GB767937A - Improvements in or relating to cut-outs for electrically heated utensils for heatingliquid - Google Patents

Abstract

767,937. Thermal switches. HOTPOINT ELECTRIC APPLIANCE CO., Ltd. Nov. 9, 1953 [Nov. 7, 1952], No. 28033/52. Class 38(5) A cut-out for an electrically-heated utensil, e.g. a kettle, comprises a bimetal strip 25 carried by a frame 18 which also supports for sliding movement an operating member 29 adapted when released to eject a plug from the kettle socket. The member 29 carries at its inner end a second bimetal strip 34 having a lug 35 adapted normally to underlie the end of strip 25, thereby maintaining engagement between a tongue 40 on the frame and a shoulder 39 on the member 29 which is urged to the right by a spring 32. The frame is slid into a cylindrical casing 12 and secured in place by an insulating contact-carrying base 16, thermal contact between a flange 26 of bimetal 25 and the sheath 11 of the heater 10 being assisted by a spring 45. When the heater 10 is covered by water and is energized, both bimetals deflect in the same direction and the member 29 is not released. If the heater becomes uncovered, however, bimetal 25 deflects more than bimetal 34 (which is heated primarily by the water) and releases the lug 35 so that the member 29 is forced upwards and to the right to disengage tongue 40 and shoulder 39 and to eject the plug. The bimetal 34 is laterally adjustable by a screw 41 having a guide extension 43 movable in a slot 42 in the frame. According to the Provisional Specification, the frame is in'two parts joined at each end by plates one of which has a metal stud securing the bimetal 25 and in thermal contact with the sheath 11.