Described herein is a fluid circuit device. The device incorporates at least one pressure balancing valve located between at least two fluid volumes that can be in a pressure differential arrangement wherein the at least one pressure balancing valve acts to address a pressure differential by opening a fluid volume or volumes to a third pressure equalising volume. In use, the fluid circuit device may in one embodiment be used in an energy absorbtion apparatus.

A valve system, for use with a cylinder having an extensible rod, includes a first valve assembly having a first inlet/outlet port, a check valve biased toward a closed state, the check valve having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the first inlet/outlet port and the check valve, and a first pilot port selectively communicable with a source of pressurized gas for opening the check valve. The valve system further includes a second valve assembly having a second inlet/outlet port, a second pilot port through which the pressurized gas must flow before being introduced to the first pilot port, and a valve body at least partially receivable within a second port of the cylinder.

A hydraulic jack including a load cylinder, a pump, a release valve and a flow regulator. The pump is configured to provide pressurized fluid to the load cylinder. The release valve is in fluid communication with the pressurized fluid. The flow regulator is configured to alter a flow path of the fluid therethrough as an inverse function of a pressure drop of the fluid across the flow regulator. The fluid regulator being in fluid communication with the release valve.

Embodiments of the invention provide a ram assembly for a hydraulic tool. The ram assembly includes a ram piston having a ram cavity. The ram piston receives a hydraulic pressure reaction force. The ram assembly further includes an overload assembly disposed in the ram cavity or in a cavity defined by a manifold. The overload assembly includes a burst disc positioned at a first end of the ram cavity or manifold, a lock nut positioned at a second end of the ram cavity or manifold, and a spacer positioned between the burst disc and the lock nut. The spacer transfers a supporting force applied to the lock nut to the burst disc. The hydraulic pressure reaction force and the supporting force both act in the same direction, and thus, are additive forces acting on the burst disk.

A work machine (1) comprises at least one structural element (21), at least one pressure medium operated actuator 22) for establishing at least one operation of the work machine, and at least one detection device (23) to determine the position of the structural element (21) of the work machine. An arrangement for controlling at least one operation of the work machine (1) comprises: a control valve arrangement (24) for controlling the actuator (22), and a control device (25) for controlling the control valve arrangement (24). The control device (25) is adapted to control said control valve arrangement (24) for adjusting the pressure and/or volume flow on the return line of the actuator (22) as dependent on the position of the structural element (21).

An actuator includes a casing having a first annular groove formed in an inner peripheral portion thereof; a piston having a second annular groove formed in an outer peripheral portion thereof, provided in the casing to form a pressure chamber together with the casing, and driven by a drive fluid from an outside of the actuator; and an annular seal member having a first fitting portion to be fitted into the first annular groove and a second fitting portion to be fitted into the second annular groove to seal the pressure chamber.

A fluid pressure cylinder includes a first cylinder portion and a second cylinder portion disposed in parallel, and a supply-and-discharge port. The first cylinder portion is partitioned by a first piston into a head-side first accumulation chamber and a rod-side second accumulation chamber. The second cylinder portion is partitioned by a second piston into a head-side release chamber and a rod-side drive chamber. Pressurized fluid is supplied to and discharged from the second accumulation chamber and the drive chamber through the supply-and-discharge port. An end of a first piston rod connected to the first piston and an end of a second piston rod connected to the second piston are connected to each other. The first piston includes a communication switching valve switching communication between the first accumulation chamber and the second accumulation chamber, between enabled and disabled.

A pneumatic cylinder includes a cylinder body, a piston assembly, a connecting rod, and at least one pressure-relief valve. The cylinder body is formed with a cylinder chamber, and has an exterior disposed with at least one inlet-outlet passage and at least one pressure-relief opening, wherein the inlet-outlet passage is connected to the cylinder chamber. The piston assembly is contained within the cylinder chamber. The connecting rod is connected to the piston assembly, and protrudes out from the cylinder body. The pressure-relief valve is disposed in the pressure-relief opening, and has two ends connected to an outside of the pneumatic cylinder and the cylinder chamber respectively. When a gas pressure within the cylinder chamber is greater than a threshold value, the pressure-relief valve works to allow the cylinder chamber connecting to the outside for pressure relief.

An actuator includes a piston assembly movably disposed within an assembly housing having a fixedly supported end and an opposing end that receives a movable piston assembly. The piston assembly includes a piston rod and an attached piston head having a fixed orifice as well as an orifice with a check valve to create rate control of the assembly. Hydraulic fluid is caused to move through the axially movable piston head based on compressive and tensile loads imparted to the assembly. A plurality of pre-loaded springs are configured to selectively provide pressure relief in the event the orifices of the piston become clogged, wherein the plurality of pre-loaded springs, such as disc springs, further provide an energy absorbing function of the assembly based on loading conditions.

In a fluid pressure cylinder having a body having a pair of cylinder holes, a pair of pistons movably accommodated respectively in the pair of cylinder holes, a pair of piston rods secured respectively to the pair of pistons, and an end plate connected to end portions of the pair of piston rods, each of the pistons partitions the corresponding cylinder hole into a head-side cylinder chamber and a rod-side cylinder chamber. The body includes a solenoid valve configured to switch between supply of pressurized fluid to the head-side cylinder chambers or the rod-side cylinder chambers and discharge of the pressurized fluid from the head-side cylinder chambers or the rod-side cylinder chambers, and the solenoid valve is disposed inside a surface of the body.