GB494335A - Improvements in thermostatically controlled electric ovens or stoves - Google Patents

Abstract

494,335. Thermal switches. ESTATE STOVE CO. Feb. 18, 1937, No. 4906. Convention date, April 13, 1936. [Class 38 (v)] [Also in Group XXXV] A thermal switch comprises an element 37 carrying pairs of connected contacts adapted to bridge respective pairs of terminals 35 in the leads supplying oven heaters. The element 37 is carried by a lever 38 pivoted at 39, and engaging a nut 28 on the end of a screw 29 secured to the bellows 22 of a temperature responsive device which comprises an element 20 in the oven. A control member 15, with suitable indicating means, may be rotated into various positions, including an off position, and is arranged to turn the nut 28 on the screw 29 to close the circuit and to determine the temperature at which the element 37 will open it. In the off position, a cam-shaped portion 56 of the control member 15 operates a spring-controlled plunger 50 whereby an arm 58 is caused to open the switch and hold the element 37 locked against circuit closing operation by the temperature responsive element. In a modification, movement of the control member 15 back beyond the off position causes a cam depression to permit a spring-controlled sliding bar, carrying a contact bridge, to close the circuit of an independent heating element.