GB698851A - Improvements in or relating to thermally responsive electric switches - Google Patents

Abstract

698,851. Thermal switches. GENERAL MOTORS CORPORATION. Jan. 2, 1952 [Jan. 10, 1951], No. 118/52. Class 38 (v) A switch comprises a tubular housing 2 secured in an adaptor 6 arranged to be screwed into the cooling water system of a motor vehicle engine so as to give an indication of the temperature thereof, the housing containing a contact operable by a bimetal strip 4, and an adjustable co-operating contact. In one form, Fig. 1, the bimetal strip 4 is secured to the lower end of the housing and carries an insulating pad 27 which on temperature increase pushes against the contact spring 48 to close contacts 48, 54. The latter is carried on a spring 46, springs 46 and 48 being secured to terminals 38, 40 in an insulating block 8. The contact 54 is adjusted by limiting its movement under its own resilience by the head 63 of a screw 60 threaded into the block 8. Calcium chloride is arranged in a container 28 so as to reduce the humidity. In a modification, Fig. 3, bimetal strip 4 carries the movable contact 94 which cooperates with a spring contact 90. The bimetal is earthed through the housing, and the insulating block 76 carries a single terminal 80 connected to spring 90 and having the adjusting screw 88 threaded therein. The screw is frictionally locked in position in each arrangement by a spring wire 72. Spring 90 forms a downward lug on an annular member clamped in place by the block 76.