Gear and clutch design, comparing a 'Salerni' scheme with a suggested new constant mesh design.
| Identifier | ExFiles\Box 6\2\ 02-page069 | |
| Date | 29th April 1930 guessed | |
| (3) With the gear shewn (sketch 1.) there is no need of through drive clutches, either friction or jaw type, until we come to the top gear, which usually presents no difficulties, and a jaw clutch can be used for this (with or without a Salerni ring) as shewn in the sketch. I shew a design (sketch 6) of how the pawls for the 1st, 2nd, and perhaps 3rd, and reverse, can be equalized (balanced) and synchronously operated in pairs. The advantage of the design shewn is that the stresses are low and the slack in the joints has little ill effect, and the movement in one part does not affect the other, (patentable). The 1st. speed ring should be easy to manage be- cause it should never be allowed to run backwards. My idea is that it should be brought to rest by a light brake (say quarter engine torque) then any movement backwards of this brake makes or allows the pawls to engage. (This first speed ring could be held by free-wheel or silent ratchet. Patentable claim. The 2nd. and 3rd. speed rings must be allowed to revolve freely in both directions, but like the 1st. we only need to hold them firmly in one direction (i.e running backwards), which may make the problem easier. I am inclined to think that for a quick change top to 3rd. in traffic, Salerni scheme may prove too slow. Messrs Day and Hardy will I hope be able to continue their studies on this subject, and comment on my suggested merit scheme, which has much in its favour for silence, and has the merits of being equivalent to constant mesh, without the disadvantage of the usual design. My notes are very incomplete and not collected into a complete scheme, but may provide some materail to go on with, and possibly to patent. I hope you will be able to get some sense out of it all, and pick out a fairly good combination. R. {Sir Henry Royce} See Original for Sketches. | ||
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).