GB502330A - Improvements in and relating to electric incandescent lamps - Google Patents

Abstract

502,330. Electric incandescent lamp filameats. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 24, 1938, No. 24913. Convention date, Aug. 24, 1937. [Class 39 (ii)] In a method of supporting a filament and attaching it to its leading-in conductors, more particularly in high-wattage lamps, the end portions of the filament 16 are wound in the form of coils 28 to receive and make contact with mandrels 30 which extend therethrough, and separate coils 29 having the same pitch as the coils 28 are screwed over the,latter so as to short-circuit the turns thereof and increase the contact with the mandrels. In the example the upper ends of the mandrels 30 are welded to channel-shaped leading-in conductors 14 which are held in spaced relationship by an insulating cross-bar 17 provided with holes for the passage of the mandrels, and the coiled end segments 28 of the filament are located between the bridge 17 and hooks 31 at the lower ends of the mandrels. The filament is of the biplane type comprising a number of parallel coiled segments supported at their upper ends by wires 23 which are secured in the insulating cross-bar 17, the lower ends of the segments being secured to anchor wires 24 which are rigidly mounted on an insulating bridge-member 25. This bridge 25 is guided by two wires 26 which have one end secured in the bridge and their other ends coiled loosely around wire extensions 15 on the lead-in conductors 14 and slidable freely to allow for expansion of the filament. A further guide wire 27 extends from the bridge 25 through a hole in an insulating cross-bar 18 at the lower ends of the extensions 15. Specifications 409,235, 418,648, and 435,663 are referred to.