenuonal antenna in

combination with auxiliary surring means

In the preferred form of the invention, illustrated in

FIG 7c, the antenna has two concentrated bends 134,

135 to define its three portions The radia) arm portion

133 has a length which is preferably greater than the

transitional poruon to improve radiauvon patterns and-

for facilitate impedance matching while maintamming a

bow profile. In practical cases the total radia) iength of

the antenna may be on the order of 2.0 to 5.0 inches

It is one of the features of the antenna that the bends

134, 135 are so related to one another that the antenra

bes in the plane of the lower heating element 28. Ai-

though the antenna illustrated in FIG. 7e can be em-

ployed with convenvonally formed U shaped heating

elements whose surfaces are remote from the antenna,

for those cases where the antenna Up overlies a heater

surface, the preferred heater shape, as shown in FIG

2c, is circumferentially distributed about the antenna

path at a substantally constant radius so that the effect

of the heating element 28 upon the radiated energy

remains substanually constant throughout the rota-

tonal cycle.

Moreover, by spacing the radia! portion 133 of the

antenna, and the heaung element 28, at the same rela-

tively close spacing to the adjacent (bottom) wal! 22,

there is minimum encroachment upon the space within

the cavity, in other words, 1 high degree of compact-

ness is achieved. In a practical case, the spacing of the

heating element and antenna from the adjacent wal! is

on the order of one and one-half inch. By keeping the

antenna within the confines of the botiom heanng ele-

ment, and with the latter distributed as shown in FIG

2c, the antenna itself does not take up any additional

space within the cavity, making the utilization of space

much more efficient than where a stirring device or

conventional type of rotating antenna is employed.

It will be understood, however, that the invention is

not limited to the exact profile illustrated in FIG. 7a

and, if desired, the slightly higher profile, Diustrated in

FIG. 10, may be used In this embodiment, in which

corresponding reference numerals are used with addi-

tion of subscript ¢ to indicate corresponding parts of

the device, the included angle e at the first bend 1340

is increased and the included angle at the second bend

135c ss decreased. Preferably the angle ¢ should be

kept within the range of 105° to 165°, while the n-

4,0:

ht is found that the structure described above pro-

duces a field which is so uniform and a result which s

8© predictable, that “formula cookery”, based upon

convenuonal cookbook instructions, is possible for the

first time Specifically, in the case of pastry and similar

baked goods. the foodstuff, in norma! quantity, is sub-

jected to microwaves for a period of five minutes, after

which baking is completed using thermal energy at the

temperature, and m just one-half of the time, given in

the conventional cookbook. In the case of other foods.

both types of energy are applied from the beginning of

the cycle and the total cooking time is reduced to one-

quarter of that given in the cookbook.

What is claimed is:

1. In a combined microwave-thermal range, the com-

bination comprising a frame having walls defining a

rectangular oven cavity and a lower space, 8 door en-

closing and sealing the front surface of the cavity

against passage of air and microwave energy, s thermal)

element in the cavity, conto! means for operation of

the thermal! element at a norma’ temperature level for

food preparation and at a high level for a self-cleaning

mode, the walls of the cavity being insulated, the bot-

tom wal! of the cavity having an inlet opening. means

defining @ cavity air vent at the top of the cavity, a

microwave power supply including a blower and a mag-

netron having cooling fins, the blower having a blower

inlet for drawing in cooling air and an outlet for supply-

ing such sir under slight pressure to the cooling fins, a

waveguide having an inlet connected to the magnetron

and extending under the bottom wall of the cavity to

terminate at an ouet, means for connecting the outlet

of the waveguide to the inlet opening of the cavity for

conduction of microwave energy into the cavity, means

defining air passages of limited cross section for con-

dusting air from the magnetron into the waveguide so

that a poruon of the pressurized air passes through the

waveguide and into the cavity for ventilating the cavity |

when the magnevon and blower are turned on, the

“blower zjet being located wf 2 lever below the botiom

wall of the cavity so that when the biower and magne-

on are turned off and the thermal element is turned

“on ait is thermall, convected fom the Blower mict

“through the air passages into the waveguide and min

withstanding the auto ignition ure which exists in

node 1 5 level below that which is c

ay = anes neler oe eee

2. In a combined microwave-thermal! range, the com-

bination comprising a frame having walls defining 2

rectangular oven cavity and a lower space, a door en-

closing and sealing the front surface of the cavity

agains! passage of air and microwave energy. a thermal!

element in the cavity, contro! means for operauon of

the thermal! element within a normal temperature range

for food preparation and at a high temperature level for 60

a self-cleaning mode, the walls of the cavity being insu-

lated, the botiom wal! of the cavity having an inlet

opening. means defining a cavity air vent at the top of

the cavity, a microwave power supply having a housing

mcluding a magnetron and blower, the blower having a

blower inlet and arranged to draw in cooling air for

supplying under slight pressure to the magnetron with

duscharge of at least a poruon of the air into the housing

A15

to create slight pressure therein. a waveguide having an

inlet connected to the magnetron and extending under

the botiom wall of the cavity to terminate at an outlet.

means for connecting the outle: of the waveguide to the

inlet opening of the cavity for conduction of microwave

energy into the cavity. means defining a patiern of

small air passages from the housing to the waveguide so

at least a portion of the pressurized air from the hous-

ing passes through the air passage and waveguide and

into the cavity for ventilating the cavity when the mag-

netron and blower are turned on, all portions of the

wee al and a piel Se

~ 3. Ina combined microw: ave-thermal vas range, “the com.

binauion comprising a frame having walls defining a

rectangular oven cavity and a lower space, a door en-

closing and sealing the front surface of the cavity

against passage of air and microwave energy, a thermal

element in the cavity, the walls of the cavity being

insulated, the bottom wall of the cavity having an iniet

Opening. means defining a cavity air vent at the top of

the cavity, a microwave power supply having a housing

including a magnetron and blower, the blower having a

blower inlet and arranged to draw im cooling air from

outside the housing for supplying under slight pressure

to the magnetron, the cooling air being discharged

from the magneton into the housing for creating inter-

nal pressure therein, a waveguide coupled to the mag-

netron and extending along the housing and under the

bottom wal! of the cavity, the waveguide having an

outlet alined with the opening in the bottom wall of the

cavity, a hollow open-ended conductor extending

through the opening for couplmg the outlet of the

waveguide to the cavity, means for securing the upper

end of the hollow conductor to the bottom wall of the

cavity and the lower end of the conductor to the wave-

guide for conduction of microwave energy imto the

cavity, the wal) of the waveguide having a pattern of

small openings communicating with the housing so that

& portion of the pressurized air from the blower and

Magnetron passes through the waveguide and hollow

conductor into the cavity for ventilaung the cavity

when the magnetron and blower are turned on, the

housing having a relatively large vent opening through

which the pressurized air therefrom passes outward!)

to reduce the internal pressure in the housing thereby

to reduce the flow of air through the pattern of smal!

openings and into the cavity to a predetermined low

level, the blower miet and farge vent opeing being

Jocaied at a level below the bottom wall of the cavity so

thai when the biower and magnetron are turned off and

the thermal element is turned on flow of air through ti

datge vent opening is reversed in direction flowing in-

wardly through such vent opening into the bousing and

the small openings via the waveguide mto the

“gavity with final exiting through the cevity si vent.

4. in a combined microwave-thermal! range, the com-

bination comprising a frame having walls defining 8

rectangular oven Cavity and a lower space. a door e1)-

closing and sealing the front surface of the cavity

against passage of air and microwave energy, a thermal

element in the cavity, the was of the cavity being

insulated, the bottom wall of the cavity having an inlet

opening. means defining a cavity air vent at the top of

the cavity. a microwave power supply having a housing

including a magnetron and blower, the blower having #

blower inlet and arranged to draw im cooling ai for

supplying under slight pressure to the magnetron, a

waveguid: coupled to the magnetron and extending

under the bottom wal] of the cavity, the waveguide

having an outlet alined with the opening in the bottom

wall of the cavity, 8 hollow open-ended conductor

extending through the opening for coupling the outlet

of the waveguide to the cavity, means for securing the

upper end of the hollow conductor to the botiom wall

of the cavity and the lower end of the conductor to the

waveguide for conduction of microwave energy imto

the cavity, an antenna element centered in the hollow

conductor and projecting into the cavity for guiding

microwave energy to the latter, means for conducting

at least a portion of the pressurized air from the blowez

and magnetron through the waveguide and hollow con-

ductor into the cavity for ventilating the cavity when

the magnetron and blower are turned on. the blower

“gilet being located at a level below the boom wall of

“the cavity so that when the blower and magnetron are

“turned off and the thermal siemeni & turned on az

‘tonvected through the blower inlet. waveguide and

hollow conductor into the bees Lad exiting through the

“avity a vent at the top thereof.

8. in a combined microwave-thermal range, the com-

bination comprising a frame having walls defining a

rectangular oven cavity and a lower space of conform-

ing shape, a door enclosing and sealing the front sur-

face of the cavity against passage of air and microwave

energy, @ thermal element in the cavity, contro] means

for operation of the thermal element within a norma!

temperature range for food preparation and at a high

temperature level for a self<cleaning mode, the walls of

the cavity being insulated, the bottom wall of the cavity

having an inlet opening. means defining a cavity air

4c-"

3»

vent at the top of the cavity. a microwave power supply

having a housing mcluding a magnetron and blower,

the blower having 2 blower miet and arranged to draw

im cooling ait for discharge under slight pressure to the

magnetron, a waveguide having an inlet connected to

the magnetron and extending under the bottom wall of

the cavity to terminate at an outlet, means for connect-

ing the oudet of the waveguide to the miet opening of

the cavity for conduction of microwave energy into the

cavity, the waveguide being open to passage of cooling

ait from the magnetron $0 at least @ portion of the

pressurized air from the blower and magnetron passes

through the waveguide and into the cavity for ventilat-

ing the cavity when the magnetron and blower are

turned on, the tiower indet being Jocated at a teve!

below the boriom wall of the cavity 90 that when the

= E i sufficiently constricted 10

ing mode at a

evel below that which ix Of producing an #x-

ieee sanction wth the produce af thermal decompo:

(6. ay, ® combination as claimed in claim § in which

the constriction in the air passage through the blower

inlet, magnetron and waveguide is in the form of a

pattern of small openings in the wal] of the waveguide

and in communication with the housing. the openings

being of sufficiently small dimension so as to preclude

the escape of microwave energy therethrough

7. The combination as claimed in claim 6 in which

the openings in the wal! of the waveguide and the vent

opening are sufficiently limited in total area as to limit

the flow of air for microwave cookery to within the

range of three to eight c.f£.m. when the blower is on and

to reduce the flow of convecied air under baking and

self-cleaning conditions to within the range of 0.5 to 2

c.f.m.

Feb. 25, 1969

Al7

E M. TINGLEY

3,430,023

DOOR CONSTRUCTION AND VENTILATING SYSTEM POR MICROWAVE OVEN

Sheet _/_ of 3

Filed Sept. 1) 1967

16 _

X10

INVENTOR

Ecaert NM. Tincvey

Arrys.

