External pressure vessel linked to hydro:pneumatic cylinder - provides hydraulic overload protection for cylinder by allowing oil to escape into external pressure cylinder

摘要

A hydro-pneumatic cylinder assembly, used to absorb axial loads on a piston rod, has a pneumatic and a hydraulic chamber. a piston, which includes two spring loaded valves for opposite oil flow, separates the two cylinder chambers. An external pneumatic pressure vessel is connected to the cylinder chamber. When the load on the piston rod is excessive, the hydraulic pressure which is acting on the piston, forces the valle open. Thus hydraulic oil is able to escape into the external pressure vessel and so producing a hydraulic overload protection for the cylinder assembly. When the load is removed, the gas pressure in the vessel returns the oil to the cylinder chamber.