Abstract: A hydraulic circuit is disclosed which includes one or more i) linear; or ii) rotary hydraulic actuator, wherein total number of cylinder chambers is N, M pressure rails, a valve arrangement, including M hydraulic rail ports each coupled to a pressure rail, N hydraulic chamber ports each coupled to a chamber of one or more actuators, N proportional valves each corresponding to one of the N hydraulic chamber ports, X sets of on-off valves and check valves coupling two or more hydraulic rail ports to each of supply sides of each of the N proportional valves, and Y sets of on-off valves and check valves coupling two or more hydraulic rail ports to each of return sides of each of the N proportional valves, and a controller configured to in real-time operate the N proportional valves and the associated on-off valves to achieve one or more desired functional parameters.

Abstract: A hydraulic valve bank has at least two valve sections, a connection section, and a pressure channel for pressurizing the valve sections. The pressure channel connects the connection section to each valve section for pressurizing them. Each valve section has a spool, an electrohydraulic pilot control for actuating the spool and an upstream pressure compensator. The valve bank is a load-sensing system and has a load pressure collecting channel for signaling the highest load pressure. A common pilot pressure signal is applied to the electrohydraulic pilot control of each valve section via the connection section. A single pilot control pressure influencing valve changes the common pilot pressure signal, and is connected to the pressure channel to be acted upon in a first switching direction, and to the load pressure collecting channel to be acted upon in a second switching direction. A mobile hydraulic system includes such a hydraulic valve bank.

Abstract: Hydraulic fluid is fed to a hydraulic cylinder via a feed line, and the hydraulic cylinder raises and lowers a mechanical device with a tool, where a lowering motion of the tool is reached by closing a second valve. Thereby, a third valve and a first valve are opened so that a first pressure is set between the first valve and the third valve, which corresponds to a pressure in the feed line and the cylinder at which the predetermined pressure or force effect can be exerted with the tool on the surface of the object. When a second pressure in the feed line between the hydraulic cylinder and the second valve is reduced to a value corresponding to the previously reached first pressure, the second valve is opened so that a pressure is maintained in the feed line up to the piston inside the hydraulic cylinder.

Abstract: The present invention pertains to method for monitoring operation of a hydraulic system, in particular of a hydraulic system of a working machine, having at least one hydraulic actuator. The method comprises a step of determining a predefined operating condition of the hydraulic system; a step of determining an input power parameter being indicative of a power provided by an engine to the hydraulic system during the predetermined operating condition; a step of determining an output power parameter being indicative of a power provided by the hydraulic actuator during the predetermined operating condition; and a step of determining a fault condition of the hydraulic system based on the input power parameter and the output power parameter.

Abstract: A first switching valve that switches between flow passages which allow communication between a first pressure-receiving chamber and a fluid supply device side and flow passages which allow communication between a second pressure-receiving chamber and the fluid supply device side, according to a change in a fluid pressure to be applied, and a second switching valve that is switched to flow passages which apply the fluid pressure to the first switching valve, are provided. The second switching valve includes return device, and is provided to be reciprocatable between an operation position to which the second switching valve is moved by a stroke of a piston and a return position to which the second switching valve is moved by the return device. The piston and the second switching valve are movable independently of each other.

Abstract: A hydraulic system for an industrial truck with a lifting frame has at least one telescoping mast that can be raised and lowered in a stationary mast and a load handling means that can be raised and lowered in the telescoping mast. The hydraulic system has a free lift cylinder for raising and lowering the load handling means and at least one mast lift cylinder for raising and lowering the telescoping mast. A control valve device is provided for the control of the lifting operation and the lowering operation of the free lift cylinder and of the mast lift cylinders. A mast transition damping device is provided that includes at least one electrically actuated proportional valve. The proportional valve of the mast transition damping device, in the unactuated state, has a throttling connection that effects a throttled volume flow, and in the event of an electrical control action, can be actuated toward an open position.

Abstract: There is an outer surface having a first upper O ring groove and a second lower O ring groove. The outer surface has a pressure line aperture therein. The outer surface has a snap ring groove and a third sweep O ring groove. The top end cap has a lower portion and an upper portion. The pressure line aperture has a thread. The inner surface forms a passageway through the length of the top end cap.

Abstract: A load-controlled hydraulic supply for a utility vehicle includes a variable-displacement pump supplied with hydraulic fluid from a hydraulic reservoir. The variable-displacement pump has a mechanically actuable control slide for changing a volume flow delivered. An electrical actuator is configured to actuate the control slide. A controller is configured to control the electrical actuator in accordance with a determined load requirement on a consumer side.

Abstract: A fluid end includes a housing having a bore extending toward a cavity and a wear sleeve positioned within the bore. The fluid end also includes a plunger positioned within a plunger bore extending through the wear sleeve, the plunger reciprocating within the plunger bore. The fluid end further includes a wear sleeve retainer coupled to the housing and positioned to block axial movement of the wear sleeve, the wear sleeve retainer having external threads along a body that engage internal threads formed in the housing. The fluid end also includes an anti-rotation system, coupled to the housing, the anti-rotation system engaging the wear sleeve retainer to block rotation of the wear sleeve retainer in at least one direction. The fluid end further includes a packing nut coupled to the wear sleeve retainer.

Abstract: The present invention provides a controller for hydraulic apparatus (100). The controller is configured to determine (310) that an energy return criteria has been met by movement of a first movement component of a first hydraulic actuator. In response thereto, the controller is further configured to select (320) at least one among a plurality of energy control strategies based on at least one operational characteristic of the hydraulic apparatus, and to control (330) the hydraulic apparatus to implement the energy control strategy during movement of the first movable component in such a way as to meet the energy return criteria. The plurality of energy control strategies comprises a first energy control strategy and a second energy control strategy. The at least one operational characteristic of the hydraulic apparatus comprises an indication of an expected energy recovery of one or more of the energy control strategies.

Abstract: The present disclosure relates to a piston assembly, the piston assembly comprising a cylinder extending along an axis and having an open axial end, a cap assembly closing the cylinder at its open axial end, wherein the cap assembly comprises an insertion portion received in the cylinder at its open axial end, and a piston axially movably disposed within the cylinder and partially received in the insertion portion of the cap assembly. The present disclosure further relates to a variable displacement hydraulic unit including said piston assembly.