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).
Production inspection and test specification for a duplex button switch.
| Identifier | ExFiles\Box 64\3\ scan0279 | |
| Date | 9th July 1926 | |
| (VERSION 1) x7650 EFC/T9.7.26. X.7650. DUPLEX BUTTON SWITCH. X.7781. SPECIFICATION OF PRODUCTION INSPECTION AND TEST. (1) Inspection shall be made that :- (a) The carbon contacts exactly bed together, and that both pairs of contacts make contact simultaneously. Also that the lower carbons shew no signs of sticking in the base when pushed right down. (b) The cylindrical metal contacts are making correct line contact centrally and that both pairs make contact simultaneously. (c) The flexible connections to the carbon contacts exhibit no signs of fraying. (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 .035+5 -3 .019+13 -8 Carbons in A + .010+7 -4 .020+3 -5 0 contact. Coppers in A + .024+4 -2 0 0 contact. where A = initial button depression which should be .012". EFC. | ||