Abstract: A reciprocating piston device, such as a pressure pump, a vacuum pump or a compressor comprising a cylinder and a piston reciprocable in the cylinder. The piston includes a piston body having a cavity therein and a pivot arm mounted on the piston body for pivotal movement in the cavity. The pivot arm has a passage therein which is within the piston body and which receives a rotatable drive member, such as an eccentric. As the eccentric is rotated, the piston is reciprocated within the cylinder with the pivotal movement of the pivot arm accommodating one component of movement of the eccentric.

Abstract: A pressure switch comprising a housing, a first contact mounted in the housing and a support mounted in the housing in spaced relationship to the first contact. A pressure responsive member is mounted in the housing for moving a second contact into and out of engagement with the first contact and with the support. A first spring urges the pressure responsive member in opposition to the fluid pressure acting on the pressure responsive member. The pressure responsive member includes a bistable spring which carries the second contact. The bistable spring augments the first spring as the pressure responsive member moves from a low pressure position toward a high pressure position and opposes the first spring as the pressure responsive member moves from the high pressure position toward the low pressure position.

Abstract: A pressure regulator comprising a regulated pressure chamber and first and second conduits leading to the regulated pressure chamber. The first and second conduits are adapted to communicate with fluid at first and second pressures, respectively. Each of these conduits terminate in ports in the regulated pressure chamber. The ports are opened and closed by a resilient, metal valve strip. An actuator driven by a torque motor controls the valve strip.