Cam actuated lubrication pump

Claim 1

A pump adapted for use in a lubrication system comprising a housing, a cup-shaped member reciprocally mounted on a first end of said housing, a rod fixedly secured to said member and disposed internally thereof, a piston reciprocally mounted on said rod to define a pair of isolated and expansible first and second chambers on either side thereof, first compression spring means disposed in said first chamber between said piston and said member and second compression spring means disposed in said second chamber between said piston and said housing, inlet means, including normally closed first valve means, for communicating fluid into said second chamber upon expansion thereof in response to reciprocal movement of said piston in a first direction and outlet means, including normally closed second valve means, for communicating pressurized fluid from said second chamber and exteriorly of said pump upon contraction of said second chamber in response to reciprocal movement of said piston in a second direction opposite to said first direction, said pump being operable to automatically limit fluid flow through said second valve means when the combined pressure of the fluid and the spring in said second chamber equals the compression force of the spring in said first chamber.