GB637447A - Engine starters - Google Patents

Abstract

637,447. Turning-gear. BENDIX AVIATION CORPORATION. March 28, 1947, No. 8470. Convention date, May 15, 1946. [Class 7 (v)] In an engine starter mechanism comprising a motor and a starter clutch member 52 connected to the motor through a screw-and-nut device 46, 38 arranged to move the member 52 axially for engagement with a member 54 of the engine to be started and then impart a rotary motion thereto, the member 52 having an axial bore accommodating a mesh rod 62 which extends into the device 46, 38 the rod 62 comprises a shank portion 60 disposed within the axial bore and an inner portion 64 which is of larger diameter than the axial bore and constitutes a seat axially abutting against member 52 whilst an annular seal 72, fitted around the shank, is squeezed between the seat and the member 52 by clamping means 74, which may consist of a nut, securing the rod 62 to the member 52. When a shaft 36 is rotated by. the motor through speed-reducing means, a sun-gear 34 turns planet gear 30, carried upon a barrel 26, that in turn meshes with a fixed orbital gear 32 on the starter casing, so that by reaction the barrel 26 is rotated ; the latter, by means of multi-plate clutch 40, turns the nut 38. The screw shaft 46 is splined to the member 52, which latter is engaged by a combined oil seal and friction device 56, so that rotation of the barrel 26 causes the shaft 46 to move to the left and bring about engagement of the members 52 and 54. Upon further leftward movement of the shaft 46 being prevented by abutment of shoulder 78 and 80 on the shaft 46 and nut 38 respectively, the starter commences to crank the engine, which upon starting causes the member 54 to override the member 52. When the starter motor is de-energised the member 52 is cammed back to the position shown. Axial movement of the shaft 46 is transmitted to the jaw member 52 by means of the rod 62, the rightward shaft movement being limited by abutment with a flange 76 on a bearing sleeve 48 for the shaft 36. A spring 82 around the bearing sleeve 48 is contained between the rod 62 and a ring 84 in a groove on the shaft 46, the spring serving to both hold the member 52 and rod 62 in the position shown and to allow the former to yield axially when it initially engages the members 54. In order that the nut 74 may be removed or assembled to the rod 62 without a special tool for holding the member 52, the portion 64 of the mesh rod 62 is provided with flats which co-operate with similar flats in the shaft 46 when the latter is in its extreme right- or left-hand position. In a modification, the mesh rod is made hollow and of greater length than the previous mesh rod and encloses a spring, which replaces the bearing sleeve spring and has a flange that in conjunction with a nut, prevents complete separation of the jaw member and the screw shaft. The seal may be in a groove in either the jaw member or the mesh rod.