GB1490988A - Electrical switches - Google Patents

Abstract

1490988 Mechanical switches; indicators for switches LUCAS ELECTRICAL Ltd 28 Feb 1975 [14 March 1974] 11423/74 Heading H1N An electrical switch has an indicator lamp 16 associated with an electrical resistor whereby the lamp 16 is illuminated more brightly in one of the two positions of the operating member 13 of the switch than in the other. The switch is used as a hazard warning switch in a road vehicle and includes a rectilinearly movable operating member 13 which houses a bulb 16 visible through a lens 17 and which is retained set in either of two positions against the return of a spring by a detent (15), (Fig. 2, not shown). One terminal of the bulb 16 is connected by a conductive strip 18 to a printed circuit board 19 carried by the operating member 13 and engaging a fixed contact blade 21 whilst the other bulb terminal is connected via a ball 23 and spring 24 to a plate 25 integral with a contact member 26 extending round three faces of the operating member 13. The contact member 26 is so shaped that in the outermost position of the operating member 13, it engages a contact blade 31, Fig. 5, whereby the bulb 16 is dimly lit when the lighting switch (32) (Fig. 6, not shown) of the vehicle is closed. When the operating member 13 is depressed into its other position, the contact member 26 is disengaged from the contact blade 31 and bridges contact blades 27-29 causing the bulb 16 to be lit and the hazard warning system to be operated regardless of whether the switch (32) is open or closed. In the lower position of the operating member 13, a lower proportion of the resistance pattern on the printed circuit board 19 is connected in series with the bulb 16 so that the bulb 16 is illuminated more brightly. The board 19 may alternatively carry a conventional resistor which is connected in series with the bulb 16 in one of the positions of the operating member 13.