An example valve includes a first port fluidly coupled to a source of fluid, a second port fluidly coupled to an actuator, a third port fluidly coupled to a reservoir, and a fourth port configured to export a load-sense (LS) fluid signal. The valve can operate in: a neutral state, wherein fluid is allowed to flow from the second port to the third port, while the first port and the fourth port are blocked; a first actuated state, wherein fluid flow is throttled from the second port to the third port, while the first port and the fourth port remain blocked; or a second actuated state, wherein fluid flow from the second port to the third port is blocked, while fluid flow is allowed from the first port to the second port and from the second port to the fourth port.

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, and 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. The hydraulic system includes a first fluid tube in which a return fluid flows toward the second control valve. The first fluid tube couples the first control valve to the second control valve. The hydraulic system includes a second fluid tube in which a supply fluid flows toward to the first hydraulic actuator. The second fluid tube being connected to the first hydraulic actuator. The hydraulic system further a third fluid tube in which the return fluid in the first fluid tube flows toward the second fluid tube.

An example valve includes: a first port fluidly coupled to a chamber of an actuator; a second port fluidly coupled to a reservoir; a third port configured to provide an output pilot fluid signal and receive an input pilot fluid signal; a fourth port fluidly coupled to a source of fluid; a main poppet configured to be subjected to a first fluid force of fluid received at the first port acting on the main poppet in a proximal direction to cause the main poppet to be seated at a main poppet seat to block fluid flow to and from the first port; a piston configured to move axially to contact the main poppet; and a spool that is axially movable between a first position and a second position to operate the valve in either a pilot-operated check valve mode of operation or a proportional flow control mode of operation.

Distributed trailing edge wing flap systems are described. An example wing flap system for an aircraft includes a flap and an actuator. The flap is movable between a deployed position and a retracted position relative to a fixed trailing edge of a wing of the aircraft. The actuator is to move the flap relative to the fixed trailing edge. The actuator is hydraulically drivable via first pressurized hydraulic fluid to be supplied by a hydraulic system of the aircraft. The actuator is also hydraulically drivable via second pressurized hydraulic fluid to be supplied by a local power unit. The local power unit is selectively connectable to an electrical system of the aircraft. The electrical system is to power the local power unit to supply the second pressurized hydraulic fluid.

A large manipulator includes a chassis, a turntable arranged on the chassis and rotatable around a vertical axis via a rotary drive, and an articulated mast including two or more mast segments pivotably-movably connected, via articulated joints, with the respectively adjacent turntable or mast segment via a respective drive. The large manipulator further includes a mast sensor system configured to detect position of at least one point of the articulated mast or a pivot angle of at least one articulated joint and configured to generate sensor output signals. The large manipulator further includes a control device configured to actuate the drive in a normal operation for mast movement and to limit speed of movement of the articulated mast depending upon the sensor output signals. The drive is manually controllable in an emergency operation. The large manipulator further includes at least one limiting means, which, in the emergency operation, limit speed of the drive to a pre-specified maximum value.

A control valve assembly for indirect pneumatic control and method for controlling a working fluid pressure, which enable precise, sensitive and speed-variable controlling. The assembly includes two valve units, a working fluid inlet, and a control fluid inlet. A working fluid channel connects the working fluid inlet through the two valve units to an outlet. A valve piston arranged within a valve cylinder of the valve units is movable between open and closed positions. A spring element biases the valve piston toward the closed position, and a control pressure chamber applies a control pressure counteracting the spring element's bias. When a control pressure is applied in the first chamber, the first valve piston is moved to the open position. Two opposite valve surfaces form a valve opening opened at varying widths when the valve piston is moved in the valve cylinder because of a changing control pressure, and the working pressure can be finely adjusted corresponding to the valve opening width depending on the control pressure.

A system for enabling an upper swing body of construction equipment to swing freely. A working device is attached to the upper swing body to lift and move an object. A swing motor is connected to a power unit to swing the upper swing body. A controller is electrically connected to the working device and the swing motor to detect forces applied to the working device, and based on the detected forces, generating a control signal to control the swing motor so that the upper swing body swings freely. The system enables the upper swing body to swing freely to reduce energy consumption while ensuring safety when the upper swing body lifts a load.

An example valve includes: a piston movable between a neutral position and an actuated position; a check poppet configured to be coupled to the piston, wherein in the neutral position, the check poppet is seated on a seat formed on an interior peripheral surface of the housing and blocks fluid at the first port; a solenoid actuator sleeve movable between an unactuated state and an actuated state, wherein in the actuated state, the solenoid actuator sleeve allows pilot fluid to apply a fluid force on the piston in a distal direction; and a feedback spring that applies a biasing force in a proximal direction on the piston against the fluid force, wherein the piston and the check poppet are configured to move axially to the actuated position based on a relationship between the fluid force and the biasing force.

A valve member having a supply pressure and a method of controlling the supply pressure in the valve member includes a valve body having a fluid inlet, a fluid outlet, and a controlled port. The valve member includes a spool moveable within the valve body to fluidly connect at least one of the fluid inlet and the fluid outlet with the controlled port. The spool includes an end in fluid communication with a control pressure port and a pin received within the end of the spool that is moveable relative to the spool. Fluid flow through the control pressure port acts against a cross-sectional area of the pin and an annular area of the spool to modulate the supply pressure through the valve member.

A flow control circuit for an actuator is provided. The actuator includes a first chamber and a second chamber, wherein the first chamber experiences a volume change that is larger than a volume change experienced by the second chamber upon actuation of the actuator. The flow control circuit includes a first port configured to be connected to the first chamber, a second port configured to be connected to the second chamber, and a flow control valve assembly including one or more valves configured to provide a flow of pressurized fluid from a pressurized fluid source to one of the first and second ports along a fluid supply path and further configured to provide a flow of fluid from the other of the first and second ports to a fluid sink along a fluid return path. The flow control circuit further includes a fluid bypass path comprising a bypass valve.