Hydraulic cylinder assembly

Claim 1

A HOLDING VALVE ASSEMBLY ADAPTED FOR USE WITH A RECIPROCATING HYDRAULIC PISTON AND CYLINDER DEVICE HAVING AN INLET PORT AND A DISCHARGE PORT, COMPRISING: A VALVE HOUSING MEMBER, A DISCHARGE PASSAGE IN SAID HOUSING ADAPTED TO BE CONNECTED TO THE CYLINDER DEVICE DISCHARGE PORT TO RECEIVE DISCHARGE FLUID FROM THE DEVICE, A VALVE SEAT IN SAID PASSAGE, A VALVE MEMBER IN SAID PASSAGE POSITIONED TO CLOSE IN OPPOSITION TO THE PRESSURE OF THE DISCHARGE FLUID SO THAT DISCHARGE FLUID TENDS TO OPEN SAID VALVE MEMBER, A LOW PRESSURE RETURN PASSAGE IN SAID VALVE HOUSING SELECTIVELY CONNECTABLE WITH SAID DISCHARGE PASSAGE THROUGH SAID VALVE MEMBER, RESILIENT MEANS FOR BIASING SAID VALVE MEMBER TO A CLOSED POSITION, SAID RESILIENT MEANS BEING OF SUFFICIENT STRENGTH TO MAINTAIN SAID VALVE MEMBER CLOSED AGAINST THE PRESSURE OF THE DISCHARGE FLUID IN SAID DISCHARGE PASSAGE, SAID VALVE SEAT LIMITING MOVEMENT OF SAID VALVE MEMBER BEYOND SAID CLOSED POSITION, CONTROL MEANS FOR SELECTIVELY OPENING SAID VALVE MEMBER AND PERMITTING DISCHARGE FLOW FROM SAID DISCHARGE PASSAGE TO SAID RETURN PASSAGE INCLUDING FLUID ACTUATED MEANS SEPARATE FROM SAID DISCHARGE PASSAGE CONNECTED TO OPEN SAID VALVE MEMBER WHEREBY DISCHARGE FLUID LEAKAGE IS MINIMIZED AND BYPASS PASSAGE MEANS IN PARALLEL WITH SAID VALVE MEMBER COMMUNICATING WITH SAID LOW PRESSURE RETURN PASSAGE AND SAID DISCHARGE PASSAGE FOR SUPPLY FLUID UNDER PRESSURE TO THE DISCHARGE PORT OF THE DEVICE.