GB1302209A - - Google Patents

Abstract

1302209 Thermal switches DANFOSS AS 5 Feb 1970 [14 Feb 1969] 5523/70 Heading H1N In an electric switch having first and second fixed contacts as 56, 57 Fig. 5 mounted on opposite sides of a spring strip 37 to face in opposite directions or in the same direction (shown) with one mounted on a "U" shape extension 55 and both engageable by movable contacts 40, 58 on spring strips 36, 38 when released by a snap-acting abutment member 60 having surfaces engageable with projections as 46, 59 on the strips 36, 38. The arrangement is such that only the low mass of the strips 36, 38 and contacts 40, 58 is subjected to rebound since the larger total mass of the snap-acting part 60 and plate (12) Fig. 1 (not shown) is free to continue its movement. The snap-acting assembly is more fully described in the Specification 1,295,034. The spring strips 36, 37, 38 are located between four support walls 32, 33, 34, 35 having knife-edge projections as 42, 43, 54 to support each block at three points. In the example of Fig. 1 (not shown) at least one on the knife-edge supports may comprise an adjustable set-screw (45) whereby the response of the blades may be adjustable. The ends of each blade are bent over to form flanges 52 for welding to terminals 48, 49, 50. In the example described the initial actuator for the snapacting drive may be a thermal bimetal (not shown) or a pressure bellows (23) Fig. 1 (not shown) with its response varied by an adjustable compression spring (25).