Patent GB-677110-A (GB)
Title: Engine starter drive
IPC: F02N15/02
Filed: 1950-07-13
Abstract: 677,110. Turning-gear. BENDIX-AVIATION CORPORATION. July 13,1950 [July 21, 1949], No. 17595/50. Class 7(v) In an engine starter drive including a power shaft 1, a pinion 2 journalled thereon for longitudinal movement into and out of mesh with a gear 3 of the engine to be started, means, such as a screw shaft 4 and nut 19, for drivably connecting the pinion to the power shaft and including a pair of dental overrunning clutches 7 and 11 and yielding means, for example a flat spring 49, urging the clutch member into engagement, there is provided means, such as balls 54, responsive to overrunning of the driven clutch member 11 above a given speed for separating the clutch members 7 and 11 and holding them apart; the starter drive may also be enclosed in a barrel 33 which further acts as a stop limiting the axial movement of the driven clutch member 11 in the direction to mesh the pinion with engine gear 3 whilst an annular member 41 fixed in the barrel has an inclined surface 44 with which the balls 54 co-operate. The clutch member 7 has teeth 8 adapted to engage the teeth 9 of the driven clutch member 11 splined on the extended hub 13 of the pinion whilst a spring 15 located between the clutch member 11 and a shoulder 16 on the pinion is. housed in a telescopic casing 17, 18. Be-' tween the flanged nut 19 on the screw shaft 4 and a flanged driving slip coupling member 23 splined on the nut 19 is located a cylindrical block 22 of rubber or similar material, the slip member 23 having projections 25 adapted to engage similar projections 26 on the driving overrunning clutch member 7. A sleeve 27 holds the nut 19, coupling member 23 and clutch member 7 as an assembly with the elastic block 22, the latter being under initial compression whilst a single-turn spring 47 retains the sleeve against the shoulder of the reduced part of the barrel 33. The barrel 33 encloses the drive so that the meshed position of the pinion 2 with the engine gear 3 is defined by abutment of an end flange 35 of the barrel and the screw shaft; an anti-drift spring 38 is located between flange 35 and the screw shaft in order to maintain the parts in the idle position. The end of the barrel 33 adjacent the pinion has mounted thereon the annular member 41 incorporating the inclined part 44, the inner end of which is slidably journalled on driving overunning clutch member 7. The pinion 2 is maintained in mesh with the engine part by a plunger 55 that is moved, by closure of the starting switch, into engagement with one of a number of sockets 56 in a ring 57 of plastic or like material journalled on the reduced part of the barrel. In operation, rotation of the power shaft 1 causes the nut 19 and hence the whole assembly to move to the right until the pinion 2 meshes with the engine gear 3; if tooth abutment occurs the spring 15 is compressed until sufficient torque has been built up to facilitate indexing. The pinion is rotated by the projections 25, 26 and teeth 8, 9, and the slip coupling and the over-running clutch are then additionally loaded by the further compression of the elastic block 22 and the screw-jack action of the screw shaft 4 and nut 19; the plunger 55 drops into one of the sockets 56 so that the barrel 33 cannot move leftwa ' rdly whilst the starting switch is closed. When the engine starts the teeth 8, 9 overÀ run until the engine speed is sufficient to force the balls 54 outwardly against the inclined part 44 so disengaging the clutch teeth 7 and 8. Specification No. 621,983 is referred to.