GB620172A - Improvements in or relating to photographic shutters - Google Patents

Abstract

620,172. Photographic shutters combined with flash-lamps. KODAK, Ltd. Sept. 17, 1946, No. 27884. Convention date,' Oct. 12, 1945. [Class 98 (i)] A photographic shutter having a built-in switch adapted to close a flash-lamp circuit comprises a shutter blade having one end of a spring attached to it; a pivotally mounted arm carrying one contact of the switch and having one end of a second spring attached to it for holding it clear of the other fixed switch contact; and a trigger mechanism to which the other ends of the springs are so connected that depression of the trigger tensions and releases the springs so that the switch is closed after incomplete movement of the trigger. As shown a shutter blade 3 apertured at 5 and a cover blade 15 are pivotally mounted at 4 and 16 on opposite sides of a supporting plate 1 having an exposure aperture 2 and an arcuate slot 17 through which passes a pin 18 on the shutter blade, and an L-shaped lever 32, stepped at 33, is pivoted beneath and coaxially with the shutter blade. On depressing the trigger 7, which is pin-and-slot connected to the cover blade and carried in lugs 8 of a bracket 9 attached to the plate 1, against the action of a spring 10, the cover blade is rotated clockwise to uncover the aperture 2. This movement tensions the hair-pin springs 19, 34 which are connected between a pin 20 on the cover blade and pins 18, 31 on the shutter blade and the lever 32 respectively. Due to the relative dispositions and strengths of these two springs, the spring 34 commences its driving action before the spring 19 so that the edge 35 of the lever 32 aids the movement of the shutter blade pin 18 until the pin 31 which forms the movable contact engages the fixed contact 30 of the switch S closing the flash-lamp circuit as the edge of the aperture 5 reaches the exposure aperture 2. Thereafter the shutter blade is driven solely by the weaker spring 19 across the exposure aperture, and finally the pin 18 passes beneath a spring blade 13 secured at 12 to the plate 1, preventing rebound of the shutter blade. On releasing the trigger 7, the spring 10, being stronger than either of the springs 19, 34, drives the cover blade anticlockwise to cover the aperture 2, the shutter blade being unable to move under its spring 34 until the pin 20 on the cover blade passes under the tip 23 of the spring blade 13 to release the shutter blade pin 18. Instead of the springs 19, 34 being connected to the pin 20 on the cover blade, they may be connected directly to the trigger as by the pin 14. Also the trigger may be pivotally mounted. Specifications 537,209 and 620,060 are referred to.