Patent GB-553557-A (GB)
Title: Improvements in engine starter gearing
IPC: F02N15/06
Filed: 1941-11-25
Abstract: 553,557. Turning gear. BENDIX AVIATION CORPORATION. Nov. 25, 1941, No. 15193. Convention date, Jan. 22. [Class 7 (v)] In an engine starter comprising a pinion 9 moved into engagement with an engine gear 10 by means of a screw shaft 6 and nut 11, a clutch member 2 on the power shaft 1 is adapted to engage a clutch surface 8 on the end of the screw shaft to transmit full driving torque to the pinion when the axial movement of the screw shaft or the nut is arrested by a yielding member 13 and to disconnect when the pinion overruns the starting motor. As shown, the pinion 9 and the screw shaft 6 are slidably journalled on the shaft 1, and the pinion is rigidly connected by a barrel 12 to the nut 11. An outer barrel 5 is rigidly mounted on the clutch member 2 and carries an annular member 13 of elastic material for cushioning the axial movement of the pinion and nut assembly towards the engine gear 10. The pinion and nut are yieldingly held in idle or operative position by a spring detent 17 carried by the nut and adapted to engage either of grooves 18, 19 in the outer barrel. Initial rotation of the screw shaft 6 with the shaft 1 is ensured by an elastic friction ring 21 anchored in the enlarged end of the screw shaft and expanding into gripping engagement with a bush 23 fixed in the barrel 5. When the pinion moves into mesh with the engine gear 10, the flange 16 of the nut is yieldingly arrested by the member 13 and the screw shaft then moves to the right in the nut 11 until the clutch 8 is engaged and the screw shaft is positively driven. When the engine starts, the acceleration of the pinion by the gear 10 disengages the clutch 8, but disengagement of the pinion from the gear 10 is prevented by the detent 17 until the speed of the pinion and nut is sufficient to engage a spring ring 24 with the bush 23. This causes deceleration of the screw shaft 6 and consequent retraction of the pinion and nut assembly. In a modification, Fig. 4, a sleeve 32 fixed on the power shaft 31 has a driving head 34 on which is non-rotatably mounted a barrel 36. A driving clutch member 37 slidably journalled on the sleeve 32 has a radial flange 38 with lugs 39 engaging slots 41 in the barrel 36, an elastic annulus 42 being loosely mounted between the barrel and the flange 38. Axial movement of the member 37 on the sleeve 32 is limited by the engagement of a spring ring 43 on the sleeve with a recess 45 in the member 37. A screw shaft 47 is slidably journalled on the sleeve 32 between the clutch member 37 and a stop nut 46 and has teeth 48 for engagement with the clutch 37. A spring friction ring 50 may be provided to initiate rotation of the screw shaft. A nut 54 on the screw shaft has lugs 55 engaging slots in a barrel 53 rigidly secured to a starter pinion 51 slidably journalled on the shaft 31. Latch members 59 movable radially in the barrel 53 are normally held by springs in position to engage a flange 62 on the stop nut 46 in order to retain the pinion 51 in mesh with the engine gear until the speed is sufficient to release the latches by centrifugal action.