Pump piston with flexible member

Claim 1

A high pressure pump for handling corrosive liquids comprising: a cylinder formed of ceramic material; a piston, also formed of ceramic material and subject to breakage by the application of bending forces, located within the cylinder and adapted to be reciprocated therein for moving said liquids; an actuator spaced from the piston and adapted to reciprocate along an axis generally coaxial with the cylinder axis for moving the piston; means connecting the actuator and piston; said connecting means including an elongate laterally flexible member disposed between the actuator and piston and terminating at one end in a head, means securing said head to the piston and which head includes radially directed shoulder means facing the actuator, and means mounting said flexible member to said actuator; said connecting means also including a hollow cylindrical portion extending from the actuator and coextensively surrounding the elongate flexible member and terminating at one end in a radially directed surface adjacent the facing shoulder for abutment thereagainst; whereby substantially only tension forces are exerted in an axial direction on the piston by the elongate flexible member when the actuator moves in one direction and substantially only compressive forces are exerted in an axial direction on the piston by the cylindrical portion abutting against the shoulder means when the actuator moves in the other direction even when the axes of the cylinder and actuator movement are slightly misaligned from said general coaxial relationship.