Systems, methods and devices are described providing a selective hydraulic or electrically powered prime mover that is a bi-directional power unit system, including movement within a device used to compress and/or expand a fluid and provide fluid movement. The use of a hydraulic power unit is involved and comprises at least a pump or other fluid moving device, a first set of selective control valves delivering pressurized fluid to the device(s), and a second set of selective control valves returning unpressurized fluid from the device(s), a reservoir comprising a compensator tank, a port for operation at ambient pressure, and a pressure measuring device measuring ambient pressure allowing for unbalanced flow to and from the device as well as thermal expansion or compression. The use of a multiport and in some cases a swashplate pump that incorporates the features and functions of several valves for the system is also described.

Systems, methods and devices are described providing a selective hydraulic or electrically powered prime mover that is a bi-directional power unit system, including movement within a device used to compress and/or expand a fluid and provide fluid movement. The use of a hydraulic power unit is involved and comprises at least a pump or other fluid moving device, a first set of selective control valves delivering pressurized fluid to the device(s), and a second set of selective control valves returning unpressurized fluid from the device(s), a reservoir comprising a compensator tank, a port for operation at ambient pressure, and a pressure measuring device measuring ambient pressure allowing for unbalanced flow to and from the device as well as thermal expansion or compression. The use of a multiport and in some cases a swashplate pump that incorporates the features and functions of several valves for the system is also described.

This invention discloses in particular an actuation cylinder (10) for controlling the movement of a ring-gate (40) of a hydraulic machine, said actuation cylinder (10) comprising a body (18) forming a first chamber (22) provided with a first duct (26) and a second chamber (24) provided with a second duct (28) which are designed to receive an actuating fluid through said first duct (26) and said second duct (28), said chambers being separated from one another by a piston (20) connected to an actuating rod (14) and able to move in said body in a first direction in which the volume of the second chamber increases while the volume of the first chamber decreases, and in a second direction in which the volume of the second chamber decreases while the volume of the first chamber increases, said piston being provided with a rod (30) connected in said second chamber to an area (20b) of the piston turned toward said second chamber, said area (20b) having a surface less than an area (20a) of the piston turned toward the first chamber.

This invention discloses in particular an actuation cylinder (10) for controlling the movement of a ring-gate (40) of a hydraulic machine, said actuation cylinder (10) comprising a body (18) forming a first chamber (22) provided with a first duct (26) and a second chamber (24) provided with a second duct (28) which are designed to receive an actuating fluid through said first duct (26) and said second duct (28), said chambers being separated from one another by a piston (20) connected to an actuating rod (14) and able to move in said body in a first direction in which the volume of the second chamber increases while the volume of the first chamber decreases, and in a second direction in which the volume of the second chamber decreases while the volume of the first chamber increases, said piston being provided with a rod (30) connected in said second chamber to an area (20b) of the piston turned toward said second chamber, said area (20b) having a surface less than an area (20a) of the piston turned toward the first chamber.

A valving system has an actuator member connected to move with an actuator piston and change the position of a valve member. There is a smaller face fluid chamber acting on a small area piston face, and a larger face fluid chamber acting on a larger face of the actuator piston. The torque motor has an armature and a flapper caused to move by current received at the armature. The flapper moves between two fluid ports to control the pressure in the larger face chamber. The flapper further has a positioning extension engaging a first feedback spring operable between it and a forward face of the actuator piston and providing a spring force in combination with a spring force from the positioning extension. A control is operable to provide current to the armature to control the fluid received in the larger face chamber. The controller is programmed to associate the current supplied to the armature to an actual position of the valve member. A method is also disclosed.

A compressed gas motor. The motor has a port and a hollow cylinder delimited by a wall with a ventilation opening, a rear closure, and a plunger axially movable in the cylinder. The plunger divides the cylinder into front and back chambers. The ventilation opening is periodically opened towards the back chamber during operation of the motor by movement of the plunger. A compression spring in the front chamber urges the plunger towards the rear closure and/or a tension spring in the back chamber draws the plunger towards the rear closure so that the back chamber is closed relative to the ventilation opening by the plunger and the back chamber is connected with the port when the same pressure prevails in the front and back chambers. The motor can be used in surgical drive systems, medical lavage systems and medical devices. Also disclosed is a method for operating the motor.

A single acting actuator for an aircraft landing gear assembly is disclosed having a piston mounted in a cavity and moveable relative to a housing between a retracted position and an extended position, the piston dividing the cavity into first and second pressure chambers. At least one of the pressure chambers is associated with first and second outlets, with the actuator being arranged such that, in respect of the relative movement in which the pressure chamber is the decreasing volume pressure chamber, in a first stage of the relative movement the first and second outlets are open thereby allowing actuator fluid to flow out of the pressure chamber through the first and second outlets and in a second stage of the relative movement the second outlet is open but the first outlet is closed, thereby acting to slow the relative movement of the piston with respect to the housing.

A piston assembly including a shaft having a piston arrangement. The piston arrangement has a retract-area on one side and a extend-area on the opposite side. The retract-area is larger than the extend-area so that when fluid exerts a force on the retract-area the piston arrangement generates and applies a retract force to the shaft. Upon release of the fluid pressure to the retract-area and application of the fluid pressure to the extend-area the piston arrangement generates and applies an extend force to the shaft. The retract force is greater than or equal to the extend force.

A piston assembly including a shaft having a piston arrangement. The piston arrangement has a retract-area on one side and a extend-area on the opposite side. The retract-area is larger than the extend-area so that when fluid exerts a force on the retract-area the piston arrangement generates and applies a retract force to the shaft. Upon release of the fluid pressure to the retract-area and application of the fluid pressure to the extend-area the piston arrangement generates and applies an extend force to the shaft. The retract force is greater than or equal to the extend force.

Provided are embodiments of a pressure-compensated load transfer device that includes a plate having a first shaft vertically installed on one side and a second shaft vertically installed on the other side to be coaxial with the first shaft. Also included is a first bellows having an opening in one side to surround the first shaft, with the other side thereof being fixed to the one side of the plate. Further included is a plurality of second bellows each having an opening in one end, with the other end thereof being attached to the other side of the plate. A housing is also included, and the housing includes a high-pressure working hole communicating with the opening of the first bellows and a high-pressure channel coplanar with the high-pressure working hole and communicating with the openings of the second bellows. The plate is back-and-forth movably received in the housing.