Als

DOOR CONSTRUCTION AND VENTILATING SYSTEM FOR MICROWAVE OVEN

Filed Sept. 11 1967 Sheet 2 of 3

QoEoOnQnP © oS “et

Sosa IN

ie) S34

8 aes

4 ’

——= O

MULT idem

"EZ

S pa a’ a I

~~ o NVENTOR

ie = Easert MM. TiInGLEY

ue ty: Wolf. , Hubtard , Volt Ora

AtTTYs.

Al19

3,430,023

E. M. TINGLEY

Feb. 25, 1969

DOOR CONSTRUCTION AND VENTILATING SYSTEM FOR MICROWAVE OVEN

-. 8

Sheet

Filed Sept. 1) 1967

Cv~

aie

SSS:

ARAN

INVENTOR

EasBertT M. TiInGLEeY

ArrTyYs.

by: Woh, NaMaral, Yala Canam

A20

United States Patent Office

3,430,023

Patented Feb. 25, 1969

3.436 023

DOOR CONSTRUCTION AND VENTILATING

Egbert M Tingley, Kankakee ML, assigoor to Geo. D

y> cakee, assignor to le

. Roper Corporation, Kaukakee, Ill., a corporation of

Filed Sept. 11, 1967, Ser. No. 666,805

US. CL 219—10.55

Int. C. HOSb 9/06

6 Claims

+ ABSTRACT OF THE DISCLOSURE

A door construction for a microwave oven providing

both a vapor seal and a seal against the escape of micro

wave energy from the oven cavity and a modified venti-

lating system for use therewith. ®

It is an object of the present invention to provice a

door construction for a microwave oven which permits

viewing of the coments of the oven dut which neverthe-

less prevenis escape of vepors and microwave energy

from the oven cavity. It is 2 more specific object to pro-

vide a door construction which serves as a highly efficient

microwave and vapor shield, consisting of a minimum

pumber of parts which are simply formed and easily

assembled but which form a door which is structuraily

strong and attractive in appearance. It is another object

of the invention to provide a door which precludes flow

of vapors through the perforations conveniionally em-

ployed and which utilizes a modified ventilating system

of ircreased effectiveness.

Ovber odjects and advantages of the invention will

become apparent upon reading the attached detailed de-

scription end upon reference to the drawings in which:

FIG. 1 is & front view of a range including a microwave

oven incorporating the present invention;

FIG. 2 is a back view of the door employed in the

oven of FIG. 1;

FIG. 3 is a section, broken for purposes of foreshorten-

ing. looking along the line 3—3 in FIG. 1;

FIG. 4 is a section taken along the line 4—4 in FIG. 1;

FIG. 4a is a cross section taken through the conductive

gasket;

FIG. 5 is a fragmentary section taken through the latch

mechanism and looking along the line 5—S in FIG. 1;

FIG. 6 is a diagram showing the associated ventilating

sysiem.

While the invention has been described in connection

with a preferred embodiment, it will be understood thas

1 do not intend to be limited to the particular embodi-

ment dut intend, on the contrary, to cover the variouw,

ahernative and equivalent constructions included within

the spirit and scope of the appended claims.

Turning now to FIGURE | there is shown a range 10

having a microwave oven 11 at the top with an oven

cavity 12 and an adjacent control panel 13. Behind the

control panel is a space for containing the microwave

generating compcnents as well as a blower system to

which reference will later be made. Arranged below the

be carried on simultaneously.

cavity 12 of the microwave oven has a liner 20

of conductive metal and which is con

any openings except the perforations

admission and exhausting of air and the

is flanged outwardly to provide a front facing 21 of

conductive metal which completely surrounds the front

opening of the cavity.

In accordance with the present invention a door is

provided for the oven having a peripheral frame and a

conductive panel or liner which is centrally perforated

and sealed by a rear cover glass, about which extends a

continuous conductive gasket for engaging the facing

of the oven cavity to prevent escape of boih vapor and

mucrowave energy. Further in accordance wita the in-

venticn a seat is provided im the front edge of the

peripberal frame for mounting a front cover glass to

produce a rigid box-like construction while enabling the

con:emts of the oven to be clearly viewed. Thus, turning

to the drawings, the door of the microwave oven. in-

dicated at 30, has a peripheral frame 31 cf zicture frame

shape including a side flange 32 and an inwardly extend-

ing Gished flance 33 which is recessed to form a peripheral

seat 34. Extending over, and enclosing, the entire rear

surface of the frame 31 is a conductive liner panel 40,

the centra] portion of which is punched with a two

dimensional patte:n of perforations 41 and the periphery

of which is formed with a side flance 42. The latter is

dimensioned for snug telescoping within the side flange

32 of the door frame, with the two parts deing secured

together by self-apping screws 43. If desired for further

rigidity the inner flange of the frame ma; be provided

with a series of integral pedestals 44 encaced by screws

45 which penetrate registering countersunk openings in

the liner panel.

For the purpose of covering the pattern of perforations

41, a rear cover glass $0 is used baving a continuous

vapor scaling gasket £1 which is of resilient maierial of

U-shaped cross section. When the cover glass 50 is seaied

La position, the thickness of the vapor sealirg gasket de-

fines a thin space 52 maintaining the glass out of contact

with the metal panel over the region of tke perforations.

To seal the liner panel with respect to the front facing

21 of the oven cavity, a continuous gasket 60 is used

(FIG. 42) formed of resilient hollow tubing 61 which

is surrounded by a wire mosh 62 stitched at 63 to define

an anchoring web 64. The tubing is preferably made of

heat-resistant synthetic rubber, for example of the silicone

type, and the wire mesh may be of loos knitted con-

3 struction using a gauge of wire which is sufficiently thin

to provide a high degree of flexibility and of sufficienldy

wie mesh so as to preserve the vapor sealing effect of

the rubber surface. The wire may, for example, be form-

ed of a nickel-chromium alloy or of stainless steel.

In accordance with one of the aspecis of the invention

a subframe is provided surrounding the cover glass and

having an inner clamping edge or flange which overlies

end engages the peripheral edge of the cover glass and

an outer clamping edge or lip which presses agains: the

anchoring web 64 of the door sealing gasket 60. Referring

to FIGS. 2 and 3, the subframe, indicated generally at

78, is formed of four separate sections 71-74 arranged

closely end to end. The inner edge of each section has an

integral lip or flange 75 which is suitably offset to accom-

modate the thickness of the vapor sealing gasket 51 and

cover glass; 50 while the outer edge of each section is pro-

vided with a raised clamping lip 76 for providing a local-

ized line of prevsure along the neck portion of the anchor.

ing web 64 of the gasket 60. Each section is secured ia

place on the liner panel by a central row of screws 77.

Since the sections of the subframe are independent of one

‘another, each section is capable of self-adjustment, teeter-

totter fashion, about the line of fastening so as to apply

balanced concentrated forces to the cover giass and web

of the gasket, respectively. The net effect is to insure that

a sealing force is evenly applied about the ent’re peripb-

port for admission of microwave energy. The oven liner ery of the cover glass while insuring that a good electrical

A21

3,430,023

and mechanical connection is obtained aloug the lexgth of

the conductive gasket 60. Ii has been found con®erient, in

manfacture, to employ a simple jig for assembling the

parts together. First the sec-ioas of the subframe ace laid

io place on the jig, face doan, topped by the cover glass

and the web of the conducive gasket. The liner ponel is

then placed, face down, on the assembly with the ‘asten-

ing screws 77 being imseru d and tightened. Follov ing this

it is a simple matter to telescope the liner panel into posi-

tion within the peripheral frame.

To complete the assemt'y, an outer cover glass 80 is

seated in the ledge 34 formed in the peripberal ‘-ame.

The outer cover glass in exzzced along its left-hani edge

by a flanged msert 8i and along its right-hand ecg: by a

flange 82 integral!y formed in a panel 83. The cove: g'ass

80 is preferably silvered alo>z the edge as indicated a: 85,

leaving a clear central porcon 86 for viewing throzzh the

perforations 41 im the liner panel.

For the purpose of mozn:ing the door on the ranze, and

for exerting suffic.eni clarc>izg pressure in the closes posi-

tion to compress the res: ‘22! gasket, I employ a simple

form of binge 90 along ::e left-hand edge and a latch

mechanism 91 at the rizhi-hand edge. While tie latch

mechanism does not pe: % form a part of the r-resent

invention, brief meniion m2y be made of the mes=iaism

with reference to FIG. $. Heze it will be seen wat ibe

mechanism 91 has a hant’e 92 which is pivoted a: 93.

A toggle member $, a'so 7. o1ed at 93 has an ove>-~<enier

compression spring $§ which is anchored at 96 acJZ con-

pled to ibe toggle member at pivot 97. The togg's mem-

ber engoges a catch 98 wt':h is secured to the f-2me of

the oven. Thus when the ¢s>r is closed the catch 98. strik-

ing the toggle member above its point of pivoting. causes

the toezle member to scap over-<enter to the ;ssi:ion

shown, the spring 95 serv 23 to apply an inward p=:! upon

the catch 98, thereby compressing the gasket 60 evenly

aboot its entire length. The conductivity of the wire mesh

insures that thers is e!ectricz! continuity between ‘se oven

liner and the door liner io z-eclude any escape of =!sro-

wave energy. Aft the same time the convolutions c: the

wire forming the mesb are assommodated by the resilient

surface of the rubber gasketing material so that an eff-

cient vapor seal is preserved.

Experience shows that the above door construction not

only drings about an efficient vapor and inicrowave seal

out that the layers of giass spaced from one anocLer on

Opposite sides of the rear panel, form a box-like s:-asture

which is self-reinforcing t9 provide a high decree of

strength and mecharical r:z:dity. The structure is coasid-

ered electrically and mecb2zically superior to we struc-

tures conventionally used and possesses the additio=2] ad-

vantage that it can be moa=factured at low cost. Tne as-

sembly, including its part'y siivered front cover glass, pro-

vides a richer more finist:d appearance than overs doors

where the perforations are ieft uncovered for venting pur-

poses.

in accordance with one of the more detailed aspects of

the invention the sealed door is employed in conjzaction

with venting means which provides a well defined ¢ircula-

tion path within the oven civity. Thus, referring to FIG. 6,

which is diagrammatic, ths oven liner 20 is shown to the

right of which is moun‘ed microwave generating apparatus

10@ whick is coupled to the oven cavity by means of a

wave guile 162 having a port 102 For the purpose of

cooling the microwave generator and for inducing a well

defined circulatioa of air in the oven cavity, a blower 105

is provided having a drive motor 106 and an air intake

conduit 107. The co:fat of the blower is split into two por-

tions, a major portion 112 and a minor portion 112. The

mincr portion of the air is forced through suitable pass-

ages and cooling fins in ‘b=: microwave generator follow-

ing which the air is dirsc:ed upwardly through perfora-

tions 113 into the waveg-ide 101 for discharge through

the microwave port 102 imo the oven cavity. The major

portion of the ar from the blower is directed into perfor-

ations 115 formed in the upper wall of the oven liver along

the rear edze thereof. Although not specifically shown in

FIG. 6, it will be unders:ood that the air is conducted to

the inlet ports 115 between the outer wall of the oven and

the oven liner 20. In order to assist in directing the air

downwardly through the perfora:ions, a series of deSe<-

tors 116, arranged at an angie to the air stream, are pro

vided.

