Abstract: An electromechanical actuator includes: an actuator rod housed in an actuator housing; a linear variable differential transformer “LVDT” fixed to the actuator housing; and an anti-rotation component configured to contact the outer surface of said LVDT. The outer surface of the linear variable differential transformer comprises a first anti-rotation surface feature and the anti-rotation component comprises a second anti-rotation surface feature. The first and second anti-rotation features are sized and shaped relative to each other such that, when in contact with each other, they are configured to prevent rotation of the actuator rod in use.

Abstract: An actuator pressure intensifying assembly includes a mode valve and a gear motor assembly, the mode valve arranged to receive, at an input port, a supply pressure and to provide, at an output port, a control pressure to an actuator, the mode valve further configured to move, in response to the supply pressure exceeding a predetermined activation threshold, from a first mode in which the supply pressure flows directly from the input port to the output port in a first fluid flow path, and a second mode in which the supply pressure flows from the input port to the output port in a second fluid flow path which includes the gear motor assembly between the input port and the output port which intensifies the supply pressure such that the control pressure is higher than the supply pressure.

Abstract: A force fight mitigation system comprising: control means configured to provide a position command to each of two or more actuators arranged to position a surface, the position command indicative of a desired position of the actuator relative to the surface; means to detect the actual position of the actuator relative to the surface in response to the position command; and means to determine an offset between the desired position and the actual position and to store a rigging correction based on the offset; wherein, for each actuator, an offset is determined for each of three or more desired positions.

Abstract: An actuation system for a control surface for an aircraft includes a first, second, third and fourth actuator, a first and second bell crank, and at least one push pull rod system. Each of the first and second bell cranks comprises a first and a second crank arm, the first and second crank arms intersect with and are joined to each other at an intersection, the first and second crank arms extend from the intersection at an angle to each other, the first bell crank is pivotally connected to the sub-structure by a first pivot extending through the first bell crank's intersection, and the second bell crank is pivotally connected to the sub-structure by a second pivot extending through the second bell crank's intersection.

Abstract: An assembly for manual control of an HSTA for controlling the position of a moveable surface, the assembly comprising a user-operated manual control element (1?) e.g. a trim wheel in the cockpit, a first motor and a first resolver connected to the manual control element and a second motor and a second resolver arranged to communicate with the first motor and the first resolver and to cause corresponding movement of the actuator, in use.

Abstract: A screw actuator having a screw shaft and a nut arrangement is described herein, the nut arrangement comprising: a primary nut; a first secondary nut having a first thread; a second secondary nut having a second thread; and a first attachment means. The first nut, first secondary nut, and second secondary nut are connected to the first attachment means with a first, initial, axial spacing between the first and second secondary nuts. The first secondary nut is mounted to the first attachment means via bearings that allow the first secondary nut to rotate relative to the first attachment. The first secondary nut is connected to the second secondary nut via a screw thread connection having a pitch lower than a pitch of a screw thread of the screw actuator shaft.

Abstract: A trimmable horizontal stabiliser actuator (THSA) control system includes least one main THSA motor for driving the THSA in response to inputs from a flight control computer (FCC), a pilot trim control system for manual control of the THSA by a pilot overriding the FCC. The pilot trim control system comprises a trim control for receiving an input from the pilot, the trim control including a trim control sensor for detecting the input from the pilot and providing a pilot trim control signal; a THSA trim control motor for driving the THSA in response to the pilot trim control signal; and an electronic override system for giving inputs from the pilot priority over inputs from the FCC.

Abstract: A twin-disc tribometer assembly includes a first sample drive shaft arranged to receive a first sample disc and a second sample drive shaft arranged to receive a second sample disc; a first drive motor configured to rotate the first drive shaft and a second motor arranged to rotate the second drive shaft. The first and second drive shafts are configured to be positioned relative to each other such that a sample disc mounted on the first drive shaft will make a point contact with a sample disc on the second drive shaft as the drive shafts rotate. The assembly is configured to allow the shafts to rotate relative to each other in a non-continuous reciprocating motion or a non-collinear motion where one sample disc is tilted with respect to the other.

Abstract: A system for controlling an electromechanical actuator of an aircraft includes a locking device configured to mechanically lock said actuator in a first fixed position and to mechanically unlock said actuator from said first fixed position and a controller configured to be in bi-directional communication with both said locking device and said actuator. The controller is configured to monitor a position of said actuator during flight and to detect when said actuator has not moved for a set amount of time, said controller further being configured to instruct said locking device to lock said actuator in said first, locked position when said set time has been reached. In addition, there is provided a method for controlling the thermal properties of an electromechanical actuator of an aircraft.

Abstract: A system for detecting and controlling the position of a spoiler of an aircraft wing is described herein comprising: a hydraulic actuator having a piston rod operably connected to the spoiler, the piston rod being moveable between a retracted position, a neutral position and an extended position; and means for providing power to said hydraulic actuator; and a mechanical device for detecting whether the piston rod is in the retracted position, the neutral position or the extended position; and means, operatively connected to the mechanical device, that is configured to provide a change in a load applied to said hydraulic actuator, wherein said means is configured to change said load based on whether said piston rod is detected as being in said retracted position or said extended position.

Abstract: A ram-body for use with a spherical bearing has an inner circumferential surface. The ram-body comprises at least a first concave section provided in said inner circumferential surface. In some examples, a second concave section may be provided diametrically opposite to the first concave section. In some examples, the concave sections may be lunular shaped. A method of manufacturing the ram-body is also described. A ram-body and spherical bearing assembly is also described.

