Fluid pressure responsive electric switch

Abstract

A fluid pressure responsive electric switch (100) is shown in which first and second discrete electrical switches are controlled. A first movable support ring (122) mounts first and second snap acting discs (120a, 124a) on opposite sides thereof, the discs each having the normally concave surface facing the support ring. The first disc receives a force through a pressure to force converter (134) which is transferred through the second disc to a second movable support (126) and a third snap acting disc (128a) having a normally concave surface facing a related movable contact arm. When the system pressures exceeds a first minimum level the third disc (128a) snaps allowing a motion transfer pin to transfer a force to the movable contact arm (118a) of a compressor actuation switch (118) to energize the compressor. When system pressure increases to a second higher level the first disc (120c) snaps and transfers motion via a motion transfer pin (120c) to the movable arm (116a) of a fan actuation switch to energize the fan. If the system pressure increases to a third still higher level, the second disc (124a) snaps thereby allowing the spring bias of the movable arm (118a) of the compressor actuation switch to separate from the mating stationary contact to thereby de-energize the compressor. According to a second embodiment the switch (200) includes only the fan actuation and compressor high pressure cut-out functions by eliminating the third disc and by making the second support (130c') stationary.