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).
The design and testing of a new headlamp foot switch.
| Identifier | ExFiles\Box 168a\2\ img140 | |
| Date | 3rd August 1934 | |
| 6139 E.{Mr Elliott - Chief Engineer} From Ha/Wst. By.{R.W. Bailey - Chief Engineer} Ha/Wst./MA.3.8.34. R.R. DESIGN OF HEADLAMP FOOT SWITCH. The first R.R. foot operated changeover switch for headlamp dipping has now been examined and tested on the bench. Our general impression is that this switch is an advantage over the German Bosch and the Lucas switch of similar design and with one or two minor improvements as outlined below we consider it should prove immensely superior to any that we have seen. In testing this switch it has been borne in mind that, in service, it will probably get a tremendous amount of work. For this reason although generally satisfactory, certain modifications are indicated; mainly with a view to reducing wear and lengthening the life of this unit. It was first noticed that, in the event of wear occurring, at the rubbing surfaces between the rotating blades and the brackets supporting them, across which the current has to pass, pressure will be reduced between them to the detriment of the contact. It is thought that a steel spring washer might be inserted on the outer end, between the plain washer and the blades. It was found that, owing to clearance existing between the base of the support carrying the laminated contacts, and the moulded insulation locking rib, it is possible for the contacts to twist round on the terminal bolt, and prevent the rotating blade from entering properly. As regards section capacity, and contact capacity the switch is quite satisfactory; a current of 10 amperes being passed through one set of contacts, (corresponding to two, 60 watt lamps on one side, and spot lamp on the other) and maintained for an hour, without perceptible rise in temperature. At the end of this period the voltage drop across the contacts was only .017 volt. | ||