US2919336A

US2919336A - Combination electronic and electric ranges

Info

Publication number: US2919336A
Application number: US742659A
Authority: US
Inventors: Donald E Hahn
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1958-06-17
Filing date: 1958-06-17
Publication date: 1959-12-29
Anticipated expiration: 1976-12-29

Description

Dec. 29, 1959 D. E. HAHN 2,919,336

COMBINATION ELECTRONIC AND ELECTRIC RANGES Filed June 17, 1958 3 Sheegs-Slzeet 1 INVENTOR. Donald E Hahn A If ysl 3 Sheets-Sheet 2 INVENTOR.

Donald E Hahn Dec. 29 1959 D. E. HAHN COMBINATION ELECTRONIC AND ELECTRIC RANGES Filed June 17, 1958 Dec. 29, 1959 D. E. HAHN COMBINATION ELECTRONIC AND ELECTRIC RANGES Filed June 17, 1958 3 Sheets-Sheet 3 Patented Dec. ,29, .1959

COMBINATION- ELECTRONIC AND ELECTRIC RANGES .Donald E. Hahn, Chicago, Ill., assignor to General ElectricCompany,:a corporation of New York ApplicationJune 17, 1958, Serial No. 742,659

9 Claims. (Cl. 219-1055) The present invention'relates to combination electronic and electricranges', and vmore particularly to, such ranges ,fthat areaespecially .designed for home use. It is an objectlof theinvention to providea range of the,,character noted that incorporates a deep well cooking unit of the electronic type, whereby this unit being relatively small is ideally suited to the quick thawing, of 'frozen foods and to the, cooking of small quantities of foods. 1

,Another object of thelrinvention is to providea range of the character noted thatincorporates a deep well cooking unit of theelectronic typeand an oven cooking unit of the electronic type and an improved arrangement for selectively controlling the supply of microwave energy control circuit, wherein suitableinterlocks are incorporated therein so as positively'to in'sureproper closure of the cover of the deep well cooking unit prior to the supply of microwave energy thereto and proper closure of the doorcf .the oven cooking unit prior to the supply of microwave energy thereto.

A still further object of the invention is to provide ,in electronic cooking apparatus, an improved and simplified arrangement for controlling the selective connection 'of'the microwave generator to the different wave guides extending to the different cooking cavities incorporated therein.

Further features of the invention pertain to the particular arrangement of the elements of the range and of the electric control circuit therefor, whereby the above- Outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification, taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary front perspective view of a combination electronic and electric range embodying the present invention;

Fig. 2 is a fragmentary plan view, partly broken away, of the range shown in Fig. 1; V

Fig. 3 is. a fragmentary front elevational view, partly broken away, of the range shown in Fig. 1;

Fig. 4 is an enlarged ,side elevational view, partly in section, of a microwave generator and a valve mechanism that is incorporated in the range shown in Fig. 1;

Fig. 5 'is a lateral sectional view of the microwave generator and .thevalve mechanism, taken in the direction of the arrows alongthe line 5-5 in Fig. 4; and

Fig. -6 is a diagrammatic illustration of the electric control circuit for the range.

Referring now to Figs. 1 to -3,-inclusive, of the drawings, the combination electronicand electric range 10 there illustrated and embodying the features of the present. invention essentially comprises an upstanding body 11 of generally box-like form provided with-asub- .stantially. horizontally. disposed cooking top 12 terminating adjacent to the rear thereof in .an upstanding backsplash 13. A metal liner -14 of substantially box-like form is housed in theright-hand portion of the body 11 immediately below the cooking top 12; which liner 14 de fines an.oven cooking cavity 15 therein andis provided with an open'front that. is suitably closed-by a cooperatingfront door,.16. vMore particularly, the front door 16 is mountedfor pivotal movements about the lower edge thereof between-a substantially vertical closed position and a substantially horizontal open position; and the front door 16'includes a metal inner wall 17 that cooperates With a flexible metallic gasket "18 that is carried aboutthe open front of the liner '14, as shown in Fig. 3.

