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).
Description of the four-wheel braking system and its servo mechanism.
| Identifier | ExFiles\Box 178\1\ img079 | |
| Date | 9th July 1924 | |
| DESCRIPTION OF THE R.R. SYSTEM OF FOUR WHEEL BRAKES. In the RR. system, all the four wheels are braked by application of the foot pedal. The hand brake operates only on the rear wheels and is exactly the same as on the standard rear braking system of the 40/50 HP. RR. In order to obtain adequate effort to operate the brakes - there being now four brakes instead of two - without increasing the leverages and consequently the pedal travel, a servo is employed. Briefly, the servo consists of a rotating drum driven indirectly by the propeller shaft through gearing carried in the gearbox, and friction plates to which are attached pull rods operating the brakes through a special form of equaliser. The foot pedal when depressed holds the friction plates against the rotating drum giving them the tendency to rotate with the drum owing to the frictional force between the two surfaces and varying in intensity with the amount of pressure applied to the foot pedal. The tendency of these friction plates to rotate operates the four brakes through the equaliser and a system of levers, the degree of braking depending upon the pedal pressure in exactly the same way as with the ordinary system but it can be seen that much lighter pedal pressure is required to obtain the same braking owing to the assistance from the servo. The braking is not wholly dependent upon the servo because part of the pedal effort is taken direct - through the (contd). | ||