GB572528A - Improvements in or relating to apparatus for viewing and printing from transparencies - Google Patents

Abstract

572,528. Optical-projection apparatus; photographic enlargers. PICTOR I A L MACHINERY, Ltd., and WARMAN, H. March 20, 1944, No. 5186. Addition to 563,785. [Classes 97 (i) and 98 (i)] The invention of the parent Specification is modified by providing therein means for feeding a transparency in the form of a film bearing a series of pictures across the light path in a gate between the light source and projection lens. The gate may be formed by two transparent members displaceable one relatively to the other to clamp or release the film. The apparatus shown comprises a cabinet 10 divided by a partition 12 into upper and lower compartments 14, 16, of which 16 houses a mirror 70 and has a clear-glass window 22 upon which may be superimposed a ground-glass screen 26 in a frame hinged at 28, and 14 encloses the film projection head 30 and may be closed by a roll-top shutter 20. The projection lens 40, adjustable by a lever 42 for focusing, protrudes through an aperture in the partition 12, and is carried by a bearing 34 which is secured to the partition and rotatably supports a base member 33 on which are mounted a lamp housing 62 with removable cover, a reflecting prism 50 receiving light through an aperture 68 and reflecting it downwardly through a condenser 48 to the lens 40, and the film supporting and feeding means. After angular adjustment, the head may be locked to the fixed bearing 34 by a knurled set-screw. The film supply and take-up spools are rotatably supported on wings 73 carried by the casing of the prism 50, and are provided with crank handles 80 for winding. The film gate comprises two transparent flats 56, 58, of which 56 is fixed below the condenser 48 and 58 is carried by a sleeve which is adjustable vertically in the base 33, in order to clamp the film between the flats or to release it, by means of a lever 88 in the form of a split ring operable by a spring-biassed thumb-piece 98 which may be held depressed by a latch 102. An inspection aperture 116 having a hinged door is provided in the lower compartment. According to the Provisional Specification, the gate may be formed by two condensers.