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).
Design issues and proposed solutions for a servo mechanism, including thread angles, cone schemes, and lever adjustments.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan138 | |
| Date | 1st March 1924 | |
| ORIGINAL URGENT & IMPORTANT SECRET FROM R.{Sir Henry Royce} E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. R1/M25. 3. 24. Copy to - H.S. - M.{Mr Moon / Mr Moore} N. SCH. 1769. Lec. 1846. X9910 SERVO. For the experimental ones in hand we shall not make the swivel plates but trust to the alignment being sufficiently correct. If we find difficulty in getting sufficient end pressure with say 30° thread, and we cannot have longer levers to Wlg foot pedal (which should be done in schemes like RHM. and Des.60.) then we could get a multiplication of about 2 1/2 by double cone scheme, { Before spending time on this (which is inferior to the flat ) plates See that all other pro- portions are correct for reas- ons given - (heat & wear etc.)) } i.e. ferodo cones of about 30° which would be 2 to 1 approximately and the increased mean dia. would make this 2 1/2 times. We must at once get sufficient assistance from the servo which we can reduce afterwards if advisable. We have failed somewhere perhaps because (1) through misunderstanding about the angle of the thread, (2) not allowing the servo to move through a large angle - i.e. 75° for the full range, i.e. application and wear. I still believe this is wrong and if so it will make the application too sudden, also not enough power, and too great heat in servo. with 8 to 1 reduction. If you allow your levers on the front axle clearance for a 2" stroke on the ropes then 80° should carry the front ropes this 2" and the back one 2" in RHM. scheme, and all others say 3" so as to permit 3/8 more leverage to the back brakes (with the same clearances and allowances for wear.) (1) | ||