A wing (9) having a base section (11) and a tip section (13) pivotably connected to the base section (11) such that the tip section (13) is pivotable between a deployed position and a stowed position in which the spanwise length of the wing (9) is smaller than in the deployed position. The wing arrangement also has an actuating arrangement (19) including a linear hydraulic actuator (21) coupled between the base section (11) and the tip section (13) such that it is operable to selectively move the tip section (13) between the deployed position and the stowed position, a first and a second hydraulic connection portion (79a, 79b) connected to the linear hydraulic actuator (21) such that they are in fluid communication with different chamber sections (27a, 27b) of a cylinder (25) of the linear hydraulic actuator (21), and a first hydraulic subsystem (81a) and a second hydraulic subsystem (81b).

A servo-control having at least one movable cylinder that includes a hydraulic directional control valve. The hydraulic valve includes a control shaft that is rotatable about a longitudinal axis, the control shaft being connected to a distributor slide. The servo-control including a stationary abutment member secured to a cylinder and an input lever situated outside the cylinder. The input lever is connected to the control shaft and includes a stop portion arranged in the abutment member. The servo-control includes movement means for moving the input lever longitudinally, a first abutment surface of the abutment member limiting a travel amplitude of the stop portion when the input lever is in a first position.

A servo-control having at least one movable cylinder that includes a hydraulic directional control valve. The hydraulic valve includes a control shaft that is rotatable about a longitudinal axis, the control shaft being connected to a distributor slide. The servo-control including a stationary abutment member secured to a cylinder and an input lever situated outside the cylinder. The input lever is connected to the control shaft and includes a stop portion arranged in the abutment member. The servo-control includes movement means for moving the input lever longitudinally, a first abutment surface of the abutment member limiting a travel amplitude of the stop portion when the input lever is in a first position.

A hydraulic pump to synchronize the operation of a pair of hydraulic actuators wherein each hydraulic actuator comprises a cylinder including a first fluid port and a second fluid port formed in the proximal and distal end portions thereof respectively and having a piston disposed therein coupled to a piston rod at least partially disposed within the corresponding cylinder. The dual hydraulic pump includes a triple gear assembly to alternately feed pressurized hydraulic fluid to the first fluid port of each hydraulic actuator simultaneously or the second fluid port of each hydraulic actuator simultaneously to synchronize the linear movement of each piston and piston rod in a first direction or a second direction.

A hydraulic pump to synchronize the operation of a pair of hydraulic actuators wherein each hydraulic actuator comprises a cylinder including a first fluid port and a second fluid port formed in the proximal and distal end portions thereof respectively and having a piston disposed therein coupled to a piston rod at least partially disposed within the corresponding cylinder. The dual hydraulic pump includes a triple gear assembly to alternately feed pressurized hydraulic fluid to the first fluid port of each hydraulic actuator simultaneously or the second fluid port of each hydraulic actuator simultaneously to synchronize the linear movement of each piston and piston rod in a first direction or a second direction.

The invention relates to a control apparatus for a hydraulic variable-pitch propeller (12) of an aircraft, land vehicle or water vehicle, comprising: a hydraulic oil feed line (24); a control line (16) which can be connected to the variable-pitch propeller (12); a pressure generating device (73) which is connected to the hydraulic oil feed line (24) and provides hydraulic oil with a basic pressure; a servo valve (78) which is arranged downstream of the pressure generating device (73), the input pressure to which servo valve is the basic pressure and the output pressure from which servo valve during normal operation defines a control pressure in the control line (16) and which servo valve is connected to a controller (28) which delivers a control signal for changing the control pressure; and pressure reducing means which are arranged downstream of the servo valve (78) and upstream of the control line (16), which are mechanically actuated and which, in the event of a failure of the servo valve (78), change the control pressure in the control line (16).

The invention relates to a control apparatus for a hydraulic variable-pitch propeller (12) of an aircraft, land vehicle or water vehicle, comprising: a hydraulic oil feed line (24); a control line (16) which can be connected to the variable-pitch propeller (12); a pressure generating device (73) which is connected to the hydraulic oil feed line (24) and provides hydraulic oil with a basic pressure; a servo valve (78) which is arranged downstream of the pressure generating device (73), the input pressure to which servo valve is the basic pressure and the output pressure from which servo valve during normal operation defines a control pressure in the control line (16) and which servo valve is connected to a controller (28) which delivers a control signal for changing the control pressure; and pressure reducing means which are arranged downstream of the servo valve (78) and upstream of the control line (16), which are mechanically actuated and which, in the event of a failure of the servo valve (78), change the control pressure in the control line (16).

A hydraulic actuator includes a hydraulic cylinder; a piston within the hydraulic cylinder and movable in response to movement of hydraulic fluid in a hydraulic circuit coupled to the hydraulic cylinder; a synchronisation connection for receiving an input from a simultaneous transmission line; and a valve for controlling the flow of hydraulic fluid in the hydraulic circuit. The valve is a rotary valve comprising: a first valve section arranged to rotate in either a first rotational direction or a second rotational direction in response to input from the simultaneous transmission line in order to open a hydraulic flow path to the cylinder and urge the piston to move along the hydraulic cylinder in a corresponding first linear direction or second linear direction; and a second valve section arranged to rotate in either the first or second rotational direction.

A hydraulic actuator includes a hydraulic cylinder; a piston within the hydraulic cylinder and movable in response to movement of hydraulic fluid in a hydraulic circuit coupled to the hydraulic cylinder; a synchronisation connection for receiving an input from a simultaneous transmission line; and a valve for controlling the flow of hydraulic fluid in the hydraulic circuit. The valve is a rotary valve comprising: a first valve section arranged to rotate in either a first rotational direction or a second rotational direction in response to input from the simultaneous transmission line in order to open a hydraulic flow path to the cylinder and urge the piston to move along the hydraulic cylinder in a corresponding first linear direction or second linear direction; and a second valve section arranged to rotate in either the first or second rotational direction.

A wing (9) having a base section (11) and a tip section (13) pivotably connected to the base section (11) such that the tip section (13) is pivotable between a deployed position and a stowed position in which the spanwise length of the wing (9) is smaller than in the deployed position. The wing arrangement also has an actuating arrangement (19) including a linear hydraulic actuator (21) coupled between the base section (11) and the tip section (13) such that it is operable to selectively move the tip section (13) between the deployed position and the stowed position, a first and a second hydraulic connection portion (79a, 79b) connected to the linear hydraulic actuator (21) such that they are in fluid communication with different chamber sections (27a, 27b) of a cylinder (25) of the linear hydraulic actuator (21), and a first hydraulic subsystem (81a) and a second hydraulic subsystem (81b).