The present disclosure relates to a load-sense system such as a load-sense steering system that operates in a static load-sense mode for low flows and operates in a dynamic load-sense mode for high flows.

A hydraulic system for moving an implement of a working machine includes a hydraulic cylinder with a cylinder and a piston which is adapted to move in the cylinder to thereby move the implement relative to a body structure of the working machine, and an actuator pump arranged to provide hydraulic fluid to the hydraulic cylinder, the hydraulic cylinder having a first port and a second port adapted to be in fluid communication with the actuator pump, the hydraulic cylinder and the actuator pump being arranged so that the hydraulic cylinder is directly controlled by the actuator pump so that the rate of movement of the piston of the hydraulic cylinder is purely pump controlled, the hydraulic system further including a hydraulic accumulator for suspension of the implement, which hydraulic accumulator is arranged to be selectively connectable to the first port, the hydraulic system further including a further pump in addition to the actuator pump, the hydraulic accumulator being arranged to be pressurised by the further pump.

Apparatus and methods for metering fluid to a fluid actuator. An example apparatus may include a hydraulic actuator, a fluid chamber, and a hydraulic directional control valve. The fluid chamber may include a piston slidably movable between first and second ends of the fluid chamber and dividing the chamber into first and second chamber portions. The hydraulic directional control valve may direct a fluid from a fluid source into the first chamber portion to cause a volume of fluid to be discharged out of the second chamber portion into the hydraulic actuator to actuate the hydraulic actuator by a distance corresponding to the volume of fluid received by the hydraulic actuator.

A length-adjustable connecting rod for an internal combustion engine, comprises a first connecting rod member, a second connecting rod member and at least one cylinder-piston assembly for adjusting the first connecting rod member relative to the second connecting rod member. The cylinder-piston assembly can be actuated by way of a hydraulic adjustment mechanism, where the hydraulic adjustment mechanism comprises at least one oil filter in order to filter the engine oil of the internal combustion engine flowing into the cylinder-piston assembly. The invention further relates to an internal combustion engine with such a length-adjustable connecting rod and the use of such a cylinder-piston assembly for a length-adjustable connecting rod of an internal combustion engine.

The invention provides a construction machine in which the load torque at the time of engine start-up can be reduced even when the engine stops against the will of the operator. A hydraulic excavator includes a control device (35) having a pump displacement control section (37) and an unload control section (38). The pump displacement control section (37) makes the displacement of a hydraulic pump (16) variable to a minimum displacement by controlling a regulator device (20) when the speed of an engine (14) detected by a speed sensor (41) becomes equal to or less than a preset low speed N3 at the time of driving of the engine (14). The unload control section (40) controls an unloading valve (24) to the open position at the time of start-up of the engine (14).

Aspects relate to systems and methods for controlling landing gear of an aircraft. An exemplary system includes a nose gear located at a nose of the aircraft, where the nose gear includes a nose piston configured to allow for displacement of a nose wheel relative the aircraft, a main gear located aft of the nose gear, where the main gear includes a main piston configured to allow for displacement of a main wheel relative the aircraft, a hydraulic circuit in fluidic communication with each of the nose piston and the main piston, and a compliant element in fluidic communication with the hydraulic circuit and configured to provide a compliant response at one or both of the nose piston and the main piston.

A diaphragm actuator (10, 40) for a control valve is shown including an actuator housing (12, 42), in which a diaphragm (14, 44) including a diaphragm disk (16, 46) is sealingly fitted thus forming a pressure chamber (20, 50), and furthermore at least one spring (24, 54) is provided which rests against the diaphragm disk (16, 46) and the actuator housing (12, 42), with the diaphragm disk (16, 46) being connected to a valve stem (22, 52) for actuating a valve body. At least two springs (26, 56) are provided and are disposed one after another in an axial direction between the actuator housing (12, 42) and the diaphragm disk (16, 46), with a spring seat element (28, 58) linearly guided by at least one linear guiding element (30, 60) being provided between the at least two springs (26, 56).

A pump apparatus includes: a pump that ejects a hydraulic fluid; and a selector valve that switches a direction of a flow of the hydraulic fluid to be supplied to one of a first chamber and a second chamber of a cylinder apparatus, which is internally partitioned by a piston into the first chamber extending during an extending stroke of the cylinder apparatus, and the second chamber extending during a shortening stroke of the cylinder apparatus, and the selective valve has, at a channel connected to the second chamber, an orifice that is narrower than a channel connected to the first chamber.

The present invention is to reduce the flow rate of pressure oil discharged from a main pump and returned to a tank when specific work is executed with an operation amount of an operating device being made small in the state in which an engine is kept at an idling speed. According to the present invention, there is provided a main controller (20) which is capable of controlling the speed of an engine (11) to a normal work speed at which a work implement such as a boom (4) can perform normal work and which controls the speed of the engine (11) to an idling speed serving as a speed lower than the normal work speed when an operating device has returned from an operating position to a neutral position. Configuration is made such that the main controller (20) performs a control process for bringing the speed of the engine (11) to a specific work speed serving as a speed higher than the idling speed but lower than the normal work speed, on detecting execution of the specific work which is performed with an operation amount of the operating device such as a boom operating device (16) being kept small in a state in which the speed of the engine (11) is kept at the idling speed.

A fluid pressure control device includes a load holding mechanism that is configured to hold the load pressure of the load side pressure chamber. The load holding mechanism includes a switching valve having a communication passage configured to be blocked from the third pressure chamber by the second land section in a case where the spool is closed, and providing communicate between the second supply port and the discharge port in accordance with the movement of the spool in the valve opening direction. In a case where the spool is moved in the valve opening direction, at the same time when or after the second supply port communicates with the discharge port via the communication passage, the first land section is brought into sliding contact with the annular projecting section and the first supply port and the discharge port are blocked from each other.