[Solution] A pilot check valve includes a first body that has input and output ports, a main path 13 that is in communication these ports, and a check valve element that allows a flow of a pressure fluid from the input port toward the output port. The valve element blocks or allows a flow toward the input port side by supply or discharge of a pilot fluid and has a residual pressure exhaust path connected between the main path and an exhaust hole, a seal member that is provided in the exhaust path, and a push rod that moves the check valve element to a position where a flow of a pressure fluid toward the input port side in the main path is allowed and moves the seal member to a position where a flow toward the exhaust hole is allowed.

Techniques involve a hydraulic valve module having at least one hydraulic valve with a valve slide which can be adjusted by way of an electric actuator in order to supply hydraulic lines with hydraulic liquid by way of the hydraulic valve. The hydraulic valve module has a controller and an electric energy store. The controller and the electric energy store are set up to move the valve slide out of every possible valve slide position into a deactivation position by way of the electric actuator and energy which is stored in the electric energy store. This allows the safe operation of hydraulic valves without a restoring spring, wherein valves of this type and the actuators thereof can be of smaller and less expensive construction than in the case of conventional valves with a restoring spring.

Disclosed is an electric hydraulic actuator including a hydraulic cylinder and the hydraulic power generator. The hydraulic cylinder includes a hollow rod that is connected to a piston and is linearly movable to protrude outward or to retract. The hydraulic power generator includes a motor, a fluid tank, and a gear pump and a pilot check valve disposed in a pump housing. The cylinder housing and the pump housing are directly coupled to each other. The cylinder housing includes a first port through which the working fluid is transferred to a first side of the piston and a second port connected to a return pipe that is provided in the hollow rod. The pump housing includes a third port that is configured to communicate with the first port and a fourth port that is configured to communicate with the second port.

Disclosed is an electric hydraulic actuator including a hydraulic cylinder and the hydraulic power generator. The hydraulic cylinder includes a hollow rod that is connected to a piston and is linearly movable to protrude outward or to retract. The hydraulic power generator includes a motor, a fluid tank, and a gear pump and a pilot check valve disposed in a pump housing. The cylinder housing and the pump housing are directly coupled to each other. The cylinder housing includes a first port through which the working fluid is transferred to a first side of the piston and a second port connected to a return pipe that is provided in the hollow rod. The pump housing includes a third port that is configured to communicate with the first port and a fourth port that is configured to communicate with the second port.

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.

A redundant control system for a vehicle includes: one or more actuator housings; a plurality of actuator pistons coupled to the actuator housings, each of the actuator pistons mechanically coupled to one another and a common output device; a plurality of primary stages coupled to the actuator housings, each of the primary stages operatively coupled to move a respective actuator piston relative to at least one of the actuator housings, and each of the primary stages functioning independent of any other primary stage when the control system is operating in a flight-operation mode; and an auxiliary stage operatively coupled to move a first of the plurality of actuator pistons relative to at least one of the actuator housings when the control system is operating in a ground-operation mode, with each of the plurality of primary stages being responsive to movement of the first actuator piston by the auxiliary stage.

A control device, for a hydraulic consumer (22) and susceptible to vibrations, includes a valve (24) having a control spool (40) controllable by an actuating device (46). The valve (24) has a pressure supply port (P), to which a pressure compensator valve can be connected, which can be supplied with pressure fluid from a pressure supply device. The actuating device (46) has a motor (74). A load-pressure-dependent force on the control spool (40) can be generated by a control device (66). That force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change of the force and acts as a damping of the vibrations of the consumer (22) against this change of force.

A material handler comprises a motor, an interface device, and a controller. The controller is configured to receive an input from the interface device and can include a variable frequency drive (VFD). The controller provides a variable frequency drive (VFD) signal to the motor to control movement of one or more components of the material handler. If the interface device is inactive for a predetermined amount of time, the controller adjusts a frequency of the VFD signal from an operating frequency to a standby frequency with the standby frequency being lower than the operating frequency. Adjusting the frequency from the operating frequency to the standby frequency can include adjusting the frequency of the VFD signal to one or more intermediate frequencies. When adjusting the frequency of the VFD signal, the controller can skip at least one frequency or range of frequencies, for example, to avoid undesirable operating characteristics.

A material handler comprises a motor, an interface device, and a controller. The controller is configured to receive an input from the interface device and can include a variable frequency drive (VFD). The controller provides a variable frequency drive (VFD) signal to the motor to control movement of one or more components of the material handler. If the interface device is inactive for a predetermined amount of time, the controller adjusts a frequency of the VFD signal from an operating frequency to a standby frequency with the standby frequency being lower than the operating frequency. Adjusting the frequency from the operating frequency to the standby frequency can include adjusting the frequency of the VFD signal to one or more intermediate frequencies. When adjusting the frequency of the VFD signal, the controller can skip at least one frequency or range of frequencies, for example, to avoid undesirable operating characteristics.

A valve device includes: a pilot chamber cover to which pilot pressure is introduced, the pilot chamber cover including a through hole extending in a direction intersecting with an axial direction of the spool; an operating pin configured to swing with movement of the spool in the axial direction; a rotating shaft configured to turn with swinging of the operating pin; a coupling plug coupled to the rotating shaft, a part of the coupling plug inserted into the through hole, the coupling plug being configured to switch between a coupled state where rotational force of the rotating shaft is transmitted to the coupling plug and a canceled state where the transmission of the rotational force of the rotating shaft to the coupling plug is canceled; an operating lever coupled to the coupling plug; and a sealing member between an inner peripheral surface of the through hole and the coupling plug.