This invention discloses in particular an actuation cylinder (10) for controlling the movement of a ring-gate (40) of a hydraulic machine, said actuation cylinder (10) comprising a body (18) forming a first chamber (22) provided with a first duct (26) and a second chamber (24) provided with a second duct (28) which are designed to receive an actuating fluid through said first duct (26) and said second duct (28), said chambers being separated from one another by a piston (20) connected to an actuating rod (14) and able to move in said body in a first direction in which the volume of the second chamber increases while the volume of the first chamber decreases, and in a second direction in which the volume of the second chamber decreases while the volume of the first chamber increases, said piston being provided with a rod (30) connected in said second chamber to an area (20b) of the piston turned toward said second chamber, said area (20b) having a surface less than an area (20a) of the piston turned toward the first chamber.

An actuation system for controlling flight control members of a vehicle. Each flight control member is controlled by two or more linear hydraulic actuators. Synchronization members extend between the hydraulic actuators on the same flight control members to synchronize the movements of the hydraulic actuators for consistent movement across the length of the flight control members. Brakes can maintain the positions of the synchronization members and thus the flight control members. Motors can provide for moving the synchronization members to control the positioning of the hydraulic actuators and flight control members.

A harvester head may include a position adjustable reel having a first segment and a second segment, a hydraulic supply comprising a pump and a reservoir, a first plurality of hydraulic cylinders coupled to the first segment to reposition the first segment, a second plurality of hydraulic cylinders coupled to the second segment to reposition the second segment, a first bidirectional valve operably coupled between the hydraulic supply and the first plurality of hydraulic cylinders, a second bidirectional valve operably coupled between the hydraulic supply and the second plurality of hydraulic cylinders, at least one sensor to sense relative positioning of the first segment and the second segment and a controller. The controller may output control signals to the first bidirectional valve and the second bidirectional valve based upon signals from the at least one sensor to synchronize positioning of the first segment and the second segment.

A harvester head may include a position adjustable reel having a first segment and a second segment, a hydraulic supply comprising a pump and a reservoir, a first plurality of hydraulic cylinders coupled to the first segment to reposition the first segment, a second plurality of hydraulic cylinders coupled to the second segment to reposition the second segment, a first bidirectional valve operably coupled between the hydraulic supply and the first plurality of hydraulic cylinders, a second bidirectional valve operably coupled between the hydraulic supply and the second plurality of hydraulic cylinders, at least one sensor to sense relative positioning of the first segment and the second segment and a controller. The controller may output control signals to the first bidirectional valve and the second bidirectional valve based upon signals from the at least one sensor to synchronize positioning of the first segment and the second segment.

A hydraulic system includes first and second control valves controlling a flow rate of operation fluid to be supplied to first and second hydraulic actuators, respectively, a supply fluid tube connecting the first control valve and the second control valve and being connected to a return fluid tube, and a discharge fluid tube connected to the second control valve. The second control valve is switched between primary, secondary, and tertiary positions, the primary position blocking between the supply fluid tube and the discharge fluid tube and allowing return fluid to be supplied to the second hydraulic actuator, the secondary position communicating between the supply fluid tube and the discharge fluid tube and stopping supplying the return fluid to the second hydraulic actuator, and the tertiary position communicating between the supply fluid tube and the discharge fluid tube and allowing the return fluid to be supplied to the second hydraulic actuator.

A hydraulic system includes first and second control valves controlling a flow rate of operation fluid to be supplied to first and second hydraulic actuators, respectively, a supply fluid tube connecting the first control valve and the second control valve and being connected to a return fluid tube, and a discharge fluid tube connected to the second control valve. The second control valve is switched between primary, secondary, and tertiary positions, the primary position blocking between the supply fluid tube and the discharge fluid tube and allowing return fluid to be supplied to the second hydraulic actuator, the secondary position communicating between the supply fluid tube and the discharge fluid tube and stopping supplying the return fluid to the second hydraulic actuator, and the tertiary position communicating between the supply fluid tube and the discharge fluid tube and allowing the return fluid to be supplied to the second 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.

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.

In one aspect, a piston assembly for a fluid-driven actuator may include a piston defining a passage extending between first and second chambers of the actuator. The piston assembly may further include a valve having a valve head and a valve stem. The valve may be positioned within the passage and slidable between an open position and a closed position. The valve stem may extend outward from the passage into the second chamber when the valve is positioned in the closed position. Additionally, the piston assembly may include a spring compressed between the valve head and the piston. The spring may be configured to bias the valve to the closed position. The valve may be configured to move to the open position when a pressure in the second chamber exceeds a pressure threshold or when the valve stem contacts a cylinder of the fluid-driven actuator.

A control system may be used to control actuators that actuate movement of flight control surfaces of an aircraft. Each actuator is couplable to a flight control surface and includes a motion control assembly having a hydraulic motor and a drive path from the hydraulic motor to the flight control surface. Each hydraulic motor includes an extend port and a retract port. The system includes a hydraulic control module fluidly connected to the extend port and the retract port of each hydraulic motor and a controller operable to output hydraulic power from the hydraulic control module to the motion control assembly to actuate movement of the flight control surfaces. The controller is configured to identify an actuator that positionally leads the other actuators and reduce hydraulic power to the motion control assembly assigned to such actuator.