GB399521A - Improvements in or relating to apparatus for optically projecting designs on to a screen or other surface - Google Patents

Abstract

399,521. Changing-signs. MITCHELL, C., 27, Balmoral Road, Blackpool. March 29, 1932, No. 35613/31. [Class 3 (i).] Optical-projection apparatus comprises in combination a kaleidoscope, a source of light, a projection lens or lens system, means for continuously rotating the kaleidoscope whereby the continuously changing' designs produced therein by multiple reflection may be projected upon a ground glass or similar screen, a transparent screen adapted to carry advertising or like matter between the ground glass screen and the kaleidoscope, and means for traversing the transparent screen past the ground glass screen, the arrangement being such that the matter carried upon the transparent screen is superimposed upon the projected designs. As shown in Fig. 1, a casing 1 is provided with a ground glass screen 2 and is divided into three parts by means of partitions 3, 4 and 4a. A kaleidoscope 5 is mounted on rollers 6 carried by spindles 7 journalled in plates 8, and carries a sprocket 10 driven by a chain 11 from a sprocket 12, which together with a sprocket 13 is fast on a shaft 14 driven by a motor 17. Between the screen 2 and the partition 3 are journalled four rollers 18 each having a driving sprocket 18<1>, a chain 19 passing over all the sprockets. One roller carries a bevel wheel 20 meshing with a bevel wheel 21 on a shaft 22 carrying a sprocket 23 connected with the sprocket 13 by a chain 24. A flexible transparent screen 25 carrying advertising or like matter runs over the rollers. Between the aperture 4<1> in the partition 4 and the condenser 27 are two sheets of glass 30 separated by strips 31 to constitute a heat trap. The kaleidoscope, Fig. 5, may comprise a tube 32 containing reflectors 33 having end caps 34, 35, the former carrying a projection lens 36 and the latter three sheets of glass 37, 38, 39, loose pieces of coloured gelatine 40 being located between sheets 37, 38 and a loose piece of gelatine 41 carrying advertising matter between sheets 38, 39. The electric motor 17 may be replaced by a clockwork or other motor.