Patent ID: 6976418

Claim:
A fluid circuit operative to selectively provide regenerative fluid flow between respective ends of a fluid actuator, the fluid circuit has a reservoir, a source of pressurized fluid connected to the reservoir, and said actuator having first and second inlet/outlet ports selectively connected to the source of pressurized fluid and the reservoir, the fluid circuit comprising: a first poppet valve arrangement disposed between the source of pressurized fluid and the first inlet/outlet port of the actuator and operative to proportionally control the flow of fluid from the source of pressurized fluid to the first inlet/outlet port of the actuator; a second poppet valve arrangement disposed between the first inlet/outlet port of the actuator and the reservoir and operative to proportionally control the flow of fluid from the first inlet/outlet port of the actuator to the reservoir; a third poppet valve arrangement disposed between the reservoir and the second inlet/outlet port of the actuator and operative to proportionally control the flow of fluid from the second inlet/outlet port of the actuator to the reservoir; a control valve arrangement connected to the source of pressurized fluid and disposed between the source of pressurized fluid and the second inlet/outlet port of the actuator and operative to proportionally control the flow of fluid from the source of pressurized fluid to the second inlet/outlet port of the actuator, the control valve arrangement being configured to control the regenerative flow of fluid from the second inlet/outlet port of the actuator to the first inlet/outlet port of the actuator; a controller that is operative in response to an input command to control the fluid flow into and out of the respective ends of the actuator, wherein the control valve arrangement includes a first proportionally controlled poppet valve disposed between the source of pressurized fluid and the second inlet/outlet port of the actuator and a second proportionally controlled poppet valve disposed between the first inlet/outlet port and the second inlet/outlet port of the actuator free of a check valve.