Patent ID: 6871574

Claim:
A control valve assembly for a hydraulic system having a pump supply line, a tank return line and a double acting actuator, the control valve assembly comprising: a first workport and a second workport for connection to the double acting actuator; a two-position, three-way first control valve connected to the pump supply line and the tank return line and including a first common port, the first control valve having a first position in which the pump supply line is connected to the first common port and a second position in which the tank return line is connected to the first common port; a two-position, three-way second control valve connected to the pump supply line and the tank return line and including a second common port, the second control valve having a first position in which the pump supply line is connected to the second common port and a second position in which the tank return line is connected to the second common port; a first pilot operated check valve having a fluid path connected between the first common port and the first workport with a free flow direction from the first common port to the first workport, and having a first pilot inlet connected to the second common port; a second pilot operated check valve having a fluid path connected between the second common port and the second workport with a free flow direction from the second common port to the second workport, and having a second pilot inlet connected to the first common port; and a pilot valve plunger having a first state which opens the first pilot operated check valve when pressure in the second intermediate passage is greater than pressure in the first intermediate passage and having a second state which opens the second pilot operated check valve when pressure in the first intermediate passage is greater than pressure in the second intermediate passage, the pilot valve plunger also producing load sense signal that indicates which of a pressure at the first intermediate passage and a pressure at the second intermediate passage is greater.