A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

A hydraulically actuatable jib for a loading crane includes at least two jib extensions, the first jib extension being designed as an outer jib extension and the second jib extension being designed as an inner jib extension. At least two feed cylinders extend and react the at least two jib extensions. A hydraulic circuit for a working fluid includes a retraction line for retracting the feed cylinders in a pressurized manner, and the retraction line opens into the feed cylinder of the outer jib extension. A tank is provided for releasing the working fluid, and a control valve can be switched into an open position when the outer jib extension reaches a defined retraction position, particularly when the outer jib extension is substantially fully retracted. The valve thereby supplies the feed cylinder of the inner jib extension with pressurized working fluid.

A valve structure (1) for driving reversible ploughs (40), comprising a first port (3) adapted to be in fluid communication with a pump (P) in a first configuration of the plough (40) and adapted to be in fluid communication with a tank (T) in a second reversed configuration of the plough (40), and a second port (4) adapted to be in fluid communication with the tank (T) in the first configuration of the plough (40) and adapted to be in fluid communication with the pump (P) in the second reversed configuration of the plough (40), a body (2) which includes a first seat (5) and a second seat (6), the seats housing respective moving spools (13, 14), a first interconnection port (7a) for the connection of the valve structure (1) to a first chamber (10a) of a first hydraulic cylinder (10) for longitudinally aligning the plough (40), and a second interconnection port (7b) for the connection to a second chamber (10b) of the first hydraulic cylinder (10), a third interconnection port (8a) for the connection of the valve structure (1) to a first chamber (12a) of a second hydraulic cylinder (12) for reversing the plough (40), and a fourth interconnection port (8b) for the connection to a second chamber (12b) of the second hydraulic cylinder (12). The valve structure (1) comprises hydraulic components configured to control the relative displacement of the spools (13, 14) to automatically control the movement of the cylinders (10, 12). A check valve (31) enables the fluid to flow in the second reversed configuration of the plough (40).

A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

A valve structure (1) for driving reversible ploughs (40), comprising a first port (3) adapted to be in fluid communication with a pump (P) in a first configuration of the plough (40) and adapted to be in fluid communication with a tank (T) in a second reversed configuration of the plough (40), and a second port (4) adapted to be in fluid communication with the tank (T) in the first configuration of the plough (40) and adapted to be in fluid communication with the pump (P) in the second reversed configuration of the plough (40), a body (2) which includes a first seat (5) and a second seat (6), the seats housing respective moving spools (13, 14), a first interconnection port (7a) for the connection of the valve structure (1) to a first chamber (10a) of a first hydraulic cylinder (10) for longitudinally aligning the plough (40), and a second interconnection port (7b) for the connection to a second chamber (10b) of the first hydraulic cylinder (10), a third interconnection port (8a) for the connection of the valve structure (1) to a first chamber (12a) of a second hydraulic cylinder (12) for reversing the plough (40), and a fourth interconnection port (8b) for the connection to a second chamber (12b) of the second hydraulic cylinder (12). The valve structure (1) comprises hydraulic components configured to control the relative displacement of the spools (13, 14) to automatically control the movement of the cylinders (10, 12). A check valve (31) enables the fluid to flow in the second reversed configuration of the plough (40).

Disclosed are a fork leveling system and a method thereof, and a telescopic boom forklift. The fork leveling system includes an active leveling oil cylinder, a passive leveling oil cylinder and an electric control oil supplement valve, where a rodless cavity of the active leveling oil cylinder is communicated with a rodless cavity of the passive leveling oil cylinder, and a rod cavity of the active leveling oil cylinder is communicated with a rod cavity of the passive leveling oil cylinder; and an oil inlet of the electric control oil supplement valve is connected to an oil pump, and an oil outlet of the electric control oil supplement valve is connected to the rodless cavity of the active leveling oil cylinder and the rod cavity of the active leveling oil cylinder.

A hydraulic system for controlling bleed down and retraction of a boom within a safety envelope includes a backup battery power supply, and at least a first boom lift hydraulic cylinder configured to raise and lower the boom. The first boom lift hydraulic cylinder includes a solenoid bleed valve electrically connected to the backup battery power supply. The hydraulic system also includes an input device controllable by an operator of the boom. The input device may, for instance, be used by the operator to initiate bleed down and retraction of the boom from an elevated position. To accommodate independent failsafe features of the system, the input device is configured to selectively actuate the solenoid bleed valve using electrical power supplied from the backup battery power supply.

A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

Systems and methods for hydraulic droop control of an aircraft wing. One embodiment is a hydraulic droop panel system for an aircraft wing. The hydraulic droop panel system includes a first hydraulic actuator attached to a flap of the aircraft wing, and a second hydraulic actuator attached to a droop panel of the aircraft wing and fluidly coupled with the first hydraulic actuator. The second hydraulic actuator is configured to move the droop panel to a droop position corresponding with movement of the flap and the first hydraulic actuator.

Systems and methods for hydraulic droop control of an aircraft wing. One embodiment is a hydraulic droop panel system for an aircraft wing. The hydraulic droop panel system includes a first hydraulic actuator attached to a flap of the aircraft wing, and a second hydraulic actuator attached to a droop panel of the aircraft wing and fluidly coupled with the first hydraulic actuator. The second hydraulic actuator is configured to move the droop panel to a droop position corresponding with movement of the flap and the first hydraulic actuator.