For the purpose of venting the air which is forced into

the oven cavity, a series of outlet perforations 117 are

formed along tbe front edge of the upper wall of tbe

oven liner. The perforations 117 are isolated from the

in'ct perforatioas 115 by an interposed vane or bariier

118. It is found that the major portion of the air follcws

a well defined circulation path, sweeping downwarLy

from the inlet perfora:ions 115, forwardiy within the cev-

ity and thence upwardly aiong the sealed door surface for

discharge through the perforazions 117. The air from :he

microwave pert 102 eniering the central portion of :be

oven is turbuiently mixed with the main air stream prior

to venting through the perforations 117. The positive air

flow pattern is to be con:rasted with the usual door venting

in which there is a simp’e ¢rift of air through the door

perforations. Following discharge the air and vapors may

be allowed io enter the room or may be directed into an

external discharge duct

I claim as my invention:

1. In a microwave oven baving structure defining a

Cavity with an opening surrounded by a front facine of

conductive metal, a door for closing the opening and

overlying the front facing comprising, in combiration. a

peripheral frame, a conductive liner panel secured to the

rear of the frame for overixing the conductive facinz

the central portion of the liner panel being perfor2:e4

over an area, a rear cover class covering the perforatiors

and having a resilient vapor sealing casket extending con-

tinuously about its edges, a resilient conductive gasket

baving a conductive web surrounding the cover class. a

subframe secured to the liner panel between the cover

glass and the conductive gasket, said subframe having

inner and out-r clamping edges for respectively engaging

the vapor sling gasket at the edge of the rear cover

giass and the web of the conductive gasket to clamp

the same in place on the panel, and a front cover glass

secured to the foot of the peripheral frame.

2. The combination as claimed in claim 1 in which the

subframe is of rectangular shape formed of four sep2-

rate pieces having clamping lips along the edges ani

baving fasteners spaced between the edges for exerting

concentrated lines of pressure against the vapor sealing

gasket and the web of the resilient gasket respectively.

3. The combination as claimed in claim 1 in which the

subframe is of rectangular shape formed of four sepa-

rate pieces of metal spaced closely end to end and each

having a flange spaced from the panel along one edre

overlying the edge of the glass for clampingly engaging

the vapor sealing gasket and a lip along the other edge

for clampingly engaging the web of the resilient conduci-

ing gasket, each piece of the subframe being separate!y

secured to the panel by means of a central row of screws

so that a concentrated line of pressure is simultaneously

applied along the entire length of each of the gaskets for

clamping the same in position.

4. In a microwave oven having structure defining a

cavity with an opening surrounded by a front facm; of

conducting metal, a door for closing the opening and

overlying the front facing comprising, in combination. a

peripheral door frame having a side flange, © conductive

liner pane! having a side flance telescoped into the flaree

of the frame and having a central perforated area, a rear

cover glass covering said perforations and having a resi-

jent vapor sealing gasket extending continuously arounZ

its edges, a resilient conductive gasket formed of rubber

surrounded by wire mesh, a subframe surrounding the

glass and having screws for securing the same to the rear

A22

3,430,023

surface of the liner panel, said subframe having clamping

lips along the edges thereof for applying clamping pres-

sure simultaneously to the vapor sealing gasket and the

resilient conductive gasket upon tightening of said screws,

said door frame defining a recessed seat along the front

edge thereof, and a front cover glass having means for

securing the Same intimatzly seated on said seat for rigid-

ifying the frame while permitting viewing of the oven

contents through the perforations.

5. In a microwave oven having structure defining a

cavity with an opening surrounded by a front facing of

conducting metal, a door overlying the front facing com-

prising, in combination, a frame, an extensive liner panel

of conducting metal having a central two-dimensional

pattern of perforations, a rear cover glass plate for over-

lying the perforations, a resilient conductive gasket on

said liner pane! extending around the cover glass, the

top wall of the cavity having a set of inlet perforations

along iis rear edge and a set of outlet perforations along

its front edge, barrier means for isolating the two sets of

perfcrations, means including a blower for applying rres-

surized e'r to ine miet perforations, means including a

latch for maintaining the door in closed position witb the

conductive gasket compressed to prevent escape of air

and vapor about the periphery of the door, said cover

giass being sealed to the liner panel about its edges to

prevent escape of air aod vapor through the perforations

in the door panel.

6. The combination as claimed in claim § including a

microwave generator having a waveguide for conveying

microwave energy to the cavity and providing passages

for flow of cooling air, and means for diverting a portion

of the air from the blower through said passages into the

oven cavity.

References Cited

UNITED STATES PATENTS

3,177,334 4/1965 Kinkle ~......... 219—10.55

S.20RAOL 486 Z/ TUG LORE cccccccceces 219—10.55

3,321,604 $§/1967 Stecca et al. ....-.- 219—10.55

KENNETH W. SPRAGUE, Primary Examiner.

US. CL XR.

126—200

A23

April 22, 1969 4. BCERM

MICROWAVE HEATING APPARATUS

Filed Nov. 21, 1966

3,440,386

Steet / of 4

INVENTOR

Aleem? Boe

(ttt, hiain, Ml

Clady, tistin, Meshes

Rand

ATTOONEVS

ees oe

A24

April 22, 1969 H. 3OEHM 3,440,386

MICROWAVE HEATING APPARATUS

Filed Nov. 22, 1966 Sheet & of 4

’ |

a te

36 -

ig.

: ir a

[Oh

ppempecees <t <

4 __

588°" oN gwite

SEZ.

—~ 2 abt 04

‘To ENDS OF

LLEMEA TS 16/8 i“ 72

esses eee a4

INVENTOR

MéwmuT Boke

Bi A Aretlr, fall hubr

— toe”

AITTOONESS

A25

Apri! 22, 1969 H. BOERM 3,440,386

MICROWAVE HEATING APPARATUS

Tiled Nov. 22, 1966 Sieet 7 of a

—

is C — <a

go! sar ‘92

INVENTOR

Ae.mur GOEMM

BY oP hncter, Gallon, Kusloe

Rae and 4

AIT TORN EKS

A26

April 22, 1969 H. BOEHM 3,440,386

MICERO*AVE KEATING APPARATUS

Filed Nov. 21, 1966 sreet F of 4

2 eS

ff a4é 49

: oe Se

AANA sie

ips sé

GG LI

INVENTOR

Hewmur BoEHmM

BN tihhe, ball r, haber

Ki, and

AIT TORNEVS

A27

United States Patent Office

3,440,386

Patented Apr. 22, 1969

3.420.386

MICROWAVE HEATING APPARATUS

Helmut Bochm, New dury Park, Calif. assienor to Tech-

nology Insirument Corporation of C-lifornia, New-

bury Park, Culif., a corporativa of Califurnia

Filed Nov. 21, 1966, Ser. Na. 595,995

Int. CL HOSb 9/06

US. Cl. 219—106.55 10 Claims

ABSTRACT OF THE DISCLOSURE

A waveguide has one opening inio an oven chamber

and a seconc opening for the output prote of a magnetron

releasably attached thereto. Amenn. <clements in the

chamber are connected to sn output probe from said one

opening. Adjacent said sscond waveruide openinz, cooling

means cperates to cool the magnetron and direct air

throug. the waveguide so as to force s170F in the cham-

ber on cf openings ir its top wail. The antenna elements

can be herted by electric current. and swiich means con-

trols connections of a rowsr supz!ly to the magnetion and

an clectric curren: source to the elemeats.

This invention relatet to hestime ar paratus, and more

particularly 10 improved apparstus tor heating objects

with microwave energy.

The <praratus of my invention will be described for

cooking foodstuffs, bui will ce recogr zed as suitadle for

any use involving the arflication or ctilization of micro-

wave enercy. Move specifically, mv mmvention will be de-

scribed for cooking afparsius which utilizes a common

e‘ement in an cven c2\ity for microwave cooking and/or

cenventicnal thermasi cockine. Apparzius of this type is

divclosed and claimed in my copenJias upplication. “Eiec- °

tronic Oven,” Ser. No. 376,188, Sled Jane 18, 1964, now

Patcat No 3,320,596.

Such arravatus 2s hereiofore hnov n includes a resonant

oven cavity with cookirg elements therein, a magnetron

for genez.ting microwave energy, and waveguide sonne=-

tions for coupling the microwave energy to the elements.

The elements function 3s traveling wave amennas to ra-

di te the microwave energy throughoet the cavity to cause

foods:uffs pi:.ced there’n 19 be cooked as desirec. In addi-

tion, the elements are adapted to be heated in corven-

tionma! fashion for thermal cooking. Further. circun con-

trol means are provided for separately or simulianecusly

app'ying microwave erergy and con-ertional heating cur-

rent 10 the elements. The even is provided with openincs

to the exterior, throuch which air may circulate and

vapors from focdstu%s may escspe “iihout entering the

wavecuide system.

The presert application is directed to constructions of

paris of such apparatus to facilitate sreni economy and

etficizncy of manufacture, assembly, operaticn and main-

tenance thereof.

It is an object of my irvention to provide an improved

magnetron siructure for use in microwave cooking ap

paratus.

Another abject of ry invention is to provide means

BUiizine the wavegride system of microwave cooking ap

Paratus to prevent entry into such sysiem of vapor: from

fuodsiuffs and facili:uling escape of vapors from the oven

of such apparatus. ‘

Still another object of my invention is to provide means

for releasat'y securing 3 mognetron structure to a wavs-

guide structure wiihovi loss of microw2ve energy.

A still famher objec of my imvemtion &b to provice

Structurai'y coOperaiise magnetron and cocling fin stru-

tures with which to obtain optimum dissipction of bai

peners.eJ in the magnetron Srocture.

It is also an object of my invention to provide micro-

Wave cooking apparatus wiich comprises a minimum

number of component parts of simpie design and rugeed

cons:ruction.

The 25ove and other cbhjects and adventages of my

inven:ion will become apparent from the following de-

scription taken ir. conjunction with the accompanying

drawings of an illustrative embodiment thereof, in which:

FIGURE 1 is a perspeciive view of microwave ccok-

ing apnaratus in eccordance with my invention. showing

an arrangement for forcing air through the waecuide to

enter the cavity and preventing grease and water vapors

from entering the waveguide:

FIGURE 2 is a sectioncl view taken alone the lines

2—2 of FIGURE 1, showing the output probe excnd-

ing from the waveguide into the cavity, and a coup!ing

member extend:ng from the probe to the heater elements:

FIGURE 3 is a sectional view taken zlong the lines

3—3 of FIGURE 1, showing the magnetron structure

releasab'y lockea to the waveguive, with the output probe

of the macnetron extending into the waveguide:

FIGURE 4 is an enlarced, fragmentzry sectional view

of the rezion 4—4 indicated in FIGURE 3;

FIGURE 5 is a side elevation view, taken along the

lines 4—4 of FIGURE 3, shcwing the fock elements in

engagement wich the flang: fortion of the mayneiron-

wavesuiJe couzler; e

FIGURE 6 is a side elevation view of my macnetron

Structure with iis anode nested in onc portica of my cool-

ing fin structure;

FIGURE 7 is a perspective view of one cf the cooling

fin packaces which are clamped to the anode body:

FIGURE § is a fragmentary end view cf the assemb ied

m2enciron and cooling fin siructure 2s ses. from th: con-

necior end:

FIGURE 9 is a lenzitudiral sectional view of m\ maz-

MNetiTON Siructure: on

FIGURE 19 is 3 «eticnal view taken along the lines

10—10 of FIGLRE 9. s'.owing the arrangerient of my

unique mode-stsbilizirg straps.

