Patent GB-753553-A (GB)
Title: Improvements in or relating to a photographic shutter
IPC: G03B9/08
Filed: 1954-09-02
Abstract: 753,553. Photographic shutters. KODAK, Ltd. Sept. 2, 1954 [Sept. 3, 1953], No. 25504/54. Classes 98 (1) and 98 (2). In a photographic shutter of the kind which is tensioned before exposure and in which locking means is employed to prevent full operation of the shutter trigger before tensioning, the locking means consists of a pair of blocking members, the first of which is carried by a shutter-blade-operating ring and is movable to an inoperative position upon rotation of the ring from a rest position to a tensioned and latched position by the movement in one direction of an element which moves to and fro during each film-winding operation, and the second of which is mounted independently of the ring and is movable to an inoperative position by the said element when it returns to its initial position at the completion of film-winding. As shown, a mechanism plate 8 has spaced exposure apertures 1, 1<SP>1</SP> for use in a stereoscopic camera. A shutterblade-operating ring 5 is rotated about aperture 1 to tension a spring 6 fixed to the plate 8 at 9 and to a lug 7 on the ring 5. To hold the ring in the tensioned position, a lug 29 thereon is engaged by the hooked nose 30 of a lever 13 pivoted on a stud 25. The ring may be released for operation by operation of a release member 24, also pivoted on stud 25, by a release button 32 or a cable release screwed into a socket 36. After release of the shutter, lug 7 engages the lower edge of lever 13 and thus blocks movement of the shutter release mechanism. The shutter is tensioned by mechanism described in Specification 753,122, in which operation of a knob winds the film and sets the shutter; after the film has been wound on one frame the knob is locked until the shutter has been released. A slider 20 forming part of this mechanism moves to and fro during the winding of the film. A slot 80 formed in slider 20 engages at its left-hand end a pin 11 formed on ring 5, whereby the ring is tensioned and latched by the movement of the slider. Slider 20 also has a lug 20<SP>1</SP> which, in its rest position, engages the end 19 of a lever 14 pivoted at 15 to plate 8. As the slider 20 moves to the right during film winding, lever 14 rocks clockwise under action of a spring 16 so that a shoulder 23 thereon moves into the path of a flange 22 on the release member 24. Thus, when lug 7 has moved clear of lever 13 when the shutter is set, shoulder 23 prevents actuation of the shutter release mechanism until, at the end of the film wind, lug 20<SP>1</SP> re-engages the end 19 of lever 14 so that the shoulder 23 is moved clear of flange 22. During tensioning of ring 5, a lug 85 thereon rides over a nose 86 formed on a lever 87. When the ring is released and rotates under action of spring 6, lug 85 engages nose 86 and rocks lever 87. A pin 90 on lever 87 engages in known manner slots (not shown) in shutter blades 91, 92 pivoted to plate 8 at 93, 94 to open the blades, which afterwards close by spring action, so that aperture 1 is opened for a short interval. A second lever 96, operating in a similar manner blades 98, 99 covering aperture 1<SP>1</SP>, is linked to lever 87 by a link 95, so that simultaneous exposures are effected through the apertures. The mechanism may also be applied to a single shutter.