A valve (1) having a valve housing (2) with at least one supply connection (P), a working connection (A) and an outlet opening (T), as well as a valve piston (3) that is arranged and able to move axially within the valve housing (2). The outlet opening (T) provided in the valve housing (2) has at least first and second control edges (4, 5).

A main spool (24) has a throttle passage (30) that, when the main spool (24) moves to an axial other side against a first return spring (27) in a main spool insertion hole (13), communicates a pilot pressure chamber (25) with a first tank port (15) and limits a flow amount of hydraulic oil to be discharged to the first tank port (15) from the pilot pressure chamber (25). When the main spool (24) moves to the axial other side along the main spool insertion hole (13), the throttle passage (30) communicates the pilot pressure chamber (25) with the first tank port (15) before a state where a first pump port (17) is communicated with an output port (16) and a state where the output port (16) is blocked from the first tank port (15).

A pressure regulator has a pressure chamber connected to an inlet flow area which receives liquid flow. As liquid flows into a forward chamber of the pressure chamber, pressure is exerted on the forward face of the piston, which in turn causes the piston to slide longitudinally through the pressure chamber. A bypass fluidically connects the forward pressure chamber and rear pressure chamber such that as the piston slides into the rear pressure chamber pressure increases at the rear pressure chamber, which in turn forces the piston to move forwardly, thus regulating flow out of the pressure chamber. A hand wheel is configured to turn a movable plate located inside the pressure chamber, with the movable plate configured to impede the piston from moving rearwardly. Pressure sensors and vents with a pressurized air source may be used to keep the pressure within a desired range.

A computer-implemented method and/or system for controlling a material handler comprises: processing, by an electronic control unit (ECU), a plurality of electronic input signals from at least one joystick; determining an adjustment for at least one of a pair of solenoids based on at least the plurality of electronic input signals from the joystick; controlling the pair of solenoids by the ECU and each solenoid acting in opposition to each of a pair of biasing elements of an open-center directional control valve to move the directional control valve to an extension position or a retraction position from a central position; determining a setpoint buildup pressure for a central passageway of the directional control valve; and actuating a constrictive solenoid of a pressure buildup valve to constrict the central passageway based on the setpoint buildup pressure whereby the constrictive passageway increases a pressure in the central passageway of the directional control valve.

A handheld system includes a reference pressure source configured to generate a reference pressure. The handheld system also includes a primary pressure source coupled to the reference pressure source. The primary pressure source is configured to generate a primary pressure in a primary pressure range. The primary pressure is less than the reference pressure, and the primary pressure is induced by the reference pressure source. The handheld system also includes a secondary pressure source coupled to the primary pressure source. The secondary pressure source is configured to generate a secondary pressure in a secondary pressure range. The secondary pressure is less than the primary pressure, and the secondary pressure is induced by the primary pressure source.

A hydraulic valve assembly having a regeneration circuit, where the hydraulic valve assembly is switchable between a regenerative mode and a non-regenerative mode as the valve assembly supplies fluid to operate a hydraulic device. The hydraulic valve assembly may be automatically switchable between the regenerative mode and the non-regenerative mode, such as by utilizing a pressure control valve in the hydraulic circuit that is activatable at a predetermined pressure setpoint, or by utilizing a variable pressure reducing valve that actuates a spool in the hydraulic circuit. In other embodiments, the hydraulic valve assembly may be manually switchable between the regenerative mode and non-regenerative mode by utilizing a valve member operatively coupled to a solenoid in cooperation with one or more check valves in the regeneration circuit.

A redundant governor apparatus is provided for a vehicle air brake charging system. The apparatus comprises a first governor and a second governor. The apparatus also comprises a number of components arranged to enable (i) the first governor to act as primary and the second governor to act as backup to the first governor when the first governor is unable to act as primary, and (ii) the second governor to act as primary and the first governor to act as backup to the second governor when the second governor is unable to act as primary.

The invention relates to a discharge pressure scale (30) consisting of at least one valve housing (41) having at least three fluid connection points in the form of a functional connector (A), a return flow connector (T) and a control connector (28), wherein a valve piston (52) is guided such that it moves longitudinally against the effect of an energy accumulator (42), moving from a respective opening or regulating position, against a valve seat (94), into a closed position, wherein the control (28) and return flow connectors (T) are separated from one another, characterised in that the fluid pressure present at the control connector (28) can be guided onto a pressure-active surface (A.sub.1*) of the valve piston (52) by means of a pressure compensation device (70) in such a way that it moves into its respective opening or regulating position in a pressure-compensated manner due to the force of the energy accumulator (42).

A pressure regulation servo-valve comprising a body having a utilization port, a feed port, and a return port, a spool mounted as a sliding fit in the body, the spool co-operating with the body to define a pilot chamber connected to the utilization port. The spool and the body together further define a priming chamber connected to the feed port via a second constriction and connected to the nozzle via a third constriction, and in which there exists a priming pressure acting on the spool in the first direction.

A high flow high pressure hydraulic solenoid valve (26) includes a proportional solenoid (56), a valve body (30) operatively associated with the solenoid (56), the valve body (30) having a valve bore (32) and at least one fluid inlet port (38) for fluid communication with the valve bore (32) and at least one fluid outlet port (40) for fluid communication with the valve bore (32), a valve member (42) axially and slidingly disposed within the valve bore (32), the valve member (42) having a plurality of valve elements (44) spaced axially along the valve member (42), and at least one of the valve elements (44) having a metering face (76a, 76c) adapted to control the pressure of pressurized fluid between the at least one fluid inlet port (38) and the at least one fluid outlet port (40) of the valve body (30) and including a flow force compensating annular void (78a, 78c) to meter out fluid flow from the at least one fluid inlet port (38) to the at least one fluid outlet port (40) to minimize hydraulic, steady state flow forces on the valve member (42) during high-flow conditions.