Abstract: There is provided an actuator comprising screw shaft and a nut assembly. The nut assembly comprises a primary nut for transmitting load through the actuator along a primary load path, and a secondary nut for transmitting load through the actuator along a secondary load path. The secondary nut comprises first and second portions movable relative to one another. As load is transmitted through the actuator along the primary load path the secondary nut does not transmit load through the actuator, wherein upon failure of the primary load path the first and second portions move relative to each other, such relative movement causing the first and second portions to engage the screw shaft and enable transmittal of load through the secondary nut of the actuator along the secondary load path.

Abstract: A ballscrew actuator comprises a ballnut having at least one first helical groove formed on a radially inner surface and defining an axis (X), a ballscrew disposed along the axis (X) within the ballnut, the ballscrew having at least one second helical groove formed on a radially outer surface and opposed to the first helical groove so as to form at least one helical raceway and a plurality of balls or rolling elements disposed in the at least one helical raceway. The ballscrew is movable relative to the ballnut between a stowed position and a deployed position. The ballscrew comprises a ballscrew bore extending axially therein. A lubrication piston is mounted for sliding movement within the ballscrew bore and divides the ballscrew bore axially into a lubricant receiving portion and a pressurising portion.

Abstract: An actuator control arrangement includes a hydraulic actuator having a housing and a piston rod axially moveable within the housing, a stop disposed within the housing to limit the extent of movement of the piston rod into the housing, and a solenoid valve arranged between a pressure source and the actuator. The solenoid valve is switchable between a first mode and a second mode in response to an electric control signal, wherein, in the first mode, the solenoid valve creates a fluid flow path from the pressure source to the actuator so as to locate the stop in its neutral position and in the second mode, the solenoid valve creates a fluid flow path to release pressure from the actuator to permit the stop to move to its retracted position. In the event of electrical failure, the stop will set the actuator to its neutral position.

Abstract: A lower attachment system for a trimmable horizontal stabiliser actuator (THSA) includes a screwshaft forming a part of or coupled to a main screw of the actuator, the screwshaft having an axial direction and a primary ballnut disposed on the screwshaft and forming a part of a primary load path of the lower attachment system. The THSA also includes a lower secondary nut and an upper secondary nut as well as a secondary connection arranged for axial and rotational movement and coupled to each of the lower secondary nut and the upper secondary nut. The secondary connection is arranged to be loaded when the secondary load path is loaded and the secondary load path also includes the upper and lower secondary nuts.

Abstract: An actuator control arrangement comprising: a hydraulic actuator having a housing and a piston rod axially moveable within the housing between a neutral position, a retracted position and an extended position with respect to the housing in response to application of pressure to the piston rod; the arrangement further comprising a check valve moveable between a first position providing a flow path between a pressure source and the actuator, and a second position in which the flow path is closed off; and characterised by a mechanical link between the piston rod and the check valve, actuated in response to the piston rod passing a predetermined retracted position in a negative stroke direction, to set the check valve to the first position.

Abstract: An attachment assembly for connecting an actuator to a frame, a method for manufacturing this attachment assembly and a method for reducing backlash in an attachment assembly. The attachment assembly comprises: an outer yoke having a first end and an opposite second end and defining an internal cavity at said second end. The outer yoke has an aperture provided at its second end connected to the cavity; and an inner yoke located within the cavity. A tie bar having a ball shaped end extends through said aperture such that the ball shaped end is positioned within the cavity and cannot pass through the aperture. A spring is provided at said first end of said outer yoke that is configured to bias the inner yoke in the direction of the aperture. The attachment also includes shearable means for holding the inner yoke.

Abstract: A hydraulic actuator includes a piston and a cylinder. The piston is axially movable within the cylinder. A stroke end damping valve is provided in a hydraulic fluid flow passage of the actuator and adjacent an end of the cylinder. The stroke end damping valve comprises a damping orifice and a valve element for selectively varying the area of the damping orifice and thereby changing the damping provided by the orifice. The valve element projects from a wall of the cylinder into the cylinder and is engageable by the piston as the piston moves towards the end of the cylinder. This reduces the area of the damping orifice and thereby increases the damping effect on the piston towards the end of its stroke in the cylinder.

Abstract: A screw (20) assembly for an actuator (10) is described comprising: a screw (20); a nut (22) threaded on said screw (20), such that rotation of said screw (20) causes axial movement of said nut (22); a stop located at an end of said screw (20) and defining an axial limit of said nut (22); a first feature located on said nut (22); and a second feature located on said stop; wherein said first and second features are configured to cooperate with one another substantially upon contact of said nut (22) with said stop so as to indicate an amount of free movement between said nut (22) and said screw (20).

Abstract: An upper attachment system for a trimmable horizontal stabiliser actuator (THSA) comprises: a housing, holding a yoke and a ballscrew; a nut coupled to the housing and cooperating with the ballscrew such that rotation of the ballscrew relative to the nut results in linear motion of the ballscrew; a recess formed between the yoke and the ballscrew and arranged to receive, in use, an upper part of a tie bar of the secondary load path of the actuator; and a biasing mechanism arranged such that, in use, when no axial load is applied to the tie bar, the yoke and the ballscrew are held by balanced forces from the biasing mechanism in a position within the recess.