Patent GB-405525-A (GB)
Title: Improvements in or relating to methods of reclaiming the bulbs of burned-out electric lamps
IPC: H01K3/30
Filed: 1933-06-15
Abstract: 405,525. Repairing electric incandescent lamps. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.-(Electric Lamp Patents Co., Inc. ; 225, 5th Avenue, New York, U.S.A.) June 15, 1933, No. 17119. [Class 39 (ii).] In a method of repairing tipless electric incandescent lamps, the portion of the bulb neck which supports the mount is cut off and removed from the rest of the bulb and a new mount is inserted, after which the open bottomend of the bulb is closed, sealed, and shaped into the flare of the mount by the heat and pressure of flames directed thereon, the bulb finally being exhausted through the neck end. The caps are first removed from the bulbs by applying heat to soften the cement, and pulling the caps and bulbs apart, any cement adhering to the bottom part of the bulb being removed, preferably by a buffing wheel. To prevent collapse of the bulb during subsequent heating operations the sealing-off tip within the neck is broken by gripping between a pair of jaws, after which a series of bulbs is placed on a preheater comprising a hood with bulbreceiving apertures each disposed above a gas flame. The bulbs are then mounted upon a rotary carrier 56, Fig. 8, carrying six vertical tubular shafts 58, which are rotated continuously by a belt 66 passing around pulleys 68 at their lower ends, each shaft 58 being provided with a cross-arm 60 carrying a pair of vertical rods 62 supporting brackets 64 between which a bulb 12 is carried. The filament leading-in wires 70 extending downwardly are gripped between a pivoted jaw 72 and a flattened portion of a tubular plunger 74 extending downwardly through the shaft 58, the plunger 74 being freely slidable within the shaft so that its weight imposes a downward pull on the mount within the bulb. The bulb loaded at station a, Fig. 7, is carried through stations b, c, where its bottom end receives a preliminary heating from burners 78, 80, while at station d a more intense heating so softens the glass that, when the bottom of the plunger 74 runs off a cam track 84, the neck 35 of the bulb is stretched at 87, Fig. 10. The plunger head drops through a further step on the next movement of the carrier, thereby stretching the neck still further. A relatively light air pressure is supplied through the rod 74 to prevent collapse of the bulb, this pressure being increased at station e, where a series of fine flames from oppositely disposed burners 96 sever or cut the bulb to separate that part carrying the mount 54, Fig. 12. In an alternative method of severing the mount-supporting portion from the remainder of the bulb, a fine line is scratched around the lower part of the bulb by means of a diamond, and heat is applied thereto by an electrically heated wire. In order to ensure that the open ends of the bulbs are sufficiently wide to receive a new mount, the bulbs may be mounted on rotating carriers 109, Fig. 19, upon a rotary table 105, which carries them past burners 113, the glass thus being softened sufficiently for the neck to be opened out by a shaping tool 112 inserted therein. The apparatus for sealing a new mount into a bulb is a modification of that shown in Figs. 7 and 8, and comprises a tubular plunger 145, Fig. 36, to support a mount 149 placed thereon with its exhaust tube extending within the plunger, brackets 143 being provided to support the bulb 12. During movement from the loading station the bottom 153 of the plunger 145 rides on to a track 155 which lifts the mount to the requisite height within the bulb, whereupon the neck of the bulb is preheated by burners 157. Further heating by more intense flames causes the neck to bend inwardly towards the flare 161 of the mount, the final sealing at this point being effected by another set of burners. The softened neck of the bulb is subsequently stretched by the plunger 145 running off the track 155 and pulling the stem downwardly.