GB412536A - Improvements in and relating to tubular lamps - Google Patents

Abstract

412,536. Supports for electric incandescent lamp filaments. PETROWITZ, F., 6, Hogelmiillergasse, Vienna. Sept. 19, 1932, No. 26064. Void [Abridged as open to inspection under Sect. 91 of the Acts, Sept. 20, 1932]. [Class 39 (ii).] Tubular electric incandescent lamps are provided with a main and an auxiliary filament, the latter being of such resistance that it only glows dimly when the main filament is intact, but gives a substantially normal illumination upon the destruction of the main filament. In one form the tubular lamp 1, Fig. 1, has bipolar terminals 2, 3 at each end connected to leading in wires 4, 5 and 6, 7 respectively, these leading- in wires being connected to branch members 8 .. 11 and 12, 13 which support short lengths of filament 14 ... 18 and 19, 20 respectively. Upon the failure of one or more of the filaments 14 ... 18 a greater proportion of current passes through the filaments 19, 20. In a modification the main filament through the lamp is carried on pig-tails 22, Fig. 2, mounted on a glass rod 23, while two glass tubes 24, 25 contain conductors 26, 27 respectively to convey current to supports 28 ... 33 for auxiliary filament lengths 35 connected in parallel. Arcuate wire springs 34 fused into the glass rod 23 bear upon the inner wall of the tube to provide a resilient support. In another form adapted for tubes of various shapes a flexible suspension wire 44, Fig. 5, carries radial supports 48 for glass beads 49 into each of which two pig-tails 50 are fused. The pig-tails respectively support a filament 51 clamped at both ends directly to the lamp terminals, and two auxiliary filaments 52, 53 which are connected to the suspension wire 44 by return leads or conductors 46, 47 adjacent to a glass bead 45 dividing the wire 44 into two parts providing return paths for the current. The leading-in wires may terminate in hooks or loops at the ends of the tubes to enable a number of lamps to be connected readily in series or parallel.