GB767971A - Improvements in or relating to electric devices having a cap mounted on a glass neckpart of an envelope - Google Patents

Abstract

767,971. Capping electric lamps. GENERAL ELECTRIC CO., Ltd. April 22, 1955 [April 29, 1954], No. 12482/54. Class 39(2) Caps are secured to the tubular necks of the sealed bulbs or envelopes of electric incandescent lamps and the like by providing the neck 2 with one or more grooves, such as 3, each of substantially uniform depth and extending circumferentially part way around the neck, and arranging within each groove a bent metal strip 7 which fits closely between the sides thereof with its ends abutting against the ends of the groove and part of its surface projecting slightly beyond the surface of the neck of the bulb, the cap 8 being provided with a metal skirt 9 which fits over the bulb neck and over each strip 7 which it presses into its corresponding groove, the abutting portions of the cap 2 and metal strip or strips 7 being secured together by soldering or welding. Fig. 1 shows the neck 2 of a bulb 1 provided with a single groove 3 formed by moulding, and extending almost completely around the circumference of the neck, there being an intervening ridge of glass 4 which forms abutments for the ends of an incomplete brass ring 7. The lamp cap 8, which is also made of brass may be of either the bayonetjoint or screw-threaded type. The cap may be secured to the ring 7 by a paste solder of known kind which is applied to the inner surface of the skirt 9 of the cap prior to fitting the cap in position and, in mass production, the heating apparatus used for curing the cement located between the bulb and cap may be. adapted for melting the solder. Aluminium may be used in some cases for the ring and/or the cap in conjunction with appropriate solder and flux. Fig. 3 shows a modification whereinthe bulb neck is moulded with three short circumferential grooves 12 into each of which is fitted a bent, resilient, metal strip 13 the bowed part of which extends beyond the outer surface of the neck 11. When the skirt 14 of the cap is fitted over the neck of the bulb the strips 13 are pressed down into the grooves, and their ends abut against the ends of the grooves. The skirt is next soldered or welded to the strips 13 at the regions 15 where they are in contact.