Patent GB-656685-A (GB)
Title: Improvements in or relating to roll film photographic cameras
IPC: G03B17/42
Filed: 1948-10-14
Abstract: 656,685. Photographic cameras. KODAK, Ltd. Oct. 14, 1948, No. 26754. Convention date, Oct. 17, 1947. [Class 98 (i)] A photopraphic camera of the type having a focal plane shutter and a combined filmwinding and shutter-setting mechanism comprising a manually-operated film-winding core carrying a gear coupled by a gear train to a pinion that is rotatable to wind the shutter, said gear train including a mutilated gear which becomes unmeshed from the gear on the film winding core to disconnect the pinion from said gear when the shutter reaches its fully-wound position, is characterised in that the mutilated gear on being unmeshed is held against rotation by a pivoted lever until a required length of film has been wound over a film metering device in the camera and on to a take-up spool carried by the film winding core, whereupon the pivoted lever is urged by a spring to a position locking the metering device and this spring acts on the mutilated gear to remesh it with said film winding core gear, said lever being adapted to prevent further rotation of the film winding core until the lever is manually displaced from its locking engagement with the metering device. The camera shown includes a supply reel 4 from which a photographic film F may be wound across an exposure aperture 7 on to a take-up reel 5, the spindle 13 of which is manually rotatable by an external knob K. Spindle 13 carries a gear 14 which meshes with a mutilated gear 15 having an untoothed portion 16. Underlying and fixed to gear 15 is a further gear 17 which meshes with a pinion 18 freely rotatable on a shaft 19 on which is freely rotatable a drum 27 and on which are secured, one on each side of the drum, two pulleys 25. One end of a shutter curtain 9 is wound on drum 27 and the other shutter curtain 8 is wound on the pulleys 25, the other ends of these curtains being connected to spring rolls 12, 11 respectively. Pinned to the gear 18 is a washer 20 having a lug 21 which is adapted to engage a pin 22 mounted in a lever 23 pivoted to a pulley 25 so that the pin 22 may lie at either end of a slot 30 in the pulley 25. Counterclockwise rotation of knob K causes the film to be wound on to the spool 5 and, at the same time, the pinion 18 is rotated so that the lug 21 engages the pin 22 which in turn engages a lug 29 on drum 27 and the pulleys 25 and drum 27 are rotated to wind the shutter. Movement of the film F causes rotation of a film metering sprocket 31, the spindle of which carries a cam 37 on the periphery of which rests the bent end 39 of a lever 34, pivoted at 35 and engaged at 32a by a spring 40 secured to a stud 50. When the shutter is fully wound, means (not shown) become operative to displace pin 22 to the inner end of slot 30 and the untoothed portion 16 of gear 15 contacts gear 14 so that the latter rotates alone. At this time, a pin P on gear 15 is held between spring 40 and a lug 33 on the lever 34. Rotation of gear 14 is continued and when a new film frame has been moved into register with exposure aperture 7, spring 40 causes the end 39 of lever 34 to move into a notch 38 in cam 37; the consequent clockwise rotation of lever 34 causes pin P to snap past lug 33 under pressure of spring 40 and thus brings the tooth of gear 15 which follows the part 16 thereof into mesh with gear 14. At the same time, pin P moves into engagement with a lug 41 on lever 34 so that further rotation of knob K is prevented until the shutter has been released and an exposure effected and a handle 42 on lever 34 has been moved counterclockwise to release the end 39 of this lever from the notch 38.