Abstract: A switching device responsive to pressure at one or two inputs with pressure responsive members each of which moves an actuating member in response to pressure variations. First and second electrical switches are positioned to be operated by the respective actuating members and a third switch is mounted for movement with one of the members and actuated by the other member. In one embodiment, a first compression spring acts between a housing and an actuating member which is moved in response to pressure variations. A second spring extends in parallel with the first spring and acts between the housing and a pivotably mounted lever which is lifted by the first actuating member above a desired pressure level.

Abstract: A switching device responsive to pressure at two inputs with pressure responsive members each of which moves an actuating member in response to pressure variations. First and second electrical switches are positioned to be operated by the respective actuating members and a third switch is mounted for movement with one of the members and actuated by the other member. Springs apply appropriate forces to the member and are adjustable as to applied force.