Oven and control circuit therefor

Claim 2

A bake-broil oven comprising an oven enclosure, a bake heating element, a broil heating element, and a control circuit connected to control the operation of said heating elements, said control circuit including cycle means operable to cause cyclic operation of said broil heating element with an on-off timed cycle, said control circuit including a thermostat switch operable below predetermined selected temperatures to demand heat and a selector switch operable between two positions to provide two separate modes of operation, said control circuit when said selector switch is in a first position providing a first bake mode of operation causing said bake heating element to operate continuously on demand of said thermostat switch while said broil heating element operates on demand of said thermostat switch with said on-off timed cycle, said control circuit when said selector switch is in a second position operating to supply heat to said enclosure to maintain a low keep-warm temperature substantially below said predetermined selected temperature by operating said broil heating element with said on-off timed cycle.

Claim 3

A bake-broil oven as set forth in claim 1 wherein said control circuit in a second bake mode of operation operates said bake heating element continuously on demand without operating said broil heating element.

Claim 4

A bake-broil oven as set forth in claim 2 wherein said control circuit in a broil mode of operation operates said broil heating element without operating said bake heating element, and the same voltage is applied to said broil heating element in both said keep-warm mode of operation and said broil mode of operation.

Claim 5

A bake-broil oven as set forth in claim 3 wherein said control circuit includes a timer which functions to automatically shift from one of said bake modes of operation to said keep-warm mode of operation at the completion of a timed period.

Claim 6

A bake-broil oven as set forth in claim 4 wherein said one bake mode of operation is said second bake mode of operation.

Claim 7

A bake-broil oven as set forth in claim 5 wherein a single switch is operable to change said control circuit from said first bake mode of operation to said second bake mode of operation.

Claim 8

A bake-broil oven as set forth in claim 1 wherein said control circuit in said keep-warm mode of operation operates said broil heating unit continuously with said timed on-off cycle, and the keep-warm temperature of said enclosure is determined without thermostat means solely by a balance of the rate of heat supplied thereto and heat dissipated therefrom.

Claim 9

A bake-broil oven comprising an oven enclosure, a bake heating element, a broil heating element, and a control circuit connected to control the operation of said heating elements, said control circuit including cycle means providing a first switch adjustable between a continually closed condition and an on-off condition with a minimum on period, said cycle means also including a second switch which is closed when said first switch is in the condition of said minimum on period, said cycle means being manually adjustable when said control circuit is in a broil mode of operation operating said broil heating element from a condition in which said broil heating element operates continuously to a condition in which said broil heating element operates with a timed on-off cycle with said minimum on period, said control circuit supplying heat to said enclosure for a keep-warm mode of operation by cyclic operation of said broil heating element with said minimum on period, said control circuit supplying the same voltage to said broil heating element in both said broil mode of operation and said keep-warm mode of operation.

Claim 10

A bake-broil oven comprising an oven enclosure, a bake heating element, a broil heating element, and a control circuit connected to control the operation of said heating elements, said control circuit including cycle means providing a first switch adjustable between a continually closed condition and an on-off condition with a minimum on period, said cycle means also including a second switch which is closed when said first switch is in the condition of said minimum on period, said cycle means being manually adjustable when said control circuit is in a broil mode of operation operating said broil heating element from a condition in which said broil heating element operates continuously to a condition in which said broil heating element operates with a timed on-off cycle with said minimum on period, said control circuit supplying heat to said enclosure for a keep-warm mode of operation by cyclic operation of said broil heating element with said minimum on period, said control circuit supplying the same voltage to said broil heating element in both said broil mode of operation and said keep-warm mode of operation.

Claim 11

A bake-broil oven as set forth in claim 8 wherein said control circuit in said keep-warm mode of operation operates without thermostatic control and the keep-warm temperature is determined solely by the balance of the rate of heat supplied to Said enclosure and the rate of heat dissipated therefrom.

Claim 12

A bake-broil oven as set forth in claim 8 wherein said control circuit in a bake mode of operation operates said bake heating element continuously on demand without operating said broil heating element, and said control circuit includes timing means for automatically shifting the mode of operation from said bake mode of operation to said keep-warm mode of operation.

Claim 13

A bake-broil oven as set forth in claim 8 wherein said predetermined on-off timed cycle has a duration sufficiently short to maintain a substantially constant keep-warm temperature in said enclosure.

Claim 14

A bake-broil oven as set forth in claim 11 wherein said predetermined on-off timed cycle has a duration no longer than about one and one-half minutes and the on period of said on-off cycle is no greater than about 8 percent of the cycle.

Claim 15

A bake-broil oven comprising an oven enclosure, a bake heating element, a broil heating element, and a control circuit connected to control the operation of said heating elements, said control circuit including a thermostatic switch operable below predetermined selected temperatures to demand heat, a selector switch operable between first and second positions, and cycle means providing a cyclically operated switch which is adjustable between a position in which said cyclically operated switch is closed continuously and a position in which said cyclically operated switch operates with an on-off cycle having a minimum on period, said cycle means also including a second switch in series with said bake heating element which is closed only when said cycle means is adjusted to said position with a minimum on period, said control circuit providing a first bake mode of operation in which said selector switch is in said first position and said cycle means is in said minimum on period position in which said bake heating element operates continuously on demand of said thermostat switch while said broil heating element operates on demand of said thermostatic switch with said minimum on period, said control circuit when said selector switch is in a second position while said cycle means are in said position of minimum on period providing a bake mode of operation in which said bake heating element is controlled by said thermostatic switch and is on continuously when said thermostatic switch is closed and a keep-warm mode in which said bake heating element is off and said broil heating element operates on and off with said minimum on period, said oven being provided with a keep-warm temperature determined solely by the on-off period of said broil heating element.

Claim 16

A bake-broil oven comprising an oven enclosure, a bake heating element, a broil heating element, and a control circuit connected to control the operation of said heating elements, said control circuit including a thermostatic switch operable below predetermined selected temperatures to demand heat, a selector switch operable between first and second positions, and cycle means providing a cyclically operated switch which is adjustable between a position in which said cyclically operated switch is closed continuously and a position in which said cyclically operated switch operates with an on-off cycle having a minimum on period, said cycle means also including a second switch in series with said bake heating element which is closed only when said cycle means is adjusted to said position with a minimum on period, said control circuit providing a first bake mode of operation in which said selector switch is in said first position and said cycle means is in said minimum on period position in which said bake heating element operates continuously on demand of said thermostat switch while said broil heating element operates on demand of said thermostatic switch with said minimum on period, said control circuit when said selector switch is in a second position while said cycle means are in said position of minimum on period providing a bake mode of operation in which said bake heating element is controlled by said thermostatic switch and is on continuously when said thermostatic switch is closed and a keep-warm mode in which said bake heating element is off and said broil heating element operates on and off with said minimum on period, said oven being provided with a keep-warm temperature determined solely by the on-off period of said broil heating element.