GB519976A - Thermostatically controlled electric switch - Google Patents

Abstract

519,976. Thermostat - controlled switches. METALS & CONTROLS CORPORATION. Aug. 9, 1938, Nos. 23500, and 23501. Convention dates, Aug. 9, 1937, and Feb. 7, 1938. [Class 38 (v)] In a thermostatically-'controlled electric switch with a thermostatic element which snaps over at a given temperature, the element partly closes a chamber whereby when the temperature in the chamber rises, the pressure therein increases, and destroys any electric arc or spark produced between contacts controlled by the thermostatic element. A base 1, Figs. 2 and 4, receives an adjusting screw 6 locked by a nut 23 and rotatably supporting a thermostatic plate 9 which may be a bimetallic, snap-acting element as in Specification 178,103, [Class 38 (v)], the plate 9 has welded contacts 12, 13 and is held against rotation by a groove engaging a projection in a skirt 26 depending from the base and closely surrounding the plate. Contacts 15, 14 are mounted in the base and are welded respectively to a terminal post 17 swaged into the base and to a heating wire 16 held by a loop 18 and passing to a terminal post 20. In use, at a given temperature the plate 9 snaps over to break the circuit, and air pressure above the plate 9, due to heating, extinguishes any sparks. The switch may be arranged on a motor so that when the latter is overloaded the heat therefrom causes the plate 9 to snap over ; the heating wire may be omitted. The plate may be circular, oval, rectangular, diamondshaped &c. In Figs. 12 and 16, terminals 32, 33, 34 comprise stampings with one end bent over to form a contact and with bent side wings 37 ending in lugs 38 ; the terminals are passed through holes in the base 1 and locked by bending the lugs 38, the outer ends of the terminals being then rolled. An extension 39 of the screw 6 carries a flanged sleeve 40 on which a sleeve 44, carrying a push plate 43, is slidable ; the sleeve 44 is a squeeze fit in a knob 47 pressed by a spring 45. The plate 43 is held against rotation by a projection and groove, and carries bosses which, on depressing the knob 47, engage the plate 9 to re-set the switch.