From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The working mechanism of a 20 HP chassis starter pinion.
| Identifier | ExFiles\Box 56\4\ Scan085 | |
| Date | 11th February 1926 guessed | |
| X5850 e/c/c.e WORKING OF ROLLS-ROYCE 20 H.P. CHASSIS STARTER PINION. The pinion itself is bushed and is a close but perfectly free fit on the shaft. It is driven through the medium of a friction clutch which relies for its axial pressure on the torque of the motor in combination with the thread on the shaft. Normally the whole assembly is held out of engagement with the flywheel teeth by a light spring F.{Mr Friese} In this position a comparatively light initial axial pressure is maintained on the friction surfaces of the clutch, the flange of nut O being pressed against the cork friction washer N1. When the starter switch is closed the sudden acceleration of the motor causes this friction clutch to slip owing to the inertia of the pinion and associated parts, the whole assembly moving axially into engagement. Shortly the sleeve, N3, comes against the flange on the shaft, when the friction clutch pressure is increased by spring N4. Finally, when engagement is complete, an internal cylindrical projection within, and part of, the sleeve N also abuts against the flange on the shaft. As the sleeve N carries one side of the friction clutch, the result of this is that the pressure between the friction surfaces is then a function of the motor torque and the angle of the engaging thread. It will be observed that load is applied to the motor gradually, and therefore there is an absence of the usual engagement noise, for, first the friction clutch is Continued :- | ||