A pattern of four

top openings

21, 22, .23 and 24 are arranged through the left-hand ,side of the cooking top 12, as shown in .Fig. 1; and three conventional heating units or hotplates25, 26-and27 are respectively arranged in the left fronttop opening 21,:the right front top opening 22 and theright rear top opening 24; while the left rear top opening 23 is employed for the purpose of supporting a deep well cooking unit 31, as shown in Figs. 2 and 3. More -particularly,;an .annular metal trim ring .32 is secured inplace in the top opening 23; which ring 32 carries an upstanding metalbucket 34 disposed therebelow and within the left-hand portion of the body.11. The bucket 3.4 defines a substantially cylindrical deep well cooking cavity 35 therein; and is provided with a cooperating removable metal cover :36. The ring 32 is provided with a plurality of inwardly directed and circumferentially spaced-apart lugs 37 that are adapted to passthrough a corresponding plurality of inwardly directed and .circumferentially spaced-apart slots 38 formed in theperipheral portion of the cover 36 so as to accommodate placing of the cover 36-within the ring 32 and loclc'ngof the cover 36 in, place upon a top flange 39 carriedlabout the open top of the bucket 34. More particularly, a metallic gasket .40 of substantially annular form is supported upon the .annularfiange 39 and engagesrthe periphery of the cover-36, when-the same is in place within the ring 32. Finally, the cover 36 is provided with an upwardly extending handle 41 in order to-facili tate placement and removal thereof with respect to the ring 32.

The space in the left-hand portion of the body 11 and disposed below the cooking top 12 is accessible from the exterior through a front opening that is closed by an associated front door 42; the door 42 being pivoted for movement about the left-hand edge thereof upon the body 11 between open andeclosed positions with respect to the front of the bo'dy 11. In the arrangement, the

front doors

16 and 42 are disposed substantially flush with each other and with the front of the cooking top 12 when they both occupy their closed positions so as to lend a finished appearance to the front of the range 10. Also, there is housed in the space in the left-hand portion of the body 11 and below the cooking top 12, a microwave generator in the form of a magnetron 50 that may have an operating frequency of 2,450 megacycles; which magnetron v50 is operatively connected to valve mechanism51 provided with a casing or manifold 52 that terminates two waveguides 53., and 54, as shown in Figs. 4 and 5. The wave guide 53 is substantially rectangular in lateral cross-section and extends below the bottom of the deep well cooking unit 31, as shown in Figs. 2 and 3. Specifically, an opening 55 is formed in the bottom of the bucket 34 and communicates with the interior of the outerextremity of the wave guide 53; whereby the microwave energy from the wave guide 53 is introduced into the deep well co'oking cavity 35. The wave guide 54 is substantially rectangular in lateral crosssection and extends behind the rear wall of the oven liner 14 terminating in an opening provided therein, as shown in Figs. 2 and 3; whereby the microwave ener y from the wave guide 54 is introduced into the oven cooking cavity 15.

Continuing the reference to Figs. 4 and 5, it is noted that the valve mechanism 51 is mounted directly on the top of the magnetron 50 and that the casing or manifold 52 is of substantially drum-like form, including a substantially disk-like top and

bottom walls

56 and 57 and a substantially cylindrical side wall 58. Of course, the manifold 52 is formed of metal as are the

wave guides

53 and 54. The top of the magnetron 50 carries a dipole coupling antenna 59 that projects through a cooperating opening provided in the bottom wall 57 of the manifold 52 into the interior thereof so that the antenna 59 is arranged in radial alignment with the opposite ends of the

wave guides

53 and 54. Also, a shutter 60 of substantially drum-like form is arranged within the manifold 52 and comprises metallic top and

bottom walls

61 and 62 of substantially disk-like form, an opaque segmental substantially cylindrical side wall 63 and a par tially transparent segmental substantially cylindrical side wall 64. The shutter 60 is rotataby mounted within the manifold 50 upon a substantially centrally disposed shaft 65 secured to the top wall 61 and projecting to the exterior through a cooperating opening provided in the top wall 56; which shaft 65 carries a bevelled gear 66 on the extreme outer end thereof to accommodate rotation of the shutter 60 in a manner more fully explained hereinafter. In the construction of the shutter 69, the opaque side wall 63 may subtend an angle of 120, and the partially transparent side wall 64 may subtend an adjacent angle of 120; whereby an adjacent opening is provided in the side wall of the shutter 60 that subtends an angle of 120. As noted above, the segment 63 is completely opaque to the microwave energy, being formed of metal, while the segment 64 is partially transparent to the microwave energy, and of course, the opening provided in the side wall of the shutter 60 is completely transparent to the microwave energy. In the arrangement, the segment 64 comprises a pane of compressed iron powder or other lossy material and thus constitutes an artificial load upon the magnetron 50.

