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).
Specifications and production testing of gaps for duplex push button switches.
| Identifier | ExFiles\Box 64\4\ scan0304 | |
| Date | 26th June 1929 | |
| X7655. By/RD. from EFC. EFC2/AD26.6.29. DUPLEX PUSH BUTTON SWITCH GAPS. The gaps quoted in our EFC6/D24.5.29 were the approved gaps arrived at a good while ago and given to you at the time, see our EFC2/T6.7.26, your By/RDL/ML13.7.26 and By/RDL/ML14.7.26. It was then understood that you would instruct these. It is undesirable to have very large gaps on a switch of this type because of the danger of the switch being improperly closed, particularly with a high rate spring. Our production specification of test was prepared some time ago and is awaiting issue on the basis of the gaps given, it having been assumed that your instruction would incorporate these. If you will submit your present table of gaps (which may be a compromise) for our approval, we will, if we approve, incorporate these on the production test we are about to issue. EFC. | ||