GB372060A - Improved means for mounting electric lamps - Google Patents

Abstract

372,060. Electric lamp holders. CALLENDER'S CABLE & CONSTRUCTION CO., Ltd., Hamilton House, Victoria Embankment, London, and WILSON, A. E., 19, Oaklands Road, Bromley, Kent. April 2, 1931, No. 10118. [Class 39 (ii).] In an electric lamp adapted particularly for use in mines and in other explosive atmospheres an external support or enclosure acting through the lamp maintains electrical connection between a pin and socket mounted behind the lamp holder, the pin being ejected from its socket by a spring which becomes operative when the lamp support is broken. The slidable connections between the parts form flameresisting passages between the lamp connections and the outside atmosphere. The lamp 19 mounted in a screwed socket 17 is enclosed within a well-glass 24 protected by a guard 28 mounted upon a metal casing 1 which is provided with a tubular extension 2. An insulating-sleeve 3 within the extension 2 is reduced at its lower portion to provide support for an insulating-sleeve 11 and a surrounding metal sleeve 10 which are secured together by a screw 41 and adapted to slide between the sleeve 3 and the inner wall of the extension 2. The metal sleeve 10 has at its lower end a flange 15 brazed to a flange 16 on the lamp socket, and a helical spring 21 interposed between the lamp casing 1 and the flange 15 is held compressed by an indiarubber or other support 20 within the well-glass bearing upon the lamp bulb. The centre contact of the lamp socket is formed by a screw 38 which passes through the sleeve 11 and is screwed into a metal pin slidably mounted within a metal plug 13 screwed into the lower end of the insulating-sleeve 3. An insulating-plug 14 is interposed between the metal plug 13 and a similar plug 5 which is secured in the sleeve 3 by a pin 6 and receives the end 37 of the cable. In the event of either the lamp bulb or wellglass breaking, the lamp socket together with sleeves 10, 11 is forced outwardly by the spring 21, and the contact between the pin 8 and the plug 5 is broken, the movement of the parts being limited by a screw 22 engaging within a slot 23 in the sleeve 10. The connections may be adapted for either one or two contact pins. In the single - contact form shown the casing is earthed by a clamping-cone 34 bearing upon the armouring of the cable. An inner clamping-cone 30 is screwed upon the extension 2 of the casing, a gland 31 comprising a resilient washer 32 between two metal washers 33 being interposed.