A forklift, a hydraulic cylinder assembly (100) and a hydraulic device thereof are provided. The hydraulic cylinder assembly (100) includes a cylinder (1) having first, second oil inlets (151, 152) and first, second oil outlets (153, 154) therein; a cylinder liner (2) disposed within the cylinder (1) and being moveable between first and second positions, and defining a first oil port (21) and a second oil port (22) therein; a piston (31) disposed within the cylinder liner (2) and being moveable between a third position and a fourth position; a first oil chamber (41) and a second oil chamber (42) are defined by the cylinder (1), the cylinder liner (2) and the piston (31), the first oil chamber (41) is communicated with the first oil port (21), and the second oil chamber (42) is communicated with the second oil port (22).

A forklift, a hydraulic cylinder assembly (100) and a hydraulic device thereof are provided. The hydraulic cylinder assembly (100) includes a cylinder (1) having first, second oil inlets (151, 152) and first, second oil outlets (153, 154) therein; a cylinder liner (2) disposed within the cylinder (1) and being moveable between first and second positions, and defining a first oil port (21) and a second oil port (22) therein; a piston (31) disposed within the cylinder liner (2) and being moveable between a third position and a fourth position; a first oil chamber (41) and a second oil chamber (42) are defined by the cylinder (1), the cylinder liner (2) and the piston (31), the first oil chamber (41) is communicated with the first oil port (21), and the second oil chamber (42) is communicated with the second oil port (22).

Disclosed is a hydraulic circuit for construction equipment, having a floating function for ground leveling work, which can be implemented by a main control valve. According to the present invention, provided is a flow control valve for construction equipment, having a floating function, comprising: a valve body having, formed therein, a supply path in communication with a pump path to which hydraulic oil is supplied from a hydraulic pump, and first and second actuator paths connected to a hydraulic cylinder driven by the hydraulic oil from the hydraulic pump; a spool switchably built into the valve body for, when switched, communicating the supply path into the first and second actuator paths so as to supply, to the hydraulic cylinder, the hydraulic oil from the hydraulic pump via the supply path and the first actuator path and return, to a tank path, the hydraulic oil discharged from the hydraulic cylinder via the second actuator path; a recycling path for supplying, to a small chamber of the hydraulic cylinder, a portion of the hydraulic oil returned from a large chamber of the hydraulic cylinder to the tank path and recycling the same; and a valve for floating conversion, installed at a predetermined position of the recycling path, wherein, in case of conversion to a floating state by application of pilot pressure to the valve for floating conversion, the large chamber and the small chamber of the hydraulic cylinder are communicated, and a path for supplying the hydraulic oil to the small chamber of the hydraulic cylinder and the recycling path are communicated so as to enable a bi-directional flow of the hydraulic oil.

Disclosed is a hydraulic circuit for construction equipment, having a floating function for ground leveling work, which can be implemented by a main control valve. According to the present invention, provided is a flow control valve for construction equipment, having a floating function, comprising: a valve body having, formed therein, a supply path in communication with a pump path to which hydraulic oil is supplied from a hydraulic pump, and first and second actuator paths connected to a hydraulic cylinder driven by the hydraulic oil from the hydraulic pump; a spool switchably built into the valve body for, when switched, communicating the supply path into the first and second actuator paths so as to supply, to the hydraulic cylinder, the hydraulic oil from the hydraulic pump via the supply path and the first actuator path and return, to a tank path, the hydraulic oil discharged from the hydraulic cylinder via the second actuator path; a recycling path for supplying, to a small chamber of the hydraulic cylinder, a portion of the hydraulic oil returned from a large chamber of the hydraulic cylinder to the tank path and recycling the same; and a valve for floating conversion, installed at a predetermined position of the recycling path, wherein, in case of conversion to a floating state by application of pilot pressure to the valve for floating conversion, the large chamber and the small chamber of the hydraulic cylinder are communicated, and a path for supplying the hydraulic oil to the small chamber of the hydraulic cylinder and the recycling path are communicated so as to enable a bi-directional flow of the hydraulic oil.

A fluid pressure control device includes a switching valve configured to switch an operation of an operate check valve, a relief valve configured to open when a pressure in a load-side pressure chamber reaches a predetermined pressure, and a relief discharge passage configured to lead a relief fluid discharged from the relief valve to a tank. The switching valve includes a piston giving thrust to a spool upon receipt of a pilot pressure on a back surface, a drain chamber defined by the spool and the piston, and a drain passage allowing the drain chamber and a spring chamber to communicate with the relief discharge passage. The relief fluid discharged from the relief valve is discharged to the tank through the relief discharge passage and does not operate the switching valve.

A technique provides enhanced control over a variety of hydraulically actuated devices, e.g. flow control valves. A hydraulic control module is placed in hydraulic communication with an actuator of a hydraulically actuated device. The hydraulic control module comprises features which prevent hydraulic locking of the system. Additionally, the control module may comprise metering features to enable metered flow of actuating fluid. The features may include valves, mini-indexers, flowline configurations, or other features which maintain the ability to shift the hydraulically actuated device and/or provide metering of the actuating fluid.

The invention relates to a hydraulic circuit (10) for an aircraft turboprop comprising a hydraulic fluid tank (16), a pump (14), a component (12) that is supplied with fluid pressurised by the pump (14) and that is selectively put into operation, and a fluid recirculation circuit (20) between the pump discharge (14) and the tank (16) characterised in that it comprises a valve (22) located in the recirculation circuit (20), that is capable of closing the recirculation circuit (20) when the component (12) is not in operation and is capable of opening the recirculation circuit (20) when the component is in operation.

The invention relates to a hydraulic circuit (10) for an aircraft turboprop comprising a hydraulic fluid tank (16), a pump (14), a component (12) that is supplied with fluid pressurised by the pump (14) and that is selectively put into operation, and a fluid recirculation circuit (20) between the pump discharge (14) and the tank (16) characterised in that it comprises a valve (22) located in the recirculation circuit (20), that is capable of closing the recirculation circuit (20) when the component (12) is not in operation and is capable of opening the recirculation circuit (20) when the component is in operation.

A flow control manifold that routes pressurized fluid from one of a first fluid manifold connection and a second fluid manifold connection of the flow control manifold to an input of a work tool and directs return fluid from an outlet of the work tool to the other of the first and second fluid manifold connections not receiving pressurized fluid.

A flow control manifold that routes pressurized fluid from one of a first fluid manifold connection and a second fluid manifold connection of the flow control manifold to an input of a work tool and directs return fluid from an outlet of the work tool to the other of the first and second fluid manifold connections not receiving pressurized fluid.