GB559421A - Improvements in or relating to focal plane shutters - Google Patents

Abstract

559,421. Photographic shutters. KODAK, Ltd. June 8, 1943. No. 9186. Convention date, June 22, 1942. [Class 98 (i)] A focal plane shutter, of the type in which tapes on a leading curtain are wound on coaxial spools 20 and the following curtain is wound on a drum 17 between the spools, includes a pivoted lever 52 movable with the shutter speed dial 56 and having parts 63, 64 respectively coaxial with, and extending radially of, the dial, together with a pin or projection 50 which moves in an arcuate path with one of the spools 20 and during the unwinding of the leading curtain moves the lever 52, so causing the coaxial portion 63 to actuate means for releasing the follower curtain. As shown, the lever 52 is pivoted on a bracket 54 secured to the shaft 55 of the speed dial. The pin 50 extends from the face of the upper spool 20 through an arcuate slot in the mechanism plate, and engages the end 64 of the lever 52 to release the following blind at a moment determined by the position of the lever, as set by the speed dial, so determining the width of the slit formed between the blinds in the usual manner. The release of the following blind is effected by the part 63 of the lever 52 rocking a lever 70, so disengaging a lug 74 carried by it from a pin 75 on the drum 17. The shutter is set and the film wound by moving a handle 11 through a full stroke, which through a one-way spring clutch 28 and gears rotates the shaft carrying the film sprockets 25. Motion is transmitted from this shaft by means of pulleys and spring belts 34, 38 to the film take-up spool 10 and to a disc 40 to which is secured an annular spring 41 carrying a pin 43 which engages a pin 44 on the lower spool 20, thus rotating the spools. The drum 17, which is loose on the spool shaft, is rotated from the lower spool 20 through a pin and slot lost motion connection 118, 119, which allows the necessary relative movements between the blinds during the exposures. During the winding of the shutter, a disc 48 on the release rod 46 engages a lug 77 on the lever 70 which is thus held so that the lug 74 is disengaged from the pin 75. When the release is depressed the lever is freed so that the lug engages the pin 75 to retain the following curtain, and subsequently a second disc 49 on the rod engages a lug 42 on the spring 41 and depresses it so that the pin 44 is freed from the pin 43 and the leading blind is released. The shutter is adjusted for " bulb exposures by rotating the lever 52 to a point at which it is not engaged by the pin 50, so that the following blind is released only when pressure is removed from the shutter release knob.