More particularly, the shutter 60 has an oven position, a both oven and deep well position, and a deep well position, the shutter 69 being in its both oven and deep well position, as illustrated in Figs. 4 and 5. When the shutter 60 occupies its both oven and deep well position, illustrated in Figs. 4- and 5, the partially transparent pane 64 is interposed between the antenna 59 and the adjacent end of the wave guide 53, while the antenna 59 is in open communication with the adjacent end of the wave guide 54; whereby attenuated or reduced microwave power is supplied from the antenna 59 into the wave guide 53 and full microwave power is supplied from the antenna 59 into the wave guide 54. When the shutter 60 occupies its oven position (rotated 60 in the clockwise direction with respect to its position of Figs. 4 and 5), the opaque segment 63 is interposed between the antenna 59 and the adjacent end of the wave guide 53, while the antenna 59 is in open communication with the adjacent end of the wave guide 54; whereby no microwave power is supplied from the antenna 59 into the Wave guide 53 and full microwave power is supplied from the antenna 59 into the wave guide 54. When the shutter 61) occupies its deep well position (rotated 60 in the counterclockwise direction with respect to its position of Figs. 4 and 5), the partially transparent segment 64 is interposed between the antenna 59 and the adjacent end of the wave guide 53, while the opaque segment 63 is interposed between the antenna 59 and the adjacent end of the wave guide 54; whereby attenuated microwave power is supplied from the antenna 59 into the wave guide 53 and no microwave power is supplied from the antenna 59 into the wave guide 54.

Accordingly, it will be understood that the supply of microwave power from the magnetron 50 to the oven cooking cavity 15 and to the deep well cooking cavity 35 may be selectively controlled by correspondingly controlling the position of the shutter 60 of the valve mechanism 51.

Referring now to Fig. l, the range 10 further comprises a series of manually

operable control dials

71, 72, 73, 74,

and 76 disposed in a horizontal array and carried by the front of the upstanding backsplash 13. The dials 71, 72 and 73 may be arranged on the left-hand side of the back-splash 13 and respectively comprise the operating elements of three rotary switches, not shown, that are respectively included in the circuits for controlling the heating of the electric

surface heating units

25, 26 and 27 that are carried in the

respective openings

21, 22 and 24 provided in the cooking top 12. The rotary switches mentioned are of conventional construction and arrangement and accommodate heating of the surface heating units 25, etc., at a series of different heating rates in a conventional manner, and have not been illustrated in the interest of brevity. The

dials

74, 75 and 76 may be arranged on the right-hand side of the backsplash 13 and respectively comprise the operating elements of the three rotary controllers 81, 82 and 83, as shown in Fig. 6.

Referring now to Fig. 6, the rotary controller 81 comprises an oven and deep well selector switch and includes a rotatably mounted operating shaft 84, the outer end of which is connected to the manual dial 74, as previously noted. The rotary controller 82 comprises a program timer and includes a rotatably mounted operating shaft 85, the outer end of which is connected to the manual dial 75, as previously noted. The rotary controller 83 comprises an oven selector switch and includes a rotatably mounted operating shaft 86, the outer end of which is connected to the manual dial 76, as previously noted.

The selector switch 81 further comprises an index marker 87 that cooperates with the manual dial 74; and the extreme inner end of the operating shaft 84 carries a bevel gear 88 that is operatively connected to the bevel gear 66 carried on the extreme outer end of the shaft 65 that is connected to the shutter 60 of the valve 51. Moreover, the mechanical connection between the bevel gears 88 and 66, being indicated by the broken line 89, may be of any suitable form. Accordingly, it will be understood that as the manual dial 74 is rotated between its three positions noted, the bevel gear 88 operates the bevel gear 66 through the mechanical connection 89 so as to operate the shutter 60 of the valve 51 into its corresponding three positions, as previously explained. Also the operating shaft 84 carries a stop 90 that cooperates with two stationary abutments 91 and 92 so as to prevent rotation of the manual dial 74 beyond the extremities of its outside positions. Further, two insulating control cams C1 and C2 are carried by the operating shaft 84; the control cam C1 governs two pairs of switch springs S1 and S2 and the control cam C2. governs two pairs of switch springs 53 and S4.

The program timer 82 further comprises an index marker 93 that cooperates with the manual dial 75, and a timer motor 94 provided with an operating shaft 95. The timer motor 5 4 is of the synchronous type and preferably comprises a Telechron motor; and the operating shaft 95 is connected to an escapement mechanism 96 that is provided with an operating shaft 97. The ad- 'various filamentary cathodes 100, etc.

jacent endsof the

shafts

85 and 86 are connected together by a slip clutch 98 that accommodates relative rotation of the

shafts

85 and 97 with respect to each other. Two insulating control cams C and C6 are carried by the operating shaft 85; which control cams C5 and C6 respectively govern two pairs of switch springs S5 and S6.

