| 摘要 |
<p>A load limiter for preventing stall torque from being transmitted from a power drive unit to the flight control surfaces of an aircraft. The present invention provides such a load limiter in a package having lower weight and smaller spacial requirements than has been heretofore possible. The power drive unit of the aircraft generates torque which is transmitted from a rotating input shaft (24) to a worm gear (32), to a helical gear (38), to a ball screw, and to the flight control surface of the aircraft. If the flight control surface becomes jammed or otherwise prevented from movement, the ball screw, and consequently the helical gear (38), stop rotating. However, the stall torque of the power drive unit will continue to cause the input shaft (24) to rotate, which will in turn cause the worm gear (32) to rotate and interact with the helical gear (38). Since the helical gear (38) cannot move, the helical gear (38) will cause the worm gear (32) to axially translate relative to the input shaft (24). The worm gear (32) is normally prevented from such movement by compression and tension springs (58, 60) laterally flanking the worm gear (32), but by sizing the springs (58, 60) to be overcome by the level of the stall torque, one of the springs (58, 60) depending on the direction of rotation of the input shaft (24), will compress to allow the worm gear (32) to axially move and thus cause a toothed plate (44) attached to the worm gear (32) to engage a mating toothed plate (50, 52) fixed to the actuator housing. The engaged plates therefore ground the stall torque to the housing to prevent damage to the flight control surface and its transmission. The load limiter is disengaged by reversing the direction of rotation of the input shaft (24).</p> |
