A pneumatic unit for a hydropneumatic pressure booster has a system line that leads from a compressed air inlet to a compressed air outlet. A bypass line runs parallel to the system line and it is connected to the system line via first and second compressed air switches. A compressed air reservoir is connected in the bypass line, and a pressure intensifier is connected in the region between the first compressed air switch and the compressed air reservoir. The pneumatic unit makes available to the pressure booster a sufficiently high pneumatic pressure for carrying out at least one operational step of a connected hydraulic tool, even in the case of a pressure decrease or pressure failure in the supplying pneumatic line. For that purpose, the second compressed air switch is configured for switching the compressed air flow between the system line and the bypass line.

The present invention allows the number of components to be reduced and assembly work to be easily performed. A cylinder drive manifold device that constitutes a cylinder drive apparatus is provided with a block-shaped manifold in which a plurality of holes are formed for circulating a fluid used for driving a plurality of fluid pressure cylinders. The manifold is configured such that a plurality of switching valves for supplying a fluid alternately to a first cylinder chamber and a second cylinder chamber of each of the fluid pressure cylinders are attachable. A plurality of check valves and a plurality of throttle valves are incorporated into the plurality of holes of the manifold.

A valve for controlling a flow of a fluid between a source, reservoir, a vent, and pressure-based device. The valve has multiple positions each having a source port fluidly coupleable to the source, reservoir port fluidly coupleable to the reservoir, device port fluidly coupleable to the pressure-based device, and venting port configured to vent the fluid. The multiple positions are separately selectable and include a fill position having a fill conduit fluidly coupling the source port and device port, a recycle position having a recycle conduit fluidly coupling the reservoir port and device port, and a vent position having a vent conduit fluidly coupling the vent port and device port. The fill conduit, recycle conduit, and vent conduit each communicate the fluid only when a corresponding one of the multiple positions is selected, and the multiple positions are configured to prevent selection of more than one at a time.

An engine and corresponding driving propulsion system may provide continuous force necessary to keep the engine operating. Utilizing two pressurized tanks with high and low pressures may provide a continuous flow of pressure to the engine necessary for it to operate.

An engine and corresponding driving propulsion system may provide continuous force necessary to keep the engine operating. Utilizing two pressurized tanks with high and low pressures may provide a continuous flow of pressure to the engine necessary for it to operate.

An improved method and circuitry for fluid power applications that provides energy savings through the recycling of normally exhausted pressure by direct transfer and accumulation of exhaust pressure for additional use, including from one end of the actuator to the opposite end or within the actuator itself and for use by other devices in separate systems.

A cylinder main body of a fluid pressure cylinder includes a switch valve, a check valve, and a flow path communicating a high pressure air supply source with a head side cylinder chamber and communicating an exhaust port with a rod side cylinder chamber when the switch valve is at a second position. Another flow path communicates the head side cylinder chamber with the rod side cylinder chamber and the exhaust port when the switch valve is at the first position.

A cylinder main body of a fluid pressure cylinder includes a switch valve, a check valve, and a flow path communicating a high pressure air supply source with a head side cylinder chamber and communicating an exhaust port with a rod side cylinder chamber when the switch valve is at a second position. Another flow path communicates the head side cylinder chamber with the rod side cylinder chamber and the exhaust port when the switch valve is at the first position.

A fluid control valve includes a supply-air passage allowing a first port and a second port to communicate with each other, an exhaust-air passage allowing the second port and a third port to communicate with each other, a first check valve provided to the supply-air passage, a second check valve provided to the exhaust-air passage, a valve element that opens and closes a passage from the second port to the third port, and a valve hole in which the valve element is housed. The exhaust-air passage is provided between the valve hole and the valve element. The valve element has a first pressure-receiving surface that causes a fluid pressure at the first port to act, and a second pressure-receiving surface that causes a fluid pressure at the second port to act.

A fluid control valve includes a supply-air passage allowing a first port and a second port to communicate with each other, an exhaust-air passage allowing the second port and a third port to communicate with each other, a first check valve provided to the supply-air passage, a second check valve provided to the exhaust-air passage, a valve element that opens and closes a passage from the second port to the third port, and a valve hole in which the valve element is housed. The exhaust-air passage is provided between the valve hole and the valve element. The valve element has a first pressure-receiving surface that causes a fluid pressure at the first port to act, and a second pressure-receiving surface that causes a fluid pressure at the second port to act.