GB735064A - Electric incandescent lamp - Google Patents

Abstract

735,064. Electric incandescent heating- lamps. SYLVANIA ELECTRIC PRODUCTS, Inc. Oct. 17, 1952 [Oct. 20, 1951], No. 26160/52. Classes 39 (2) and 39 (3). An electric incandescent lamp comprises a glass bulb with a reflecting portion of the shape of a hyperboloid or paraboloid of revolution coated on its innner surface with a heatreflecting material, and containing a filament arranged in the form of a drum, i.e. strung up and down in zig-zag form around the surface of an imaginary cylinder coaxial with the reflecting surface. The lamp, which is adapted more particularly for radiant heating, has a bulb 1 with a relatively flat or shallow upper portion 2 and a reflector portion 3 coated with a layer 4 of metallic gold on its inner surface. As shown the filament is in two sections 31, 32, either or both of which may be used alternatively to vary the output of heat. Three rigid leading-in wires 8-10 support between them a transverse insulating bridge 33 which provides a mounting for a series of filamentsupporting wires 36 which extend outwardly from the bridge, as shown in Fig. 3, and are bent upwardly at right-angles to extend through slots 38 in the periphery of an insulating reflector disc 37, the wires 36 being alternately long and short and terminating in hooks 40 to engage the bights 39 between the zig-zagged filament sections 42. The leading-in wires 8-10 sealed within a pinch 6 extend through the bottom 7 of the bulb and through an insulating block 11 carrying screw-threaded terminals 12-14, the block 11 being secured to a metal cylinder 24 by interengaging grooves 25, 26 formed in the two members. A metal band 28 secured to the upper portion of the cylinder 24 by welding or riveting is punched or spun at 29 to engage depressions 30 moulded in the glass. Fuse portions 43 covered by refractory insulating tubes 44, 45 are embodied in the leading-in wires. In the example a stove is formed by mounting the bulb in a refractory reflector or housing 46 with a covering plate 48 of glass which absorbs most of the visible light but is transparent to infra-red radiation. The plate 48 is strengthened by ribs 53 extending radially from an annular beading 52 on its underside.