GB708978A - Improvements in electric lampholders - Google Patents

Abstract

708,978. Lamp-holders. BULGIN & CO., Ltd., A. F. Feb. 23, 1953 [Feb. 21, 1952], No. 4650/52. Class 38(1). A lamp-holder comprises a cylindrical socket 1 and an insulating base having a cylindrical portion 4 moulded round the inner end of the socket and a rearwardly-extending projection 5 of regular, non-circular cross-section with straight sides. As shown in Figs. and 3 the projection is square and slightly tapered, and the socket has bayonet slots and a lateral connecting tag 3. A central spring-plunger contact 7 projects through the insulating base. The holder is mounted in a bracket 14 having a square hole to receive the projection 5 by means of a retaining ring 16 which is forced over the projection. Cut-away portions 18 in the aperture 17 in the ring form tongues 19 which grip the projection. The socket 1 may be internally screw-threaded to receive a screw-cap lamp Fig. 4 (not shown), and in this construction the central contact may comprise a spring blade held by a screw passing through the base Fig. 5, (not shown) or a plunger of the spring-pressed cup type mounted on a screw Fig. 11 (not shown). A sealing washer may be provided on the screw. The bayonet-type lamp-holder may have two plunger contacts in which case tag 3 is used as an earth connection. The lamp-holder may be mounted by soldering the outer end of socket i in an aperture in a panel Fig. 6 (not shown) or said end of the socket may have an external flange soldered in or behind the panel aperture Figs. 7 and 8 (not shown). In Fig. 9 the flange 26 is received in an annular groove 38 in a plastic moulding 36 which has a further annular groove 37 to receive the edge of the panel. The moulding may be of resilient material. In a further modification Fig. 10 (not shown) the moulding has an annular tongue engaging a similar groove in socket 1. According to the Provisional Specification projection 5 may have transverse notches or steps to receive the tongues 19.