GB797441A - Improvements in and relating to electric lamps - Google Patents

Abstract

797,441. Capless electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 14, 1956 [Sept. 7, 1955], No. 25655/55. Class 39(2) The coupling contacts of an electric lamp comprising a glass bulb 1 sealed by means of a flattened glass pinch are provided by the leading-in wires 2 which are extended out through the seal, formed into loops 5, and have their ends returned into the seal, the loop portion of each leading-in wire being flattened down on to the pinch. As shown in Fig. 1, the leading-in wires 2 are spaced apart by a glass bead 3 and extend down at opposite sides of an exhaust tube 6 sealed within the pinch, known means such as a thin metal sleeve or a thin porous rod being located within the bore of the exhaust tube to maintain it open until it is finally sealed or "tipped". During the forming of the pinch two horizontal notches 7 are preferably formed on opposite sides thereof to provide locating means arranged to receive spring clips in a holder adapted for use with the lamp, the holder also having contact means which engage the loops 5. Alternatively, the notches may be formed midway down the pinch in which case the rounded upper ends of the loops may be bent into the notches. As an alternative to the notches the pinch may be provided with protuberances for locating and retaining the lamp in a holder or socket. Fig. 3 shows a double filament lamp with parts of the leading-in wires of the respective filaments formed into loops 5 at opposite sides of the sealed exhaust tube 6. The pinch for a double filament lamp may be cruciform, Fig. 11, with the loop portions 5 of the leading-in wires flattened down on to the wings 4 which comprise the pinch. In any of the arrangements employed the loop contacts 5 may have flattened portions to increase the area of contact surface with contacts of a lamp holder The invention is applicable to electric discharge lamps.