The present invention provides an improved high-low hydraulic system for compacting machinery, such as balers, horizontal balers, compactors, transfer station compactors, and the like. The high-low hydraulic system comprises at least one double rotary pump, a plurality of directional control valves, a pilot-operated back pressure reducing valve, a flow control valve, a plurality of one-way valves, and a plurality of pressure switches. The high-low hydraulic system may be regenerative or non-regenerative and provides many advantages over conventional hydraulic systems. Such advantages include greater system efficiency due to a reduced back pressure during the time of the retraction stroke and clever flow sequencing, mitigation of hydraulic shocks at the beginning and end of compaction and retraction strokes, and reduced cycle time of the cylinder during operation due to the concurrent filling of the rod end side during decompression of the blind end side after the compaction stroke. Moreover, the present high-low hydraulic system allows for the cylinder to operate at three or more independent speeds. Additionally, the present high-low hydraulic system may also comprise an accumulator and pressure transducer that further assist with substantially maintaining a predetermined hydraulic pressure on the blind end side after the completion of the compaction stroke.

The disclosure provides an integral hydraulic system, which includes a valve board, a lift cylinder and a reservoir connected into one integral valve body, wherein the integral valve body is further connected to an electric motor and a hydraulic gear pump, so as to form a complete power unit that includes all the valves utilized in the different functions that control a hydraulic fluid circuit in lifting and lowering of a plunger rod of the lift cylinder.

A hydraulic system includes a hydraulic pump to output an operation fluid, first and second hydraulic devices to be operated by the operation fluid, first and second control valves to control the first and second hydraulic device, respectively, first and second communication tubes connecting the first hydraulic device to the first control valve, a supply fluid tube connecting the first control valve to the second control valve, the supply fluid tube being configured to supply the return fluid to the second control valve, first and second connection fluid tubes disposed on the first control valve, a discharge fluid tube connected to the first control valve, first and second branching fluid tubes branched from the first and second connection fluid tubes, respectively, first and second throttles disposed on the first and second branching fluid tubes, respectively, the second throttle being smaller than the first throttle.

The invention relates to a hydraulic cylinder, for example for use in a hydraulic tool, comprising at least one piston/cylinder combination composed of a cylinder body and a piston accommodated in said cylinder body and provided with a piston rod that projects from said cylinder body, wherein the cylinder body and the piston body define a first cylinder chamber while the cylinder body, the piston body and the piston rod define a second cylinder chamber, and wherein during operation the piston performs alternating forward and return operational cycles under the influence of a fluidum under pressure that is conducted to the first and the second cylinder chamber through a first and a second line, respectively, and a control valve which regulates the supply of a fluid under pressure through the first or the second line to the piston/cylinder combination.

A gangway comprises a fixed platform and a support structure connected to the fixed platform in a manner that allows the support structure to rotate with respect to the fixed platform between a raised stowed position and a lowered deployed position. A self-raising assembly is operative to rotate the support structure from the deployed position to the stowed position. The self-raising assembly includes at least one fluid actuated cylinder connected between the fixed platform and a distal end of the support structure. A raising actuator is usable by an operator to cause operation of the cylinder in a manner that rotates the support structure toward the stowed position.

In a compressed air supply system for a first compressed air consumer circuit such as an air spring system of a vehicle, a first compressed air line leads to the first compressed air consumer circuit and a distribution line leads to further consumer circuits. A priority valve arrangement is disposed between the first compressed air line, wherein the first compressed air line comprises no safety valve. The first compressed air consumer circuit can therefore be filled at a higher priority, and achieve operational readiness quickly in air spring processes such as lifting or raising activities.

An injection moulding system, water jet cutting machine or other industrial system has a synthetically controlled variable displacement fluid working machine which outputs hydraulic fluid to one or more fluid consumers, such as rams or hydraulic motors, through hydraulically stiff fluid retaining volumes and receives hydraulic fluid back from one or more fluid consumers through the same or other said hydraulically stiff fluid retaining volumes. Individual piston cylinder assemblies can be allocated to different outputs. There may be no valve between the machine and the consumers. A working chamber of the machine can be caused to undergo a motoring cycle to enable the machine to output more power than is received from a motor driving the machine. An accumulator can be used to provide a source of hydraulic compliance. The machine can be controlled using pressure control, flow control, feed forward control or variable power/variable power limit control.

Disclosure herein are hydraulic systems and method of use thereof. The hydraulic systems can include a hydraulic cylinder and a manifold. The hydraulic cylinder can have a first end and a second end. The hydraulic cylinder can include a first port, a second port, and a third port. The first port can be located proximate the first end. The second port cane be located proximate the second end. The third port can be located in between the first port and the second port. The manifold can include a first valve and a second valve. The first valve can be in fluid communication with the first port and the third port. The second valve can be in fluid communication with the second port and the third port.

An aircraft assembly having: a first part; a second part, the second part being movably mounted with respect to the first part; an electro-hydraulic actuator coupled between the second part and a first anchor point, the actuator comprising a cylinder defining a bore and a piston and rod assembly slidably mounted within the bore and an active chamber within which an increase in fluid pressure causes the actuator to change during a first phase between first and second extension states to move the second part relative to the first part. The electro-hydraulic actuator further includes a hydraulic fluid supply circuit comprising a piezo-electric pump operable to supply pressurised fluid to the active chamber to change the actuator between first and second extension states.

In a steam valve driving apparatus according to an embodiment, a control valve permits or blocks a flow of hydraulic oil from a supply port to an opening direction piston chamber. A dump valve blocks or permits the flow of the hydraulic oil from the opening direction piston chamber to a discharge port. A blocking valve permits or blocks a flow of the hydraulic oil from an accumulator to a closing direction piston chamber. The control valve permits the flow of control oil from the closing direction piston chamber to the discharge port in a state where the flow of hydraulic oil from the supply port to the opening direction piston chamber is permitted.