GB634672A - Improvements in engine starter drives - Google Patents

Abstract

634,672. Turning-gear. BENDIX AVIATION CORPORATION. May 28, 1947, No. 14225. Convention date, May 29, 1946. [Class 7 (v)] In an engine starter of the kind in which driving means, such as an electric motor, is coupled through gearing to a nut member which is rotated by the driving means but is located against axial movement, a screw shaft being threaded within the nut member and having freedom to move axially until a pair of abutting surfaces come into engagement causing the screw shaft to rotate as one with the nut and a starterclutch jaw-member co-axial with the screw shaft is coupled to the latter so as to be first moved axially into engagement with the engine crankshaft and then to be turned as one with the screw shaft, the jaw member is provided with holding means comprising a restraining member which resiliently radially presses against the jaw member frictionally to restrain its axial movement and a spring located within an axial recess formed in the screw-threaded shaft and operable to urge the jaw-member axially inwards and normally to hold it in its disengaged position. Planet gears 30 are fixed to a barrel 24 and operate between an orbital gear 32 attached to a casing 10, and a sun gear 34 journalled on a trunnion part of the barrel 24 and driven from a motor through further speed-reduction means (not shown). The nut 38 on screw shaft 46 is connected to the barrel 24 by an adjustable, spring-loaded, multi-plate frictionclutch 40 so that upon rotation of the nut 38 the screw shaft 46 is caused to advance to the left against the action of the spring 80 to move the jaw member 50 through a spring 60 into mesh with a similar member on the engine. The meshed position of the member 50 is defined by abutment of shoulders 66 and 68 on the screw shaft and nut respectively. The member 50, which is axially slidable by means of splines upon the screw shaft 46, is also connected to the latter by a rod 56 that at its front end is surrounded by the spring 60 positioned between a recess in the front of the screw shaft and a seal behind the rod opening in the member 50. The spring 80 is located between a nut on the end of rod 56 and a flanged cup-member 74 inserted in the recess in the screw shaft, the rod being slidable through cup member 74. A unit 65 in frictional engagement with the member 50 serves as an oil seal, whilst the combined action of spring 80 and unit 65 acts to maintain the member 50 in the retracted position when the starter is inoperative. The spring 80 also assists the return of the parts to the position shown after operation of the starter. If the engine backfires the reaction is absorbed in the multi-plate discclutch 40. Specification 601,235 is referred to.