A telescopic apparatus for a human-powered vehicle comprises a first hydraulic chamber, a second hydraulic chamber, a valve member, a cam member, and an actuator. The second hydraulic chamber is configured to be in fluid communication with the first hydraulic chamber. The valve member is configured to control a fluid communication between the first hydraulic chamber and the second hydraulic chamber. The cam member is rotatable about a rotational axis to move the valve member in a movement direction. The actuator is configured to rotate the cam member. The actuator includes an output shaft rotatable about an actuation rotational axis. The actuation rotational axis is offset from the rotational axis as viewed in the movement direction.

A hydraulic power generating system includes a hydraulic motor, a bidirectional generator connected to the hydraulic motor, a hydraulic cylinder, first and second tubes, a piston structure having a piston and first and second links, and a power driving device connected to the first link. The piston divides the hydraulic cylinder into first and second chambers. The first and second links are connected to the piston and disposed through the first and second chambers, respectively. The first tube is communicated with the first chamber and the hydraulic motor. The second tube is communicated with the second chamber and the hydraulic motor. When the power driving device drives the piston toward the first chamber, hydraulic oil is pumped to the hydraulic motor for rotating the bidirectional generator. When the power driving device drives the piston toward the second chamber, the hydraulic oil is pumped to rotate the bidirectional generator reversely.

A hydraulic pressure amplifier arrangement (1) comprising a supply port (IN), a return port (R), a high pressure port (H1), and a pressure amplifier unit (2) having a low pressure inlet (3) connected to the supply port (IN) and a high pressure outlet (4) connected to the high pressure port (H1) is described, wherein the pressure amplifier unit (2) comprises an amplification factor. In such a hydraulic pressure amplifier arrangement it should be possible to allow simply releasing off pressure at the high pressure port while keeping small unnecessary energy consumption. To this end a control valve (8) is arranged in a connection between the high pressure port (H1) and the return port (R).

A dynamic load damping apparatus is employed in a hydraulic steering system control circuit of an aircraft. The dynamic load damping apparatus is positioned in the hydraulic steering system control circuit in parallel with a control valve of the control circuit that functions as the hydraulic fluid source of the control circuit and an actuator that controls movements of a nose gear of the aircraft. The dynamic load damping apparatus dampens loads transmitted to the hydraulic actuator that controls the steering movements of the nose gear on the aircraft.

To be capable of dealing with a machine body lifting operation or a sudden operation, while improving energy efficiency, during a boom-lowering operation, and achieving the reduction of the number of parts, in a construction machine equipped with a boom. It is configured such that a first region Y1 at which a recovery valve passage 16e is opened and a supply valve passage 16f is closed and a second region Y2 at which the recovery valve passage 16e and the supply valve passage 16f are opened, are provided at an operating position of a first boom control valve 16 during the boom lowering operation, and the first boom control valve 16 is positioned at the first region Y1 when neither a machine body lifting operation nor the sudden operation is performed during the boom-lowering operation, and at the region Y2 when the machine body lifting operation or the sudden operation is performed.

An aircraft store ejector systems and subsystems thereof. Embodiments can include a two-reservoir re-pressurization system wherein a remote reservoir is used to maintain desired pressure in a local ejector reservoir. The system can include a release valve having a vent valve and valve piston. The release valve can control release of pressurized gas to a pitch control valve. The pitch control valve can be configured to distribute the pressurized gas between two or more ejector piston assemblies. One or more of the ejector piston assemblies can include multiple concentric piston stages and piston chambers, the piston chambers configured to contain a volume of gas. The ejector piston assemblies can be configured to compress the volume of gas within the piston chambers as the piston stages are extended out from the aircraft. Such compression can provide a return force to the piston stages.

An electro-hydraulic circuit includes a supply line that connects between a hydraulic supply device that supplies hydraulic fluid and a driving part to be driven by a hydraulic pressure of the hydraulic fluid; a switching valve disposed in the supply line to switch between switching lines for the hydraulic fluid supplied to the driving part; a pilot hydraulic line connected to the switching valve to supply the hydraulic fluid for switching between the switching lines; a check valve disposed in the pilot hydraulic line; a solenoid valve disposed in the pilot hydraulic line to change a supply state of the hydraulic fluid to the switching valve; a sealing material disposed in the switching valve to seal the hydraulic fluid; and a relief valve disposed in the pilot hydraulic line to release the pilot hydraulic pressure

A switching valve includes a sleeve on which a plurality of ports are disposed; a spool that is disposed inside the sleeve to move in an axial direction by a pilot hydraulic pressure to switch between switching lines each serving as a flow channel for hydraulic fluid that is formed by a combination of the ports; a first energizing unit that energizes the spool against the pilot hydraulic pressure; a relief hole that is disposed on the spool to discharge the hydraulic fluid with the pilot hydraulic pressure; a valve body that closes the relief hole; and a second energizing unit that energizes the valve body toward the relief hole of the spool against the pilot hydraulic pressure, and when the pilot hydraulic pressure exceeds a predetermined value, opens the relief hole.

The invention concerns a device for the direct recovery of hydraulic energy in a machine, comprising at least one single-acting storage cylinder-piston device with a storage cylinder, a storage cylinder-piston and a storage cylinder chamber, with at least one differential cylinder-piston device with a differential cylinder comprising a separate rod side and base side, and with at least one hydraulic accumulator, which may be connected to the storage cylinder-piston device and/or the differential cylinder-piston device, wherein the potential energy of the storage cylinder-piston device, which retracts under a compressive load, may be at least partially stored in the hydraulic accumulator.

An example valve includes: a valve body defining a bore, an inlet port, an outlet port, and a signal cavity; a spool movable in the bore to shift between a first position and an intermediate position, where the spool has a first end and a second end, where the outlet port is fluidly connected to the second end, where the valve body defines a spring cavity adjacent the first end of the spool to house a spring, where the first end is subjected to a load-sense pressure signal, and where when the spool is in the first position, the spool disconnects the inlet port from the outlet port and connects the inlet port to the signal cavity; and a valve actuator that, when activated, connects the signal cavity to the second end of the spool to move the spool in the bore from the first position to the intermediate position.