A hydraulic system may include an electrohydraulic control valve disposed in fluid communication between a source of pressured fluid and a hydraulic actuator. The hydraulic system may be controlled to correct for offset errors between a target actuator pressure and a current actuator pressure output from the control valve, without amplifying pressure oscillations in the fluid between the control valve and the hydraulic actuator.

A spoiler actuator can be operated by applying high pressure to a first chamber of the actuator on receipt of a command to extend the spoiler; applying high pressure to a second chamber of the actuator on receipt of a command to retract the spoiler; and on failure of a supply of the high pressure actuating an anti-extension valve to prevent extension of the spoiler; disengaging the anti-extension valve to permit extension if pressure applied to the anti-extension valve exceeds a predetermined force of a spring biasing the anti-extension valve to the engaged position, wherein additional force is applied to the anti-extension valve if the spoiler is retracted beyond a neutral position.

An actuator control arrangement includes a hydraulic actuator having a housing and a piston rod axially moveable within the housing, a stop disposed within the housing to limit the extent of movement of the piston rod into the housing, and a solenoid valve arranged between a pressure source and the actuator. The solenoid valve is switchable between a first mode and a second mode in response to an electric control signal, wherein, in the first mode, the solenoid valve creates a fluid flow path from the pressure source to the actuator so as to locate the stop in its neutral position and in the second mode, the solenoid valve creates a fluid flow path to release pressure from the actuator to permit the stop to move to its retracted position. In the event of electrical failure, the stop will set the actuator to its neutral position.

A control device generates an operation signal for controlling a pressure of hydraulic oil on a downstream side of the swing motor in a hydraulic device based on an azimuth direction, a swing speed, and a target stopping azimuth direction of a swing body during braking of a swing motor.

Apparatuses, systems and methods are provided for controlling at least one fluid actuated device; e.g., an actuator such as a hydraulic cylinder. A method is provided, for example, involving an actuatable component and an actuation system, which includes an actuation system component and an actuator. During a mode of operation, the actuation system component is fluidly coupled with a first chamber and a second chamber of the actuator using the actuation system. The actuator is operable to move the actuatable component.

A lift apparatus includes a lift assembly and a servo-control system. The lift assembly includes at least one pneumatic actuator including a movable member to provide a load to transfer a substrate between a support and a transfer plane. The lift assembly further includes at least one proportional pneumatic valve to control fluid flow between the actuator and a pressurized fluid supply or a vent, a plurality of pressure sensors each to measure pressure in a respective supply line to the actuator, and at least one position sensor to measure a position of the movable member. The servo-control system includes a controller to determine an output force based on a commanded force and an estimated force, generate a control signal based on the output force, and apply the control signal to the proportional valve to move the movable member.

Provided is a hydraulic drive device, wherein the hydraulic drive device is provided with: a cylinder (101); a rod (103); a piston (102); a hydraulic pump (107); a tank (113); a valve (106) that can be switched between a positive state of connecting the hydraulic pump (107) and a head chamber (101h) and connecting a rod chamber (101r) and the tank (113), and a negative state of connecting the hydraulic pump (107) and the rod chamber (101r) and connecting the head chamber (101h) and the tank (113); and a confluence channel (114) at which, when the valve (106) is in the positive state, at least a portion of hydraulic oil going from the rod chamber (101r) to the tank (113) is merged into hydraulic oil going from the hydraulic pump (107) to the head chamber (101h).

A hydraulic drive device includes a pump, a hydraulic machine, and a tank. The hydraulic machine is connected fluidically to first and second fluid lines, which are configured to be connected fluidically to the tank or the pump via an adjustable main valve. The device further includes a first valve with a continuously adjustable first orifice. Pressure fluid is configured to be conducted out of the second fluid line via the first orifice and into the tank. The first valve is acted upon in the closing direction of the first orifice by a first spring and acted upon in the opposite direction by the pressure at a control point. The control point is connected fluidically to the tank via a first throttle device, connected via a second throttle device to the first fluid line, and connected to the first fluid line via a third throttle device and a second valve.

A control valve for an automatic parking brake having an inlet for coupling to a source a brake pipe pressure, an outlet for coupling to a control inlet of the automatic parking brake and a pilot for coupling to the source of brake pipe pressure. The control valve is moveable between a first position where the inlet is in communication with the outlet and a second position where the inlet and the outlet are isolated from each other in response to a predetermined amount of brake pipe pressure at the pilot. The control valve includes a spring biasing the control valve into the first position.

The present invention relates to a hydraulic valve arrangement for controlling/regulating at least one hydraulic consumer of a mobile machine, with a summation interconnection of at least two hydraulic valves and at least one consumer interconnection of hydraulic valves, wherein the outputs of the summation interconnection are hydraulically connected with the inputs of the consumer interconnection, wherein at least one backflow valve is provided in the consumer interconnection. According to the invention, the at least one backflow valve for throttling a consumer return volume flow opens or closes in dependence on a consumer inflow pressure and comprises at least one main piston arranged in a bushing and at least two further pistons arranged in a lid separate from the bushing, wherein the main piston and the control piston interact with each other via a compression spring.