An electro-hydrostatic drive for realizing a rapid movement during a rapid movement phase, a force-building movement during a force-building movement phase. The apparatus comprises a hydro-machine with variable volume and/or rotational speed, driven by an electric motor, for providing a volume-stream of a hydraulic fluid, a first cylinder with a piston chamber, an rod chamber, and a plunger rod, a reservoir, a pressure source, a relief valve, a check valve, a fluid connection between the piston chamber and the hydro-machine, a fluid connection between the rod chamber and the hydro-machine, a fluid connection between the piston chamber and the reservoir, a fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir, a fluid connection, through the relief valve, between the reservoir and the pressure source. The relief valve is for pressure safety of the reservoir, and the check valve has a fluid connection from the pressure source to the rod-chamber-side port of the hydro-machine, during the rapid movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid communicates through the fluid connection between the piston chamber and the reservoir, during the force-building movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid is piped through the fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir.

An example valve assembly includes a first workport fluidly coupled to a first actuator; a second workport fluidly coupled to the first actuator; a third workport fluidly coupled to a second actuator, wherein the third workport is fluidly coupled to the first workport via a first fluid passage; a fourth workport fluidly coupled to the second actuator, wherein the fourth workport is fluidly coupled to the second workport via a second fluid passage; and a spool axially movable in a bore within the valve assembly, wherein when the spool is shifted axially in a first axial direction, pressurized fluid is provided to the first workport and to the third workport via the first fluid passage, and when the spool is shifted axially in a second axial direction opposite the first axial direction, pressurized fluid is provided to the second workport and to the fourth workport via the second fluid passage.

A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

A hydropneumatic suspension system for vehicles, at least consisting of an axle suspension (10) and a cabin suspension (12), which for supplying them with pressurized fluid, can be connected to a pressure supply source, is characterized in that both the axle suspension (10) and the cabin suspension (12) can be actuated jointly by means of an control device (14), and in that, by means of a priority detection system (16) involving a sensor device (18) for the respective suspension (10, 12), the supply with pressurized fluid of the one suspension (10, 12) takes precedence depending on demand over the other suspension (12, 10).

The present invention provides a controller for a hydraulic apparatus. The controller is configured to determine (410) that a mode change criteria has been met for the hydraulic apparatus. In response to the determination, the controller is configured to control (420) a valve arrangement to change a first actuator chamber of a hydraulic actuator between being fluidly connected to a hydraulic machine and fluidly isolated from a second chamber of the hydraulic actuator, and being fluidly connected to both the second actuator chamber and the hydraulic machine. Further in response to the determination, the controller is configured to control (430) the hydraulic machine to change a flow rate of hydraulic fluid flowing through the hydraulic machine to regulate a movement of the hydraulic actuator during the control of the valve arrangement.

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.

An example valve assembly includes a first workport fluidly coupled to a first actuator; a second workport fluidly coupled to the first actuator; a third workport fluidly coupled to a second actuator, wherein the third workport is fluidly coupled to the first workport via a first fluid passage; a fourth workport fluidly coupled to the second actuator, wherein the fourth workport is fluidly coupled to the second workport via a second fluid passage; and a spool axially movable in a bore within the valve assembly, wherein when the spool is shifted axially in a first axial direction, pressurized fluid is provided to the first workport and to the third workport via the first fluid passage, and when the spool is shifted axially in a second axial direction opposite the first axial direction, pressurized fluid is provided to the second workport and to the fourth workport via the second fluid passage.

According to one embodiment, an actuator includes a plurality of channel members each including a first port into which fluid flows and a second port from which the fluid flows out. At least one of the channel members includes a different number of second ports from a number of first ports.

A hydraulic forging press machine and a control method, whereby surging of the forging load or dead zones where the forging speed goes to zero is suppressed, and forging is performed with high precision throughout a wider range than the prior art, from low to high load. Pressure cylinders have a main pressure cylinder configured so working fluid is supplied during forging, and secondary pressure cylinders are configured so supplying and stopping of the supply of working fluid thereto are switched in response to the forging load, head-side hydraulic chambers of the secondary pressure cylinders being connected to a head-side hydraulic chamber of the main pressure cylinder via electromagnetic switching valves. Only the main pressure cylinder is used until the forging load exceeds a set load, and the number of secondary pressure cylinders used is sequentially increased as the forging load increases after the forging load exceeds the set load.

A hydraulic actuating device for a friction clutch and a gear setting element has a power unit for pressure generation by use of an electrically driven pump. Gear setting and clutch actuating sections are hydraulically connected to the power unit. A detenting device with a blocking element is associated with a piston of the clutch setting cylinder, which is operatively connected with the friction clutch and can be hydraulically loaded on opposite sides. The blocking element is resiliently biased into a blocking setting preventing piston movement and is movable by an actuator from the blocking setting into a release setting permitting piston movement. The pump is reversible in order to load the piston on one or the other side for an actuating movement. The control unit coordinates activation of the pump and actuator in order to disengage or engage the friction clutch.