The oven selector switch 83 further comprises an index marker 99 that cooperates with the manual dial 76; and the operating shaft 86 carries three insulating control cams C7, C8 and C9 that respectively control three pairs of switch springs S7, S8 and S9.

In the circuit arrangement, the magnetron 50 comprises a filamentary cathode 100, a plate 101, and an enclosing metal envelope 102'; and the plate 101 is connected to the antenna 59 disposed in the valve 51 by a conductor 103. Further, the oscillator circuit in which the magnetron 50 is incorporated includes a pair of primary power supply conductors 105 and 106, and a pair of secondary

power supply conductors

107 and 108. The primary power supply conductors 105 and 106 are connected to the primary winding of a coupling transformer 109, the secondary winding of which is connected to the input terminals of a rectifier bridge 110; and the second ary

power supply conductors

107 and 108 are connected to the primary winding of a coupling transformer 111, the secondary winding of which is connected directly to certain auxiliary equipment, not shown, supplying the The output terminals of the rectifier bridge 110 are connected between the filamentary cathode 100 of the magnetron 50 and ground potential, indicated at 143, via a resistor 112, so that a voltage of about 5000 volts DC. is supplied to the filamentary cathode 100; and a regulator 113 of any suitable type is connected between the primary power supply conductors 105 and 106 for the purpose of making asubstantially constant voltage across the primary winding of the coupling transformer 109. Furthermore, a choke coil 104 is connected to the plate 101 of the magnetron 50 and arranged in the supply circuit therefor so as to prevent the feed-back of ultra-high frequency power into the auxiliary equipment, not shown.

An oven door switch 114 is operatively associated With the front door 16 and comprises a pair of switch springs that are respectively operated into open and closed positions when the front door 16 is respectively operated into its open and closed positions with respect to the oven cooking cavity 15. A deep well cover switch 115 is incorporated in the deep well cooking unit 31 and cooperates with the top cover 36; which switch 115 comprises a pair of switch springs that are respectively operated into open and closed positions'when the top cover 36 is respectively removed and placed with respect to the top of the bucket 34 of the deep well cooking unit 31. Further, the circuit comprises a preheat timer 116 that includes a bimetallic element 117, an associated switch spring 118 and an electric heating unit 119 operatively associated with the bimetallic element 117.

In the top of the oven cooking cavity 15, an upper inner electric heating unit 121 and an upper outer electric heating unit 122 are arranged; and in the bottom of the oven cooking cavity 15, a lower electric heating unit 123 is arranged. Also, in the bottom of the bucket 34 of the deep Well cooking'unit 31, there is arranged a platform 124 that is formed of glass, or other material transparent to microwave energy, as illustrated in Fig. 3. The platform 124 may support a glass container 125 that is. provided with a removable cover 126; which cooperating parts 125 and 126 are adapted to-receive frozen food. that is to be thawed in the deep well cooking unit 31, or otherwise cooked therein, as explained more fully hereinafter.

Returning to Fig. 6, the control circuit further comprises an oven lamp 131, a deep well lamp 132, a broil lamp 134 and a bake lamp 135; as well as a relay 136 that is provided with a pair of

contact bridging members

137 and 138. Further, the control circuit comprises a source of power supply of the 3-wire Edison type, 236 volts, single-phase, A.-C., including a pair of outside

ungrounded conductors

141 and 142 and a grounded neutral conductor 143; which

outside conductors

141 and 142 are respectively connected via two fuses 144 and 145 to two

conductors

146 and 147. The connector 147 is connected to one spring of the set S7 and to one spring of the set S9, while the conductor 146 is connected to one spring of the set S8. The other spring of the set S7 terminates a conductor 148 that is commonly connected to one terminal of each of the

heating units

121 and 122; the other spring of the set S8 terminates a conductor 149 that is commonly connected to the other terminal of the heating unit 121 and to one terminal of the heating unit 123; and the other spring of the set S9 terminates a conductor 150 that is commonly connected to the other terminal of the heating unit 122 and to the other terminal of the heating unit 123. The broil lamp 134 is connected between the conductor 149 and a midtap upon the heating unit 121; while the bake lamp 135 is connected between the conductor 149 and a midtap upon the heating unit 123.

