An air cylinder fluid circuit is formed by connecting a switching valve, which switches the supply and discharge of compressed air, and cylinder port parts of an air cylinder by means of pipes, wherein the acoustic velocity conductance of the pipes is smaller than the acoustic velocity conductance of the switching valve and the cylinder port parts.

A fluid pressure circuit for controlling a rod of a cylinder controlled in accordance with an operation command includes a tank, a fluid pressure actuator configured to pressurize fluid supplied from the tank for extending and retracting the cylinder, a flow control valve arranged between the fluid pressure actuator and the cylinder device configured to switch a flow passage of pressurized fluid and discharge via a first throttle return fluid from the cylinder, a variable regeneration switching valve configured to discharge return fluid from the cylinder to the flow control valve upon non-regeneration and upon regeneration, branch part of the return fluid and discharge via a second throttle the fluid branched, a regenerative motor configured for regeneration by fluid branched by the variable regeneration switching valve, and a third throttle connected in series with the first throttle upon the regeneration to limit flow of return fluid.

A work machine including: a hydraulic cylinder 20 configured to drive a work implement 3; a control valve 22 configured to connect a delivery line of a hydraulic pump 21 switchingly to a bottom fluid chamber and a rod fluid chamber of the hydraulic cylinder 20 and a tank; a pilot pump 23 configured to output a pilot pressure to drive the control valve 22; an engine 24 configured to drive the hydraulic pump 21 and the pilot pump 23; and an accumulator 26 configured to accumulate a return hydraulic fluid from the hydraulic cylinder 20 is provided with: a bypass line 41 configured to connect the bottom fluid chamber of the hydraulic cylinder 20 and a delivery line 21a of the hydraulic pump 21 by bypassing the control valve 22 and be provided with the accumulator 26 thereon; a pressure-accumulation control valve 27 provided between the bottom fluid chamber of the hydraulic cylinder 20 and the accumulator 26; a release control valve 28 provided between the accumulator 26 and the delivery line 21a; and a hydraulic system controller 30 configured to open the release control valve 28 if an engine revolution speed N becomes lower than a set value Ns.

A device for actuating a parking lock of an automatic transmission for a motor vehicle. A piston, which a hydraulic medium can be applied from a reservoir by a valve apparatus in order to actuate the parking lock by a valve apparatus, which has a first valve and a second valve, which is arranged downstream of the first valve and upstream of the piston in the flow direction of the hydraulic medium from the reservoir to the piston and which has at least one device connection, by way of which the hydraulic medium can be applied to the piston, the second valve having at least two switching states, and a working chamber, which is bounded by the housing element and by the piston and into which the hydraulic medium can be introduced from the reservoir by the valve apparatus in order to apply the hydraulic medium to the piston.

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.

A working machine includes a lower body, a turning body, a turning manipulating member which turns the turning body, a hydraulic motor which rotationally drives the turning body, a brake device which brakes the hydraulic motor, a main hydraulic source which supplies hydraulic oil to the hydraulic motor, and a direction control valve which controls a flow direction of the hydraulic oil according to the manipulated variable of the turning manipulating member, in which in a state where the hydraulic motor is braked by the brake device based on a manipulation of a brake manipulating member, when the turning manipulation is performed by the turning manipulating member, a brake applied to the hydraulic motor by the brake device is released with respect to turning in an indication direction indicated by the turning manipulation such that the turning body turns in the indication direction.

Embodiments of the present disclosure describe both mechanically-operated and electrically-operated, locally-actuated partial stroke testing devices and systems for testing operation of an emergency isolation valve.

A technique provides enhanced control over a variety of hydraulically actuated devices, e.g. flow control valves. A hydraulic control module is placed in hydraulic communication with an actuator of a hydraulically actuated device. The hydraulic control module comprises features which prevent hydraulic locking of the system. Additionally, the control module may comprise metering features to enable metered flow of actuating fluid. The features may include valves, mini-indexers, flowline configurations, or other features which maintain the ability to shift the hydraulically actuated device and/or provide metering of the actuating fluid.

A hydraulic system embodying a method for combining two or more hydraulic functions from operatively associated distributor valves to selectively increase fluid flow using only hydraulic switches and valves is provided. Each two or more preselected hydraulic functions may each have a piloted diverter valve operatively associated with the other(s) so that when a control valve of the first hydraulic function is selectively positioned to a maximum pressure the first diverter valve actuates the second (and other) diverter valve(s) to couple to the first hydraulic function. Solving the problem where a user has two hydraulic flows that are limited by the diameter/distance of the hoses or pipes to a maximum flow rate almost regardless of pressure but needs to increase that flow to efficiently perform a task.

The present invention relates to a control valve, for hydraulic lifters used on tractors, and having a body (10), at least one main inlet line (11) which transfers fluid into the body (10), and a check valve (23) for controlling the passage of fluid, coming from the main inlet line (11), to a cylinder line (14).