Referring to FIGURE 1, there is shown a cahine: 10

for mizrovave cooking apprratus baying an oven cham-

ber 12 ard :. door 14 through whi.h to insen and remove

foodstuffs. Foesiufls are supported o7 a rack i§ in the

chamber. Positioned above and below the rack 15. and

adjacent the top end batiom surfaces within the chamber,

are ciements 16. 18. which are adapted to be excited by

and to radiate microwave enersy. Additionally, the ele-

ments 16. 18 may be connected to a current source and

thereby heated so as to rise tie temperature of the inie-

tior cf the oven for cooing foodstuffs thermally in the

conver ion::! manner. For radiating microwave ensrcy,

the elements are directly coupled to a microwave source,

thereby tc function as traveling wave antennas for radi-

aiing the microwsre ererzy throughout the resonant cav-

ity defired by tre oven chamber 32 and the closed dvor

14, therety to cook the fooustu'f in the cavity solely by

microwave enercy. Further. the elements 16. 18 ~iay be

heated by conventional currert and/or excited by micro-

Wave energy, thereby to cause the foodscuff to be cooked

by a combination of microwave cooking and/or thermal

couvking.

Refer.ing to FIGURE 2 along wich FIGURE 1. the

top, tottom, tack and side walls of the chamber 12 ae

form -d of insulazed metal walls, which may, in a manner

conscntional for electric ovens, comprise inrer anJ outer

meta! walls with insulation 2@ betucen them. The termi-

nals of the element: 36, 18 extend throuch and are an-

cho-e:d to ine inner and outer metal walls at the back of

the canir.ct 19. If desired, spacer sleeves 22 mzy be pro

vided ir.termcdia:e such wall: for additional support in

securing the terminals in place. However, outer metal

A28

3,440,386

walls and spacers 22 may be eliminated, in which case the

insulation 20 is suitably secured to the cavity walls.

In the particular example shown, a waveguide 24 ex-

tends slong the ouitr wall ai the back of the cabinet 10,

and has an oper.ing in which a slceve 26 is secured. The

slecve 26 forms part of a coaxial line, and is in electrical

contact at its inner end with the back wall of the cavity.

An output probs 28 exienc’s from the interior of the

waveruide 24, through the siceve 26, and into the inte-

rior of th: chamber 12, where it is connected to a vertical

metal bar 39 that has its upper ard lower ends cunduc-

tively connected to the elerncnts 16, 18.

In this latier connection, ihe elements 16. 18 may have

a variety of shapes. In the particulsr arrangement shown,

each element is formed with a U-shaped center portion

in which the bend is located adjacent the rear well of the

chamber 12. Thus, the connecting bar 30 is locaied at

the rear of the chamber, and hcnce is clear of the sup

porting rack 15.

In the embodiment shown, the waveruide 24 extends

along the exterior of the back wall of tre cabinet 10 and

past the chambcr 12 to the rear of a cosypartment 34.

Referring to FIGURES 1 and 3, the companmeu 24

houses a macne:ron power supr'y 36, 2 fom 38 ond its

moior 40, and a cooiing fin structuie 42 suppomingc a

macretron 44 which has its output probe exiending into

a shicld 46 thzi is inserced in the waveguide 24. As best

secn in FIGURE 1, one or n: 02 air ie: pipes. shosn

as elbow pipes 48. extend from the end of the wavezuide

24 ard toward the interior of ti€ companment 34. Thus,

air from the fan 38 passes through the cooling fin struc-

ture 42 and enters the waveguide through the piges 48.

The pipes 48 are made sufficiently small tc prevent

keshace of microwsve energy therethrough. With this

urrancement, air blow. trast the cocling fins 42 is vtitized

both to enhance dissipation cf heat from the m-c.etron

through the fins. and also to project wir thvough tlie wave-

guide 24 .... into the intesicr of the oven chamter 22.

Extending throu”. che top of the chamber 12 ure a

plurality of openin hows: provided by cyiinJrical cle-

ments §2 (sec FIG. RE 2) inserted betweer the outer

and inner meta! walls. As with the pipes 48, the cylindri-

cul eleraents £2 aze sufficiently small to prevent unJesired

le:hage of microwave enerzy from the chamter to the

exterior of the cabinet 10. By thus fercing air throesh

the waveguide 34 and into the chamber 12, I insure that

grease particles and vapors from foodstufis cooked in the

chamber 12 cannot enter and cont.:minate the wavezvide

24. but are instcad forced through the openings in the top

of the chamber and to the exterior of the cabinet. Further,

such forcing of air through the waveguide aids in cooling

the waveguide, as wheie the elements 16. 18 are heated by

current to raise the temperature wi:hin the oven for ther-

mal cooking. For preventing undesired matter from erter-

ing the waveguide. I prefer to operate the fan during mi-

crowave and/or thermal cooking.

The macnetron 44 is supported in the fin siructure 42.

_ Further, and in accordarce with another fea.ure of my

invention, the magne.ron is scleasably locked to the wave-

guide 24. In this !autcr connection. ard referring 10 FIG-

URES 3-5, a short, externally threaded element §6 is

secured to the macneiron structure and sutrounds the

shicld 46. A disz-like coupler element 58 is thrcadid oto

the element £6. and is provided with a Hance 60 that is

undercut to form a reduced diameter axial shoulder ¢2

which is matingly received ir an opening 64 in the con-

frontirg wali of the waveguide 24.

As shown, the inner face of the flange 60 abuts the

confronting wall of tre waveguide. The diniension of the

abutling surface of the fiance 6@, i.e, the distance from

the periphcry of the shoulder 62 to the periphery of the

flange 60, is at least a quarter of a wavelensth of the

Microwave encre) injected into the waveguide 24. In this

manne:, the annuler space between the cur froniing walls

of the shouiter 62 aad the orcring 64 is made micro-

wave-licht, i.e., leaksge of microwave energy Sctwaen the

abuttinz surfaces of the flange 60 and the| wavecude 24

is avoided.

The flange 5O is veleasaMy locked in place, ands the

example shown this ts accempusics by mars at iprine-

biased lock elements 66. As best seen in FIGURE 4, the

lock element 66 is carried on the exc of a stub stafi 68

which extends through a body 7@ that is secured to the

top cf the waveguide 24. e.g, as Sy orazinc. At its Outer

end, the shaft 68 carmes a handle 72. and sprite ciasing

means, shown in the form of Belleviiic springs 74 is lo

cated between the handle 72 and the sleeve 70. Thus, the

handle 72 and herce the shaft 68% and lock elen:nt 66.

are biased to the right in FIGURE 4.

The lock element 66 nas a tapered end which is darted

to be brought against the cuter surface of the flarze 60.

by suitabdl, forciag the handle 72 to the Ictt acunst the

bies springs 74, then rotating the Nondle to drins the ex-

tension 76 arainst the outcr su-face of the farce 60.

Thereuroy, the hoagie 72 is released to permit the ticsing

springs 74 10 force the exiension 76 agin: the flange

60, aud thereby hold it against the confronting surface

of the waveguide 24.

With this arrungement, it will be seen that I provide a

mesns for easiiv and relessably locking the magnetron

structure 44 to the waveguide 24. By sinyply rotaiing the

handle 72 to remove the evtens‘on 76 from Icclins en-

facement on the, Rance 60. the macr.ctron is quickly dis-

engoged from the weveguise for repiscemect or repair.

AS previous.) mentioned. the misnetron @3 is sum

ported in the cooling fin structure 42, ard the mzgnciron

and cooling fin s.ructures are structursliy cooperatively

related to effect sfizient heat dissipation Referring to

FIGURES 1 and 6-8, the couling fin siructure is formed

of 2 pair of identical cooling fin packages 80. As best

seen in FIGURE 7, each of the pocacecs is a fan-shaped

cooling fin siz-eture formed of a pluratity of Feat dissi-

fating elemen's. e.g. sluminum places. which are stacked

together at one end. and whic. are bert at differemt eacles

10 form the desired fom shupe Pl.iics 82 are potiioned

on the opposite ends of the stackhco portions cf the plates,

and are svitebly faziened toecther with the stack. as by

rivets §4. The inner edzes of the stacked porwuns of the

plates are made circular. znd the radius of curvature con-

forms to that of tbe anode bods 86 of ithe Mcenetron 44

(see FIGURE 6). Each of the platcs 82 is provided with

an axial! extension &8, to permit the cooling fin packaces

to be clamped wo the anode body 86, as by locking or

snap rings 89.

The magnetron suructure 48 fits in the space between

the confronting portions of the coviing fin packaces. Re-

ferrine io FIGURES 6 and @. pole preces 90 ev‘end from

the oprosize enc's of the arode bods 86. Slid2oiy laced

over the pole pieces 90 sre magnetic sleeves 92 which

have flat external surfoces (see FIGURE &). A U-shaped

permancnt magnet 94 is pesiticned on the side of the

anode bedy 86 opposite the shie!d 46, with the flat svr-

faces at the ends © its lecs placed aginst the contronung

flat surfaces of the macnetic sleeves 92

Referring to FIGURE 6, the magnetron is arranced

to be evacuated throuch a tude 96 that extends through

the lower pole piece 9@, and such tube 96 is surrounded

by a protective cover or shicld 98 which ex-ends into and

is secured to the pole piece 90. Electrical connections

to the magcetron are made throuch a tuve 100 exiending

out of the upper pole piece 90. A connecto~ 102 is fitted

over the uppsr end of the ti be 100. ard a cavle 104 cx-

tends from the tube for conrxection to Uie power supp'y.

Thus, the magnetron 44 is ananecd so that al! parts

are located between the confrontirg piss of the two

cooling packages. Soch arrangemcni facilictes opumum

surface-to-surface contac: between the anode body % and

the edces of the plaies forniing une conlirg fin pxch aces.

In this latter connection, the circumferentiz] length of the

edges of the cooling piates which engage the anode body

3,440,886 A29

86 cre between one-fourth end one-half the circamfer-

ence of the anode body.

As previously mentioned. ths axial extensions £8 cm the

Fates $2 are provided to be enci:cled by snap rings 89

for helding the cooling fin packages in place. In U.is con-

nection, and referring to FIGURES 6 and 8, the plates

82 are located above und below the anode body 8&5, and

the snap rincs 8&9 encircle the exiensions 88 on bowb

plates 82. thereby firmly securing the cooling fir pack-

aces 80 in place.

To exhance contact between the abutiing pertions of

the ancde body 84 and the cooling fin packages 80, a suit-

able heat conducting material. e.¢., a silicone creace, may

de costed om the edges of the plates of tre coo'ing fin

mructurss before they are clamped to *he anode hody.

FIGURES 9 and 10 illustrate the details of internal

construction of the improved magnetron of my invention.