One spring of the set S5 terminates the conductor 146 and the other spring thereof terminates the conductor 108; and one spring of the set S6 terminates the conductor 147 and the other spring thereof terminates the conductor 107. The contacts controlled by the contact bridging member 137 respectively terminate the

conductors

106 and 108; while the contacts controlled by the contact bridging member 138 respectively terminate the conductors and 107. In the preheat timer 116: the heating unit 119 is corrected between the conductor 107 and the grounded neutral conductor 143; the bimetallic element 117 is connected to the conductor 107; and the switch spring 118 is connected to a conductor 151.

One switch spring of the set S1 is connected to a conductor 152 and the other spring thereof is Connected to the conductor 106; one switch spring of the set S2 is connected to a conductor 153 and the other spring thereof is connected to the conductor 106; one switch spring of the set S3 is connected to a conductor 154 and the other spring thereof is connected to the neutral conductor 143; and one switch spring of the set S4 is connected to the conductor 154 and the other spring thereof is connected to a conductor 155. The two switch springs of the deep well cover switch are respectively connected to the conductors 155 and 154, and the two switch springs of the oven door switch 114 are respectively connected to the conductor 154 and to the neutral conductor 143. Further, the winding of the relay 136 is bridged between the conductors 151 and 155; the oven lamp 131 is connected between the conductor 152 and the neutral conductor 143; and the deep well lamp 132 is connected between the conductor 153 and the neutral conductor 143.

Considering now the general mode of operation of the range 10 and assuming that an electronic cooking operation is to take place in the oven cooking cavity 15 simultaneously with an electronic cooking operation in the deep well cooking unit 31, the cook places one portionof the food in the oven cavity 15 and closes the front door 16 so that the oven door switch 114 is operated into its closed position. Also, the cook places the other portion of food in the glass container closing the cover of the same and places the composite container and cover 125126 into the deep well cooking cavity 35 in supported position upon the platform 124. The removable cover 126 is then brought into place within the ring 32 and latched in position so as to close the deep well cover switch 115. The manual dial 74 of the oven and deep well selector switch 81 is operated into its both oven and deep well" position illustrated; whereby the shutter 60 of the valve 51 is operated into its position, as illustrated in Figs. 4 and 5, so as operatively to connect the magnetron 50 to both of the wave guides 53 and 54. Finally, the cook sets the manual dial 75 of the program timer 82 out of its or off position in accordance with the desired cooking time interval. When the manual dial 75 is thus set out of its 011 position, the control cams C and C6 close the switch springs S5 and S6; whereby the

conductors

146 and 147 are connected to the

conductor

108 and 107 in order to bring about operation of the auxiliary equipment associated with the microwave generator or oscillator that includes the magnetron 50. Also, the connection of power to the conductor 107 completes a circuit for energizing the electric heating unit 119; whereby the bimetallic element 117 of the preheat timer 116 is heated and deflected ultimately into engagement with the contact spring 118, after a suitable time delay, such, for example, as 90 seconds, thereby to connect power to the conductor 151. At this time, the neutral conductor 143 is connected via the closed oven door switch 11.4 to the conductor 154 and therefrom via the closed deep well cover switch 115 to the conductor 155; whereby the winding of the relay 136 is energized causing the latter relay to operate. Upon operating, the relay 136 closes the

contact bridging members

137 and 138; whereby the conductors 1618 and 107 are connected to the primary power supply conductors 1136 and 195 eflFecting energization of the coupling transformer 109 and the consequent operation of the oscillator, including the magnetron 50, so that the microwave power is supplied from the magnetron 59 to the antenna 59 disposed in the valve 51 and thus radiated into the two wave guides 53 and 54. The microwave energy is conducted by the wave guide 54 into the oven cooking cavity to elfect cooking of the food therein; and the microwave energy is conducted by the wave guide 53 into the deep well cooking cavity 35 to efiect cooking of the food therein.

Also, the connection of power to the primary power supply conductor 1% completes paralel circuits for illuminating the oven lamp 131 and for illuminating the deep well lamp 132, thereby to provide signals that microwave energy is being supplied respectively to the oven cooking cavity 15 and to the deep well cooking cavity 35. Also, the connection of power to the conducotr 1'86 completes a circuit for operating the timer motor 94, whereby the escapement mechanism 36 is operated so that periodically the operating shaft 97 is stepped effecting corresponding stepping of the operating shaft 85 through the slip clutch 98, with the result that the manual dial 75 is driven step by step in the counterclockwise direction back toward its home position as time proceeds.

