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.

There is provided a lower attachment for a trimmable horizontal stabiliser actuator (THSA) for connecting the THSA to a flight control surface. The attachment includes: a nut assembly for providing a load path through the THSA to the flight control surface when the THSA is connected to the flight control surface. The nut assembly includes a nut for location on a screw shaft of the THSA, a failsafe plate for coupling to the flight control surface, and a transfer plate for transferring load between the failsafe plate and the nut. The nut assembly has a first unloaded configuration in which there is no contact between the nut and the transfer plate, and a second loaded configuration in which there is contact between a first pair of opposed surfaces of the nut and the transfer plate.

A braking device for a flight control system includes a drive shaft for applying a drive torque to a flight control surface. The braking device comprises a housing component comprising a first braking surface. The system also includes a trolley having a second braking surface configured to contact the first braking surface to provide a braking torque. The trolley is configured to receive an input torque from the drive shaft, wherein the trolley is configured to apply a contact force between the first and second braking surfaces in response to the input torque. Also provided is a flight control system comprising the braking device and a drive shaft for applying a drive torque to a flight control surface, and an aircraft comprising the flight control system.

A linear actuator arranged to convert rotary motion to linear motion. The linear actuator includes a linear shaft arrangement, having a first shaft portion and a second shaft portion and extends along a longitudinal axis (A) of the linear actuator. At least one of the first shaft portion and the second shaft portion of the linear shaft arrangement can be translated linearly along the longitudinal axis upon actuation. A first drive system has a first rotary component extending at least partially around the longitudinal axis. A second drive system has a second rotary component extending at least partially around the longitudinal axis at a different axial position to the first drive system. The linear actuator, when the first drive system fails, allows rotation of the second rotary component so that the second shaft portion moves relative to the first shaft portion.

An actuator system comprising a shared link (121) arranged to pivot about a first axis (131) relative to a reference structure, a controlled element (125) arranged to pivot about a second axis (126) relative to the reference structure, a first member (146, 152) arranged to pivot about a third axis (134) relative to the shard link and a fourth axis (136) relative to the controlled member, a first actuator arranged to control a first variable distance (LI) between the third axis and fourth axis, a second member (147, 153) arranged to pivot about a fifth axis (133) relative to the shared link and a sixth axis (135) relative to the controlled element, a second actuator (141) arranged to control a second variable distance between the fifth axis and the sixth axis, the system configured such that a change in the first variable distance causes rotation of the controlled element about the second axis when the second variable distance is constant and vice versa.

An actuator includes a housing member configured for connection with a first component, a drive screw connected to the housing member, a rod disposed at least partially in the drive screw and at least partially in the housing member, a retaining nut connected to the rod, a mounting member configured for connection with the first component, and a drive nut engaged with the drive screw and configured for connection with a second component. If the drive screw mechanically disconnects or is fractured, the rod may be configured to translate to engage one or more friction surfaces to restrict back driving of the drive screw.

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 THSAalso 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.

An actuator includes a drive assembly, a ball screw, and a ball nut. The ball nut may include a first nut member, a second nut member; and an arm extending from the first nut member. The arm may include a first portion and a second portion. The first portion may extend radially outward from the first nut member. The second portion may extend substantially axially from the first portion such that at least some of the second portion is disposed radially outward of the second nut member.

An upper attachment system for a trimmable horizontal stabilizer 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.

A torque transmission device comprises: an input drive shaft, a housing, an earth ring, a bearing cage, and a plurality of bearings held by the bearing cage between an inner surface of the earth ring and an outer surface of the input drive shaft. The earth ring is mounted within the housing such that an outer surface of the earth ring contacts an inner surface of the housing along a contact area, thereby providing a frictional interface at the contact area for transmitting torque from the earth ring to the housing.