Abstract: A stop module halts rotation of a shaft of a rotational drive system when an axial stroke limit is reached without the use of frictional brake plates. The module has a fixed nut and a pawl carrier coaxially mounted on the shaft for axial travel along the shaft and rotation with the shaft. The pawl carrier includes a screw portion mated with the nut such that rotation of the pawl carrier with the shaft causes the pawl carrier to travel axially along the shaft. A pawl member is pivotally coupled to the pawl carrier, and a stop element is fixed at an axial limit location. The pawl carrier is axially displaceable from a non-limit position wherein the pawl member is clear of the stop element during rotation to a limit position wherein the pawl member is interfered with by the stop element during rotation to stop rotation of the shaft.

Abstract: A no-back device usable in a Horizontal Stabilizer Trim Actuator (HSTA) includes a ratchet and pawl brake mechanism in which a pivot pin supporting the pawl includes a sensor for directly measuring torque developed by the brake mechanism. A signal generated by the sensor may be evaluated to determine the apparent operational integrity of the no-back device.

Abstract: A torque limiter limits transmission of torque between an input shaft an output shaft. The torque limiter may be incorporated in a geared rotary actuator for actuating an aircraft control surface. The torque limiter is responsive to output torque associated with the output shaft instead of input torque associated with the input shaft. The torque limiter includes a structural ground and a gear assembly for transmitting rotational motion of the input shaft to the output shaft. The gear assembly includes a reference gear coupled to the structural ground such that movement of the reference gear relative to the structural ground is dependent upon an output torque at the output shaft. The reference gear is stationary relative to the structural ground when the output torque is below an output torque limit, and the reference gear moves relative the structural ground when the output torque exceeds the output torque limit.

Abstract: A stop module halts rotation of a shaft of a rotational drive system when an axial stroke limit is reached without the use of frictional brake plates. The module has a fixed nut and a pawl carrier coaxially mounted on the shaft for axial travel along the shaft and rotation with the shaft. The pawl carrier includes a screw portion mated with the nut such that rotation of the pawl carrier with the shaft causes the pawl carrier to travel axially along the shaft. A pawl member is pivotally coupled to the pawl carrier, and a stop element is fixed at an axial limit location. The pawl carrier is axially displaceable from a non-limit position wherein the pawl member is clear of the stop element during rotation to a limit position wherein the pawl member is interfered with by the stop element during rotation to stop rotation of the shaft.

Abstract: A power-off brake for stopping a rotating shaft comprises a solenoid including a coil and armature, an opposing plate axially spaced from the armature, and a ball carrier rotor between the armature and opposing plate. The ball carrier rotor rotates with the shaft and carries spherical balls in recesses angularly space about the shaft. The armature and opposing plate have respective braking surfaces. In one embodiment, at least one braking surface is ramped to urge the plurality of balls radially outward against an internal surface of a surrounding outer race as the armature is forced toward the opposing plate under spring loading when current to the solenoid coil is shut off. In another embodiment, the braking surfaces are not ramped, such that the balls are merely clamped between the braking surfaces upon solenoid deactivation. Increased rolling friction stops rotation of the ball carrier rotor and the shaft without problematic wear.

Abstract: A torque limiter limits transmission of torque between an input shaft an output shaft. The torque limiter may be incorporated in a geared rotary actuator for actuating an aircraft control surface. The torque limiter is responsive to output torque associated with the output shaft instead of input torque associated with the input shaft. The torque limiter includes a structural ground and a gear assembly for transmitting rotational motion of the input shaft to the output shaft. The gear assembly includes a reference gear coupled to the structural ground such that movement of the reference gear relative to the structural ground is dependent upon an output torque at the output shaft. The reference gear is stationary relative to the structural ground when the output torque is below an output torque limit, and the reference gear moves relative the structural ground when the output torque exceeds the output torque limit.

Abstract: A power-off brake for stopping a rotating shaft comprises a solenoid including a coil and armature, an opposing plate axially spaced from the armature, and a ball carrier rotor between the armature and opposing plate. The ball carrier rotor rotates with the shaft and carries spherical balls in recesses angularly space about the shaft. The armature and opposing plate have respective braking surfaces. In one embodiment, at least one braking surface is ramped to urge the plurality of balls radially outward against an internal surface of a surrounding outer race as the armature is forced toward the opposing plate under spring loading when current to the solenoid coil is shut off. In another embodiment, the braking surfaces are not ramped, such that the balls are merely clamped between the braking surfaces upon solenoid deactivation. Increased rolling friction stops rotation of the ball carrier rotor and the shaft without problematic wear.

Abstract: Systems and methods for providing differential motion to wing high lift devices are disclosed. A system in accordance with one embodiment of the invention includes a wing having a leading edge, a trailing edge, a first deployable lift device with a first spanwise location, and a second deployable lift device with a second spanwise location different than the first. The wing system can further include a drive system having a drive link operatively coupleable to both the first and second deployable lift devices, and a control system operatively coupled to the drive system. The control system can have a first configuration for which the drive link is operatively coupled to the first and second deployable lift devices, and activation of at least a portion of the drive link moves the first and second deployable lift devices together.