At the expiration of the time interval preset upon the manual dial 75 of the program timer 82, the manual dial 75 is rotated back into its home or off positions; whereby the operating shaft 85 rotates the cams C5 and C6 to operate the switch springs S5 and S6 back into their open positions. Opening of power from the conductors 107 and 168 effects the deenergization of the coupling transformers 109 and 111 and brings about the restoration of the relay 136 so that operation of the magnetron 59 is arrested and the

lamps

131 and 132 are extinguished. Also, power is removed from the con ductor 106 so that operation of the timer motor 94 is arrested when the manual dial occupies its home or off position; whereby the cooking operation is thus completed.

In the foregoing explanation of the mode of operation of the control circuit to effect the supply of microwave energy to both the oven cooking cavity 15 and to the deep well cooking cavity 35, it is reiterated that the circuit for retaining operated the relay 136 includes the deep well cover switch 115 and the oven door switch 114 in series circuit relation; whereby the opening of the top cover 36 or the opening of the front door 16 will correspondingly operate the associated switch or 114 into its open position effecting deenergization of the winding of the relay 136 and the consequent restoration thereof. Upon restoring the relay 136 interrupts at the

contact bridging members

137 and 138 the power supply connections to the coupling transformer 109, thereby to arrest operation of the magnetron 50; whereby the arrangement described constitutes an interlock in the operating circuit for the magnetron 50 so as positively to insure closure of the top cover 36 and closure of the front door 16 when the oven and deep well selector switch 81 occupies its both oven and deep well position and during operation of the magnetron 50.

Reconsidering the operation of the circuit, when it is desirable to effect electronic cooking only in the oven cooking cavity 15, the cook sets the manual dial 74 of the oven and deep well selector switch 81 into its oven position; whereby the valve 51 is set in its corresponding position so as to block the passage of microwave energy into the wave guide 53 while leaving the wave guide 54 connected to the manifold 52 of the valve 51. Also this operation of the selector switch 81 causes the cam C1 to open the set of switch springs S2 in order to prevent illumination of the deep well lamp 132, and causes the cam C2 to close the set of switch springs S4 in order to provide a bypass circuit around the deep well cover switch 115, so as to render the operation of the circuit independent of the position of the top cover 36 with respect to the associated ring 32. The subsequent operation of the circuit incident to setting of the manual dial 75 of the timer 82 is substantially identical to that previously described, except, of course, in this case the microwave power is supplied only to the oven cooking cavity 15.

Reconsidering the operation of the circuit, when it is desirable to effect electronic cooking only in the deep well cooking cavity 35, the cook sets the manual dial 74 of the oven and deep well selector switch 81 into its deep well position; whereby the valve 51 is set in its corresponding position so as to block the passage of microwave energy into the wave guide 54 While leaving the wave guide 53 connected to the manifold 52 of the valve 51. Also this operation of the selector switch 81 causes the cam C1 to open the set of switch springs S1 in order to prevent illumination of the oven lamp 131, and causes the cam C2 to close the set of switch springs S3 in order to provide a bypass circuit around the oven door switch 114, so as to render the operation of the circuit independent of the position of the front door 16. The subsequent operation of the circuit incident to setting of the manual dial 75 of the program timer 82 is substantially identical to that previously described, except, of course, in this case, the micowave ggwer is supplied only to the deep well cooking cavity At this point, it is reiterated that when the oven and deep well selector switch 81 occupies either its both oven and deep well position or its deep well position, the shutter 60 incorporated in the valve 51 is operated to place the partially transparent pane 64 in interposed relation between the antenna 59 and the adjacent end of the wave guide 53 extending to the deep well cooking cavity 35 so that the pane 64 itself comprises an artificial load upon the magnetron 50 in order to attenuate the microwave power that is supplied to the deep well cooking cavity 35. This arrangement is necessary by virtue of the fact that the oven cooking cavity 15 is substantially larger than the deep well cooking cavity 35, so that the volume of the deep well cooking cavity 35 is otherwise substantially mismatched With respect to the power of the magnetron 50 without the artificial load mentioned. This arrangement protects the mag netron 50 against mismatch, particularly when the deep 9 well cooking cavity 35 is employed alone for an electronic cooking operation.

of course, ordinary broiling and baking operations utilizing electric heating may be carried out in the oven cooking cavity either independently of the electronic cooking operation carried out therein, or in conjunction therewith, as desired. Specifically, in order to carry out a broiling operation in the oven cooking cavity 15, the dial 76 of the oven selector switch 83 is operated from its off position into its broil position, whereby the control cams C7 and C8 close the sets of switch springs S7 and S8, with the result that the conductors 148 and 149 are connected to the

conductors

147 and 146.

