GB514732A - Improvements in and relating to methods of and apparatus for manufacturing incandescent electric lamps and similar articles - Google Patents

Abstract

514,732. Making electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd. May 12, 1938, No. 14209. Convention date, May 15, 1937. [Class 39(ii)] In the manufacture of electric incandescent lamps a mount comprising a pair of leading-in wires with a filament attached thereto is arranged within a bulb 15, Fig. 4, with the leading-in wires extending longitudinally through the open neck of the bulb, and heat is applied to the neck to soften and fuse it around the leading-in wires while an opening is maintained through the neck by a rod or mandrel 28, after which the bulb is evacuated within an exhausting-chamber and then sealed hermetically either by softening and pinching the glass or by fusing over the opening a quantity of molten glass while the bulb is within the exhausting-, chamber. During the sealing of the leading-in wires the bulb is held neck uppermost within a suction cup 19, and the wires are held within grooves along opposite sides of a spindle 22 by means of clamping-jaws 23, 24 which are pivoted in a block 26 and normally held in clamping position by a compression spring 27 between their upper ends. The spindle 22 is hollow and encloses the mandrel 28 which extends throughout its length, so that when the spindle is lowered the tapered end of the mandrel is positioned within the neck of the bulb. The neck is then heated and the softened glass is compressed between a pair of oppositely directed jaws 29 actuated by rotating a hand wheel 36 thereby compressing the glass around the mandrel. The lamp is now removed to an evacuation chamber and after evacuation, and gas-filling if desired, the hole is closed by electric heating and compression, Fig. 7 (not shown), or by sealing additional material over it, Fig. 11 (not shown).