The magnetron is one h:.\ing a strapped vanc-iype tuning

cavity, and to this end there is brazed to the inner wall

cf the anode be Jv or biozk €£$ a plurality of «pace vanes

110, to onc of which the probe 112 is brazed ard exiended

out of the body ant! into the shicld $5, all in a conven-

tion2a! manner.

However, TE employ unique means for strapping the

vanes for mode stabilizing purposes. In this connection.

each of the vanes 110 is mrovided adjacent its inner end

with 2 groove 114. the sides of which cre straight and

paralic:, and the boitom of which is V-shored. Unlike

conventional siranr:d vane macnetren casiuics. ahercin

adjacer: grooves are raJis!ly stocecred. the ersoves 114

in my impreved struciure ore not stagccred. As best seen

in FIGURE 10, the inner s'des of all the crooves 114

are spaced the some radial cistarce from tne inner wall

of the tod, 86. Sirail ly, the outer sides of all the

grooves are swacet the sume disiance from the inne- wal!

of the body.

Tous. af vanes 140 are made of the same dimensions,

With crooves Iocuted im the same positicns Za all sneh

elements. Accora aly, the vanes can be easity assembled

by an operstor without t:kir2 the tine Heretofore re-

Quiied 19 msbhe Cerin that edjacent vanes i:zve their

fLroorves stageered.

Such e2se of assembly of the vanes is made pocsidle

by my unique strapping arrangement. Twclve vanes are

sbown in the particul:r examp!e, and a'terrste unex of

these vines are connected by respective outer and inner

hex>gonal straps 116. 118. The corner penions ef the

Outer strup 116 are brazed to the outer sides of alternate

grooves, and the mid-portions of the sides of the inner

Strap 218 cre crazed to the inner sides of the remaining

Frooves. Inspection of FIGURE iv will show that the

comer portions of the inner strap are locaed inwardly

of respective grooves, and do not touch the ad)>cent inner

wa'l of such grooves. .Also, the mid-portions of the sides

of the Suter strap 216 pass through alemate grooves

Without .vuching i.ny portion thereof,

Tm addition, the shapes of the grooves 114 and straps

116, 11S facilitate assembly of the strops. The inner srap

118 preferably is dimensiored so that when it is siipped

into the grooves. the nyid-portions of its sides are in fric-

tional engacemert with the inner sides of the grooves to

which such mid-portions are to be brazed. The strap is

ttus restricted against anculur disp'acement prior to

brazing. Also, since the bottoms of the grooves slope

aws} from the sides thercof, the tct.om edges of the

milf *:.ions of the sidcs of the strap 118 come to rest

against the outer er.d of the V, ie, where the sides ond

bovioms of the grooves are jcined.

The corners or argles of the cuter sirap 116 are simi-

Lrty located in position againt the outer sides of the

grooves m which they are inserted. In essembly, the

outer strap 116 is positioned with its corners aligned

wit't those of the inrer strap 118. which automatically

orien the trap 11€ properly for connection to alternate

wares. As witb the other sirap, the shape of the growve

‘

Timits inner movement of the strup 114. and hence serves

to locate it properly for brazing. Also, the strap 116 pref-

erably is dimensiored so that s!icht force has to be ex-

erted to force it inwardly, whereby its corners frictionally

engace the ouier sides of the grooves is, which they are

located. Such corner poriions are then br: zed and secured

in place. \

As previously indicated, the straps 116, 118 perform

the usaa! mode stabilizing funciion. In this connection,

my strap arrangement is one that is readi'y oJjcctsble

after assembly to provide such corrections as are neces-

sary for the desired mode stabilizaticn and resonance

frequency. To this end, all that is necessary is to deform

one or more portions of the straps intermediate tic peints

at which they are brazed. Thus, one or more correr ror-

tiens of the inner strap 118 and/or ore or more of the

mid-portions of the sides of the strap 116 may be forced

inwardly or outwardly to change the capacitance of the

straps as needed. Since the straps are ribbon-like meta!

cleiments, they retain such deformaiion.

For exse of manefocture and assembi:. the pole pieces

99 are made identica!. As best seer ir FIGURE 9, each

of the pole ricces is formed as a cylindrical element hav-

ing a central openirz that has a sma!) cytinerics! portion

124, a fructo<onizal portion 326, and a recessed, erlarged

diameter portion 128.

“The pole picces 90 ace mounted in the anode Nock 86

aith their rourded end faces extending imo the ends

of the block. In the arrancemeni sheen. the pole pieces

are secured ct the ends of the Bicck by means of flanced

tings 130, 132 that are brazed. respectively, to the pole

risce 90 and the bieck. In the pertiou'sar arrancement

shuwn, the rings 130 nest in the rirgs 132. ard are

welded togciher as indicated at 134, e.g, 2s by beliarc

acidirg.

The tube 100 is surported in one of the pole pieces 99,

as by inscriing i: ir. tne enlarged diameter portion 128 of

the openires thereit., an! brazing it to the pole piece. An

erd cnp 140 1 itsered in the outer end of the tube 100

and bonded .dereto, and cornector pirs 141-144 (see

FIGUKES S ind 9) extend throush aad are bonded to

the cap. In thy arrangement shown, the pin 141 evtends

throuzh the cenier of the cop 146 and the pins 142-144

are spaced pins equidistant from the center pin 141.

Withia the interior of the tube 100. the center pin 141

is connecied to the heater lead 146 for a heater element

148 located in a sleeve cathode 150 that passes through

the center of the vanes 110. The heater 148 is connected

at $§2toan erd shizld £4 that is fired around the cathode

150 at one exd thereof.

A similar end shield 156 is fitted around the opposite

end of the cathode 150. and a tute 1§8 i, secured at one

end to the shic'd 156. As shown. the tude 188 surrounds

the heater lead 146 and the inner end of the connector

33 141. the cuter end of the tube 158 being spaced from the

inner face of the cap 140. Frictions!ly fitted around the

cuter end of the tube 188 is a clip element 160 which, as

bes: seen in FIGURE 8, has outwardly exterding legs

stich pass around and frictionally engace the connector

pins 142-144. Thus, the conne: tor pins 142-144 are con-

nected together electrically.

Through the connector 102 and the cable 164, the

hester 148 (via the pin 141) 2nd the ezthode 159 (vin

the pins 142-144) are adapted for connection to suitable

heater and cathode potentials. To this end, the connector

362 is formed with an insulating becy 166. throsgh which

kaJs 168 extenc from the cate 103 for connection to

resreciive pins 141. 142. In the arrangement shown, the

en2s of the leads 168 are supported ir socket connector:

frictivnally fitted over the outer ends of the pins 141, 142.

The body 166 is surrounded by a shicld 170 waich is fric-

Benally fitted over the outer end of the tube 100.

The improved magnetron of my invention includes a

Bove! choke structure for isolating the power supply from

the microwave energy developed in .he anode block 8&

8,440,386 30

7 “

tubular element 172 which has

that gererally conforms <o the

the opening in the pole piece

has its smaller en fitted over the

thereto adjacent iis inner end, 2s by

length of the element 372 is such that

©.P surrounding the clemest 172, meas-

outer end of the element 172 to the ianer

tre piece 90, is a qucarter-wavelencth o1 the

damental frequcacy of the energy gencrated withia

the anode block 86.

At such fundamental frequency, which for microwave

cooking purpoces preferably is in the region of 2,400

mHz. the confronting surface portions of cll element;

Gefining the pop, ic., the portions of the elements 172

and the end shicld 156 together with the corfroating sur-

face portions of the pole piece 99 and tube 1C0. function

as a low impedance coaxial line at such funcumental fre-

quency. Since such terminates at the outer end of

the element 172, the space within the tube 160 beyond

the outer end of the element 172 cunstiiutes an effective

hich impedance to the microwave energy. Accordingly,

this construction forms an effective choke to preven; the

microwave enercy from being coupled through the pi Pcon-

neciors to the power supply.

In addition, the choke construction of my invenuon is

adap:ed to minimize the effects of ircublesume ha-mronics.

In this connection #* will be observed thot the cozxial lise

atuve-meniioned is a stepped affair. The gar is smallest

ir the regics of the porticn 124 of the orcning in the pele

piece $8. is somewhat wider in the frusto-conical recon

thereof, and is widest along the enlarged diameter portion

of the elemen: 172. Such stepwise variations in the width

of the gp. together with the differinz lencths of the cylin-

drical and frusto-conical portions thereof, pro: ide effective

cooxia! lines which are successive low-to-high imped=nce

transformers. The @imensions p.eferably are selected to

effectively isolate the most troublesome harmonics, ¢.¢.,

the second and fourtn harmonics.

After the marnetron is asscmbied. it is evacuated via the

tube 96. The tube 96 is braved at its inner end aithin the

smal dismeter portion ef the pole piece $0 in which it is

icserred. After assembly of the macnetror., the tude 96 is

connected to a Vacuum pump for evacyatirg the eniire

Structure in a conventional msure:, jollawing which the

mbe 96 is pinched off and closed at its ovter end as indi

eted in FIGURE 9.

In addition to the advantages of my magnetron structure

as above described, I achieve a marked improvement over

Prior art structures m the concentration of m-gnetic lines

of force at the ends of the vanes 110. Since the inner ends

of the pole pieces 90 are rounded. whereby ibeir center

porticns are closest to use inner ends of the vanes 11@,

anc: since the pole pieces are inwardly tapered as described

and have the greatest portion cf their masses located ine

mediately adjacent the ends of the vanes. they are effective

portion of the anode b'ock 86.

Any snitabdle switching means may be emploved to

effect cooking by microwave and/or thermal energy with

the above-described apparatus. For example, one switch

Grevit may be provided fcr connecting the ends of the

elements 16, 18 to a source of heating current, and an

other for connecting ihe power supply 36 to the map

getron connector cable 104. Such switch circuits may te

oper: ted by separate knobs. or by a sinsle control knob

as sh wn at 180 in FIGURE 1 on the front ponel of the

comp. rtmert 34. ‘

Ip this latier connec:ion, there is iustrated in FIGURE

3 a switch box 182 to whici: are connected the power sip-

aE at

ply 36 and a cord 18; having a plug 186 to be connected

to the house currem supp!y. The switch box 182 has ovtput

connections to the cadie 104 and to the ends of the ele

ments 16, 18. Swit=h circuits +s referred to are included

knob 180, as threvsh a mechanical conncciion 188 fos

opzrating movacle certocts of the circuits.

Preferably. such circuits hive some fixed contacts ia

common. so thai in certzin positions of the knod 180 there

is cooking simuitaneously by micronay: end thermal

erercy. Sul! forber, ithe fan motor 40 is picterably di-

recthy conrected via the switch Bex Le) to tie cond E83,

thronch a switch that rem.ins clos) in ell but the “oil

position of the Anod In th:s menrezs, ihe fan is hoi min-

int st all times the oven is in use.

White the swi:ch 182 and connections sre shown sch.-

maticaily vutsids the oven structure in FIiGiU RO 3. at

is preferrcsd that a corresponding paysicsi sirectire be

located in the comparurent 34. In such cree, a shaii froin

the sv.itch box or hovsine preterbl) is on the iv cf

the knob 180 and directly connected thereto: Uc cond Idd

e\tcn’s through the companmen: io the svitch howd:

the conrections fiom the sower surply 36 cad t's con:

tions from the sv ich mech:uisn. vo ths fun 4 ard ths

caNe 104 are sll lecds confined in the com> mest M:

and the conzecticns to the ends of th> eix> cris 16. 18

sre Icads that evtend from the switch bovsins throosch

the rear@f he compsament. from which ibe extend to

and are secrred to the terminzis of the clevsents srajecurs

5 throuch the back ef the oven structure.

