The present invention aims at providing a new electro-hydraulic control terminal adopting modularized and configured cartridge valve RHCV. It has obvious advantages of hybrid combination and flexible customization when RHCV is applied in the independent control terminals based on “single loop resistance” to control hydraulic actuators including distributed cylinders and motors. It can follow the rules that functional diversities as many as possible can be achieved through technical diversities as few as possible, thus producing a new generation of electro-hydraulic product family and platform to meet the needs of customers.

An example tool includes a hydraulic actuator cylinder; a piston slidably accommodated within the hydraulic actuator cylinder, where the piston includes a piston head and a piston rod extending from the piston head along a central axis direction of the hydraulic actuator cylinder, the piston head divides an inside of the hydraulic actuator cylinder into a first chamber and a second chamber, and the piston rod is disposed in the first chamber and configured to move one or more jaws of the tool; a pump configured to provide pressurized fluid; and a sequence valve configured to block the pressurized fluid from flowing into the second chamber of the hydraulic actuator cylinder until pressure of the pressurized fluid exceeds a threshold pressure value.

To perform a work with the same operability under a dead weight of a front work equipment in any of a float work and a normal work, when a bucket descends in the air, and after contacting the ground, to perform a work with the operability being maintained as it is when performing the float work, and to perform a work while pressurized hydraulic fluid is supplied from a hydraulic pump when performing the normal work. A lower-ing control during a float working mode is performed in a valve passage state in a first region at which the lowering control is performed under the dead weight of the from work equip-ment without being supplied with hydraulic fluid from the hydraulic pump, regardless of whether or not the bucket is in contact with the ground, and the lowering control during a normal working mode is performed in a valve passage state at the first region in a non-ground-contacting state and at a second region in which the hydraulic fluid can be supplied from the hydraulic pump n a ground-contacting state.

A hydraulic control system HCS for controlling a variable ratio transmission of a power generating system. A hydraulic motor/pump unit 140 is operably connected to a superposition gear, and is connected to a hydraulic circuit that comprises an orifice 28 and/or a relief valve 29 that opens at a predetermined hydraulic pressure. The hydraulic circuit switches between a variable low-speed operating mode and a torque limiting high-speed operating mode. In the torque limiting high-speed operating mode the hydraulic motor/pump unit 140 is driven by the superposition gear and drives hydraulic fluid through the orifice 28 and/or relief valve 29 to provide a passive torque limiting function. In the variable low-speed operating mode the hydraulic motor/pump unit 140 drives the superposition gear and the hydraulic control system provides a desired rotor 101 speed by controlling hydraulic fluid flow rate through the hydraulic motor/pump unit 140.

A hydraulic mechanism is mounted on a forklift. The hydraulic mechanism has a control valve and a pressure compensation circuit for compensating pressure within the hydraulic mechanism. The pressure compensation circuit has a relief pressure valve and an unloading valve for releasing pressure within the pressure compensation circuit to a discharge oil passage. Upon instructed to perform cargo handling operation, the unloading valve is switched to an open state, and the relief pressure valve is thereby actuated, so that rapid increase of pressure within the circuit is avoided. Further, the unloading valve is switched to an open state, and the pressure within the hydraulic mechanism is thereby released to the discharge oil passage, so that the cargo handling operation by the tilt cylinder and the lift cylinder is restricted.

An extension boom system for heavy equipment having, the extension boom system including a first actuator mounted on a base, and connecting a second stage, a second actuator mounted on the second stage and connecting the second stage to a third stage, a third actuator mounted on the third stage and connecting the third stage to an extendable portion, and a controller configured to control the first actuator, the second actuator, and the third actuator so as to selectively operate in a first operation mode and a second operation mode. In the first operation mode, the first actuator, the second actuator, and the third actuator are operated substantially simultaneously, and wherein in the second operation mode, two of the first actuator, the second actuator, and the third actuator are actuated substantially simultaneously, while another of the first actuator, the second actuator, and the third actuator is not actuated.

The subject matter of this specification can be embodied in, among other things, a fluid actuator system including a fluid actuator having a housing having an inner wall defining an interior cavity, a piston having a piston head configured for reciprocal movement within the interior cavity, the piston head contacting the inner wall and dividing the interior cavity into a first fluid chamber and a second fluid chamber, a first valve configured to control fluid flow between the first fluid chamber and a bypass conduit, and a second valve configured to control fluid flow between the bypass conduit and the second fluid chamber.

A housing (100) for housing hydraulic components, wherein the hydraulic components are configured for operating a hitch mechanism of a tractor, is a single-body component that is configured to house a plurality of valve mechanism and a reciprocating piston therein. The housing (100) comprises cavities for locating valve mechanisms therein and a cylinder (110) for accommodating a reciprocating piston (210). The housing (100) together with a plurality of valve mechanisms (122, 124, 126, 128, 130, 132) disposed in corresponding cavities, forms a predetermined hydraulic circuit (1000). The hydraulic circuit (1000) has minimum number of leakage joints, minimizes number of components and therefore assembly and machining operations.

A fluid pressure cylinder includes a first cylinder portion and a second cylinder portion disposed in parallel, and a supply-and-discharge port. The first cylinder portion is partitioned by a first piston into a head-side first accumulation chamber and a rod-side second accumulation chamber. The second cylinder portion is partitioned by a second piston into a head-side release chamber and a rod-side drive chamber. Pressurized fluid is supplied to and discharged from the second accumulation chamber and the drive chamber through the supply-and-discharge port. An end of a first piston rod connected to the first piston and an end of a second piston rod connected to the second piston are connected to each other. The first piston includes a communication switching valve switching communication between the first accumulation chamber and the second accumulation chamber, between enabled and disabled.

When viewed in section, a cylinder hole in a fluid pressure cylinder has a polygonal shape including inner circumferential surfaces parallel to a plurality of surfaces constituting a body. A piston has a polygonal outer edge having a shape corresponding to the shape of the cylinder hole and partitions the cylinder hole into a head-side cylinder chamber and a rod-side cylinder chamber. The body is cut off so that a first side surface has a stepped shape, and a solenoid valve is disposed in a solenoid valve arrangement space formed by cutting off the body. The solenoid valve is disposed inside a virtual outer shape defined by most-protruding faces in the respective surfaces.