Abstract: A servo valve comprising: a fluid transfer valve assembly includes a valve body having a supply port and a control port (C). The valve body cincludes first and second nozzles and a drive member therebetween, arranged to regulate flow of fluid from the supply port to the control port in response to a control signal. The drive member comprises an elongate member arranged to rotate in response to the control signal, and a cylindrical disk mounted on, and arranged to rotate with, the elongate member, between the first and second nozzles, the cylindrical disk having a cam profile such as to vary the spacing (A, B) between the disk and at least one of the nozzles as the cylindrical disk rotates relative to the first and second nozzles.

Abstract: A damping valve for a hydraulic damper (D) comprises a valve housing comprising an inlet chamber and an outlet chamber. A housing valve seat is arranged between the inlet chamber and the outlet chamber. A valve element having a cylindrical first portion is slidably received in a cylindrical bore of the valve housing and a second portion has a valve surface for selectively engaging and disengaging the housing valve seat to allow passage of hydraulic fluid between the inlet chamber and the outlet chamber. A spring element is mounted within the valve housing for biasing the valve element into engagement with the housing valve seat. The bore of the valve housing has a closed end defining a bore chamber between an end of the first portion of the valve element and the closed end of the bore. A first passage provides fluid communication between the bore chamber and the inlet chamber.

Abstract: A servo valve comprises a first spool extending along a first spool axis, a second spool extending along a second spool axis, a first piezoelectric actuator, and a second piezoelectric actuator. The first piezoelectric actuator is operatively connected to the first spool for translating the first spool in response to a voltage applied thereto. The second piezoelectric actuator is operatively connected to the second spool for translating the second spool in response to a voltage applied thereto.

Abstract: A servo valve comprises a first spool extending along a first spool axis, a second spool extending along a second spool axis, a first piezoelectric actuator, and a second piezoelectric actuator. The first piezoelectric actuator is operatively connected to the first spool for translating the first spool in response to a voltage applied thereto. The second piezoelectric actuator is operatively connected to the second spool for translating the second spool in response to a voltage applied thereto.

Abstract: A servo valve includes: a fluid transfer valve assembly comprising a supply port and a control port (PA, PB); a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive means configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive means comprises an elongate member arranged to rotate in response to the control signal. The elongate member has a cam profile in the fluid flow path such as to vary the pressure acting on the ends of the spool as the cam profile rotates.

Abstract: A damping valve for a hydraulic damper (D) comprises a valve housing comprising an inlet chamber and an outlet chamber. A housing valve seat is arranged between the inlet chamber and the outlet chamber. A valve element having a cylindrical first portion is slidably received in a cylindrical bore of the valve housing and a second portion has a valve surface for selectively engaging and disengaging the housing valve seat to allow passage of hydraulic fluid between the inlet chamber and the outlet chamber. A spring element is mounted within the valve housing for biasing the valve element into engagement with the housing valve seat. The bore of the valve housing has a closed end defining a bore chamber between an end of the first portion of the valve element and the closed end of the bore. A first passage provides fluid communication between the bore chamber and the inlet chamber.

Abstract: An apparatus for converting rotational movement into linear movement is disclosed. The apparatus comprises: a screw member having a threaded external surface and a sleeve member having a threaded interior surface for receiving the threaded external surface of the screw member, wherein the threaded surfaces are configured so that rotation of the screw member relative to the sleeve member, in use, causes the screw member to move axially relative to the sleeve member. The apparatus may also comprise a force applicator for applying pressure to the region between the screw member and sleeve member so as to urge the external surface of the screw member and the opposing interior surface of the sleeve member apart from each other.

Abstract: A servovalve includes: a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive assembly comprises a piezoelectric actuator configured to vary the flow of fluid to respective ends of the valve spool in response to the control signal.

Abstract: A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive assembly comprises a steerable jet pipe moveable by an amount determined by the control signal to cause corresponding movement of the valve spool. The jet pipe terminates at one end in a nozzle and at the other end being in fluid flow engagement with and fixedly connected to a fluid supply torsion tube arranged to receive fluid from a fluid source. Movement of the valve spool is caused by fluid flowing from the nozzle to engage with the valve spool.

Abstract: A check valve has a valve housing defining a first valve opening and a second valve opening. A first flapper is pivotably mounted around a first axis for rotation relative to the housing between an open position at which it permits fluid flow through the first valve opening and a closed position at which it prevents fluid flow through the first valve opening. A second flapper is pivotably mounted around a second axis for rotation relative to the housing between an open position at which it permits fluid flow through the second valve opening and a closed position at which it prevents fluid flow through the second valve opening. The first axis is spaced laterally from the second axis. A method is also disclosed.

