LOAD CHECK AND PRESSURE COMPENSATING VALVE

2088269 9204544 PCTABS00011 Pressure compensating valves located downstream of the directional control valves are useful in providing load independent, proportional flow control hydraulic systems and normally serve as load checks. The subject load check and pressure compensating valve (32, 33) is designed for use in a hydraulic system in which the pressure of a common pressure signal directed to all the pressure compensating valves of the system is limited to a predetermined maximum level. The pressure compensating valve includes a valve element (56, 57) disposed downstream of a metering orifice (54, 55), a separate load piston (74, 75) disposed in end-to-end relationship with the valve element in a common bore (46, 47) and a pressure compensating spring (84, 85) disposed in a chamber (82, 83) behind the load piston and biasing the load piston and valve element to the load check position. The common pressure signal is communicated to the chamber containing the spring while the actual load pressure of an associated hydraulic motor is directed to a chamber (78, 79) between the valve element and load piston so that the valve element is held in the load check position by the actual load pressure when the actual load pressure is greater than the pump discharge pressure.