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).
Design and operating pressure of a two-way press button starter switch, including proposed modifications.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan002 | |
| Date | 13th March 1929 | |
| EFC. FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} R.{Sir Henry Royce} By HS{Lord Ernest Hives - Chair} SECRET. SS.{S. Smith} TWO WAY PRESS BUTTON STARTER SWITCH. Regarding the above switch we believe your criticism is that it requires too much pressure to operate, and that the mechanism has been compressed into too small a space. We have not seen the model but we should say for the type of switch it is not too small for the duty, and once the best proportions and clearances have been established for the operating parts we believe it will be quite satisfactory. The best way to arrive at this will be to send a model to R.{Sir Henry Royce} Perhaps one could be sent by the car leaving this week as per our telegram. Regarding the operating pressure we do not know what has been arranged, and it may be excessive. We suggest you give us the initial and final pressures measured separately from the three following sources:- (1) The bow spring. (2) Carbon contact springs. (3) Copper brushes. and we will say what we think they can be. Subject to R's approval we propose to alter the press button to a larger diameter either flatter sphere or hollow so that it will not sink into the thumb when operated. On the original design of this switch we used a triangular flange with curved sides as in fig. 1. to agree with the character of the other instrument board fittings. Subsequently we altered this to fig. 2. for the sake of simplicity, but we are now asked by 'CamachaHenry Royce's office in West Wittering' to revert to fig. 1. to improve the appearance of the instrument board. FIG I FIG II Finally it is proposed to arrange that the switch casing will not come apart when released from the instrument board to avoid suffering damage at coachbuilders between the removal of the test board and the final fitting of the body. Of the two schemes drawn we propose to instruct Sch. (2). The above slight modifications are shewn on LeC. 2684. of which a blueprint is attached to R's copy of this note, and the original to BY's copy. E.{Mr Elliott - Chief Engineer} | ||