GB440192A - Improvements in or relating to electric incandescent lamps - Google Patents

Abstract

440,192. Electric incandescent lamp bulbs. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. June 14, 1934, No. 17687. Convention date, June 24, 1933. [Class 39 (ii)] An incandescent lamp, adapted for use in motor-car head lamps, has a spherical bulb and at least two filaments F1, F2, Fig. 2, one of which co-operates with a screen R arranged within the bulb. According to the invention ribs are formed on the larger part of the surface of the bulb, adjacent the screen opening and bounded by two planes V4 forming angles of 95 to 105‹ with V5, the plane of symmetry of the bulb normal to the road when the lamp is arranged in a reflector, the ribs extending along the lines of intersection of a group of planes having a common intersecting line I-I which is located in the plane V5 and is tangential to the bulb at the intersection S of the lamp axis with the bulb. The ribs produce a laterally spreading beam without dazzling rays. As shown in Fig. 3, the bottom half of the bulb has two sets of similar ribs BL, BR, based respectively on lines SS11 and SS1 which are inclined 5‹ to 15‹ from the line I-I, these ribs co-operating with the main unscreened filament. A blank space G is left between the upper and lower sets of ribs to facilitate centring of the filaments during manufacture. The Specification as open to inspection under Sect. 91 comprises also the use of ribs formed by the intersection of the bulb with a group of'planes having any common intersecting line tangential to the bulb. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 404,223 and 429,424.