Abstract: Referring to FIG. 2, disclosed is an aircraft compound no-back/offset gearbox (2) with an integral load proportional safety (no-back) brake (50). The four gears are all 16 diametral pitch, involute external spur gears with 20 degree standard pressure angles. The two gear stages are interconnected with a mechanical fuse or shearout (40) designed to fail under excess shear loads and protect components downstream of the input shaft (10) from excess torque in the event of a system jam. The shearout (40) is essentially a quill shaft with external splines at both ends and an hourglass-shaped shear neckdown in the middle. The purpose of the no-back brake (50) is to prevent air loads from causing slat movement in the event of a torque tube disconnect. Referring to Figure, the no-back consists of a set of ball ramp (22) and brake plate components connected to the gearbox's output shaft.

Abstract: Cooperating brake discs, rotors, and stators all are located at the same side of a pair of cam plate flanges. The cam plate flanges are coupled to an inner sleeve and input gear, respectively, with balls and ball ramp sockets for forcing apart the cam plate flanges when an output side is driven relative to an input side. The brake is effective to prevent relative rotation of the output side relative to the input side, but is released by rotation of an input gear for driving the inner sleeve.