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).
The control and performance of a braking system on a Commer lorry.
| Identifier | ExFiles\Box 120\3\ scan0090 | |
| Date | 26th October 1934 guessed | |
| - 2 - former is always rubbing round. They say the loss amounts to about 1-HP. at 100 m.p.h. and the brakes do not run hot. The armature plate is driven without rotational slack, from the brake drum by means of plate springs. The control is by introducing a series of resistances and the braking effect is thus not depended on pressure but on position. They could however provide a spring on the pedal which gave a resistance resembling the conventional brake pedal. Their idea is that there should be two pedals only controlling the car, viz. an accelerator and a decelerator and that their loads should be approximately alike. In addition there is a sort of over-riding hand control whereby the total available braking can be varied to suit different loading or conditions of road. As arranged on the Commer lorry they explained that it was rather a patched up job. The stroke of the pedal was much longer than was necessary and having very light pressure seemed floppy. One inch or an inch and a half seems all that is necessary for stroke. Nevertheless very nice braking could be obtained, very smooth and controllable, while with the hand control full on, very strong braking could be obtained on this 6 ton lorry without of course any effort on the part of the driver. There was no sign detectable of unequal braking. The connection to the moving axles was by specially designed cables, one live and one earth. They said they had had trouble in getting a good terminal. No adjustment is provided on the brakes, the servo movement being capable of wearing out the liners. The mechanical parts are very simple and if there is sponge it can not be felt. Failure of the complete system is of course unavoidable, but an individual brake only puts itself out of action. Da.{Bernard Day - Chassis Design} | ||