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).
Four-wheel brake tests, including an extract about the countershaft and overrun mechanism.
| Identifier | ExFiles\Box 73\1\ scan0182 | |
| Date | 18th June 1924 | |
| R.R. 495A (20H) (D.A. 652 20-3-24) J.H.D. X9910 EXPERIMENTAL REPORT. Expl. No. 9941 REF: Hs{Lord Ernest Hives - Chair}5/Lg18.6.24. 9910 S E C R E T. FOUR WHEEL BRAKE TESTS. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. RG.{Mr Rowledge} c. to DA.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} WOR.{Arthur Wormald - General Works Manager} Below is an extract from a report we have received from our man (A.J.Lidsey) who is in charge of the tests in France. We have tried a car at Derby by locking the dogs on the countershaft and did not notice any disadvantage or any difference in the braking. Extract :- "The stiffness of the levers coming from the servo, as reported on 35-PK (10.6.24.) refers to the countershaft between the servo and the rear brake equaliser shaft. In depressing the brake pedal, the countershaft turned as a whole, the overrun part of the it being stiffened up owing to dirt and sand getting in. Having seen this working as a solid shaft, we rather fail we see the benefit gained by using the overrun mechanism. When the shaft is solid, depression of the brake mechanism applies the rear brakes as before, and also moves the servo levers 'A' and 'B', as shewn in sketch, the overrun part of the business being done by the two lugs on the servo coming up against the levers 'A' and 'B', just as efficiently as the separate countershaft. If the separate overrun dogs are necessary, the countershaft should be provided with some form of cover against dirt as it is in a very exposed place and gets choked up with sand etc." Hs.{Lord Ernest Hives - Chair} sketch attc. | ||