A pressure back-up valve (300) includes a release piston (320) movable between first and second stop positions and a closing body (340) movable to a closing position in which this separates first and second connection pressure chambers (327, 326) when the release piston (320) is in a first stop position. The release piston (320) moves the closing body (340), in the second stop position, into an opening position. The release piston (320) is pressurizable on a first pressure surface (A1) from a first side via a third connection pressure chamber (324) and on a second pressure surface (A2) from a second side via a second connection pressure chamber (326). The closing body (340) is pressurized, in the closing position, from a first side via the second connection pressure chamber (326) on a first pressure surface (A4) and from a second side via the first connection pressure chamber (327) on a second pressure surface (A3) of the closing body (34).

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

The present invention relates to a subsea hydraulic control device (10) for hydraulically controlling a subsea module (2). The control device (10) comprises a hydraulic distribution unit (12) with a valve unit (13) and a manifold unit (50), where hydraulic fluid lines are provided in the valve unit (13) and in the manifold unit (50). The hydraulic distribution unit (12) comprises a low pressure hydraulic input port (21) connectable to a low pressure fluid source (LP) and connected to a low pressure fluid line (22) within the hydraulic distribution unit (12), a high pressure hydraulic input port (31) connectable to a high pressure fluid source (HP) and connected to a high pressure fluid line (32) within the hydraulic distribution unit (12), a return port (41) connectable to a return fluid reservoir (R) and connected to a return fluid line (42) within the hydraulic distribution unit (12) and a number of hydraulic output ports (24, 34) connectable to subsea actuators (A) of the subsea module (2). A section of the low pressure fluid line (22) is provided as a first fluid bore (B22) in the manifold unit (50) and a section of the high pressure fluid line (32) is provided as a second fluid bore (B32) in the manifold unit (50). The configuration of the respective bores (B22, B32) in the manifold unit (50) is determining which of the output ports (24, 34) being a low pressure output port (24) connected to the low pressure fluid line (22) and which of the output ports (24, 34) being a high pressure output port (34) connected to the high pressure fluid line (32).

A tillage implement has a frame with a center section and first and second outer wing sections hingedly attached to respective outer ends of the center section. Controlling a pressure in a secondary side of a hydraulic circuit enables adjustment of the downward pressure precharge provided by hydraulic cylinders based on a desired stiffness of the implement. Flow from a hydraulic supply through a pressure-reducing valve puts the downward pressure precharge on gauge wheels. Once this desired downward pressure precharge has been achieved, flow from the hydraulic supply is shut off and a check valve holds the pressure such that the hydraulic cylinders hold the gauge wheels in the desired position.

A pressure back-up valve (300) includes a release piston (320) movable between first and second stop positions and a closing body (340) movable to a closing position in which this separates first and second connection pressure chambers (327, 326) when the release piston (320) is in a first stop position. The release piston (320) moves the closing body (340), in the second stop position, into an opening position. The release piston (320) is pressurizable on a first pressure surface (A1) from a first side via a third connection pressure chamber (324) and on a second pressure surface (A2) from a second side via a second connection pressure chamber (326). The closing body (340) is pressurized, in the closing position, from a first side via the second connection pressure chamber (326) on a first pressure surface (A4) and from a second side via the first connection pressure chamber (327) on a second pressure surface (A3) of the closing body (34).

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.

A fluidic control system (1) for controlling a vehicle, which includes a controller (2) and a closed fluidic circuit. The circuit includes a pump (3) for pressurizing fluid in the circuit, valve means (40, 50, 60), an actuator (4, 5, 6) and a precharge accumulator (7). The valve means (40, 50, 60) is fluidly connected to the inlet and outlet of the pump (3) and the actuator (4, 6) is fluidly connected to the valve means (40, 50, 60) for selectively receiving pressurized fluid therefrom. The precharge accumulator (7) includes a movable member (73, FIG. 2) that describes a variable volume (71) fluidly connected to the circuit between the valve means (40, 50, 60) and the inlet of the pump (3). The system (1) also includes a sensor (70) for determining the position of the movable member (73) for estimating the quantity of fluid and/or detecting an abnormal pressure variation within the circuit.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

In one embodiment, a system, comprising: one or more pairs of oppositely rotatable, laterally extending rolls, wherein for each pair, at least one of the rolls is moveable relative to the other of the rolls; a hydraulic circuit, comprising: a tensioner circuit comprising: for each pair of rolls, one or more pairs of hydraulic cylinders arranged in parallel, each configured to resist movement of the at least one of the rolls at a respective end of the at least one of the rolls; an accumulator arranged in parallel to the hydraulic cylinders; and plural control valves; and a computing system configured to cause the one or more pairs of hydraulic cylinders to adjust the resistance to movement of the at least one of the rolls of the respective pair of rolls by sending signals to one or more of the plural control valves.

A hydraulic circuit for a lift truck comprises a feed-through cylinder communicating with a free lift cylinder and a lift cylinder.