Patent GB-780394-A (GB)
Title: Machines for making stems for electric lamps and discharge tubes
IPC: H01J9/32
Filed: 1955-08-24
Abstract: 780,394. Making stems for electric lamps and discharge tubes. SYLVANIA ELECTRIC PRODUCTS Inc. Aug. 24, 1955 [Aug. 24, 1954], No. 24383/55. Class 39(2) In a stem-making machine wherein a plurality of components which comprise a stem are associated in each of a series of supporting devices which are indexed through a succession of work stations, a leading-in wire shaping and inserting device 10, Figs. 1 and 3, at one station comprises a die having an aperture extending therethrough from a wire-receiving surface, the die being disposed above and in register with a flare tube 9 held by a supporting-device at that station, with a punch or pusher member 286 comprising a part of a wire-loading device 12 adapted to be located above and in register with the aperture in the die and to be moved through the said aperture, whereby the wire on the surface of the die is engaged intermediate its ends, bent or doubled back on itself, and pushed through the aperture into the flare-tube. After the insertion of an exhausting-tube within the flare tube while at a subsequent station the flare is heated to a plastic state by burners 41, and a stem or pinch formed to seal the two ends of the wire loop therein. At a subsequent station the lower end portion of the loop is shaped as shown in Fig. 11, by apparatus 14, and it is then advanced to apparatus 16 at which the bight of the loop is severed by a pair of co-operating cutters 400, 402 operating in opposite directions in a horizontal plane. The machine comprises a conveyer formed by an upper chain 38, Figs. 2 and 3, and a lower chain 34, of which the upper chain has a plurality of heads 40 each for supporting a flare 9, and the lower chain 34 has a plurality of weld blocks 42 each co-operating with a head 40 to form a work-supporting unit which carries the stem components assembled therein to certain successive work stations. The respective chains are disposed in upper and lower horizontal planes and pass around sprocket wheels on spaced vertical shafts 46, 50 associated with indexing mechanism in known manner. A main horizontal driving shaft 56 is geared to two parallel cam shafts 66, 70 carrying cams which actuate the devices at the various work stations. Leading-in wire feeding. Wire 76 from a reel having an associated brake shoe is fed around a pulley 78, Fig. 4, at one end of a supporting-plate 72 mounted on a bracket secured to the rail 22, Fig. 2, of the machine. The wire passes through an aperture in a guide plate 84 on the face of a jaw-mounting block 82 mounted on the plate 72 and carrying a jaw 86 on a pivot 88, and a co-operating jaw 90 forming part of an L-shaped member pivoted at 92 and provided with a cam-follower roller 94. Both jaws 86 and 90 are spring- loaded to exert a positive grip on the wire 76. A second pair of pivoted, spring-loaded jaws 100, 104 is spaced behind the jaws 86, 90 on a block 96 which is provided with an apertured guide plate 98 and carried by a movable platform 97, the wire being also. threaded through a snout 108 mounted on a block 110 on the platform 97 and arranged to guide the wire towards a pair of cutters 116, 118 on a cutter support 112 mounted on the fixed supporting plate 72. A further pair of jaws 130, 132, also mounted on the plate 72 and behind the cutters, comprises a stationary jaw 130 cooperating with a movable jaw 132 secured on one end of a rotary pin 133 journalled in a block 131 and connected by a lever 134 to a cam-controlled actuating-rod 136. The movable platform 97 is a lateral extension of a carrier 138, which is pinned to a horizontal rod 140 having secured thereon a block 142 carrying a lateral pin 144 whereby it is linked to one end 146 of a cam-actuated connecting-rod 158. A cam support plate 148 with its ends secured to the carrier 138 and block 142 respectively is provided with bar cams 150 and 152. In operation the connecting-rod 158 reciprocates the horizontal rod 140 within end brackets 156, so that the free end of the wire is fed through the snout 108 due to the wire being gripped by the feeding-jaws 100, 104 on the movable carrier 138, during which movement the grip of the first jaws 86 and 90 is released by cam roller 94 riding on bar cam 150, a temporary grip being effected, however, when the roller enters the gap between the bar cams 150, 152. The free end of the wire, with the snout, is moved between the open wire cutters 116, 118 and between the open jaws 130, 132, whereupon the movable jaw 132 is closed and grips the wire, as shown im Fig. 6, and the return stroke of the carrier 138 commences, the grip of the wire-feeding jaws 100, 104 mounted thereon being thereby relaxed. As the carrier 138 moves back the leading-in wire transfer and loading apparatus is swung about a vertical shaft 256 into its operative position and receives the wire in a die 260, Figs. 6 and 7, as soon as the snout 108 has retracted a sufficient distance; a transverse groove 261 is provided in the die, into which the wire snaps. The die 260 is also provided with an aperture 263 through which the punch 286 disposed above it can be lowered into engagement with the wire. The wire 76 thus held at one point by the jaws 130 and 132, and by the punch 286 and die 260 at another, is cut from the supply length by the cutters 116 and 118, and as soon as the wire has been severed the jaws 130, 132 release their grip on the cut segment thereof, which can them be transferred and delivered to a head of the stem machine. The severed wire segment, held on the die 260 by the punch 286 is transferred to a position above and in register with a stem machine head, as shown in broken lines in Fig. 10, during which movement a deflector 277 is brought into engagement with a pair of wire spreaders 470 and moves them temporarily out of position for delivery of the wire to the stem machine head, which carries a flare 9 fed to it previously in known manner. With the wire spreaders displaced, the punch 286 is moved downwardly, and the walls of the die 260 which define the aperture 263 deform the substantially straight wire into a U-shape, the bight of which lies between a pair of weld block plates 484. 488, Fig. 9b. During the return stroke of the punch 286 and die 260, the wire-feeding mechanism 10 is feeding another length of wire. The assembly comprising the flare tube 9 and looped length of wire is indexed around to work stations at which an exhaust tube is fed thereto in known manner, and burners 41 heat the flare before the stem press is formed and the wire sealed therein. Shaping of the leading-in wire is next effected by the shaper 14, comprising a standard 350, Fig. 2, which is. pivoted on screws 352 amd is swung into operative position by a cam-actuated connecing-rod 360, whereby the U-shaped wire loop is engaged between a pair of rollers 388, Fig. 11, mounted eccentrically on the heads 385 of a pair of spindles 384. The spindles 384 are clamped on the inner ends of a pair of arms 382 connected by links 380 to a slide 370 and cam-actuated connecting-rod 372. At a subsequent work station the wire cutter 16 severs the bight of the wire 76 to define a a pair of leading-in wires. Cutters 400, 402, Fig. 12 are mounted horizontally on the upper ends of levers 404, 410 which are pivoted on a pin 414, Fig. 3, and connected by links 420, 422 to a cam-actuated connecting-rod 432. A guide wire 421, which overhangs the cutter 400 slightly, helps to prevent deformation of the leading-in wires by maintaining a pressure thereon when the cutters start their reverse movement after serving the bight of the wire. The filament may be attached to the ends of the leading-in wires either before or after the bight is severed. Specification 639,048 is referred to.