GB749708A - Improvements in photographic roll film cameras - Google Patents

Abstract

749,708. Photographic roll film cameras. GETALDUS OPTICKA INDUSTRIJA ZAGREB. Sept. 9, 1953, No. 24951/53. Class 98(1). A roll film camera having a normally retracted. focal plane mask and means for advancing the film after exposure to an extent equal to the unmasked area comprises two or more gear trains of different ratios connecting parallel shafts, the gear-wheels on one of the shafts. being freely mounted and means being provided for selectively keying any one of said wheels to its shaft. As shown, the length of the exposure aperture 4 is reducible by a spring blind 6 which may be unrolled by rotating a knob 13 which co-operates with a scale and is attached to a shaft 12 bearing rollers 11 carrying -tapes 10 secured to the blind, a ratchetwheel 14 on the same shaft preventing return movement of the blind until a ratchet pawl 16 is manually operated. The film is moved by a sprocket 17 keyed to a shaft 18 of a gear-box, this shaft surrounding an axially movable rod 19 having a key on its inner end adapted to engage in a keyway in a selected one of three different gears 21 freely rotatable on the shaft and permanently in mesh with different gears 23 which are pinned together but are freely rotatable on the shaft 12, the lowest gear 23 being in mesh with a gear 24 on a spindle 25 manually rotatable by a key (not shown). By this arrangement three different-sized areas of film may be exposed and the film then wound on the appropriate distance. For non-perforated films the sprockets 17 are replaced by driven knurled rollers against which the film is held by spring-urged pressure rollers.