Accordingly, the upper inner heating unit 121 is energized directly between the conductors 148 and 149, while the upperouter heating unit 122 and the lower heating 'unit 123 are energized in series relation across the con- 'broil lamp 134 is adequately energized to be illuminated as. a signal that the broiling operation is in progress. In order to carry out a baking operation in the oven cooking cavity 15, the dial 76 of the oven selector switch 83 is operated from its ofi position into its bake position; whereby the control cams C8 and C9 close the sets of switch springs S8 and S9, with the result that the conductors 149 and 150 are connected to the

conductors

146 and 147. Accordingly, the lower heating unit 123 is energized directly between the conductors 149 and 150, while the upper inner heating unit 121 and the upper outer heating unit 122 are energized in series relation'across the conductors 149 and 150. The circuit arrangement causes very substantial heat to be developed by the lower heating unit 123 for the baking purpose; and the bake lamp 135 is adequately energized to be illuminated as a signal that the baking operation is in progress.

In the interest of brevity, the usual oven timer for controlling the time duration of the baking operation that has been set up by the oven selector switch 83 has been omitted, but it will be understood that such conventional arrangement will ordinarily be provided; which conventional arrangement normally comprises a clock-switch provided with a start-clock time setting device and a stopclock setting device, so that the baking operation may be carried out during two corresponding preset clock times. Also in the interest of brevity, the construction and arrangement of the rotary switches for controlling the energization of the surface heating units 25, etc., have not been illustrated, and are ordinarily provided to accommodate the selection of any one of a number of heating rates by connecting in different circuit arrangements the two sections of each of the surface heating units 25, etc.

In view of the foregoing, it'is apparent that there has been provided in an electric range of the household type, electronic facility for carrying out either selectively or in combination, microwave cooking operations in the oven cooking cavity of the range and in the deep well cooking cavity of the range, together with an improved and simplified electric control circuit for presetting the desired electronic cooking operations.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the inveniton.

What is claimed is:

1. A combination electronic and electric range comprising an upstanding body provided with a substantially horizontal cooking top having a top opening therethrough, a metal bucket arranged in said body below said top opening and defining a deep well cooking cavity therein accessible from the exterior through said top opening, a metal top cover removably carried in said top opening and cooperating with the top of said bucket to close said deep well cooking cavity, a metal liner arranged in said body below said cooking top and defining an oven cooking cavity therein having a front opening thereinto, a metal front door carried by said body and cooperating with the front opening into said liner to close said oven cooking cavity, a first wave guide communicating with the interior of said deep well cooking cavity, a second wave guide communicating with the interior of' said oven cooking cavity, a microwave generator, manually operable microwave switching mechanism for selectively connecting said wave guides to said microwave generator, said microwave switching mechanism being operative into a first position to connect said first wave guide to said microwave generator and to disconnect said second wave guide from said microwave generator, said microwave switching mechanism being operative into a second position to connect said second wave guide to said microwave generator and to disconnect said first wave guide from said microwave generator, said microwave switching mechanism being operative into a third position to connect both of said wave guides to said microwave generator, a first manually operatble control switch for selectively operating said microwave generator, an electric heating unit arranged within said oven cooking cavity, a source of electric power supply, and a second manually operable control switch for selectively connecting said electric heating unit to said source of electric power supply.

2. Electronic cooking apparatus comprising first metallic walls defining a first substantially closed cooking cavity, second metallic walls defining a second substantially closed cooking cavity, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, manually operable microwave switching mechanism for selectively connecting said wave guides to said microwave generator, said microwave switching mechanism being operative into a first position to connect said first wave guide to said microwave generator and to disconnect said second wave guide from said microwave generator, said microwave switching mechanism being operative into a second position to connect said second wave guide to said microwave generator and to disconnect said first wave guide from said microwave generator, said microwave switching mechanism being operative into a third position to connect both of said wave guides to said microwave generator, and a manually operable control switch for selectively operating said microwave generator.

3. The electronic cooking apparatus set forth in claim 2, and further comprising means responsive to operation of said microwave switching mechanism into either its second position or its third position for atenuating the microwave power supplied via said second wave guide from said microwave generator into said second cooking cavity.

