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 design and proportions for a sequence starter's gear teeth.
| Identifier | ExFiles\Box 64\2\ scan0134 | |
| Date | 23th December 1927 | |
| EAC. ) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} ) (At Le CanadelHenry Royce's French residence.) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} to BJ. WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} X/6235B R1/M23.12.27. RECEIVED & DESPATCHED FROM WW. 29.12.27. EAC.10. SEQUENCE STARTER. This is very nearly right now, but requires some work to find the correct proportions, etc. Apparently the first part of the engagement will always be gentle, and therefore it should be quite safe to leave the corners of the teeth square and sharp. The disengaging corners should be rounded after leaving a certain amount of face to avoid cutting, unless experience shews this to give violent and objectionable thrust at the final point of disengagement. This you should carefully watch, and also prove by referring to Bosch practice. Regarding the helical angle of the teeth, this is a R-R.{Sir Henry Royce} idea, and should if not overdone help both the engagement and disengagement. When we have tested the set you are making of 5º and found these to be better, we might try a set at 10º, but 5º is an incline of about 1 in 12, and perhaps if this shews no disadvantage in engagement and disengagement we might try the 10º - i.e. it would be 1 in 6 incline. I do not know any reason why the gear should be more noisy: it ought to be slightly more silent if cut with equal accuracy, (which appears possible if we do not need to harden and grind the teeth: I have the impression that you are hardening the pinion only, and not grinding.) Fellowes and Sunderland cutting available, and probably better than others. You have three points that are R-R.{Sir Henry Royce} novelties. Supposing Bosch has a patent earlier than ours for the sequence of engagement, we still have hold-out magnet idea, taper armature, and spiral gear teeth, in such a scheme. Kindly let me know the situation. My own part of the work at the moment is to get the best and simplest design for the main switch and hold-out magnetic apparatus. This I hope to send in a weeks' time. R.{Sir Henry Royce} | ||