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).
The issue of the 3rd gear disengaging in the 25HP Synchromesh gearbox and the recommended solution.
| Identifier | ExFiles\Box 104\4\ scan0125 | |
| Date | 1st May 1932 | |
| R.{Sir Henry Royce} From HS{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to SS.{S. Smith} Nor. c. to L. Da.{Bernard Day - Chassis Design} c. to Hy.{Tom Haldenby - Plant Engineer} 85310 HS{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/MA.S. 5. 32. 25HP. SYNCHROMECH. 3rd. GEAR COMING OUT OF MESH. This trouble has occurred on a large proportion of cars on production test. The gear works out on the overrun particularly at high speeds but on bad cars at low speeds also. When we first tested the 25HP synchromesh gearbox the top gear was found to come out on the overrun. The 3rd. and 4th gear sliding piece then had the driving splines under the top gear teeth. The sliding piece was therefore altered so that the splines were nearer the 3rd gear teeth and a bearing was provided under the top gear teeth. This bearing consisted of splines in the sliding piece running on a plain shaft. Top gear is no longer came out but later the trouble developed of 3rd coming out. We have therefore tried the arrangement shown on Lec.C.37 in which the splines on the shaft are so positioned that in either gear the drive through the sliding piece is taken from the teeth at one end to the splines at the other. suggested by E This has proved successful on 3 cars 3rd gear showing no tendency to work out even with the selector springs absent. We recommend standardising this modification and also fitting it to all cars that cannot be got off test with the present 3rd motion shaft. HS{Lord Ernest Hives - Chair}/M.Grylls. 1 print Att: | ||