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).
Modifications to the leverage of the brake servo system to address wear.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan6 | |
| Date | 1st January 1924 | |
| R.R. 293A/100 T/ (S.H. 169. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2200 TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} SECRET ORIGINAL DAL/M26. 1. 24. re. EAC.111. BRAKE WEAR ON SERVO ETC. Y9910 You will receive by the same post a note from R.{Sir Henry Royce} suggesting reducing the leverage between the servo and rear brakes, and we have wired the essentials of this suggestion to you at R's request. We sent the same suggestion to R.{Sir Henry Royce} a day or two ago and accordingly have worked it out fairly fully by this time, and we shall send you probably tomorrow a drawing giving full particulars of the necessary modifications. In the meantime we might say that we should like to keep the leverages as shewn on N.sch.1723., that is to say, the existing lengths of lever on the pressure distributing gear and the bell crank transmission lever, and to effect our reduction of leverage to the servo by altering the levers on the servo itself, that is to say, there will be a shorter operating lever on N.sch. 1723. and in addition the long horizontal lever on the bottom servo shoe will have to have its leverage reduced by half, by altering its fulcrum. It is essential of course that the leverage to the servo should be reduced at the same time that the leverage between the servo and the back brakes is increased. The reason we wish to keep the operating leverages as originally instructed is because we wish to keep the pull in the rod to the servo as high as possible. We feel sure that with this increase of leverage you will be able to pull the servo round and stop chunking by that means. That however is not of course an essential part of this suggestion. The suggestion involves we think a quick adjustment between the servo and the back brakes which may or (1) | ||