Patent GB-903309-A (GB)
Title: Improvements in or relating to the mass-production of electric incandescent filamentlamps
Inventor: ALLWOOD WILLIAM NORMAN
IPC: H01K3/04
Filed: 1960-01-06
Abstract: 903,309. Making incandescent electric lamps; controlling burners. GENERAL ELECTRIC CO. Ltd. Dec. 21, 1960 [Jan. 6, 1960], No. 480/60. Classes 39 (2) and 75 (1). In the mass production of electric incandescent filament lamps at least two successive stages in the manufacture are carried out at fixed operating stations, the different manufacturing operations constituting the first stage being effected whilst the appropriate lamp component is mounted in a holder located at a first fixed operating station, the lamp component being automatically transferred from said holder to a further holder located at a second fixed operating station on the completion of the first stage of operations, and the manufacturing operations constituting the second stage being carried out with the component supported by a further holder at the second fixed operating station. The manufacture may be carried out in parallel by a plurality of similar manufacturing groups, the operations of which are controlled by a common control means, with each stage of manufacture taking place at a plurality of fixed operating stations each forming part of a different group, a corresponding number of similar lamp components being fed simultaneously each to a respective holder at different operating stations of the first stage at which one or more manufacturing operations, the same for each component, are carried out on the components, and the components being then transferred simultaneously each to a respective holder at a different operating station of the second stage at which one or more subsequent operations are carried out on the components. A complete system for the manufacture of lamps is described comprising: (1) a pinch forming unit. The foot tube 27, Fig. 2, is fed down a pair of rails 32 to a pick-up arm 29, a gate 33 being provided to ensure that only one tube is fed to pick-up position at a time. The arm 29 is pivoted on a shaft 28 to bring the foot tube coaxially above a mandrel 34 having diametrically opposed grooves, which is then raised to protrude from the foot tube as at 36, an exhaust tube 39 and lead-in wires 43 being brought into position by feeding arrangements 38, 44 and fed into the mandrel 34 which is then lowered out of the foot tube. The foot tube 27 is then heated by gas burners and the pinch formed by a pair of hammers acting on the softened glass, a hole being blown in the side of the pinch by a blast of air down the exhaust tube; (2) a filament inserting device. The completed foot tube is passed by a transfer device to a pair of jaws in which the ends of the lead-in wires are first flattened by hammers, then bent outwards and upwards, the ends of a filament fed into the hooked ends and the ends flattened down to clamp the filaments. The filaments may be fed from an intermittentlyadvancing magazine by means of vacuum chucks on a support pivoted to swing into place above the ends of the lead-in wires; (3) a support wire inserting unit. The foot tube 27.1, Fig. 7, is fed by jaws 63 on a swinging arm 9 to jaws 64, finely-divided phosphorus to act as a getter being applied to the filament during transit. The jaws 64 support the foot tube 27.1 with the flanged end upwards over a mould 65 and with the lower end in position to be heated by burners 72. Surrounding the mould are a set of wire feeding means 67 in which the wire is fed from a spool 68 radially into the mould through slits 71. The softened end of the foot tube is pressed on to the mould 65 to form a button securing the support wires which are then severed with shears (not shown); (4) a support wire coiling unit having means to support the filament and to coil the ends of the support wires around it; (5) a sealing-in unit. The foot tube 27.1 is fed on to a support member 78, Fig. 11, by a transfer arm that inverts it during transfer, and a bulb 81 is deposited thereon by a vacuum chuck 79 and is held by a cradle .82, the bulb and foot tube being then sealed together by heating during slow rotation by burners 86. The burners are fed with gas and air from sources 111, 112 through a valve 87 comprising three superposed plates 114, 115, 116, the outer plates 114, 116 being fixed and the central plate 115 being rotatable. The plate 114 has ports 121, 122 connected to a supply 111 of coal gas and ports 123, 124 connected to a supply 112 of compressed air, constrictions in the supply pipes to the ports 121, 123 limiting the gas and air pressures to these ports. The plate 116 has ports 131, 132 connected to a mixer 113. Ducts 135, 136 extending through the plate 115 connect the ports 131, 132 to the ports 121, 123, and 122, 124, respectively, in different positions of the plate so that the gas/air mixture is fed to the burners initially at low pressure and subsequently at high pressure; (6) an evacuating, flushing and gas filling unit. The sealed bulb is transferred to this by a vacuum chuck and the exhaust tube inserted in an exhaust chamber communicating with a vacuum pump, a source of nitrogen for flushing the envelope and a source of argon for the gas filling, the pumping, flushing and filling operations being effected by valves operated in sequence by microswitches controlled by a set of arms driven by an electric motor. After filling with argon, the bulb is sealed by burners swung into operative position (7) a capping unit to which the bulb 81, Fig. 13, is then transferred and on which the ends of the lead-in wires are fed through holes in the bases of caps 140 to which they are soldered by movable soldering bits 102. The lamp is finally brought into contact with terminals T of a testing device incorporating means responsive to the current flow to control a movable shoot 22.1 to feed satisfactory lamps to a conveyer 23 and to deposit faulty lamps in a separate receptacle 20.