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).
Overcoming faults in braking systems and introducing a new servo-assisted scheme EX.13184.
| Identifier | ExFiles\Box 13\1\ 01-page50 | |
| Date | 16th May 1934 | |
| -2- Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux}19/KW.16.5.34. To overcome these various faults, numerous schemes have been tried. To obtain an ideal working condition the servo must upon the lightest load being applied to the foot pedal, take up and maintain the movement necessary to bring the brake shoes in contact with the drums and any further load then applied used in applying the load of the shoes on the drum surfaces. To obtain this action the servo must be efficient and at the same time have no grabbing or fierce effect. This could be obtained by various means were it not for the reason that the foot pedal has a limited travel. Oil and air dashpots have been tried, but consistency with these methods is hard to obtain and from results are not a manufacturing proposition. To obtain the desired results we have conceived the idea of assisting the servo in its first operation; i.e. to take up the brake clearance smoothly before the friction load of the servo comes into operation. To do this, we have incorporated a direct pull on the front brakes via a spring which does not interfere with the servo action. Its function is to bring the brake shoes in contact with the drums only and in doing so release the load that is applied to the friction surfaces of the servo necessary to take up the first movement of the braking. It is so arranged that the load applied to the foot pedal is not increased more than approx. 10% when the car is at rest. With the car moving, the increased foot pedal load can hardly be detected. Under all normal conditions of applying the brakes it is impossible to produce thumps either with an efficient or inefficient servo. The layout of the scheme EX.13184 shows clearly its method of operation. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||