A valve device that changes the direction of flow of a hydraulic fluid supplied to and discharged from a cylinder mechanism to actuate the cylinder mechanism, the valve device including: a control valve including a main spool axially movable between different positions; a lock valve including a plunger and a pressure chamber; and a selector valve including a selector spool operable in conjunction with the main spool to axially move between different positions, the selector spool being located adjacent to the main spool and having an axis crossing an axis of the main spool.

The invention relates to a valve, which is characterized in that between a neutral position (38) of a control spool (STS) and one of its end positions (34, 42) a regeneration position (36) is provided, in which two utility ports (A, B) are interconnected in a fluid-conveying manner, or a floating position (40) is provided, in which these utility ports (A, B) are interconnected in a fluid-conveying manner. The invention relates to a further valve, which is characterized in that by a further motion of the control spool (STS) in the same direction, as that, in which a fluid connection is established between the utility ports (A, B) starting from the neutral position (38), this fluid connection is interrupted.

A hydraulic system includes a hydraulic pump to output an operation fluid, first and second hydraulic devices to be operated by the operation fluid, first and second control valves to control the first and second hydraulic device, respectively, first and second communication tubes connecting the first hydraulic device to the first control valve, a supply fluid tube connecting the first control valve to the second control valve, the supply fluid tube being configured to supply the return fluid to the second control valve, first and second connection fluid tubes disposed on the first control valve, a discharge fluid tube connected to the first control valve, first and second branching fluid tubes branched from the first and second connection fluid tubes, respectively, first and second throttles disposed on the first and second branching fluid tubes, respectively, the second throttle being smaller than the first throttle.

Manual hydraulic override pumps for use with actuators are described herein. An example apparatus includes a manifold including a reservoir port to be fluidly coupled to a reservoir of fluid, a pump port to be fluidly coupled to a pump, a first actuator port to be fluidly coupled to a first chamber of an actuator, and a second actuator port to be fluidly coupled to a second chamber of the actuator. The example apparatus also includes a rotor disposed in a cavity formed in the manifold. The rotor is rotatable between a first actuating position in which the rotor fluidly couples the first actuator port and the pump port, and a second actuating position in which the rotor fluidly couples the second actuator port and the pump port.

The present invention relates to An open center hydraulic system (100), the open center hydraulic system (100) comprising a tank configured to hold hydraulic fluid, a pump configured to provide pressurized hydraulic fluid from the tank, a shunt valve configured to adapt an first opening area between a first input port and a first output port of the shunt valve dependent on a first control signal, wherein the first input port is coupled to the pump and the first output port is coupled to the tank, a first actuator valve coupled to the first input port and configured to adapt a second opening area of the first actuator valve dependent on a second control signal, a hydraulic valve control unit configured to determine a first opening area value and a second opening area value based on user input data and a predetermined relation dependent on the user input data, sending the first control signal, indicative of the first opening area value and sending the second control signal indicative of the second opening area value.

An injection molding apparatus including: a valve pin driven by an actuator, the valve pin extending axially through at least a portion of the channel length of the fluid flow channel, the fluid flow channel and the valve pin being configured or adapted such that the valve pin is movable axially upstream and downstream between an upstream position where the downstream flow of the injection fluid is restricted by a bulbous protrusion (B) of the pin being axially aligned (AL) with the throat (T) of the channel, an intermediate position where downstream flow of injection fluid is unrestricted (WG) and a fully downstream position where downstream flow of injection fluid is stopped at both the gate and at the throat.

The subject matter of this specification can be embodied in, among other things, a fluid valve assembly that includes a first fluid port, a second fluid port, a third fluid port, a valve spool configured to be positioned at a first position, a second position away from the first position, a third position away from the first position opposite the second valve position, the valve spool defining a first fluid duct configured to fluidly connect the first fluid port to the second fluid port in the first valve position, a second fluid duct configured to fluidly connect the first fluid port to the third fluid port in the second valve position, and a third fluid duct configured to fluidly connect the first fluid port to the second fluid port in the third valve position.

A hydraulic system includes a first hydraulic device, a second hydraulic device, a first control valve to control the first hydraulic device, a second control valve disposed on a downstream side of the first control valve and configured to control the second hydraulic device, a communication tube connecting the first hydraulic device to the first control valve, a supply fluid tube connecting the first control valve to the second control valve, a connection fluid tube disposed on the first control valve, the connection fluid tube connecting the communication tube to the supply fluid tube, a discharge fluid tube connected to the first control valve, a setting portion disposed on the discharge fluid tube and configured to increase a pressure in the discharge fluid tube, a branching fluid tube branched from the connection fluid tube and connected to the discharge fluid tube, and a throttle disposed on the branching fluid tube.

Hydraulic systems and associated methods configured to reduce leakage past a spool valve when the system is in a neutral state. Leakage reduction is achieved by shifting the spool valve within the spool bore. The shifting direction can depend on whether the system has a relatively high load or a relatively low load in the neutral state. The amount of shifting can depend on the pressure differential between the supply line and the work port, and/or the pressure differential between the work port and the tank line.

A dual spool valve and methods of controlling hydraulic fluid that is moved to a hydraulic actuator of an aircraft. The dual spool valve may include ports to receive and discharge hydraulic fluid. The dual spool valve may also include first and second valve sections that are selectively positionable to control the flow of hydraulic fluid into and out of the actuator. One position provides for hydraulic fluid to move through closure lines. Method of controlling the dual spool valve may provide for selectively positioning the valve sections to control the flow of hydraulic fluid, and to position the valve sections to move hydraulic fluid through a closure line during certain circumstances.