Patent GB-740821-A (GB)
Title: Inertia starter
IPC: F02N5/04
Filed: 1953-01-05
Abstract: 740,821. Turning-gear. SILBERSTEIN, V. April 5, 1954 [Jan. 5, 1953], No. 259/53. Class 7(5) Construction. In an inertia starter comprising a flywheel 24 adapted to be rotated and then coupled to an engine gear 63, means for decoupling the flywheel from the gear 63 when the engine has started, a preferably manually driven shaft 42, an axially displaceable pinion 4 adapted to engage the gear 63, a step-up connection consisting, of gears 31, 34, 35 and 44, from the shaft 42 to the flywheel, an automatically operative clutch 17 between the flywheel and pinion, and an auxiliary stepdown,drive, including gear 14, 51 and a chain:49, between the shaft 42 and the pinion - 4 in parallel with the step-up connection and clutch, which drive is adapted to move the pinion axially into an engineengaging position before the clutch operates, there is provided a ratchet mechanism, for example the gear 14 and a ring 15, and a lost-motion device between a shaft 5 and ring 15, the device being incorporated in the auxiliary drive. A torsion shaft 3, on which is mounted the pinion 4, is retractable within and threaded to the hollow shaft 5, the pinion 4 having an extension 67 that is engaged by a spring-loaded ball 6 to prevent rotation of the pinion when it is in the retracted position; the ball 6 is carried by the nose portion 55 of the main casing 21. The pinion 4 is urged into the retracted position by a spring 11 whilst the bevel gear 14, which is slidably journalled upon the ring 15 in such a way as to form a one-way friction clutch, engages the bevel gear 51 on a shaft 68 that is drivably connected by the chain 49 to the shaft 42; the step-up is enclosed within covers 30 and 41. The flywheel 24 is moved axially by three levers 20 pivoted therein to effect engagement with the driven member of the clutch 17 which is coupled to the shaft 5. In a modification, the ring is replaced by a ratchet wheel whilst the co-operating pawl is located on the associated bevel gear; a brake is provided between the ratchet wheel and bevel gear. Operation. The shaft 42, which is retained against inadvertent operation by a locking device 59, 60, is turned to rotate the flywheel 24 and the bevel gear 14, the ring 15 being carried along gear 14 until the lostmotion between shaft 5 and ring 15 has been taken up whereupon the ring tightens against the inside of gear 14 and the latter, with ring 15 and shaft 5, rotate together causing shaft 3, held by ball 6, to screw out and engage the pinion 4 with the engine gear 63, at which time shaft 3 is freed from ball 6. The engine is then cranked at a slow speed through the auxiliary drive. Upon reaching a predetermined speed the levers 20 move outwards under centrifugal action and urge the flywheel 24 into frictional engagement with the driven clutch member so that shafts 3 and 5 are driven at high speed to start the engine whereupon the lost-motion connection reverses so that the ring 15 becomes the driving member and slip occurs between ring 15 and gear 14 to prevent the latter being driven too fast. When the engine starts the pinion 4 is overdriven and shaft 3 is screwed back into its retracted position; ring 15 or the separate brake act to bring the clutch and shafts to a standstill. The danger of the pinion being accidentally engaged with the moving engine is lessened by the lost-motion connection. Specifications 697,873 and 699,873 are referred to.