4. Electronic cooking apparatus comprising first metallic walls defining a first relatively large substantially closed cooking cavity, second metallic walls defining a second relatively small substantially closed cooking cavity, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, an artificial load, switching mechanism operative into a first position to connect said first wave guide to said microwave generator and to disconnect both said artificial load and said second wave guide from said microwave generator and operative into a second position to connect both said second wave guide and said artificial load to said microwave generator and to disconnect said first wave guide from said microwave generator, and manually operable means '11 for selectively operating said switching mechanism into its first and second positions.

5. Electronic cooking apparatus comprising first metallic walls defining a first relatively large substantially closed cooking cavity, second metallic walls defining a second relatively small substantially closed cooking cavity, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, and a valve for selectively connecting said first and second wave guides to said microwave generator, said valve including a completely transparent window for connecting said first wave guide to said microwave generator and a partially transparent window for connecting said second wave guide to said microwave generator, said partially transparent window including a pane formed of microwave attenuating material and effective correspondingly to attenuate the microwave power supplied by said microwave generator into said second cooking cavity via said second wave guide.

6. Electronic cooking apparatus comprising first metallic walls defining a first substantially closed cooking cavity, second metallic walls defining a second substantially closed cooking cavity, a first wave guide communicating with the interior; of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, a device operative into a first position to connect said first wave guide to said microwave generator and operative into a second position to connect said second wave guide to said microwave generator, first manually operable means for selectively operating said device into its first and second positions, and second manually operable means for presetting the time interval of operation of said microwave generator.

7. Electronic cooking apparatus comprising first metallic walls defining a first cooking cavity having a first access opening thereinto, a first metallic closure element movable into open and closed positions with respect to said first access opening, a first control switch operative into a control position when said first closure element occupies its closed position with respect to said first access opening, second metallic walls defining a second cooking cavity having a second access opening thereinto, a second metallic closure element movable into open and closed positions with respect to said second access opening, a second control switch operative into a control position when said second closure element occupies its closed position with respect to said second access opening, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, manually operable means for selectively connecting and disconnecting said wave guides with respect to said microwave generator, a first control circuit responsive jointly to the connection of said first wave guide to said microwave generator and to operation of said first control switch into its control position for operating said microwave generator, and a second control circuit responsive jointly to the connection of said second wave guide to said microwave generator and to operation of said second control switch into its control position for operating said microwave generator.

8. Electronic cookin apparatus comprising first metallic walls defining a first cooking cavity having a first access opening thereinto, a first metallic closure element movable into open and closed positions with respect to said first access opening, a first control switch operative into a control position when said first closure element occupies its closed position with respect to said first access opening, second metallic walls defining a second cooking cavity having a second access opening thereinto, a second metallic closure element movable into open and closed positions with respect to said second access opening, a second control switch operative into a control position when said second closure element occupies its closed position with respect to said second access opening, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a microwave generator, a manually operable device having three control positions, said device in a first of its control positions connecting said first wave guide to said microwave generator and disconnecting said second wave guide from said microwave generator, said device in a second of its control positions connecting said second wave guide to said microwave generator and disconnecting said first wave guide from said microwave generator, said device in a third of its control positions connecting both of said wave guides to said microwave generator, a third control switch having two control positions, means responsive to operation of said device into its respective first and second control positions for operating said third control switch into corresponding first and second of its control positions, a first control circuit for operating said microwave generator and completed jointly in response to operation of said first control switch into its control position and to operation of said third control switch into its first control position, a second control circuit for operating said microwave generator and completed jointly in response to operation of said second control switch into its control position and to operation of said third control switch into its second control position, and a third control circuit for operating said microwave generator and completed jointly in response to operation of said first control switch into its control position and to operation of said second control switch into its control position.

9. Electronic cooking apparatus comprising first metallic walls defining a first substantially closed cooking cavity, second metallic walls defining a second substantially closed cooking cavity, a first wave guide communicating with the interior of said first cooking cavity, a second wave guide communicating with the interior of said second cooking cavity, a metallic manifold having first and second openings therein respectively communicating with said first and second wave guides, a microwave generator, an antenna connected to said microwave generator and arranged within said manifold, metallic shutter mechanism arranged in said manifold in interposed relation with respect to said openings and said antenna and selectively operative to open and to close said openings to said antenna, and manually operable means for selectively operating said shutter mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 2,632,090 Revercomb et al Mar. 17, 1953 2,632,838 Schroeder Mar. 24, 1953 2.669,645 Schneider Feb. 16, 1954 2,782,292 Long Feb. 19, 1957 2,788,494 Vogeley et al. Apr. 9, 1957