A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve, and a discharge fluid tube in which the operation fluid flows. The hydraulic system further includes a first fluid tube in which a return fluid flows toward the second control valve. The hydraulic system further includes a second fluid tube in which a supply fluid flows toward the first hydraulic actuator, a third fluid tube coupling the first fluid tube to the discharge fluid tube, and a fourth fluid tube in which the return fluid flows toward the second fluid tube, the fourth fluid tube being connected to the first fluid tube.

In an exemplary method of monitoring performance of a fluid driven actuator for a valve, pressurized fluid is supplied through an actuator supply line to an inlet port of the actuator during a first time period to operate the actuator. Changes corresponding to a fluid flow condition in the actuator supply line are measured during the first time period, and the measured changes are analyzed to identify a non-compliant condition in at least one of the valve and the actuator. An output communicating the identified non-compliant condition is then generated.

An in-port sequencing valve configured to be utilized with a clamping device of a workpiece clamping system having a fixture plate, a number of fixture datums, and a number of clamping devices. The in-port sequencing valve includes a housing, a pre-load adjuster, a valve spring, and a valve piston. The pre-load adjuster is configured to be set to a selected valve activation setting. The valve spring is compressed an amount corresponding to the valve activation setting. The valve piston is configured to be shifted from a closed position to an open position when a force due to hydraulic fluid pressure overcomes a threshold spring force of the valve spring corresponding to the valve activation setting. The in-port sequencing valve can be set to a selected valve activation setting so that the clamping devices clamp the workpiece in a selected order according to the valve activation setting.

A hydraulic system includes first and second valve assemblies connected to a common pump. The first valve assembly includes a main valve housed inside a manifold. A pressure compensator valve maintains a constant pressure drop across a variable orifice of the main valve. A pressure limiter valve is in communication with the main valve and the pressure compensator valve, and allows an actuator connected to the first valve assembly to operate independently of the second valve assembly so that fluid flow to a work port of the first valve assembly is not interrupted by operation of the second valve assembly.

A hydraulic circuit for an agricultural implement consisting of a hydraulic cylinder that exerts a force on a component of the implement. A pressure reduction valve located between a hydraulic power source and the hydraulic cylinder maintains pressure to no more than a preset maximum to protect the hydraulic cylinder by routing excess hydraulic fluid back through a hydraulic line into a reservoir. A pressure relief valve with a preset maximum pressure greater than that of the pressure reduction valve is located between the pressure reduction valve and the hydraulic cylinder, and is connected to the reservoir through a dedicated return line. If hydraulic fluid pressure in the circuit increases to greater than the maximum of the pressure reduction valve, hydraulic fluid is diverted back to the reservoir through the pressure relief valve and a dedicated return line.

An aircraft assembly having: a first part; a second part, the second part being movably mounted with respect to the first part; an electro-hydraulic actuator coupled between the second part and a first anchor point, the actuator comprising a cylinder defining a bore and a piston and rod assembly slidably mounted within the bore and an active chamber within which an increase in fluid pressure causes the actuator to change during a first phase between first and second extension states to move the second part relative to the first part. The electro-hydraulic actuator further includes a hydraulic fluid supply circuit comprising a piezo-electric pump operable to supply pressurised fluid to the active chamber to change the actuator between first and second extension states.

Power machines and control systems used thereon include a lift cylinder, a tilt cylinder, and a slave cylinder mechanically connected to assist the lift cylinder with raising a boom. With a lift control valve controlled to cause extension of the lift cylinder to raise the boom, pressure from a hydraulic source is provided to the slave cylinder to aid in raising the boom. Resulting increased pressure on a side of the slave cylinder opens load holding valves, allowing hydraulic pressure from the tilt cylinder to be communicated to the slave cylinder such that tilt cylinder pressure due to a heavy load on an implement aids in raising the boom.

A gas-powered drive system has a drive which includes a first chamber and a second chamber which are separated from one another by a piston. One of the chambers is connected to a gas source to drive the work element and the other chamber is connected via an exhaust air throttle to a gas sink by means of a reversing valve to movement of the piston. A control valve is assigned to the driving chamber through which the driving chamber can be filled with gas from the gas source. The opening cross-section of the control valve is set as a function of a control pressure.

A technology is disclosed for controlling the function of a pneumatic valve actuator. The piston of the valve actuator is biased to be in first state and move to a second state when pressurized. A conduit connects the pressure side and non-pressure sides of the valve actuator for supplying the non-pressure side of the valve actuator with gas from the pressure side of the valve actuator. A control valve is connected to the conduit for controlling a release of gas from the pressure side of the valve actuator. The valve controller also has pressure-relief valve connected to the conduit between the control valve and the non-pressure side of the valve actuator for reducing the pressure in the conduit.

An attachment for a tractor is disclosed, the attachment includes a rotary reducing component that includes a plurality of cutters and a hydraulic system having an activated state and a deactivated state. The hydraulic system includes an inlet for receiving hydraulic fluid and an outlet for discharging hydraulic fluid. The hydraulic system also includes a hydraulic motor positioned between the inlet and the outlet. The hydraulic motor is mechanically coupled to the rotary reducing component. The hydraulic system includes a first sensor positioned at the inlet of the hydraulic system for sensing parameters representative of the activated or deactivated states of the hydraulic system. The hydraulic system also includes a selectively operable hydraulic brake positioned at the outlet of the hydraulic system. The hydraulic brake is configured to control the rotation of the rotary reducing component when triggered. The attachment also includes a controller in communication with the first sensor and the hydraulic brake. The controller triggers the hydraulic brake when the controller determines the first sensor senses a parameter representative of the hydraulic system being in the deactivated state, and the controller disables the hydraulic brake when controller determines the first sensor senses a parameter representative of the hydraulic system being in the activated state.