From the fore -virg. it sil! be apr reat tht vanors

mod.fciuons cor be made in the strecturcs Mustruted and

desortod without ctparting from the spi: ond scope of

m: invention. Accsorcing!y. Ide 20% intend that ey invea-

30 vicn & limited, except as by the appe-J22 clsirs.

Icl>im:

1. In combization:

&@ Microwave ca‘ty having operires to the evtcrior

the-eof throush which to permit varor to pass.

wherein sui! cavity is an o.en cham*er with a

fromt doo-. said chamber heving tartom. ter.

rear ard side wal's, the orcnings 20 the 2x-

tericr of the cavity ceive in the top we':

a conduit threzzh which te intradree micros ave cacres

imo said cAVis. COMPrsizg a wavervile,

$aig wa eovide c2jncent ons end hairs an ore+-

ing. suid asvecuice being mounied exeric ly

of the rear wall. said rear wail havirg an o7-n-

ine sligned with the waveguide opening:

antenna mear.. in ssid chamber;

ap Ovtpet free: cxtendinz through said vaveruide

Opes*ng ard coupled to said antenna mzans.

said wavervids adjacent its other end havine a

second Cpening throuch which to inirozuc:

Mictow..e energy into the wa\ccuvice:

& mapnetron having an output robe eatenting into

Suid second cpening:

means reisasahly holding said mapretror and wave-

guide tocethes: and

meurs to force air ‘hrough said conduit and ino the

cavity at suTicie t pressure to keep vopor in the

cavity from passing into saiz cond:it, such forced

ar siding *he eszare of vapor through said opsnires.

2 The combination of claim 1, wherein said wavecuice

kas an opening in s2id other end through which to cdmit

air wo the waveruide:

& pipe connection to ssid end openire: and

fan means for Mowing air into suid pine consection

‘3. The combina:'30 of claim 1. whersin oi! ar.enna

me:ns includes an element which is adzptea to ce bestec

by clectr’c currert;

means to supzly electric current to said element;

a power supply for said mogrctron; and

switch means operable for connectinr: sid e'emem

to a source of electric current and fer connecting

saic power sspply to said magnetron serarately or

amultanesusiy.

4 The cor.bination of claim 3, inclucing means fo-

Operating suid fan means at ail tim... during operatun of

ia the switch bux, icr operatioa in different positions of ix 73 said swiich means

A3l

3,440,336

§. The combivatioa of claim 1, wherein said magnetron

has a cylindrical anode block, ssid mazreiron output

probe extending out of the lateral surface of ssid block;

a pair of pole pieces extemiing ovt of the ends of the

block;

eiement having a face abutting iaid waveguide

around said second waveguide opering, the radial

dimension of sait face teing a: ‘east a qu2ner wave-

length of the microwave enersy propagaied through

said savegui«; and .

an evzcuation tube extending out of one pole f-.ece; . mear< for releasst'y clamping szid disc element and

an electrical lead support tubs eatercdirg out of ihe waveguide togeiher.

other pole piece: and lv. In combination:

a permanen: maznet eaterding along and spzced from ~ a microvave cavity having openings to the exterior

s2id block opposite said macnctron output probe and ,,, thereof throzei: which to permit vapor to pass,

having its ends engaging said pole pieces. wherein soid cavitv is an oven chamber with a

6. The combinaiion of claim §, further including: front door. said chamber having bottom, top.

2 peir of cooling fin packages formed of stacked plates. rear and snie walls. the openings to the exterior

the plates at one edge of each stack being cu:ved ol tne cavity teing im the top wall;

said puchaces being locaied on opposite sides of said a source of microwave energy;

dlock with the curved piates of each package extend- & waveguide Outside said cavity and having an input

ing a quamer of the circumference of said block; openins ccupied to said source, said waveguide

and having an output opening;

means to hckd said packages with the curved edges cf 29 «= mean: for directing mizrowave energy at siid output

the plotes thereof un contact with the lateral surface

of said block.

97. The cortiration of claim 6. including a pair of

opening sole’, to sold wnienna means to cause said

antenna meam to ridisit Microwave energy throuch-

out suid covity; and

means to force air throuch said waveguide into said

chamber at sufficient pressure to keep vapor in ihe

chamoer from passing imto said waveguide. such

forced ait aid-rg the escape ci vapor througn said

magnetic slecses surroundme said pols pieces. suid sleeves

having a fizt exernal surface. said magnet being U-shaped 35

and having flat faces vt the ends of its legs engaging

said flat external surfaces.

&. The combinaticn of claim 6. wherein the plates of openings.

each pachage re shaped to define a fan-shaped cvo!ling References Cited

— sos a Te gPye *) UNITED STATES PATENTS

aa ee 2.748.239 $/1986 Long et al. ---.-_- 219—10.85

‘ ‘es: 4

snap-rings ercircling covte-ponding C-shaped flates of yen pene — et al. -.... 219—10 =

said packszes 20d to relcasabdly hold the curved edzes 4.319. @ one = savepeonce 319 10.85

ef ssid plates sgainsi said block. as {US$ 8/1967 Deaton --_--...-.. 219-—10.85

$. The comt:ration cf cisim §, including:

a circu'ar cleront surrcunding said magnetron output

prob. and cstendineg from son: bioca, the cxterior

port nr of said circular element being threaded;

a dix. clement threadedly secured to said circular ele-

roemt, said disc element baving a circular shoulder

siidat'e in saad second waveguide opening, said disc

FOREIGN PATENTS

1,249,130 21/1960 France.

40 RICHARD M. WOOD, Primary Examiner.

L. H. BENDER, Assistant Examiner.

Paes Ser f pag os “i +.

amma on vinevsran -

- ** sEnvece

é- te PROPRItTA PDUs TRIELLE

A32 ye ay PARES 28 oan

fs omeme prom" BREVET DINVENTION

py. 2 819. 463

Clasel ication internationale :

N° 1.249.196

F24c—HOSb

_——-

Caisinidce électrique avec dispoaitif complémertaire & micro-ondes.

| Sockete dite: MIWAG MIKROWELLEN AG resident en Suisse.

Demandé le 24 février 1960, 16° 29°, Paria. ] § Marz 1961

Delivré le 14 novembre 1960.

(Demande de brevet déposee en Republique Federale Allemande le 25 ferrier 1959,

sous le n° D ZU.068 N Iii d

echafit m. b. H.)

Un connsit dee apparmie dare tesquet on peul

chaufler dans une exxrinte metallique ferin~ des

denrees alirx nlaires au moyen de micre-ondes et

dais leaquels on peut faire rissuler oy dorer ce

denrées suivant les besoins oo suivant be gout do

consonunateus au moyen de crayons infiarouges.

Dane beaucsp de can an peut obtenir une eee.

Koration per rapport aux proceder Ge cuss

ordinaires pour a qui concerne te gud. kes qua

lites nutritives et Uanpect dee alumenta Loe otili

sation particuliare des appareils en questo esi

cunstituee par be degourdiasement et be chauflage

rapides d'aliments deja cuits, préparts en portions

pretes a Cire servies, puis refroidia Dans ber cui

eines dee hot: !s, dew sanatoriuma et dew hopiteus,

Ud est pursible de luger en supplement ore appareils

qui prennent beaucoup de place Mais dan kes

jostallations domestiques, on pd arrive pas. le plu

pat du temps, a loger de tele apparcile en raison

@e mance de place.

Liiavention comerne ane cuisinié¢re électrique

fen type ct de dimensions classiques, aver plaques

chaufflanics ot four avec dispositif pour les gril.

* Jedes. Ello est caractériace par le fait que dans

. Feapace se trouvant eu-dessou du fow, entre les

27) bh. au nom de dxwmicie dite :

Deci-cabr Miarowercen Gesell.

Niet en igus oermale i! sufb: dap porter quel

que modifiations levers pour ce qui Converne

be four, Lequipement en interrupteurs et lonsta!

lation

Le punde dondes pour Lamence de Lenerypre

des micro-undes peut ctre dispes aventapeusement

contre lesperot portereure de Vencemt du four

une fente etant prévue a peu pres au milieu de

ladite peroi. Les dumensions a donner aua guides

| Ponder de ce genre et aur feutes deceouplement

sont connucs Caprese la Ltterature eperialise

Le tube électronique generatear qui est hale

tuellement un magnetron refroidi par de Uair eins:

que le partis de reseau correspondaute pour Vel

pentatien en courant sont par comequent loge

me atenant dais te rone ta plus froide de la. ainse

pu-dese us du four dans le-pace se rowsant entre

bes pieds de la cuisini¢re. expace qui autrenent. ac

errait pas utilise Cette disposition iacilite dune

maniere considerable le solution du probbeine du

refroidiseement. Le courant d'air fourvi per un

ventilateur normal suffi en effet pour aseurer of

refroidiasement.

Suivant Tinvention. une partic de lair de refroi-

disement est refoulee, & travers des ouvertures

pieds de la cuisinicre, sont disposce un générateur | mévagees a cet effet, dane le guide d'ondes dca

Ge micro-apdes at son dispositif d’alimentaiion en | adic sé happe en passant a travers le fente d’eccow.

' Garant, génératew: & partir duquel l'énergie des | plement, te four et bes ouvertures d'afration de

oe est amente ev four par Mintermédiaire | ce dernier. Cette construction ssivast l'inventice

_,: Mem guide d'ondes dispost te long dune parai | eert a protzger be tube Gectronique générateur

= letra de foes ot par Notormidiaire d'une tente Sans cette construction, des vapours af des fumées

‘a mol, lt o: de graisee ee déposeraient Jane fa tubctere dee

Es Sait DR. Que on’ tints dian ext couplemer, de tube Grctronique ot dans ke

o> evec dee dimeations plus grandes que calles | Condes, pe qu! coaduirait & des perturbations

+, @q fe Gulstaldry -domestique sormple. Ele ue S cas Oh. Se

Soe eed pe a disposer une fendtre didectrique avant la fente

.,@tisine. Ea ovtre, gag sy gt couplage ow dane ta fente de conplage Kant dound

'/ Micdétalree poor ta calage, le chambre gt be pram | que copie fendire coral, alle eusel, cowiliée at que

See en repens f conedgrent, Mpdaptation serait endonumagie

& micze-<oden A Fexicution de sbrto | te cuted. ~". @'D 2d ce produise pas, ere du foactionne-

C-Ga Fede de feacloules DP mL

1.249.130

gacet Ge fear same ork ~~ code es rei ctrmrat de

fe tubelare de couplsge t de guide d'cadea oo

qui, bers dan foacticrnemeet shenest mer micro

eondes. eurart sum kee consequences indiqures plus

hevt. bee cireuils des Gements chaufants dips

dane be fowor et bk cireit du motrur do vemilateu

pewent per un interruptewr coremun The cette

manirre. le protection du tube clectromique gene

rateur ew essuree pour tewt made de fom tionne

ment du four

Confurmement a invention fest prow paral

telement @ fa pare: leterale peortant te fenie de

couplage ov te fenies de couplace. une plaque

refin hisssnte plus pete que la paro leterale et

disjnreee dune maricie telie quil ee forme entre

lade plague et bes wearer aveleinantes. un miter

valle annulerre. Pour regler Vadsaptatren. on peu!

faire varser te distanc:

sente et le parcr lateral ywortant le fente et your

agin sur le repartitien cu chang dens le four

cutie la plaque reties bes

er peut fare varie tle larveurs de lintervall

annulaire par un mourement de translation Ls

parte centrale de la plague refs hissante est en

retrait clans le direction omertee vers la porte du

fou cl lee heord~ de le plaque refochrecante sant

recourbes Au seisinage de le fente de couplage

fe paren leterale fait seille vers Veatereur a yxu

pres symetriquement par rapp rt a la plaque ref:

chissante Lee aaille~ respec tives ef oppose de

la plaque reflechisscnte et de la pater tat rate

fourniasent une fargeur de variation plus gran:

pour Veecord. Le reglape de Vadaptation appre

price et le reglaye de le repartition de champ

desiree sunt plus commode &@ canuter parce qu:

de petites modifications de position be le plaque

reficx hissante ne sont pas aussi critioues Le contact

thermique entre ta parei du four et te guide

dondes eat plus farnle que lorsque le pero laterale

ext plane et le four peut étre mieux isole extérieu

remert contre lee pertes de chaleur.

