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).
Tests and modifications to improve brake linkage efficiency and operation.
Identifier | ExFiles\Box 16\3\ Scan045 | |
Date | 19th April 1929 guessed | |
contd :- -3- (c) We carried out tests to establish the efficiency of the linkage. We attach a chart showing the results obtained. The torque at the camshaft was measured by a lever fitting over the cam. All the pull off springs were left in the system except those on the brake shoes. Under light loads the pull off springs cause the linkage to appear to have an artificially low efficiency. The original rear brake countershaft had insufficient support and tended to self-lock under increasing load. W.W. instructed an improved support which largely overcame the trouble. The direct braking efficiency as will be seen is still rather low owing to having the largest number of levers and shafts to negotiate. In order to get an approximation to the theoretical 100% efficient linkage distribution therefore, the direct braking will have to be rather more than we have hitherto calculated. We have not yet established why the linkage from the servo to the front brakes shews a higher efficiency than that to the rear brakes. In order to overcome (1) we are discarding Halo and trying out woven cotton discs, similar to the lining of the old Silver Ghost clutch. With 30° cams these linings can be soaked in oil and then give very smooth application. Such treatment enables the pins on which the plates slide to be lubricated thus improving the mechanical operation of the servo and assisting in overcoming (2). contd :- | ||