A hydraulic circuit for a pair of cylinders of an articulation system includes a pump, a reservoir, a directional control valve (DCV), a pair of actuator valves (AVs) and an articulation charge circuit (ACC). The DCV is fluidly coupled to the pump, the reservoir and the pair of cylinders via a supply line, a fluid return line and a pair of cylinder supply lines (CSLs) respectively. Each CSL has a load check valve (LCV) therein. The AVs are fluidly coupled with the DCV and the pump via a pilot supply line (PSL) for actuating movement of the DCV. The ACC, associated with the PSL and each cylinder supply line downstream of the associated LCV, charges a corresponding CSL with fluid from the PSL for increasing a pressure in the corresponding CSL when the pressure in the corresponding CSL falls below the pressure of fluid associated with the PSL.

The invention concerns a device for the direct recovery of hydraulic energy in a machine, comprising at least one single-acting storage cylinder-piston device with a storage cylinder, a storage cylinder-piston and a storage cylinder chamber, with at least one differential cylinder-piston device with a differential cylinder comprising a separate rod side and base side, and with at least one hydraulic accumulator, which may be connected to the storage cylinder-piston device and/or the differential cylinder-piston device, wherein the potential energy of the storage cylinder-piston device, which retracts under a compressive load, may be at least partially stored in the hydraulic accumulator.

An apparatus for monitoring the pressurisation of a control valve for a hydraulic actuator and a control valve. The apparatus including a spool movable along an axis (X), wherein the spool is configured to control the flow of hydraulic fluid through the control valve based on its position along the axis (X), and wherein in an unpressurised state of the control valve the spool occupies a first axial position, and in a pressurised state of the control valve the spool occupies a second, different axial position. The apparatus also including a position sensor configured to monitor the position of the spool within the control valve and detect whether the spool occupies the first axial position or the second axial position, wherein the first axial position and the second axial position correspond to neutral positions of the spool.

An example valve includes: a sleeve; a first poppet configured to be seated on a first seat defined on an interior surface of the sleeve when the valve is in a closed state, and where the first poppet is configured to move axially within the sleeve; a second poppet disposed, at least partially, in the first poppet, where the second poppet is configured to be seated on a second seat defined on an interior surface of the first poppet, and where the second poppet is configured to move axially within the first poppet; a first spring that interfaces with the second poppet and applies a first force on the second poppet in a distal direction toward the second seat; and a second spring that interfaces with the second poppet and applies a second force on the second poppet in a proximal direction opposite the distal direction.

An example valve includes: a sleeve; a first poppet configured to be seated on a first seat defined on an interior surface of the sleeve when the valve is in a closed state, and where the first poppet is configured to move axially within the sleeve; a second poppet disposed, at least partially, in the first poppet, where the second poppet is configured to be seated on a second seat defined on an interior surface of the first poppet, and where the second poppet is configured to move axially within the first poppet; a first spring that interfaces with the second poppet and applies a first force on the second poppet in a distal direction toward the second seat; and a second spring that interfaces with the second poppet and applies a second force on the second poppet in a proximal direction opposite the distal direction.

A hydraulic system includes: an arm hydraulic cylinder; a first hydraulic pump and a second hydraulic pump; an arm first direction switching valve; an arm second direction switching valve; and a controller that controls an operation of the arm second direction switching valve when the arm hydraulic cylinder is extended and operated. Further, the arm first direction switching valve incorporates an arm regeneration passage capable of supplying oil when the arm hydraulic cylinder is extended and operated, and the controller monitors a pressure state of the arm hydraulic cylinder, and when determining that oil flow through the arm regeneration passage is possible, the controller blocks oil flow between the arm hydraulic cylinder and the arm second direction switching valve, and otherwise, the controller operates the arm second direction switching valve so that oil can be supplied from the second hydraulic pump to the bottom chamber.

An apparatus for monitoring the pressurisation of a control valve for a hydraulic actuator and a control valve. The apparatus including a spool movable along an axis (X), wherein the spool is configured to control the flow of hydraulic fluid through the control valve based on its position along the axis (X), and wherein in an unpressurised state of the control valve the spool occupies a first axial position, and in a pressurised state of the control valve the spool occupies a second, different axial position. The apparatus also including a position sensor configured to monitor the position of the spool within the control valve and detect whether the spool occupies the first axial position or the second axial position, wherein the first axial position and the second axial position correspond to neutral positions of the spool.

An electro-hydraulic valve actuator having a modular manifold assembly with a network of channels that fluidly connect a hydraulic cylinder assembly to a hydraulic power assembly. The hydraulic cylinder assembly includes a piston rod that can directly or indirectly open or close a process valve. The hydraulic power assembly has a main pump and motor, and the manifold assembly includes a main manifold block to which is mounted the hydraulic cylinder assembly and the main pump and motor. The main manifold block has pluggable channel ports that can be unplugged to provide fluid communication with corresponding channel ports of at least one auxiliary manifold block that can be mounted to and integrated with the main manifold block. The at least one auxiliary manifold block has either a second pump and motor or a manual override pump.

A hydraulic valve assembly includes a first spool valve and a first selector valve for actuating a first hydraulic consumer port or a second hydraulic consumer port, and a second spool valve and a second selector valve for actuating a third hydraulic consumer port or a fourth hydraulic consumer port. A shut-off valve is arranged in a common pressure channel. A branch channel with first and second pressure branch channels branches off the pressure channel upstream of the shut-off valve. The first selector valve connects the first pressure branch channel to a first connection line in a first switching position and connects the second pressure branch channel to a second connection line in a second switching position. The second selector valve, in a first switching position, connects the first connection line to the control channel and, in a second switching position, connects the second connection line to the control channel.

A hydraulic system for a working machine, includes a first hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a control valve to control the hydraulic device based on an operation extent of the operation member, a holding member to set a held operation extent that is the operation extent held in the operation of the operation member, and a pedal to be operated to change the held operation extent set by the holding member.