Lew herreaus du gril sunt diaposes d'une ma

picre telle que be gril. peur la direction de pola

risation principale régnant dans te four. ext per

arable ev champ. Dans ke mode d'alimentation

heute fréquence qui a et¢ montré ici, il faut donc.

par exemple, que les ouvertures entre bes barreaur

coient, dans leur direction longitudinale. paratieles

& la direction longitudinale de la feote Palimen.

tation. Afin que soient évilées doe pertes baute

fréquence indésirables, le gril est supporté. avec

heolation, par lee perois laicralea. On peut sup-

porter be gril em dispant des points dappe!

leclants oe bica, le gr Kant revéte dun boo

émaiMage, le faire repoeer eur des nervures d'appul

des par. 's letérates. .

Audemows da four cat logte aus! la partie de

réseau power Malimeniation em courant du tab-

Aectrunique gtadrateer, partic de réviae duet be

ogs9 D> Zs. so SPOR ve ae 0,° .% .

=i * S w. » 4 a ®

. -~ **

. —

» i= ~ e--

tansformatren distinct dont bee enroeleemens

ercondgires soa! moatés ce eerie. Confornrvarat o

Prmveation, Man des dewr tansformatrar haste

tension, quant te tube electronique eu pret 4

functionner. demeure em permancace sous temainn

cate primaire se teimion secondaire fournit «

la cathe une charge peealable fable poe:

laquelle Petat dive illation n'est pas encore afteint

Comperee @ Teaccwtion normale avec un tran

formaiewr heute tension seulement, cette dispnn)

Don presente dew aventages importants bn raeor

de la faible charge prealable de ta cathode evan!

que seit attert Petat dos illatven bors de le mie

en serve. en evite dune mannre sure ks pertur

bathers pre Costes parce quien eppelle la « mated»

du mummers! > ciuy maynetron Dy cote primaire de

transforimateus haut jormpue \

magnetron est pret a entrer en aervice ¢ est.adir:

chauffe. vl est presu une eerie de prises pour be

wt vlace dew tensiome de eervice permet

deflectur: ce régtape avec des movens de couplare

fablement charges, ¢tant donne que fun dee trans

formateurs montes en paraliele céte primaire ne

besoin de transmetire que le moitie environ de

la pulssance neceasaire caty haute tension LD) autres

svantapes de cetic disposition de rearau resident

en ee que le refroidesen ent est plus favorable en

taron de lepanaeur plus faible dew different

enroulemente et en ce qoe le hauteur de conatru:

tron et le poids sont plue petite

Sur les figures |e ton a repreeent* un exemp!.

de reali ation de PTinvention. en tenant eompi-

seulement des element« qui ent en rapport ave

le four de le cuiminiere

La figure 1 reprewnte be tour aver guide d'onde-

et aver magnetron refroidi par Pair. tel qui!

apparait a un olwerveteur regardant lea face arriere

de la cuisiniere;

Le figure 2 montre une coupe de leppareil

faite suivant fa ligne A-R de le dgure 1:

La figure 3 mortie achématiquement lee harreass

du gril, dans cette réalination de l'appareil.

l denigne bes parcie du four de le cuisiniére

Le porte 2 ferme louverture du fowr. Le réchau!

fenetonm ut

re qui

tee diapositife aormaas powr te marche 4’

régime oo & régtine modéré du for. Le

tron 5 est repréeenté avec son almant ct oe

Thee

‘i

iit

Ses ° gon! > Se «. ESSE: — act eet" aye aeeTes ™ “oe , ~

SH vee ‘ w z. ss » e: “a. aa, che SF ~~. .* = by > oe ad Fs *.

- : a ns .» odes ~ — 2 on . 4 i 249.130)

gtese & dun be tes 0. enate te an. S* La sone centrale de le plaque réfiéchisante

teteur 10 soulie Pair de refroidissemeat eutre bes | cat em retrait et bes bords de cette plaque sont

a - = . c e =

*- » * . . ee . .

M@ «as * . ee

oh se Sane, dep «6 - oe

— * * 5 ORR 8 *. o. ° “e* eg .

oo ek a ha “» *9 “+? oe - -

- . . . :

-. 7% XY @ Sc ose 0 2. @s e

- ae 2 "6 at Ses Ne - Yer-s Oo - a: ™ .

‘s > ef. - * ° ‘4 e , a ot ee ie ill

as yy “+ es Ss ta 3? . Ny

@-° . = ieee \y - ee Tact “3

7 ° US ene GO. SB « S°Y*.“S os , -— Gs. &€

aes OO ii. ‘ <e@ ‘ ’

téles de refroidiseement du magnéiron Une partic

de Tair de refrokdiseement est refoulée & tray ore

les owvertures 11 dans le guide dundes 7 dvi

‘le e'échappe en paseant par ts fenic 8 ct une

ouverture ménagee dans ta paroi du feu en

entrainant ler vapeurs et fee fumes de graine

Le trajet de Vair est indiygué par des fixhes

Lee nervuree dappui 12 portent be gril 13) qui

@ ét* represente en traits interrompus. Le die.

wition des harreaur de gril est indiguee eur te

&gure 3.

Rests

Cuimemiere elevtrique du type et de dime: sim

classiques axe plaques chauflentes et four ave

dispositif pour lee grillades. cuisiniere Gle tiiqgue

carect timte par be points sunaents. stpancment ou

en combineaisons :

entre tes piede de fa cuisiniete. sont disyn.ss

wn generateur de micre-undes et aon dren sotil

Malimentation en courant. génerateur & pert

duquel Penergie de microonde et amense eu

four par Uontermediacre d'un vuide dundee diuvine-

te lone dune peroi lat-raie et par ft ynterie naire

dune fente au moins.

2 Le gene Dunde et dayrn* contre le parei

post-reure et une lente ext shagerwe a pu pee

au milieu de ledite parni:

3° Devant le parei let-rale portant le fente ov

les fenton de couplage et. a une faible ditane

de fatite parei, eat diqurece um plaque ef «hie

ante dent tes dimensions sont plur petite~ que

cefles de le poroi latrale. cette digueaitor tert

teshiee dun> maniere ttle qual se forme ent.c

la plaque réflechisante et be varoia qui en sont

veisinen en interalle annulaire.

varver le distame entre ta plaque réBhinanie

et le pars) letére.: portant le fente et. pour agir

war be repartition de chamr dans be fowr. un neut

faire varier bee largears de I'intervale annuaire,

recourbes ;

6° La peroi letérale, au voisinage dc be

oe des fentern fait erillie, vers Verterieur.

forme de cevetic:

TH eet presu un refreidinement par vent:

leteur pour be tule electronique genérateur et

une partic de Vair de relrwidiasement est refoulee

dans te guide dunes;

& Les cirwit- dee elements cheuflants dipwose-

dans be four et be cireunt du moteur du ventilateur

pasent par un interrupteur commun.

Lee bereweun du pril sont diepees dune

manure telle que ledit gril cet permeable an

champ cars ba direction ce peclaremation principal

rrgnant clan. be four:

heh da cri eet supporte par lee parce lateral

dont if eat isole

TP Dhan. te eas of eet pres un eouptac:

ao demarrage et up Bet aa

la pertee reseau den é@metteur cletrorique et or

parteuler dun emettieur a magnetron: dan. lego!

peur

anediujue du tube eletroamique est subelivix

deur aransformateurs distinets dont be enroul

couplage de aervice

le tea a-formateur haute ten-ren fa ten-ron

ment. wsoondeiues eont monte en ene. tun de-

transformateurs heut> ten=ien. lorsque be tul~

eka tromque est vret a entrer en eernice. ast ee

perma oraccerde cot) promaire a le tenes

du twau cf sa tension secondaire a une valeur

telle qu tl est fourm a le cathete une fartie charc-

prealalle peour laquelle Peat duwillation nest).

encore atteunt et Venrouler ent primaire du wor!

transfurmateur est tanurd) en pleine march

la tenswen du reweau:

12> Eh est preva c&e prumeiie du tran-Tormates

haute tension, qui 6 Petu de d-marrace et ~ !

seus tension, ume erie de priws poor be revlace

tes tensions cle marche secondaire:

Socitet dire MTB AC MILROB ELLEN AC

Pe precernae

Seworwot, Riecty «@ Burceoe

Re ee ee Re eee em wae de be Coerenten Pe 09>.

ry ‘

ww. 6 *

"Ee <* er 3 — >. ‘ ae ® “Nv » *- & ° e . °

ad he f : zs ” edie. *< — . at .° :

: . . . e -*~

1341 Bocises dite ; 2 planchen — A!

ey. = = i oe

Nee ee eee —— ee eee ee ee

J T

ard. oe

' ed ey

A37

FLANCE coeccves

Patent 1249130, International Classes F 24 ¢ = H U5 b

Application filed under Ser. No. P.V. n°. 819.462 on

February 24, 1960, at 4.29 P.M. in Paris.

Granted November 14, 1960.

Assipné: MINaG MIKR WELLEN aG, a denizen of Switzerlanc.

sriority claimed for Western Gormany 7 ot February

25, 1959( Scr. No. of application there: D 3.063 VIII

d/21 h ); name of assigne there: Neutsche tikrowellen

GmbH.

