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).
Review of the operation of the Salerni coupling device on RAC.7.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan181 | |
| Date | 11th November 1930 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe} c.c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c.c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c.c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/GR.{George Ratcliffe}1/MJ.11.11.30. SALERNI COUPLING ON RAC.7. Briefly reviewing the operation of this device. The coupling itself consists of three members as shown in figure. X. The sliding member free to slide on the third motion shaft has dogs (not shown) capable of engaging with dogs on Z the fixed member rigidly attached to the propeller shaft. Y. The synchroniser ring floats freely on X and always rotates at the propeller shaft speed due to projections P on Z. The coupling is shown in the free wheeling position. When the coupling is engaged the dogs on X slide into the dogs on Z and then the dogs on X (inside Y) can mesh with inner dogs on Z. The motion of X. follows that of the clutch pedal. Therefore the clutch pedal, if depressed, cannot be released if the dogs are in the position shown until Z. has rotated sufficiently to bring the dogs into the right position. Due to a system of levers the action of the clutch pedal is as follows :- (1) Suppose coupling to be initially engaged and clutch pedal up. Depressing the pedal disengages the clutch and the Salerni coupling into position shown in figure 111 (X no longer meshes with Z) (2) Letting up the clutch pedal either- (a) engages coupling if dogs on Y or Z are suitably positioned. or (b) does not allow coupling to engage. (3) Depressing again the clutch pedal after 2b either - (c) re-engages coupling due to a toggle system that throws this mechanism into operation in the free wheeling position only if dogs on Y shift into correct position. or (4) Clutch pedal cannot be moved until the prop. shaft and hence Z have been rotated into a suitable position. It is therefore sometimes impossible to engage any gear | ||