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).
Critique and modification request for a press button starter switch due to excessive operating pressure.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan114 | |
| Date | 2nd May 1929 | |
| EFC. FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} [Strikethrough] "HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer}" [Strikethrough] ORIGINAL SECRET SS.{S. Smith} PRESS BUTTON STARTER SWITCH - LeC. 2641. E1/M2.5.29. X7655 The model of the above received this morning is a very nice little switch, very well turned out, but the finger pressure to operate it is about 5 times too much. It requires 17 lbs. to fully depress, and 11 lbs. to just make contact with the metal brushes. We intended the bow spring to be made of bronze, although this is not stated on our drawing. This would reduce the pressure to 40% of the present amount with a given travel from zero. The thickness of the spring also should be reduced to .8 of the sample, and this should halve the pressure. With these modifications the operating pressure should fall within the following limits:- 3 to 4 lbs. to fully depress. 2 to 2.5 lbs. to just contact metal brushes. If you could send a bridge piece with a spring riveted on, modified as above, we could try it on the model forthwith. R.{Sir Henry Royce} is away today but we will shew him the switch on his return, when we will send further notes and criticisms. E.{Mr Elliott - Chief Engineer} | ||