GB661195A - Improvements in engine starter drive - Google Patents

Abstract

661,195. Turning-gear. BENDIX AVIATION CORPORATION. Jan. 18, 1949 [Jan. 19, 1948], No. 1434/49. Class 7(v) In an engine starter drive comprising a power shaft 2, a driving clutch member 7 splined thereon and having inclined teeth, a screwshaft 4 slidably journalled on the power shaft, a driven clutch member 5 connected to the screwshaft 4 and having correspondingly inclined teeth for co-operating with the teeth of the driving clutch member 7. a pinion 22 threaded in the screwshaft for longitudinal movement into and out of mesh with a gear 23 of an engine to be started, and an abutment member 11 for defining the normal position of the screwshaft 4 and for arresting the gear engaging movement of the pinion 22, the abutment member 11 being carried by the power shaft 2, there is provided spring means, such as helical springs 15, for pressing the driving clutch member into operative engagement with the driven clutch member.. In operation, rotation of the power shaft 2 is transmitted through the ratchet clutch 5, 7, the driven member of which is formed as part of the screwshaft 4, the clutch being at first lightly loaded by the springs 15. The. pinion 22 traverses the shaft 4 into mesh with the engine, gear 23. Should tooth abutment occur the spring 15 will yield and cause the clutch to slip and effect correct indexing. After the pinion is in mesh, the shaft 4 slides leftwardly over shaft 2 until the member 7 engages a series of heavy springs 15a which present a. greater resistance to further movement of shaft 4 and so increase the clutch loading. Further axial movement of the shaft 4 is prevented when it abuts a self-lubricating thrust bearing 29 on the power shaft in which position the clutch loading is a maximum. Whenever normal cranking torque is exceeded either during initial acceleration of the engine or as the result of a backfire, the clutch members will ratchet over each other until the overload ceases. The shaft 4 is retained on the shaft 2 by the abutment 11 between which and the pinion, is located an antidrift spring 25, the front of the pinion being recessed and fitted with a thimble 26, which, in the meshed position, bears against the abutment. The extreme leftward position of the pinion is defined by a backstop 24 attached to the screw shaft 4.