Electric Cooking Stove with an Additional Microwave Device

Une knows already equipment where one nay heat

inside a closed metal container articles of food under

use vf microwaves and where one may brown or glaze the

foostufis as needed or s0 as to suit the tuste of the

consuner, usiog infrared rays. In many cases one gets

an inprovement compared to the ordinary inanner of cook=

ing what coucerns the taste, the nutrient qualities and

the looks of the food. A specinl use of such equipment

is the takiny- off of the chill and the rapid heating

of tood wich is already cooked aud prepared in meal-=

- sized portions roudy to be served, nnd rrezen aftor

their preparatione In kitchens of hotals, sanitaria

ond hospitals one uses a greater nunber of such pieces

of equipment which then take up lots of space. here-

fore in the households one often cannot prevail oneself

of such an equipment, y - ad because there is lack of

Bpace.

he present invention has as subject- watter an

electric kitchen stove of the ty-e and dimensions comm

“*AQra

ii a i Ti it i a a i i

2 A38 ;

unly used, with heating ; lates and an oven with equipn-

ent for grilling. It is characterized in that in the

space located underneath the oven, between ( and anong)

the feet of the kitchen stove is located a generator

reed microwaves and its device for ourrent supply, from

which generator the energy of the microwaves is supplied

to the oven by aide of a wavgguide which is located at

a lateral wall of the oven, so that the microwaves may

pass along throuysh at least one slot.

‘his means that this kitchen stove needs not to be

constructed with daheunnie large dimensions, i.e. such

greater than the ordinarfly present kitchen stove.

a also no money has to beespent for the box, the

Chamber and the electric leads of an additional kitchen

stove for microwaves, If one is in the process of prod-

ucing a greater nunbder of the ordinary electric kitchen

etoves all one has to do is to apply some slight modif-

ications at the stove itself, place certain circuit-

- breaker(s) d ,ay for the installing thereof.

‘The ea ste for transferring the microwave enorgy

should preferably be located against the rear Wuix

~ortion of the surrounding wall or enclosure of the

giaxva oven, und at least one suth slot is located

close to the middle of this wall portion. (he dimensions

with which such wavdguides are ‘to be endowed and also

the kinds of enersy- transfer slots to be shaped are

known in the pertinent literature.

The electronic generator tube which mostly is 4

magnetron which is cooled by air and also the portion

of the circuit needed for supplying current thus would

it LL el

? 439

have to be iocated in the coldest zone or the stove's

body, below the oven in the space between and anong

the oven's feet, a space which otherwise is not used

for anything. This placing renders the problem of cool-

ing much easier, a stream of air coming from an Ordinary

air blower is all what is needed to bring about such

cooling.

According to the invention a portion of the cool-

ing air is pumped across openings which have been rach=

ined for this very reason into the wave aide through

which if flows so that next it moves alony the coupling

slot, the oven and the aeration openings of this one.

This construction according to the invention serves

to protect the electronic generator tube. If one would

not construct like this then vapors amd ;,rease fumes

would become precipitated in the connection tubing for

the electronic tube and inside the = a what would

lead to trouble in the operations of the kitchen stove.

One cannot place a dielectric window ahead of the conn-

ecting slot because such a window would simply become

dirty thus its operation and jurpose would become

inpaired. In order to avoid that, whensocver the oven

is used without microwaves, a coatings becomes deposited

in the connecting tubing and the wave guide, the con-

struction is visualized like this...also with the idea

‘that later on an operation with microwaves will not

lead to the bad effects mentioned above......that

the circuits of the/pating elements which are containexd

in the oven and the circuit of the motor for the blower

Pass through a common circuit=- breaker. In this way

~1187

ooo ee

A40

che ,rotec on of t..e el: ctronic generutor tube is

brought about for sny kind of operations of the oven,

According to the invention one furthomore installs

in parallel to the lateral portion which carries the

one or the several Coupling slot(s) a reflector plate

which is smaller than said lateral portion and installed

_an_ annular_space

like this that there becones foriedybetween this plate

and the adjacent wall portions . In order to regulate

the adaptation one may let vary the distance between

the reflector plate and the lateral wall portion which

has the slot, and in order to act upon the distribution

of the field in the Mu oven one may let vary the width

of the annular space by a translatory motion. ‘The cen-

tral portion of the reflector plate is receding in the

direction poing towards the oven door,and the edges of

the reflector plate are bent. Close to the coupling

slot the lateral wall protrudes outwardly, more or less

synnetrically with respect to the reflector plate. ‘The

corresponding opposite protrusions or the a

plate and of the lateral wall portion define a sreat—

er adjustment width so that one is able to PP.

The regulationdof the right adapting and also of the

desired field distribution are easier to achieve tc -

ause small changes in the position of the reflector

plate are not too critical. ithe thermal contact between

the oven wall and the naveeuide {4s amaller than this

would de the case for a flat lateral wall portion, and

4t 4s easier to insulate the oven outwardly against

heat losses.

The bars of the grill are arranged in such a manner

514188

EE SESESSOSIZ“C“=~ er ,

wae

ER EE EEE OEE EEE ee

that the g. wld tor the mur direction Jf polarization

existing in the over is permeable for the field. With

the wigh- frequency supply discussed here it thus will

become necessary e.g. that the openings between ( and

among ) the bars must in the longitudinal direction

be parallel to the longitudinal direction of the feed

Slot. In order to avoid undesirably hish high= frequ -

ency losses the grill is Carried,with placing of the

Suitable insulation,by the lateral wall portions, and

One may let the grill be carried by placing suitable

insulators or, if the grill is coated with a good layer

of annie then it may be carried by supportinj; ribs

in the lateral wall portions .

below the oven is also located the circuit portion

for supplying current to the electronic generator tube, .

and the high=- voltage transformer for this circuit por

tion is subdivided into two individual transfomers the

Secondary windings of which are connected in series.

According to the invention one of the two high= voltage

transforners, when the electronic tube is ready to be

put on stream,remains pormanently under the voltage of

the primary side, and its secondary voltase furnishes

to the cathode a weak preliminary charge for which the

State of ocillation ( alternating ) has not yet been

reached.

tn comparison with the ordinary construction with one

high- voltage transformer only this setup offers sign -

ificant advantages. Due to the weak preliminary (start-

er ) charge of the cathode before the state of oscill -

ation is reached for the actual operation one avoids

for sure the disturbances created by what is often call-

NT a“ain“Yn“n“AndAm“N<M<an~—<~—~—n mas Tt Tt ttt tt

A42

ed the " sacepy state "cl the magneti.a or designated

by similar names. At tho »rimary side of the high= volt-

age transformer which when the magnetron is ready to

become put on stream ( i.e. then when it is hot ) one

bas provided a number of taps for the regulation of the

operating voltage, what santas possible to do such

regulating with weakly charged coupling means, as nanely

one of the transformers, which is mounted in parallel

with the primary side, needs only to transmit roughly

half of the power necessary at the high- tension side.

Other advantazes of this arrangement of the circuit

are the ones that cooling occurs more eficctively

as the various coils need only be of a sualler thickn-

ess and te cause the height of the construction and its

weight are smaller.

In fipures 1 till 3-have been drawn a typical embd -

odiment of the invention, and in the drawings appear

Only these parts which have a bearing upon the oven of

the kitchen stove .

Figure 1 shows the oven with waveguide ana wit:h

air cooled magnetron, how a person would see it who

looks at the oven from the rear.

Figure 2 is a section throuyph the equipment done

along line a-B in figure 1.

Figure 3 shows schematically the bars of the grill

in this type of construction of the equipment .

1 designates the wall portions of the oven of the

kitchen stove. The door 2 closes the opening of the

oven. ‘The (re)heater 3 of the grill is attached to

insulatrs 4. In order not to render the drawings too

641390

nobulous th -o havo boon caittod ull * 230 parts which A43

aro roquirod for tho ordinary. oporation of the oven,

Oithor full- blast or with modorato hont. Tho wapne~

tron 5 has been wrawn with its tmagnots and its cool-

ing sheaths. Tho connecting tubing & protrudes in

G mannor known as such by roughly UL: into the wavee—<D

Guide 2. Tho slot 8 is located in the center of the

roar wall portion with protruding profile, at the

Correct position of the waveguide. Opposite the slot

8 one has placed in parnllel to the rear wall of the

Oven the reflector plate 9 which is nerve or less syrn -

6tric in shape and the edyes of which oro bent- around.

The blower 10-blews cooling air betwoon and auong the

Cooling sheets of the magnetron. A portion of the

cooling air 4s pumped across Openings 11 in the wave

Guide 7 frou where it escapes by passing through the

Blot 8 and an opening machinod into the wail portiog

Of the oven, entraining this way tho vapors and crease

funes. ‘The path'of wotion of the air has been indic-

-ated by arrows. he Sup,orting prooves ‘12 carry the

Brill 13 which has been drawo in broken lines. One

recognizes frum fisure 3 how tho burs of the prill are

arranged. . =

~CLAINS

A kitchen stove of the ty,o and the dimonsions

comijonly employed with houting plates und oven which

has peniteae for grilling, which kitchen stove is CHaR-

ACURIZED by the following foatures which way occur

individually or in any coubliniations

1-2 In tho spaco locuted below tho stove, betwoon

A44

and among t..< fect of the kitchen stove are placed a

genorator for microwaves and its current-supplying

device from which microwave generator the energy

in the shape of microwaves is tranamitted to the oven

under use of a navdeuide which is placed along a lat-

eral wall portion, across at least one slot(s).

2. The wave guide is located against the rear wall

portion, and a slot is located more or less in the

center of this wall.

3. Before the lateral wall portion which has the

one or the several connecting slot(s) is placed a refl-

dimensions

ector plate the Hiamshions of which are smaller than

the ones of the lateral wall portion, which setup is

brought about like this that between the reflector pla te

and the adjacent wall ond enmier (open= ) space becom =

es ereated.

4 jor purposes of adaptation one may let vacy

the distance between the reflector plate and the lat-

eral wall portion with the slot(s) and in order to aff-

ect the distribution of the field inside the oven one

may let vary the widths of the annularly shaped space.

5. ‘The central zone of the reflector plate is rec-

eding, and the edges cf this plate are bent(around).

6. The lateral wll portion close to tho slot or

slotsprotrudes outwardly in the shape of a cuvette,

7. One has installed a cooling with a blower for

the electronic generator tube, and a portion of th

cooling air is pumped into the wave guide.

8. The circuits for the heating elements which are

located inside the oven and the circuit of the motor

v1192

CC EEIESEE'S'S$¢SSs«~---~~~~~ ee

‘of the blow pass throu;h a common ci. ‘it- breaker. 445

9. ‘he bars of the grill are ra this

that the crill is permeable for the fiald in the main

direction of the polarization existing in the oven,

10. The grill is supported by the )ateral wall

portions from which ig is insulated.

11- In the case where one has provided a starter

coupling and a service coupling for the circuit portéon

of anelectronic emitter and es,ecially a magnetrc. em-

itter in which the high- voltase transformer for the

anode voltage of the electronic tube is subdivided into

two individual transformers the secondary windings of

which are connected in series, one of the high=- voltage

transformers, when the electronic tube is ready to be

put on stream, is permanently connected with the prim-

ary side to the circuit ( mains ) voltage and its

Secondary voltage has such a value that to the cathode

&@ suall preliminay charge is supplied for which the

oscillatory state has not yet been reached, and the

prinary winding of the second transformer becomes con—

ected when fully operating to the network ( mains )

voltage. .

12- at the primary side of the high- tension trags <

former auton he abtent of starting is the only one

under wibten one has provided a number of (current-)

taps for the adjusting of fhe secondary Operating volt-

ages.

For the

Company named MIWAG UIKROWELLEN AG pep. simonnot, Rinuy

& Blundell.

01193

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.