A hydraulic system includes a hydraulic actuator to be operated by an operation fluid, a first hydraulic pump to output the operation fluid, a second hydraulic pump to output the operation fluid, a control valve to which the operation fluid outputted from the first hydraulic pump is supplied, the control valve being configured to control the operation fluid that is to be supplied to the hydraulic actuator, a first fluid tube connecting the control valve to the hydraulic actuator, a second fluid tube to which the operation fluid outputted from the second hydraulic pump is supplied, the second fluid tube being connected to the first fluid tube, and a first switching valve disposed on the second fluid tube. The spool includes a communicating fluid passage being configured to supply the operation fluid to the first inner fluid passage, the operation fluid being received by the pressure-receiving port.

The present invention allows the number of components to be reduced and assembly work to be easily performed. A cylinder drive manifold device that constitutes a cylinder drive apparatus is provided with a block-shaped manifold in which a plurality of holes are formed for circulating a fluid used for driving a plurality of fluid pressure cylinders. The manifold is configured such that a plurality of switching valves for supplying a fluid alternately to a first cylinder chamber and a second cylinder chamber of each of the fluid pressure cylinders are attachable. A plurality of check valves and a plurality of throttle valves are incorporated into the plurality of holes of the manifold.

A valve for controlling a flow of a fluid between a source, reservoir, a vent, and pressure-based device. The valve has multiple positions each having a source port fluidly coupleable to the source, reservoir port fluidly coupleable to the reservoir, device port fluidly coupleable to the pressure-based device, and venting port configured to vent the fluid. The multiple positions are separately selectable and include a fill position having a fill conduit fluidly coupling the source port and device port, a recycle position having a recycle conduit fluidly coupling the reservoir port and device port, and a vent position having a vent conduit fluidly coupling the vent port and device port. The fill conduit, recycle conduit, and vent conduit each communicate the fluid only when a corresponding one of the multiple positions is selected, and the multiple positions are configured to prevent selection of more than one at a time.

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).

A hydraulic control valve maintains the pressure at a control port at a desired percentage of the pressure at two other ports as the pressure at the two other ports varies. Upon the pressure at the control port reaching a predetermined pressure setting, a fourth port will open to maintain the control port at a second desired percentage of the two other ports.

The invention discloses a hydraulic control system of a leveling hydraulic cylinder of a loading head, characterized by comprising a hydraulic pump, a two-position three-way electronic control reversing valve, a three-position four-way electronic control reversing valve, a three-position four-way cam valve and a hydraulic cylinder. The invention not only can perform leveling by using the electric control system, but also comprises the hydraulic cam valve controlling the hydraulic cylinder for self-leveling, and the two leveling manners can be independently used or switched mutually, thus achieving a better leveling effect.

An improved method and circuitry for fluid power applications that provides energy savings through the recycling of normally exhausted pressure by direct transfer and accumulation of exhaust pressure for additional use, including from one end of the actuator to the opposite end or within the actuator itself and for use by other devices in separate systems.

The present disclosure relates to a hydraulic circuit, comprising: a motion control valve including a valve spool and a hydraulic actuator for actuating the valve spool, and a hydraulic control device having an outlet fluidically connected to the hydraulic actuator, the hydraulic control device comprising a pressure-reducing valve or a pressure compensated flow control valve.

An aircraft store ejector systems and subsystems thereof. Embodiments can include a two-reservoir re-pressurization system wherein a remote reservoir is used to maintain desired pressure in a local ejector reservoir. The system can include a release valve having a vent valve and valve piston. The release valve can control release of pressurized gas to a pitch control valve. The pitch control valve can be configured to distribute the pressurized gas between two or more ejector piston assemblies. One or more of the ejector piston assemblies can include multiple concentric piston stages and piston chambers, the piston chambers configured to contain a volume of gas. The ejector piston assemblies can be configured to compress the volume of gas within the piston chambers as the piston stages are extended out from the aircraft. Such compression can provide a return force to the piston stages.

An automatic oil return structure has a main body assembly mounted between an oil storage bag and a piston, and having a pressure regulating blocking unit, a pressure regulating elastic unit, an engaging unit, and an engaging elastic unit. The pressure regulating elastic unit pushes the pressure regulating blocking unit to block a first pressure regulating channel. An engaging groove is formed radially inward on the pressure regulating blocking unit. The engaging elastic unit pushes the engaging unit toward the pressure regulating blocking unit. When a pressure in the first pressure regulating channel is higher than a set value and the pressure regulating blocking unit is pushed away to a set distance, the engaging unit is pushed to engage with the engaging groove of the pressure regulating blocking unit such that the pressure regulating blocking unit is unmovable to avoid blocking the first pressure regulating channel.