Patent GB-290165-A (GB)
Title: Improvements in and relating to methods of and apparatus for making electric incandescent lamps and similar articles
IPC: H01J9/28
Filed: 1928-05-05
Abstract: 290,165. British Thomson-Houston Co., Ltd., (Assignees of Phelps, R. G.). May 7, 1927, [Convention date]. Making lamps; bulbs; caps; leading- in wires; filaments, attaching.-In the manufacture of bulbs in which the filament has a definite relation to the base or cap, a filament is mounted in definite relation to the flattened portion of the stem, the mount is positioned for sealing into the bulb by means engaging the said portion of the stem, and after sealing the neck of the bulb is shaped to receive a base or cap by means having a definite relation to the stem and consequently to the filament. To position the filament 30 on the stem 10, Fig. 1, which is preferably formed as described in Specification 147,293, the mouth of the flare tube is seated on a support 17 and the stem is aligned thereon by a clamp 18 engaging its exhaust tube 11. These parts are mounted on a pivoted arm 15 which is swung down to locate the leading-in wires 12, 13 in grooves 22 on a slidable guillotine block, and the wires are trimmed by the cutter 23. The block is then replaced by a welding block 27, and the filament is attached to the wires by welding- points 28, 29. The arm 15 is then set vertically to bring the filament adjacent a gauge point 32 to enable it to be shaped accurately by hand. The mounts are then assembled on the sealing-in machine at position A, Fig. 2, by seating them on supports 52, Fig. 7, with the exhaust tubes clamped in split tubes 55. These have tapering ends to enable them to be contracted by a sliding movement in an outer tube 51 having a coacting tapered surface. At position B a pair of fingers 60, 61 are moved to embrace the stem and are then rocked to grip the flattened part of the pinch to set the filament in a definite plane. At position C the bulbs 80 are placed on non-rotatable supporting rings 44. In following positions the stems are sealed in by a series of gas fires which are rotated intermittently by gearing 84, 95<1>. At position D the surplus parts of the bulb necks are blown off by air from a pipe 99, Fig. 7, passing through passages 96 in the stem supports and directed bv a collar 98 on the seating 52. Between positions D and E the mount column is moved down by a yoke 48, Fig. 7, to pull down the bulb seal. At position F a pair of arms carrying moulds 108, 109 are operated first to embrace the neck of the bulb and then to move upwards to shape the neck to fit a cap in definite relation to the bulb stem. Compressed air admitted into the bulb by a pipe 112, Fig. 7, and through the tube 55 and the seating 52 presses the glass against the mould surfaces. Projections 133, Fig. 10, may thus be moulded on the neck to fit notches 136 in the cap, whereby the planes of the pins on the cap and of the filament 30 are definitely related. Alternatively, a projection 120, Fig. 2, may be formed on the end of the bulb by a mould 117 at position K, to be used to position the bulb with respect to the cap by being engaged with a recess in the bulb-supporting plate in the cementing-machine, which may be of the kind described in Specification 272,934.