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).
Modifications and proposals for the speedometer drive.
| Identifier | WestWitteringFiles\T\January1929-February1929\ Scan018 | |
| Date | 12th January 1929 | |
| FROM DA.{Bernard Day - Chassis Design} Copy to HS.{Lord Ernest Hives - Chair} ORIGINAL SPEEDOMETER DRIVE. X7310 We thank you for BY/CGH{W Clough}10/N8129. giving particulars of the standard speedometer drive end. We send herewith N. sch. 2796. shewing the proposal for omitting the screen wiper drive and having a single drive for the speedometer only. In this scheme we have used the standard speedometer drive end shewn on G.75955. In the original double scheme we had used the S.M.M.T. standard shewn on the I.A.E. data sheet No.131. As regards the thread, the diameter of the nut, the use of a knurled nut, and also the length and size of the square. It is rather mysterious to us why this standard for the large size square should not have been adopted by the speedometer makers, especially as in respect to the thread etc it appears to be neater and lighter. With reference to N. sch. 2796 it will be noticed that we have modified the method of assembling and mounting the driving wheel as this appears to us to be the most convenient arrangement. In order to maintain the strength of the gear lever bracket we have reduced the dia of the driving wheel and modified the angle of the thread. The increase of end thrust - approximately 11% - does not appear to us to be of any importance. It will be noticed that we have altered the bosses on the gearbox because of the smaller wheel. In order to use existing cases a temporary gear lever bracket can be used. DA.{Bernard Day - Chassis Design} | ||