An example valve includes: a piston movable between a neutral position and an actuated position, wherein in the neutral position: a second port of the valve is fluidly coupled to a first port, and a third port is fluidly decoupled from the second 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 a piston in a distal direction; a first feedback spring; and a second feedback spring disposed in series with the first feedback spring, wherein the first feedback spring and the second feedback spring cooperate to apply a biasing force in a proximal direction on the piston against the fluid force, wherein the piston is configured to move to the actuated position based on a relationship between the fluid force and the biasing force.

A system for damping mass-induced vibrations in a machine having a long boom or elongate member, the movement of which causes mass-induced vibration in such boom or elongate member. The system comprises multiple pressure sensors operable to measure pressure fluctuations in the hydraulic fluid pressures in the non-load holding and load holding chambers of a hydraulic actuator connected to the boom or elongate member that result from mass-induced vibration, and a processing unit operable to control a first control valve spool in a pressure control mode and a second control valve spool in a flow control mode in order to adjust hydraulic fluid flow to the actuator's load holding chamber to dampen the mass-induced vibration. The system further comprises a control manifold fluidically interposed between the actuator and control valve spools that causes the first and second control valve spools to operate, respectively, in pressure and flow control modes.

An example valve includes: a piston movable between a neutral position and an actuated position, wherein in the neutral position: a second port of the valve is fluidly coupled to a first port, and a third port is fluidly decoupled from the second 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 a piston in a distal direction; a first feedback spring; and a second feedback spring disposed in series with the first feedback spring, wherein the first feedback spring and the second feedback spring cooperate to apply a biasing force in a proximal direction on the piston against the fluid force, wherein the piston is configured to move to the actuated position based on a balance between the fluid force and the biasing force.

An example valve includes a main stage, a pilot stage, and a solenoid actuator. The main stage includes a sleeve and a piston axially movable within the sleeve. The piston defines a cavity therein. The pilot stage includes a pilot pin received at, and axially movable in, the cavity of the piston, where the piston forms a pilot seat at which the pilot pin is seated when the valve is in a closed state. The solenoid actuator includes a solenoid coil, an armature, and a solenoid spring. The solenoid spring applies a biasing force in a distal direction on the pilot pin to seat the pilot pin at the pilot seat. Energizing the solenoid coil causes the armature to move in a proximal direction, thereby reducing the biasing force that the solenoid spring applies on the pilot pin.

A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line (4), and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.

A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line, and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.

An example valve includes a main stage, a pilot stage, and a solenoid actuator. The main stage includes a sleeve and a piston axially movable within the sleeve. The piston defines a cavity therein. The pilot stage includes a pilot pin received at, and axially movable in, the cavity of the piston, where the piston forms a pilot seat at which the pilot pin is seated when the valve is in a closed state. The solenoid actuator includes a solenoid coil, an armature, and a solenoid spring. The solenoid spring applies a biasing force in a distal direction on the pilot pin to seat the pilot pin at the pilot seat. Energizing the solenoid coil causes the armature to move in a proximal direction, thereby reducing the biasing force that the solenoid spring applies on the pilot pin.

Disclosed are an adjustable load pressure compensation balancing system, an end cover, and a counterbalance valve. The adjustable load pressure compensation balancing system comprises: an adjustable orifice control module and a counterbalance valve control module, wherein the adjustable orifice control module is used for receiving control oil generated when a luffing system descends and oil from a descending cavity of a luffing cylinder; the counterbalance valve control module is used for receiving the control oil generated when the luffing system descends; the pressure applied to the counterbalance valve control module by the control oil is maximum when the luffing system starts to descend, and then decreases gradually; and the pressure applied to the adjustable orifice control module by the oil from the descending cavity is minimum when the luffing system starts to descend, and then increases gradually.

Embodiments of the present invention disclose a valve. The valve includes: a valve casing, a main valve spool and a counterbalance valve spool. The counterbalance valve spool is disposed in a main valve spool internal cavity of the main valve spool and is slidable between a first counterbalance valve spool position and a second counterbalance valve spool position. The counterbalance valve spool includes: a counterbalance valve spool body; and a first counterbalance valve spool recess formed on an outer periphery of the counterbalance valve spool body. In a state where the counterbalance valve spool is in the first counterbalance valve spool position, an inlet of an outlet passage of the main valve spool is closed by the counterbalance valve spool; and in a state where the counterbalance valve spool is in the second counterbalance valve spool position, the inlet of the outlet passage of the main valve spool is opened by the counterbalance valve spool through the first counterbalance valve spool recess of the counterbalance valve spool, so that a second working port is in communication with a return port through an inlet passage configured for the second working port, the first counterbalance valve spool recess and the outlet passage.

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.