GB326283A - Improvements in and connected with sign projecting apparatus - Google Patents

Abstract

326,283. Sieber, J. Jan. 7, 1929. Optical-projection apparatus; lenses. - In apparatus for projecting signs &o. comprising an endless film 29 loosely housed in a casing 12 and electrically driven to pass tautly over rollers 28, a lamp box 10 being provided to project upwardly a beam which is reflected horizontally by a mirror 37 above the projection lens 14, the lamp box is carried by legs 11, the film housing is suspended from the lamp box between the legs, and the motor 30 is placed in a space between the lamp box and film housing. The lens housing 13, Fig. 5, carries condenser lenses 15, 17 with a concavo-convex lens 16 between them, and a projection lens comprising elements 19, 20, 21, Fig. 6, with contacting surfaces all of equal curvature; the curvatures of the outer surfaces of the elements 20, 21 are respectively equal to that of the contacting surfaces and greater than it. The lamp 22, Fig. 7, and a reflector 27 may be mounted on a bracket 23 engaging a vertical rack 24 and carrying a pinion 25 rotatable for vertical adjustment of the lamp &c. The film is fed by a roller against which it is pressed by a roller 34, the feed roller beinz driven through bevel gears from a shaft 31 driven through a belt by the electric motor 30; friction rollers 35 are provided at the outlet from the film housing.