Patent GB-687094-A (GB)
Title: Improved method of and apparatus for mounting filament wire for electric lamps
IPC: H01K3/06
Filed: 1951-04-09
Abstract: 687,094. Making electric incandescent lamps. BRITISH THOMSON-HOUSTON CO., Ltd. April 9, 1951 [April 20, 1950], No. 8183/51. Class 39(ii) In mounting a filament wire between a pair of current-carrying wires or supports, as in electric incandescent lamps and photographic flash lamps, a pair of supporting wires 2, 3, Fig. 1A, sealed within an inverted stem tube 5 carried in a work-holding head are each acted upon by the edge of a rotary disc or roller 1 which in conjunction with a metal block 8, forces corresponding grooves or notches 6 in the wires 2, 3 and develops projections or lips 7 (shown to a larger scale in Fig. 1a), whereupon the workholding head is advanced to a further station at which a filament 9 is disposed transversely adjacent to the wires 2, 3 and an anvil 18, Fig. 4, is moved vertically upward into contact with their lower ends so that the stem tube 5 slides upwardly through its holding-jaws 16 and 17 sufficient to locate the filament wire 9 completely within the base of the notches 6. Clamping blocks 21, 22, Fig. 3c, located on opposite sides of the wires 2. 3 are then moved inwardly towards one another to bend the lips 7 over on to the filament wire, as shown to a larger scale in. Fig. 3C. After the withdrawal .of the anvil 18 and clamping blocks 21, 22 a pair of rotary cutters 25, 26 are operated to sever the mounted length of filment from the supply reel. The apparatus, which is described as an improvement in that disclosed in Specification 570,803, comprises a pair of wirefeeding jaws 12 and 13 which are operated in the manner described in the prior Specification and draw a length of filament wire 9 and hold it tensioned during the mounting operation. An additional guide 56 is provided adjacent to the friction blocks 10 and 11 between which the filament is drawn, and a further pair of holding jaws 14, 15 are provided between the guide 56 and a pair of cutters 25, 26. The jaws 14, 15 are closed upon the filament before the cutters are operated, thereby limiting the outward movement of the relatively springy wire from its normal lie. The jaws 14, 15 are located near to the fiction blocks 10, 11 and are shaped to embrace a boss 33 on their mounting bracket 34. Operation of the jaws is effected by a hollow shaft 31 and an interior shaft 32 which extend through the bracket 34 and are actuated by pairs of links 37, 39 and 38, 40 connected to a vertically movable rod 36. This operating means is similar to that of the rotary cutters 25, 26. A spring 41 tends to hold the jaws 14, 15 closed. Operation of the filament-drawing jaws 12 and 13 is effected under the control of a rocking-lever 42, in the manner described in Specification 570,803. While the free end of the supply of filament wire 9 is gripped between the faces 29, 30 of the holding jaws 14, 15 the lever 42 is moved anti-clockwise to effect the opening of the wire-feeding and tensioning jaws 12, 13 and move them longitudinally to bring their forward nib ends 52 above and below the gripping faces 29, 30 of the holding jaws 14, 15, whereupon the lever 42 commences a clockwise return movement which closes the ends of the jaws upon the wire at a point between the guide 56 and the holding jaws 14, 15. No longitudinal movement of the jaws 12, 13 takes place until the jaws 14, 15 and cutters 25, 26 have been opened by their respective controlling devices to allow the jaws 12, 13 to draw the filament wire 9 in a longitudinal direction across the wire 2, 3 of a newly positioned stem at the work station.