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).
Push-button switch failure due to earthing, with a proposed design modification.
Identifier | ExFiles\Box 34\3\ Scan044 | |
Date | 10th September 1919 | |
PUSH BUTTON SWITCH fig I - Diagram of Switch - fig II P.B. SWITCH NO.7 After several days satisfactory use on a car under test, this switch was returned due to earthing on to the cover C. On testing switch it was found to be satisfactory in the 'off' position, but on slightly depressing the push button P, the current to the arm A earthed to the cover C. This was evidently due to the flange ff of the push button coming into contact with some part of the arm A in the region of a a.{Mr Adams} The switch was O.K. on passing out of test, and the trouble has probably arisen from the wooden plug shrinking into its recess with use (or shrinkage due to drying of the plug). To prevent further trouble in this respect the use of a plug of the shape indicated in fig. II would seem preferable; the flange f f being completely covered by the head of the plug. To do this it would probably be necessary to reduce the dimension "h" - in existing switches by packing Contd. | ||