Solenoid-operated reciprocating pump

摘要

A solenoid-operated reciprocating pump includes a casing having a cylinder with a central axis. A main shaft is disposed in and secured at one end to the casing in alignment with the central axis of the cylinder. A piston having a piston head is slidably fitted over the main shaft such that the piston head is disposed within the cylinder for axial motion. A coil spring extends between the piston and casing to bias the piston in a first axial direction and an armature radially extends from the outer periphery of the piston for interaction with an electromagnet disposed around the longitudinal periphery of the piston. The electromagnet attracts the armature and hence the piston in a second axial direction opposite from the first direction. On end of the coil spring is fixed to one of the piston or the casing and the other end of the spring is rotatably supported on the other of the piston or the casing by a spring retainer seated on a plurality of spherical balls which are in turn seated on said other of the piston or the casing means. The balls are positioned at equal distances radially from the central axis of the coil spring and at equal circumferential spacings around the axis.