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).
Specifications and calculations for various clutch types, detailing spring configurations and thrust values.
| Identifier | ExFiles\Box 130\3\ scan0020 | |
| Date | 30th November 1938 | |
| -2- Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler}1/JH.30.11.38. The L.O.P's. GB.2100 GB3793 and any other showing the 10" B. & B. clutch should be altered to read 6 Black springs and 3 green springs instead of 9 brown springs as originally used. 11" Borg & Beck clutch. This clutch is fitted with 12 green springs of nominally 110 lbs. and as the working length closely approximates the nominal length of 1.687, the total thrust is approx - 110 x 12 - 1320 lbs. Less 160 for Anti rattle springs - 160 lbs. ---------------------------------------- 1160 lbs. engaged. Owing to the rate of the thrust springs, the total thrust when clutch is withdrawn assuming .060 separation, is approx. 1240 lbs. and since the finger ratio is 5.5 to 1, the max. pressure on the withdrawal thrust bearing is approx. 225 lbs. 10" Long C.F. Clutch. This clutch is fitted with 9 orange springs of nominally 135 lbs. giving a total thrust of approx. 1215 lbs. No anti-rattle springs are fitted. The finger lever ratio is 4.73 to 1. Owing to the rate of the springs, the total thrust when withdrawn is approx. 1315 lbs. or 278 lbs. on the withdrawl thrust bearing. re Separation. In the above, an actual separation of .060 is assumed but we recommend allowing for a theoretical separation of .075 to .080 so as to provide for an actual separation of .050 to .060 after allowing for 'sponge'. Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler} | ||