GB764370A - Improvements in or relating to engine starter gearing - Google Patents

Abstract

764,370. Turning-gear. BENDIX AVIATION CORPORATION. Feb. 8, 1955 [Feb. 24, 1954], No. 3733/55. Class 7 (5). In an engine starter drive comprising a power shaft 1, a driving clutch 'sleeve 2 fixed thereon and having teeth 4, a hollow screwshaft 5 with clutch teeth 6, the screwshaft being slidably journalled on the sleeve 2, a spring washer 9 holding the teeth 4 and 6 in contact, an externally and internally threaded control nut 11 on the screwshaft, a stop ring 7 on the sleeve limiting the longitudinal movement of the nut 11, a pinion 14 slidably journalled on the power shaft 1 for movement into and out of mesh with a gear 15 of the engine to be started, and a barrel 16 splined to the pinion 14, and threaded on the nut 11, a drive spring 28 connects the nut 11 to the barrel. One end of an outer barrel 22 is secured on a flange 24 of the nut 11 whilst the other extremity has an anchor plate 25 fixed thereto and bearing on the barrel 16 ; the spring 28 is connected between the plate 25 and a flange 27 formed on the barrel 16, a shoulder 32 in the outer barrel 22 being engaged by the flange 27 to limit the meshing movement of the barrel 16 with respect to the nut 11. A spring-loaded latch-member 34 is mounted in the nut and a mesh-enforcing spring 37 is located around the power shaft between a pinion flange 18 and a thimble 38 abutting the nut extension 19. Rotation of the power shaft 1 is transmitted to the screwshaft 5 via the overrunning clutchteeth 4, 6 whereby the nut 11 threads rightwardly pushing ahead of it the pinion 14 and the barrel 16 through the spring 37 until the nut 11 is arrested by the stop 7 after the pinion has initially meshed with the engine gear 15; the nut 11 is thereby compelled to rotate with the screwshaft whereupon the barrel 16 is translated to the right causing compression and torsion of the drive spring 28 which movement effects complete meshing of the pinion so that the flange 27 abuts its shoulder 32, just prior to which the barrel 16 runs off the threads 21, and the engine is cranked through the drive spring 28. When the engine fires the barrel 16 threads itself back onto the nut 11 but the pinion 14 is maintained in mesh by the latch 34 until the engine is reliably self operative .and the latch is centrifugally withdrawn to enable the parts to return to the inoperative position shown wherein they are retained by the latch.