GB493117A - Improvements relating to electric switches particularly for the control of an electric refrigerator - Google Patents

Abstract

493,117. Thermal switches. BRITISH THOMSON-HOUSTON CO., Ltd. April 2, 1937, No. 9435. Convention date, April 3, 1936. [Class 38 (v)] A snap-action switch for a refrigerator with contacts 25, 26 is operated both on and off by means of a bellows 29 responsive to the temperature of the refrigerator or by means of a bimetallic strip 38 controlled by a heating coil 40 subject to overload or by rectilinear movement of a shaft 46 with a hand knob 48. The bellows 29 acts on a lever 28 pivoted at 28a and having an arm connected to a spring 30 the upper end of which is adjustable by rotation of a knob 37, a cam carried by the knob moving in a frame 32 attached to the spring. The other end 27 of the lever 28 moves in a slot in an arm 64 of a member 53 which is also pivoted at 28a and operates the movable contact 26 through snap-action mechanism. A spring 62 is arranged between the members 27 and 53. The member 53 tends by spring action to move to the right but it may be moved to the left to open the switch by anyone of the three members 27, 38, and 46 controlled respectively by the temperature of the refrigerator, by the current flowing, and by hand. A garter spring 52 co-operates with inclined surfaces 50, 51 on the shaft 46 to cause the switch to remain " off " when hand operated, after the hand has been removed. Specification 363,121 is referred to.