Patent GB-1267991-A (GB)
Title: Camera
IPC: G03B17/42
Filed: 1969-04-17
Abstract: 1,267,991. Film advance and shutter tensioning. NIPPON KOGAKU K. K. April 17, 1969 [April 22, 1968], No.19699/69. Heading G2A. In a camera mechanism in which a film winding lever 23 drives, through a differential gear arrangement 18, 19, 21, both a film advance gear 15 and a shutter-tensioning gear 20, a selection device 2 can be set either for normal operation, in which the sequence of film wind and shuttertensioning takes place after each exposure, or to a setting in which the film transport mechanism is locked, so that actuation of lever 23 tensions the shutter without advancing the film, thus allowing multiple exposures to be made on the same film area. As shown, the winding lever is connected by a shaft 22 to the sun gear 21 of a differential system. Engaging with gear 21 are planetary gears 19a, 196 which also engage with internal teeth on a gear 18. External gear on teeth 18 drive, via an intermediate gear 14, a gear 15 and hence the film take-up spool 17. The shafts of planetary gears 19a, 19b are fixed to a base gear 19 which engages with a gear 20 which drives the shutter-tensioning mechanism. The shutter release button 1 moves within a setting ring 2 having an index 2b which can be set to one of two fixed marks 2c (for normal operation) or 2d (for multiple operation). A safety lever 4 is spring-biased so as to latch under button 1 and prevent an exposure being made. After the film has been advanced, this lever is pivoted away so as to free the button. In the normal operation, ring 2 is set to mark 2c, as shown in Fig. 1. On turning lever 23 in the direction of the arrow, gears 14, 15 are rotated first by the differential gear to advance the film, since the torque required for this is less than the torque required to tension the shutter. After a predetermined advance, it is stopped, and the resulting increased load on the differential causes gear 20 to be rotated to tension the shutter. An exposure can now be made. When multiple exposures are required, ring 2 is rotated to set index 2b against mark 2d Fig.2 (not shown). A rod 2a fixed to the ring pivots a member 6, and hence a member 3 fixed to it, anti-clockwise. Member 3 hence engages an arm of lever 4 and pivots it permanently out of the path of button 1, so that repeated exposures can be made. At the same time the movement of the member 6 allows a lever 12 to be drawn by a spring 13 so that a pawl section 12b engages and locks gear 14. When lever 23 is now turned, the film cannot be wound on because lever 14 is locked against movement, so that the movement of lever 23 is transmitted to the shutter-tensioning mechanism only. Thus the shutter can be tensioned and then the button 1 depressed to make an exposure in continuous alternation without the film being transported. When the film magazine 11 is removed, a lever 8, which has been held in a notch 11a so as to occupy the position shown in full lines, is drawn by a spring into the position shown in broken lines. Hence it pivots the member 6 into the multiple exposure position, so that there is still a torque on the differential, and so the shutter can still be tensioned even when the magazine has been removed.