GB409953A - Improvements in or relating to electric incandescent lamps of tubular form - Google Patents

Abstract

409,953. Supports for electric incandescent lamp filaments. MAYER, H., 47, Corringham Road, Golders Green, London. Aug. 3, 1933, No. 21855. Convention date, Dec. 10, 1932. [Class 39 (ii).] A filament support for tubular electric incandescent lamps comprises a wire a, Figs. 1 and 2, which extends longitudinally within the tube e without touching the wall thereof, and is bent from side to side into a succession of zig-zags or wave forms throughout its length. Preferably the zig-zagged supporting-wire a is of flattened crosssection, with the greatest dimension at right angles to the plane of the zig-zags, glass beads b being fused in known manner at spaced points c<1> on the wire to receive struts c with coiled ends to engage the turns of the helical filament f. Wire struts d which are successively displaced relatively to each other by an angle of about 120‹ may also be attached to the glass beads b, the uppermost struts being curved so that their outer end portions are at right-angles to the wall of the tube, as shown in Fig. 4. The lengths of the struts d are such that they maintain the filament centrally along the axis of the tube. These struts may be dispensed with when the tube is sufficiently short for the tension upon the wire a to maintain the wire clear of the tube wall. Before it is mounted within the tube the zig-zagged wire a is about two-thirds of the length of the tube, and has the filament f hooked upon the struts c, so that after insertion within the tube the supporting-wire can be pulled to the requisite length, thereby tensioning the filament. Preferably the zig-zagged wire a is of non-resilient metal.