Abstract: A check valve comprises an annular housing defining a generally circular opening. A plurality of radially extending arms extend across the circular opening from the centre of the valve housing to respective nodes at the periphery of the valve housing. A plurality of cross arms extend between circumferentially adjacent nodes, thereby dividing the circular opening into a plurality of primary, generally triangular radially inner openings and a plurality of secondary, generally segment shaped radially outer openings. A plurality of primary, generally triangular flapper elements close the primary openings and a plurality of secondary, generally segment shaped flapper elements close the secondary openings. Respective mounting posts are arranged at a respective node and a respective hinge pin is mounted between respective circumferentially adjacent mounting posts.

Abstract: A servo valve comprising: a fluid transfer valve assembly comprising a supply port and a control port (PA, PB); a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive means configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the drive means comprises a piezo actuator element mounted within and axially movable with the valve spool, the piezo actuator configured to extend axially in response to the control signal to cause corresponding axially movement of the spool

Abstract: A servovalve includes a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the drive assembly comprises a first fluid channel providing a flow path for fluid from the supply port to a first end of the spool and provided with a first flow control orifice. The assembly also includes a second fluid channel providing a rotating element provided with a cam profile located between the first flow control orifice and the second flow control orifice. The assembly also includes drive means arranged to rotate the rotating element.

Abstract: A hydraulic servo valve is provided. The servo valve comprises a fluid injection cavity and at least one fluid injection opening disposed in the cavity that is configured to supply fluid to the cavity. A pair of fluid receiving openings is disposed in the cavity, and a member is disposed between the pair of openings. The member is bendable and/or rotatable in order to selectively open or occlude each of the openings.

Abstract: A hydraulic servo valve comprising a pair of opposing receiving ports, a piston disposed between the pair of opposing receiving ports and an actuator in contact with the piston. The actuator is configured to provide axial movement of the piston in response to being actuated. The piston comprises a pair of opposed openings that are in operable fluid communication with a respective one of each of the receiving ports, and the axial movement of the piston is configured to vary the amount of a fluid pressure communicated between a respective one of the openings and receiving ports.

Abstract: A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive assembly comprises a steerable jet pipe moveable by an amount determined by the control signal to cause corresponding movement of the valve spool. The jet pipe terminates at one end in a nozzle and at the other end being in fluid flow engagement with and fixedly connected to a fluid supply torsion tube arranged to receive fluid from a fluid source. Movement of the valve spool is caused by fluid flowing from the nozzle to engage with the valve spool.

Abstract: A stop pin for a check valve includes a first end and a second end and extending from the first end to the second end in a longitudinal direction along a longitudinal axis. The stop pin also includes at least one slot therein extending in said longitudinal direction, said at least one slot defining a respective at least one flexible, cantilevered tongue having a free end and a connected end connected to said stop pin.

Abstract: A servo valve comprising first and second nozzles and first and second piezoelectric actuators arranged to control fluid flow through the first and second nozzles respectively. A first fluid flow path is defined between the first nozzle and the first piezoelectric actuator and a second fluid flow path is defined between the second nozzle and the second piezoelectric actuator. The first and second piezoelectric actuators are arranged such that applying a voltage to the first and second piezoelectric actuators causes a change in dimension thereof, which acts to open or restrict said first and second fluid flow paths respectively.

Abstract: A servo valve includes first and second nozzles spaced apart from each other, an elongate control member positioned between the nozzles, and a solenoid assembly surrounding at least a portion of the control member. The elongate control member has a first end and an opposing second end. The control member is configured to translate in response to the solenoid assembly being energised, such that the first end is moved towards the first nozzle and the second end is moved away from the second nozzle or the first end is moved away from the first nozzle and the second end is moved towards the second nozzle.

Abstract: A check valve including a valve housing defining a pair of valve openings; a pair of flappers pivotably mounted for rotation relative to the housing between an open position in which they permit fluid flow through the respective valve openings and a closed position in which they prevent fluid flow through the valve openings; and a stop element arranged such that the flappers will contact the stop element in their open positions. Each flapper includes a primary flapper element pivotally mounted to a hinge pin that extends across the valve, and a secondary flapper element. The primary flapper element further includes at least one flapper opening formed therethrough. The secondary flapper element is pivotally mounted such that it may rotate relative to the primary flapper element for opening and closing the at least one flapper opening in the primary flapper element.