GB195194A - Improvements in or relating to incandescent electric lamps - Google Patents

Abstract

195,194. Robin, J. T. Jan. 13, 1922. Caps; holders; multiple-filament lamps.- In a multiple-filament lamp of the type described in Specifications 6856/11 and 26186/12 in which contact-pieces on the lamp cap are brought into contact with the spring-pressed plungers of the holder by turning the lamp in order to connect one or both of the filaments to the supply, the contact-pieces are made resilient so as to yield under the pressure of the plungers and ensure positive contact. Figs. 3, 5 show the relative position of the lamp cap contacts to the plungers D<1> when the filament A<1> only is connected to the supply and Fig. 4 the position when the lamp is turned in the holder so as to connect both filaments A<1>, B<1> to the supply in parallel. The contact-members A<2> of the filament A<1> have arcuate flexible extensions A<3> overhanging and normally not touching the terminal pieces B<2> of the filament B'. When the lamp is turned in its holder from the position shown in Figs. 3 and 5 to that shown in Fig. 4, the plungers D<1> press the extensions A<3> on to the contacts B<2> and so connect the filament B<1> to the supply in parallel with the filament A<1>. The lamp is positioned in the holder by pins C<5> carried by a flexible ring C<1> having projections C<2> engaging one- or other set of recesses C<3>, C<4> in the lamp cap. Additional recesses at closer intervals may be provided to allow small angular adjustments. All of the contacts B<2>, A<2> may be resiliently mounted, for example by securing only a portion of each to the insulating-material in the lamp cap. They preferably project above the upper surface of the cap and their ends may be rounded or bevelled.