Patent ID: 7641290

Claim:
A hydraulic control circuit for a hydraulic actuator, said circuit including a bi-directional pump to transfer fluid between a reservoir and a valve controlling movement of said actuator, said pump having a pair of ports and operable in a first mode where ingress of fluid from said reservoir to said pump is provided at one of said ports and egress of fluid from said pump to said valve is provided at the other port and operable in a second mode where ingress of fluid is provided at said other port and egress is provided at said one port, said valve having a first position when said pump is in said first mode in which said other port is in fluid communication with one side of said actuator and an other side of said actuator is in fluid communication with said reservoir to induce movement of said actuator in a first direction, and having a second position when said pump is in said second mode in which said one port is in fluid communication with the other side of said actuator and said one side is in fluid communication with said reservoir to induce movement in a second direction, wherein fluid expelled from said actuator by movement of said actuator returns to said reservoir prior to delivery to a respective one of said ports of said pump.