GB360910A - Improvements relating to the projection of light - Google Patents

Abstract

360,910. Vehicle &c. lamps. MORSHEAD, L.' R.,'64, Victoria Street, London, and MARTIN, H., 31, Beauchamp Road; East Molesey, Surrey. July 10, 1930, No. 20904. [Class 75 (iv).] Lantern obturators; lens-holders special to lanterns.-In a vehicle lamp or like light projector a projected beam of light, which converges towards a focal point or zone, is divided into a number of portions, one of which is then formed into a concentrated beam, the remaining portion or portions being deflected and utilized for local illumination. signalling; or like purposes. For a near-side head lamp the centre of the filament of an incandescent electric lamp bulb i coincides with the centre a<1> of a hemispherical reflector b and the focus of an ellipsoidal reflector a, and a step or prismatic lens c is arranged to refract those rays of light which do not fall on the reflector a. The lens c may be mounted on seatings formed at the inner ends of radial pins h, which are screwed into a collar m surrounding the reflector a, and a radial. pin l which slides through the collar m and is screwed into a nut o which bears on a bow spring n in pin and slot engagement with the collar. The upper portion of the convergent beam then diverges downwardly and is concentrated into a flat-topped beam by means of a frontal focusing lens g, whilst the lower portion is cut off by means of a sector plate d<1> and is reflected downwardly through an aperture f<2> in the lamp casing f on to a second reflector x which redirects the light partly horizontally and partly downwardly. The reflector x may be adjusted about a vertical axis by means of a screwed pin x<1> and a wing nut x<2>, its lower portion may be slightly curved or upwardly inclined, and it may be protected from dust' by means of a frosted or clear glass front plate. The reflector d<1> may be carried by a bracket d<2> which is mounted on a screwed pin d<3> engaged by a wing nut d<4>, a spring washer or helical spring d<5> being interposed between the bracket d<2> and the lamp casing. The bracket d<2> may be, made in two parts hinged together under the action of a helical spring d<6>, the outer part being connected to a Bowden wire d<8> so that the driver may lower the reflector d<1> to provide a full beam for inspecting sign-posts and the like. The reflector d<1> may be replaced by simple or prismatic lenses and the frontal lens may be replaced by a compound lens, or by a cylindrical lens when the lamp is used as an aircraft landing light, and the flat-topped beam may be coloured by means of a glass or like filter pivotally mounted in front of the reflector d<1>. For an offside headlamp the cut off portion of the projected beam may be directed upwardly through a lens or aperture in the lamp casing, or the obturating reflector may be arranged to direct the light both upwardly and downwardly. Specification 340,522 is referred to.