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).
Pre-selection device for synchromesh gearboxes from the Highfield Gear Co., detailing its operation and a potential fault.
| Identifier | ExFiles\Box 136\4\ scan0078 | |
| Date | 11th April 1934 | |
| X 20(61) To E.{Mr Elliott - Chief Engineer} from HDY.{William Hardy} c. Hs.{Lord Ernest Hives - Chair} Ba. By.{R.W. Bailey - Chief Engineer} HDY.{William Hardy}1/HP.11.4.34. GRY{Shadwell Grylls} See me HE Pre Selection Device for Synchromesh Gearboxes by the Highfield Gear Co. Huddersfield. By means of a picking up device and cams the change gear lever is made to compress springs on the actuating rods according to the gear required. Depression of the clutch pedal releases the rods which are then moved by the springs. One fault appears to us to be of sufficient importance to condemn the scheme when used with manual operation, i.e. the springs have to be strong enough to change gear in reasonable time at the highest speed and are therefore needlessly strong at lower speeds. With servo actuation this feature would probably not be objectionable and the use of springs would be essential, we imagine, to provide for the occasional times when the teeth come end to end and fail to engage when starting from rest. HDY.{William Hardy} | ||