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 manual override assembly for a hydraulic power source operates to override an actuator of a hydraulic power source. The assembly includes a lever arm and connecting rods. The lever arm pivotally moves relative to a valve body of the hydraulic power source. The lever arm is connected to valve spools via the connecting rods, respectively. Each spool has a bore with an off-set opening for inserting one end of the connecting rod.

A valve has a control slide (4) guided in a valve housing (6) so as to be longitudinally movable. The control slide selectively connects a plurality of fluid connection points (P, T, A, B) in the valve housing (6) to each other in a fluid-conducting manner or disconnects the fluid connection points from each other, and can be electrically controlled by a stepper motor (2). The control slide (4) can be actuated by an emergency device (34, 52) in the event of a malfunction or failure.

A manual override assembly for a hydraulic power source operates to override an actuator of a hydraulic power source. The assembly includes a lever arm and connecting rods. The lever arm pivotally moves relative to a valve body of the hydraulic power source. The lever arm is connected to valve spools via the connecting rods, respectively. Each spool has a bore with an off-set opening for inserting one end of the connecting rod.

A cylinder driving device includes: an electric motor; a pump; a main passage and a main passage; a hydraulic cylinder; an operation check valve and an operation check valve; and a restriction valve and a restriction valve configured to restrict a flow of the working oil directed to the operation check valve and an operation check valve, wherein an opening area of the restriction valve and the restriction valve is reduced in response to an increase in a flow rate of the working oil discharged from the hydraulic cylinder to the main passage and a main passage.

A directional control valve comprising: a body, an actuator configured to switch the directional control valve between two or more states, a manual activation button configured to initiate actuation of the actuator when pressed, a safety member configured to slide along a guide of the body between a first position and a second position, a coupling member configured to couple the directional control valve to other directional control valves, and a guard removably disposed between the safety member and the coupling member. The safety member prevents the manual actuation button from being actuated when it is in the first position and the manual actuation button can be manually actuated when the safety member is in the second position. In addition, the guard is configured to prevent the safety member from sliding to the second position when the guard is disposed between the safety member and the coupling member.

The disclosure relates to a pneumatic control system for a working cylinder, which pneumatic control system enables resistance-free manual motion of the device driven by the working cylinder in the event of a failure or switch-off of the compressed air supply and is independent of electrical supply. The problem is solved by means of a pneumatic control system having a double-acting working cylinder, the two chambers of which can be connected oppositely to a compressed air source and a compressed air outlet by means of a controllable supply device having two operating positions, an independently resetting 3/2-way valve switchable by means of a control pressure being arranged before each chamber in a connecting line to the supply device, which 3/2-way valves connect the chambers to bleeding outlets in a first switching position and to the supply device in a second switching position, and a parallel circuit of a check valve and a throttle point being arranged before each chamber, the check valves of which parallel circuits block in the backflow direction, wherein the two 3/2-way valves assume the first switching position in the idle position and can be switched by means of a common control line, which is connected to both connecting lines to the supply device downstream of the 3/2-way valves by means of a changeover valve, and the parallel circuits are arranged in the connecting lines downstream of the respective 3/2-way valves.

An actuator and a spool type directional control valve is disclosed. The actuator includes a catcher and a shaft. The catcher is provided with a first connecting portion and a second connecting portion. The first connecting portion is used to connect to a spool, and the second connecting portion includes a first limiting portion and an avoidance slot which are connected in a circumferential direction. The shaft includes a shaft body and a control member. The shaft body is used to connect to an operation mechanism and is driven to rotate by the operation mechanism, so that: the control member is capable of abutting against the first limiting portion, and driving the catcher to rotate forward by a first angle a via the first limiting portion so as to drive the spool move forward to a first working position; and the control member is capable of rotating freely in the avoidance slot, and the maximum rotation angle c of the control member in the avoidance slot is not less than the first angle a. With the actuator, the hysteresis of the directional control valve may be reduced, and asymmetrical hysteresis of the directional control valve when the spool moving in different directions can also be avoided.

A directional control valve comprising: a body, an actuator configured to switch the directional control valve between two or more states, a manual activation button configured to initiate actuation of the actuator when pressed, a safety member configured to slide along a guide of the body between a first position and a second position, a coupling member configured to couple the directional control valve to other directional control valves, and a guard removably disposed between the safety member and the coupling member. The safety member prevents the manual actuation button from being actuated when it is in the first position and the manual actuation button can be manually actuated when the safety member is in the second position. In addition, the guard is configured to prevent the safety member from sliding to the second position when the guard is disposed between the safety member and the coupling member.

Universal control circuitry for an electro-hydraulic valve actuator system includes logic gate circuitry to control one or more of a closing solenoid valve, an opening solenoid valve, an emergency shutdown solenoid valve, and a hydraulic fluid pump motor to route hydraulic fluid through a hydraulic circuit to actuate a valve via a hydraulic actuator according to received commands. The universal control circuitry is configured to control operation for multiple different configurations of a hydraulic valve actuator system including double-acting configurations, single-acting spring-to-open configurations, and single-acting spring-to-close configurations, each with or without an emergency shutdown arrangement (which may be configured to trip based on an external shutdown input alone or in combination with a local system power failure), a hydraulic accumulator, and maintained or momentary input commands.