GB1059053A - Improvements in the manufacture of electric devices having closed envelopes - Google Patents

Abstract

1,059,053. Discharge tubes; electric incandescent lamps. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. June 23, 1965 [June 26, 1964], No. 26581/65. Headings HID and H1F. Electric devices having current conductors secured in a sealed envelope, e.g. discharge or incandescent lamps, are manufactured by introducing into a long tube a strand consisting of a sequence of mechanically interconnected current conductors, exhausting the tube, and closing the tube at points spaced along its length to form a series of sealed devices each of which includes at least one current conductor. Discharge tubes are formed from a strand, Fig. 1, composed of rigid conductors 2, cylindrical electrode members 3 joined by thin wire 4, and linking glass beads 5, which strand is drawn into a glass tube which is then exhausted and supplied with the desired gas filling (Fig. 3, not shown), prior to sealing the beads 5 to the tube and cutting it through at 6 to form two separate sealed tubes. The thin wires 4 are burnt out by the passage of current, and the expansion portion drawn out to provide a lead of adequate length (Fig. 4, not shown). By the use of a strand having two parallel wire portions between each pair of glass beads, lamps in which each electrode is supported at each end. the discharge path being transverse to the tube axis, may be produced (Figs. 10 and 11, not shown). In a strand employed for the mantifacture of incandescent lamps, one end of each member 3 is sealed into a glass bead, and the filament portions 4 are protected from damage, during insertion into the tube, by laying the strand in a semi-cylindrical member which, subsequent to insertion, is rotated through 180 degrees and withdrawn (Figs. 6 to 8, not shown). Lamps having two independently controllable filaments 54, Fig. 13, separated by glass fibres 57, may be manufactured by the use of a double strand. Reference is made to the use of more than two strands, and to the production of devices which are not, in the course of manufacture, separated from one another.