GB484922A - Improvements in or relating to means for the production of coloured effects by lighting - Google Patents

Abstract

484,922. Colour screens for floodlights &c. STANLEY, C. J. Nov. 11, 1936, No. 30837. [Class 75 (iv)] [Also in Group XXIX] In floodlighting, spotlighting, coloured sign, and like apparatus in which changing colour effects are produced by passing a beam of light through one or more transparent or translucent screens which are displaceable automatically or at will to and from an inoperative position entirely outside the beam, the screens are constituted by coloured sheets of transparent or translucent solid material, such as glass or gelatine, and are operated in one or both directions by the action of a fluid under pressure. Gravity or spring means may be employed for effecting the return movement. In the form shown in Figs. 1 and 2, the screens 1 are held in frames 2 by means of clips or thin cross-wires 3, and are accommodated within a casing 4 having front and back walls 5 with upper openings 6. The upper end of each screen is connected by rigid members 9 to a pair of pistons 8 working in cylinders 7 which are supplied with compressed air by means of branch tubes 11 and flexible tubes 10. Upward movement of the screen is limited by the pistons 8 striking stops 12 at the upper ends of the cylinder 7, whilst short lengths of tube 14 on the frame 2 engage vertical guide wires 13. According to the Provisional Specification, the pistons may be fixed and the screens connected to movable cylinders, and the connection may include a cord and pulley or like motionmultiplying device. For controlling the movements of the screens, compressed air is supplied by a flexible tube 18, Figs. 4 and 6, to passages 19 with ports 16, one in each of the limbs of an E-shaped member 17 accommodated within a casing 15 which is open to the atmosphere. Each port 16 is associated with a member 20 which is spring pivoted at 21, 22 and formed with a port 23 connected to one of the tubes 10, the members 20 being moved by rods 24 into any of three positions in which the corresponding screen is moved to the operative position, held in the operative position, or moved to the inoperative position. The casing 15 may be held in the hand, and the rods 24 extended to constitute finger-operated push-buttons, stops 25, 26 being provided to limit the movement. Alternatively, the push-buttons maybeoperated automatically as by means of motor-driven cams, or the screens may be operated by means of an intermittently rotated distributing valve operated electrically, electromagnetically, or by clockwork.