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).
Description of the operation of a multiplate friction clutch and its various disengagement mechanisms.
| Identifier | ExFiles\Box 165\7\ img036 | |
| Date | 20th January 1950 | |
| -2- The multiplate friction clutch is designed to give a slipping torque of 900 - 1100 lb.ins. In the disengaged position, the pressure between the clutch plates is very small, and in this condition, they would freely slip. On the armature being rotated, and a resisting torque applied to the pinion, the inner sleeve of the clutch is moved longitudinally up a worm on the driving sleeve, and in so doing, squeezes the opposing faces of the clutch plates firmly together: in this condition they will transmit the full driving torque. When the flywheel tries to drive the pinion, after a start has been made, the inner sleeve is moved back along the worm thus freeing the clutch plates, giving the overriding feature. On a start being made, and the push button released, the return spring on the shift lever disengages the pinion. As used by RR., the disengagement is not automatic, that is to say, the pinion will not disengage until the push button is released. Provision for automatic disengagement has been made, and is recommended by Lucas. To obtain this feature, the negative end of the relay magnet coil winding is connected to the positive terminal of the dynamo instead of, as we do, taking it direct to earth. Thus, with the 'automatic' scheme, when the engine is stationary the relay coil circuit is completed via the dynamo brushes to earth, and the full battery voltage can be applied to the relay coil; however, on a start being made, and the engine continuing to run, the dynamo generates a voltage, which reduces the potential difference across the relay coil sufficiently to open the relay contacts. We do not use this scheme, since F.V.D.E. object to it on account of the possibility of starting trouble, due to excessive resistance in the relay circuit, caused dry oil and dirt between the dynamo brushes and commutator. Cont'd...... | ||