Patent ID: 8381516
Filing Date: 2013-02-26
Classification: F15B

Abstract:
1. An actuator, comprising: an actuator chamber including a moveable actuator piston and an actuator rod connected to the actuator piston and retractably extendable from the actuator chamber; the actuator chamber and actuator piston defining an extend chamber and a retract chamber separated from the extend chamber by the actuator piston such that the actuator rod extends through the retract chamber; and a fluid supply means arranged to supply pressurized fluid to both the extend and the retract chambers, to maintain, at all time the fluid supply means is operative, a pressure of the pressurized fluid in the extend chamber to be substantially the same as a pressure of the pressurized fluid in the retract chamber, and to reversibly transfer said pressurized fluid between the extend and the retract chambers of the actuator, the pressure of the pressurized fluid based on a difference in area between an area of the actuator piston facing into the retract chamber and an area of the actuator piston facing into the extend chamber and a load applied to the actuator in use.