GB877053A - Improvements in or relating to combined electrical indicating and switching devices - Google Patents

Abstract

877,053. Press-button retractive switches; indicators for switches. IGRANIC ELECTRIC CO. Ltd. Nov. 25, 1957 [Feb. 19, 1957], No. 36635/57. Class 38 (5). A pilot light is combined with a change-over switch such that manual pressure on the lens unit 62 operates the switch to energize the lamp for the purpose of testing its condition. In the embodiment shown, a transformer 36 with insulating base 31 is clamped between a switch unit 38 and a member 56 by two screws 48, 49 which enter tapped holes in member 56. The assembly is mounted on a panel 63 by means of a threaded ring 64 which engages an upstanding threaded part of member 56; a cork gasket 65 provides a liquid-tight seal. A lamp holder 51 is fitted on the upper casing of transformer 36. A lens holder 57 is slidable in member 56 against the action of a spring 58 located between a shoulder on holder 57 and an internal flange 56e in member 56. A metal washer 61 is secured to the lower end of holder 57 and acts as a back stop against flange 56e. A synthetic rubber sealing ring 59 is located in a groove in holder 57. Openings near the base of members 56 and 64 allow any liquid that may penetrate the seal to drain away when panel 63 is vertical. A push-rod 39 extends from lens holder 57 through part 31 into the switch unit 38 where it engages one end of a pivoted brass contact bridge 75 which is biased by a spring 74 so as normally to bridge contacts 76 and 77 (see Fig. 9). On depression of the lens holder 57, the rod 39 causes bridge 75 to leave contact 77 and interconnect contacts 76 and 78, putting the primary of transformer 36 directly across the supply and lighting low voltage lamp 52 which is connected to the transformer secondary (Fig. 4, not shown). In an alternative embodiment (Figs. 14 to 22, not shown), a relatively high voltage lamp is used, the transformer 36 being replaced by a dropping resistor, and the lens holder is modified to accommodate the larger lamp, but the same switch unit operated by a push-rod is retained.