Patent ID: 6267571
Filing Date: 2001-07-31
Classification: F04B,Y10S

Abstract:
A pump having a long stroke and a short stroke mode, the pump comprising:two material cylinders for moving material, each material cylinder including a hydraulic cylinder and a piston rod, wherein the piston rods are synchronized so that as one piston is extended, the other piston rod is retracted;a valve mechanism which connects one material cylinder to an outlet and the other material cylinder to a material hopper, wherein the valve mechanism changes position so that as material exits one material cylinder at the outlet, material can enter the other material cylinder at the material hopper;a pump supplying the hydraulic cylinders with hydraulic fluid;a diverter valve located between the pump and the hydraulic cylinders for diverting an amount of hydraulic fluid supplied to the hydraulic cylinders;a reciprocating cylinder valve between the pump and the hydraulic cylinders which alternately drives one piston rod by supplying hydraulic fluid to its corresponding hydraulic cylinder and allowing fluid to exit from the other hydraulic cylinder;a short stroke valve located on one hydraulic cylinder that signals the material output valve and the reciprocating cylinder valve to change position when the piston rod reaches the short stroke valve; anda switch having a first position for selecting a long stroke mode and a second position for selecting a short stroke mode, wherein the second position activates the diverter valve and the short stroke valve.