Patent GB-580074-A (GB)
Title: Improvements in or relating to photographic shutters
IPC: G03B9/20
Filed: 1944-05-13
Abstract: 580,074. Photographic shutters. KODAK, Ltd. May 13, 1944, No. 9217. Convention date, June 3, 1943. [Class 98 (i)] In a photographic shutter, the driving pin of the master member engages an arm projecting from the blade operating ring, and the arm carries a hinged member which is movable to operative and inoperative positions determining the period during which the driving pin is restrained and hence the shutter speed. The trigger 11 carries a latch element 25 which engages a corresponding latch part 26 on the master member 14 when the latter is in the set.position. The setting lever 12 is carried by an arcuate slide 27, upon which is a pin 29 which engages a slot 30 in the master member 14. There are two blade rings, one 32, having slots 43 which engage pins 42 on the shutter blades, the other 35 carrying the pivot pins 44 of the blades, both rings being connected by pins and slots on a rocker arm 36. An arm 31 extends upwardly from the blade ring 32 over the master member 14 and carries a pivoted plate 52 which for the slower speeds is moved into the path of the operating pin of the master member 14. The latter carries three pins, the first 47 for moving the arm 31 in a clockwise direction against the spring to set the shutter, the second 48 moving the arm counter-clockwise for an exposure and a third pin 49 which can be positioned for slow speeds to hold up arm 31 momentarily. When the plate 52 is in the position of Fig. 8, release of the master member allows it to gain considerable momentum before the pin 48 strikes the face 51 of the arm 31 and moves it counter-clockwise to open and shut the blades very rapidly. For the slower speeds, the plate 52 is moved against the action of a spring 56 into the path of the pin 48, a pin 54 on the plate contacting a cam 55 on the setting ring. In the exposure, the pin 48 almost immediately engages the edge 53 of the plate and moves the arm 31 to the openblade position. The pin 48 then passes into contact with the curved edge .61 and at the same time pin 49 engages the curved edge of a flange 50 of the arm 31. In the further movements which may be retarded, both pins ride along the respective edges engaged by them, but the arm is prevented from moving further to the left until the pin 49 has passed beyond the flange 50. At this point the pin 48 has reached the end of the curved edge 61 and thereupon strikes the arm 31 to complete the operation of the shutter. Means for closing the shutter aperture during the setting movement comprises two supplementary blades 67, 68 pivoted at 70, 71 operated by a pin and slot connection 66, 69 on the blades. A latch 62 hinged at 63 to the arcuate slide 27 is moved during the setting action and its cam end 65 hits the pin 66 and swings the blades across the exposure aperture 2, where they are held until the pin has reached the end of the arcuate portion 79 of the latch, the pin then riding off and the supplementary blades folding back under the action of the spring 72. The pin 66 rides under the latch on its return during the running down of the shutter.