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).
Technical memo discussing modifications to the brake shoe design, including 'servo' or jointed shoes.
| Identifier | WestWitteringFiles\K\November1923\ Scan131 | |
| Date | 11th August 1920 | |
| R.R. 235A (100 T) (S.H. 159 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2500 (2) We suggest we twist round the shoe and put a 6" lever on, and by twisting round the shoes we bring the ball actuation joint to the same position as at present but slightly lower. Some of this we wired - most of it is in the designs which will be sent this week. All our recent experience shews that in the past we (and others) have been depending upon long shoes to give us our braking efficiency. If these shoes are rigid they are unreliable - i.e. wear off at end or sometimes jab, and if flexible will wear unevenly, so that some other form or more pressure is needed - i.e. from 'servo' or jointed shoes. Before settling the ratio for 'servo' and rear brakes these should have the shoes reduced to 120° or 130° or of some other design. The car as brought to WW. probably had too long servo shoes and also back shoes, but it is difficult to say what the shoes on the back brakes will do until they are joint-ed.{J. L. Edwards} R.{Sir Henry Royce} | ||