GB1114356A - Filament supports for tubular incandescent lamps - Google Patents

Abstract

1,114,356. Incandescent lamps. GENERAL ELECTRIC CO. 28 Oct., 1966 [8 Nov., 1965], No. 48450/66. Heading H1F. A double-ended incandescent lamp comprises a tubular envelope 1 closed at each end by a pinch seal 2, a dimple-like depression 8 being formed in the inner wall of the envelope, a coiled or coiled-coil filament 3 extending between lead-in conductors 5, 6, 7 in the seals 2 and a filament support wire 9 having a long leg 10 lying along the inner surface of the envelope and embedded in one of the seals 2, a short leg portion 11 extending laterally of the leg 10 and embracing the filament and a second short leg portion 12 extending into the depression 8, which may be the residue of an exhaust tube. In making the lamp, the filament, lead-in wires and support wire are assembled, the assembly is supported vertically by means of a cap member at one end of the envelope with one short leg of the support wire in the exhaust tube and the pinch seal at the lower end is formed, the filament being stretched to cause the long leg of the support wire to press on the wall of the envelope. The envelope is then inverted and the process repeated. The envelope is then evacuated, filled with inert gas and halogen and the exhaust tube tipped off with, if desired, the short leg portion 12 entrapped in the seal. The support wire 9 may be bent back on itself as shown to form the short leg 11 embracing the filament, the free end of the wire then forming the other short leg 12. Alternatively, the wire 9 may be bent back on itself to form the short leg 12 entering the depression, the other end being looped around the filament. The envelope may have two exhaust tubes spaced apart, which may be used for flushing the envelope with gas, in which case the legs 11, 12 may be relatively displaced.