GB876947A - Photographic shutter - Google Patents

Abstract

876,947. Photographic shutters. AGFA A. G., March 8, 1960 [March 10, 1959], No. 8207/60. Class 98(1) A pivoted blade photographic shutter has a main spring and a shutter operating spring of relative strengths so that the shutter operating spring can derive a plurality of setting movements from a single tensioning of the main spring, and a fully rotary shutter master member operated by the shutter operating spring and means for allowing individual settings and releases of said shutter operating spring. In the shutter of Fig. 1 the blades (not shown) are pivoted on a blade ring 3 which is controlled via a link 10 by a master member 5 which is mounted on the same shaft 8 as a spring housing 6, the teeth 27 of which engage teeth 28 on a second spring housing 29 the spring of which is tensioned in any well-known way. The master member has a cam 16 and the spring housing a cam 22. A two arm lever 18 has lugs 17, 21, 35, 36 which in certain positions engage cams 16, 22 and a lug 37 on a release arm 38 which is pivoted at 39. Normally the parts are in the position shown, with both springs tensioned. To release the shutter, an arm 38 is moved until it abuts a stop 45 and lug 37 releases lug 35 and hence lever 18, which is driven clockwise by cam 22 until an edge 24 on the spring housing 6 engages tooth 26 of the lever. However, the clockwise rotation of lever 18 has resulted in a hook 21 thereon freeing an edge 20 of the master member 5 which is then free to open and close the shutter under a driving force from the spring in housing 6 which engages the member 5. The member 5 is stopped when cam 16 meets lug 17 and forces lever 18 anticlockwise so that hook 21 thereof enters a cutaway area 19 of member 5 and lug 36 of lever 18 engages lug 37 of the release lever. When lever 38 is released it is returned by spring 40 to the position shown, thereby releasing the latching of 18 by means of lug 37 and disengaging cam 16 and lug 17, to allow member 5 to rotate a little further until edge 20 engages hook 21 and tooth 26 disengages edge 24 of the spring housing. This housing then does an almost complete anticlockwise rotation to tension its spring again and, by means of cam 22, to rotate lever 18 until by engagement of lug 35 with lug 53 the housing 6 is latched. For bulb exposures a lever is arranged to arrest the master member in the open position, with the spring housing 6 latched by tooth 26 of lever 18. When the lever 38 is released, the arresting lever unlatches member 5 and the other parts move as described above. For series exposure a lever 48 is pivoted into a position in which a part 50 of it will arrest lever 38 in a position in which it cannot be engaged by lever 18 and can, therefore, no longer prevent continuous movement of member 5 and the spring housing. In another embodiment the main spring is fixed to a film perforation roller and is connected through gearing to the spring housing 6 so that when the shutter spring is tensioned the film is moved on.