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).
Specification for the production inspection and testing of a push-button switch.
| Identifier | ExFiles\Box 64\4\ scan0113 | |
| Date | 15th December 1928 | |
| EFC3/T5.12.28. X.7655B. E.A.C.10 PUSH BUTTON SWITCH. X.7781 SPECIFICATION OF PRODUCTION INSPECTION & TEST (1) Inspection shall be made that :- (a) The carbon contacts exactly bed together, and that the lower carbon shews no sign of sticking in the base when pushed right down. (b) The cylindrical gold-silver contacts are making correct line contact centrally. (c) The flexible connection to the movable carbon contact exhibits no signs of fraying (broken strands). (2) The button depression and contact gaps shall now be ascertained, and should be in accordance with the following table :- Position. Button depression. Copper gap. Carbon gap. Off A + .000 .090 +15 -15 .063 +12 -13 Carbons in A + .030 +6 -6 .040 +5 -5 0 contact. Coppers in A + .050 +9 -9 0 0 contact. where A = initial button depression which should be .015" EFC. | ||