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).
Proposed solutions for gearbox and clutch engagement issues.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan144 | |
| Date | 3rd June 1929 guessed | |
| (2) Mr. Hardy has suggested that to overcome the difficulty in connection with the reverse, which will not engage without some special devices and further manoeuvres, that the coupling may be placed in advance of the 1st. gear, so as to cancel its action when used on the 1st. gear and the reverse. Its engagement will not be necessary for these two gears. At the same time should it become engaged it will have no ill effect. The other serious troubles are that one is very apt to stop the engine when the coupling becomes disengaged, which happens every time the clutch pedal is pushed down, and then it cannot be re-engaged without further devices and manoeuvres. To overcome this difficulty I have proposed that the disengagement is not made by the clutch pedal, but by the change speed lever (either directly or by relay - preferably vacuum relay from engine suction) so that the coupling does not become disengaged unless it is desired to change gear, under which conditions the stopping of the engine would not be any more frequent than at present. As far as I can see these two ideas overcome the difficulties, and avoid the necessity for the complicated and unsatisfactory devices which require knowledge and care in manipulating. In the scheme of detaching the clutch by means of the movement of the change speed lever it is preferably arranged that the engagement will be made by the first part of the motion of the clutch pedal, so that the idea is that the main clutch pedal does not put the Salerni coupling out of engagement, but puts it in engagement if it is out, and the movement of the change speed lever puts it out if it is in, but has no power to put it in. The sketches herewith will enable these two ideas to be covered by preliminary patents. (Sketches to Mr. Claremont.) In conjunction with this scheme the 3rd. speed would probably be single or double helical gears, and the engagement be made by a jaw clutch. As far as we can see this combination would make both a silent third, and easily engaged 3rd., 2nd., and top, and an independent 1st. and reverse. It would utilise some of the space between the gears for the Salerni coupling, but the servo drive would have to be put behind the gearbox proper. In conclusion, these two devices are hopeful and promising to solve the gearbox difficulties. They should be covered by patents as far as possible. | ||