GB563669A - Improvements in optical projection apparatus - Google Patents

Abstract

563,669. Optical-projection apparatus. CAITHNESS, A. J. L., and CAITHNESS, B. W. R. [trading as CAITHNESS BROS.]. March 23, 1943, No. 4686. [Class 97 (i)] A strip film unit and a slide carrier are so combined that the slide is located in or can be moved into the plane of the film and the combination is adjustably mounted so that either the film or slide may be brought to the operative position in correct focus. As shown, spindles 8 carrying film rollers are held in slots in angle bars 9 by springs 11 and are rotatable by hand wheels 18. The bars 9 are secured to a sleeve 23 rotatable through 90 degrees about the projection axis on a sleeve 24 extending from a back plate 25 which is movable vertically in guides on support and is air-spaced between a lamp house and a projection lens. A slidecarrier in which the slide is held in the same focal plane as that of the film, and comprising slide channels 31 connected by bars 32 extending from a plate 33, is detachably secured to one bar 9 by screws 34. Stops in conjunction with the guides permit the film unit or the slide-carrier to be held in projection'position. The film passes between glass plates 12 ; one of the plates 12 carries pins 13 passing through bridge pieces 14, and springs 15 on the pins 13 close the plates 12 on to the film. The plates 12 may be separated during film feed by operation of a U-shaped lever 19 engaging under nuts 20 carried by the pins 13. Interchangeable masks each having a finger piece 22 may be inserted in the gate. The support for the guides in which the back plate 25 slides may be carried directly on the projector baseboard.or by a bracket extending from the lamp house ; the projection lens may also be carried directly by the baseboard or by the bracket. The slide-carrier may be hinged to the bar 9 so as to be movable into or from the focal plane of the film.