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).
Investigations into the design and control of a synchro-mesh gearbox, including patent applications.
| Identifier | ExFiles\Box 6\4\ 04-page244 | |
| Date | 12th April 1930 | |
| Da{Bernard Day - Chassis Design}/Hdy{William Hardy}/1/12.4.30 contd. -3- The planet speed is .436 by engine speed, and the pitch velocity 230 ft. per min. CONTROL. We have made application for patents for :- (a) Clutch pedal interlock, with vacuum control. (b) Balanced and synchronised pawls. (c) Automatic brake and pawls. (d) Direct and indirect dogs and reverse arrangement. (e) General scheme of equivalent synchro-mesh control. We give below in detail the results of our investigations into the design of the equivalent synchro-mesh control :- (1) It appears to us to be desirable that the direct and indirect dogs should be actuated during a small part of the movement of the change lever each side of neutral, further movement being required to apply and release the brakes. If this is not done the dogs will be definitely thrown out of synchronisation and more difficulty be presented by their engagement. The use of a Salerni coupling on the indirect dogs does not seem to be without difficulties owing to the variation of the direction of the relative speed. Likewise a Salerni coupling on the direct dogs could not deal with the change from 3rd. to top as well as re-engagement after coasting. (2) Assuming that the above requirement has to be met we have worked out the following sequence of movements :- Gear change lever handle movement allowed each side of neutral equals 4°. This movement is allocated as follows :- (1) 1° for engaging the dogs. (2) 1° for the application of the brake by the release of its spring. (3) 1½° during which the brake is fully on. (4) ½° for the removal of the brake against its spring, and the simultaneous application of the pawls. | ||