GB321039A - Improvements in apparatus for projecting light - Google Patents

Abstract

321,039. Digby, T. J., and Gibbons, A. O. Oct. 5, 1928. Lens-holders special to lanterns; light reflected by trough-shaped reflectors; electric lamp lanterns; screens.-A lamp for flood lighting buildings, stage lighting or vehicle head lights has a cylindrical lens 18 so arranged that the light rays are projected in ribbon form, provision being made for adjustment of the distance between the lens and light source. The light source 7 comprises a long filamemt electric bulb supported by a stem 5 adjustably secured in a boss 4 by a screw 9. A narrow sheet metal reflector 14 is arranged behind the lamp on a shield 10 the rest of which is blackened and the open front of the case 1 has a forwardly projecting extension 17 in which the lens 18 is adjustably mounted. The lens is carried by a frame 19 adapted to be locked in any position by wing nuts 19<1> on screws 20 passing through slots 21 in the sides of the extension 17. In front of the lens is arranged a window 24 which may be coloured. The casing 1 is mounted on pivots 2 and has ventilators 25 which may be moved to project always downwards so as to keep out rain. When used for illuminating buildings the lens 18 may be inclined relatively to the lamp filament. Instead of a plano-convex lens as shown a double convex cylindrical lens may be used. To continually change the colour of the projected light the lamp 7 may be surrounded by a revolving screen comprising panes 26 - - 29, Fig. 6, of differently coloured glass held in a cage, formed by bars 32 fixed to rings 31. Peripheral grooves in the rings 31 engage rollers 34 freely mounted on posts 12, 12, 13 and the lower ring has teeth 35 engaging a worm 36 on the spindle of a small electric motor 37. The glass panes may have inclined bands of different colours and the lamp bulb may be silvered at 38 to act as a reflector. To ensure adequate ventilation the motor 37 may operate a small fan drawing a current of air through the casing.