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).
Operation and design of rear Girling brakes and handbrake leverage.
| Identifier | ExFiles\Box 85\1\ scan0304 | |
| Date | 14th March 1937 | |
| 1113 HOTEL DE FRANCE, CHATEAUROUX, Indre. France. Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}/IMW{Ivan M. Waller - Head of Chateauroux}/3/JAB. 14th March 1937. 206 To. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} 6. B. IV. REAR GIRLING BRAKES. Thank you for your memo Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}9/AP.II.3.37. which I have studied carefully. There are the following facts to be considered in conjunction with it. 1) It is the practice of many drivers to pull on the hand brake before the car has quite stopped. Under these circumstances, the servo is in operation and it is possible to get at least one more notch than would be the case if the hand brake were applied after the car had stopped. It is therefore, very difficult to pull it back further still to take the load off the pawl and ratchet which is necessary before it can be released. This difficulty has been overcome by our increased leverage. 2) Yesterday, the pedal went to the boards during the running owing to wear on the rear brakes. The handbrake with the increased leverage still held the car, but could just be sprung against the end of the quadrant. Everyone on the job likes it better as it is. It is however unnecessarily easy to work now, and I still say that a reduction of 1" in the length of the lever, i.e. 3" instead of 4" would be a good compromise. You would most certainly get complaints from Customers if they were given a handbrake with the faults we have reported. It is not lack of power, but difficulties in operation we complain about. If you have reduced the sponge in the brakes and wish to retain the same leverage, you will have to put the teeth on the ratchet closer together in direct proportion to the reduction of sponge to get the same ease of operation. It is the change in pull between one notch and the next that counts. -------- Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||