Patent GB-1373980-A (GB)
Title: Photographic camera capable of making multiple exposures
IPC: G03B17/42
Filed: 1972-12-21
Abstract: 1373980 Camera for multiple exposures MINOLTA CAMERA K K 21 Dec 1972 [23 Dec 1971 29 Sept 1972] 59179/72 Heading G2A In a camera which normally has an inter-  locking arrangement between film wind and shutter cocking so that they may operate only in alternation, means is provided for disabling this interlock so that more than one exposure may be made on the same film frame. As shown, a sprocket shaft 1 fits loosely in a sprocket 2. The shaft has a projection 1a which, under the action of a spring 3 which urges the shaft upwards, engages in a notch 2a on the interior of the sprocket. Thus a clutch-type connection is formed, so that rotation of shaft 1 also rotates sprocket 2, which winds on the film. A spool shaft 5 fits loosely into a spool 4, and collars 5a, 4a, attached respectively to shaft 5 and spool 4, are linked by a coil spring 6, again forming a clutch-type connection. Shaft 1 extends beyond the sprocket 2 to form an operating button 1b, just below which is an annular groove 7. A blocking lever 8, spring-biased clockwise, is mounted on a block 9 and urged upwards by another spring 9a. The upper end of shaft 5 has a flange 15 carrying a pin 15a, which pin, as flange 15 rotates, does not encounter lever 8 in the position of Fig. 1. A stopping lever 11 is supported by a pivot 11c on the camera housing, and is spring-biased anticlockwise. A pin 12 on lever 11 bears against one end 8b of lever 8 and thus causes the other end 8d to bear shaft 1. One end of lever 11 is formed as a tooth 11a which is engageable with a ratchet wheel 10b, but in the Fig. 1 position is retracted therefrom. In operating the mechanism, shaft 5 is rotated anti-clockwise by winding lever 25. A gear 17 on shaft 5 causes a gear 19 to be rotated, which cocks the shutter. At the same time, through further gears, the shaft 1, and hence sprocket 2, is rotated, which causes the film to be wound on one frame. An exposure is made, and then the film is wound on again. If it is desired to make more than one exposure on the same frame, shaft 1 is pressed downwards by means of button 1b, which disconnects the clutch 2a, 2b. At the same time, groove 7 is brought into alignment with lever end 8d, which enters the groove, so that lever 8 pivots clockwise. The other end 8b of lever 8 is followed by pin 12, so that lever 11 pivots anti-clockwise and tooth 11a engages ratchet wheel 10b and locks it against movement. Since wheel 10b is connected via shaft 10a to gear 10, which meshes with gear 4b on spool 4, this is also locked. When the pressure on button 1b is removed, shaft 1 moves slightly upwards, so that lever 8 is tilted, as shown in Fig. 5A. This brings the end 8c into the path of movement of pin 15a on flange 5. If winding lever 25 is now rotated, although the film transport is locked, shafts 5 and I can still rotate, so that the gear 19 actuating the shutter cocking mechanism can still be operated. As shaft 5, and hence flange 15, completes its rotation, pin 15a engages lever 8 and pivots its end 8d out of groove 7, so releasing shaft 1 to move up to the Fig. 1 position again. If a further exposure on the same frame is required, button 1b is pressed again. In order to re-wind the film, button 1b is held down continuously. In order to retract tooth 11a from ratchet 10b when the camera is being reloaded with a new roll of film, a lever 22, on the same pivot as lever 11, has an end bearing against a projection 21a on the inside of the camera lid 21. When the camera lid is opened Fig. 8 (not shown) lever 22 is spring-urged so that it engages lever 11  and pivots it clockwise, so that tooth 11a is retracted clear of ratchet 10b. In the modification of Figs. 9-13 (not shown) the movement of lever end 8d into and out of the groove 7 is controlled by a camming action of the groove itself.