Patent ID: 6012903
Filing Date: 2000-01-11
Classification: F04B,F16N

Abstract:
A positive-displacement liquid-metering pump having a continuously variable output, comprising in combination:a valve body having a metering chamber and a reciprocable piston movable through said chamber to positively displace a volume of liquid therefrom, said displaced volume comprising the output of said pump;a piston-actuator disposed in alignment with said piston to move it through said chamber in response to an applied force, said piston-actuator extending outwardly of said valve body, and a stop structure associated with said piston-actuator to limit its allowable movement;an indexing member disposed in alignment with said stop structure and having a portion engageable therewith to limit the allowable movement of said piston-actuator and thereby define the length of stroke of said piston through said chamber; anda continuously variable coupling operatively disposed between said indexing member and said valve body for changing the effective position of said stop structure relative to said valve body and thereby changing the allowable movement of said piston-actuator and the stroke length of said piston.