Patent GB-631201-A (GB)
Title: Improvements in or relating to photographic shutters
IPC: G03B9/07
Filed: 1947-03-07
Abstract: 631,201. Photographic shutters. KODAK, Ltd. March 7, 1947, No. 6488. Convention date, March 7, 1946. [Class 98 (i)] A photographic setting-type shutter, having an adjustable diaphragm and pivoting shutter blades normally covering the exposure aperture and movable in opposite directions to open and close the shutter by means including a master member tensioned by a setting lever, has means actuated by this lever moving to a set position which open the diaphragm leaves which are held open against the action of a spring by a latch releasable by operation of the shutter release trigger, preferably by movement of the trigger through a portion only of its full path. Means for opening the shutter blades independently of the master member to allow light to pass through the shutter for focusing purposes, although not forming part of the invention, may be provided and may be of the type disclosed in Specification 534,179. In the form shown in Fig. 1 the shutter is substantially identical to that described in Specification 275,462, [Class 98 (i)]. During the setting of the ring-shaped master-member 13, a nose 20 of a pawl, pivoted at 21 on the setting lever 14 and spring-urged clockwise into a notch 25 in the ring 24 operating the adjustable diaphragm, rotates the ring against the spring 40 so that it opens fully the diaphragm which is held open by means of a finger 28 on a second pawl pivoted at 29 and rotated anticlockwise by a spring engaging a recess 30 in the ring 24, the pawl nose 20 being removed from the notch 25 by the far end of the pawl striking a fixed pin extending downwardly from the shutter casing during a slight overtravel of the setting member. On depressing the trigger knob 48 from A to B, the trigger 47 pivoted at 49 rotates and a pin 57 on it strikes a projection 58 on the second pawl, releasing the diaphragm ring which rotates anticlockwise to reduce the aperture to a size determined by engagement of an arm 41 on the ring with a stop pin 42 which may be held in one of several positions by a boss 44 engaging in recesses 45. On further depressing the trigger knob to C, the trigger rotates through gear teeth 50 the master member latch 53 to release the master-member which oscillates the blades 3 to make an exposure. Fig. 4 shows the invention applied to the shutter described in Specification 491,885. During the setting of the shutter the diaphragm ring 92 is rotated against its spring 98 by the upturned end 84 of the arcuate member 83 secured to the setting lever frictionally engaging a spring arm 99 attached to the ring which is latched in the fully open position of the diaphragm by the nose 105 of a clockwise-urged pawl pivoted coaxially with the shutter trigger 87 at 90 engaging in a notch 108 in the ring, the arm 99 being raised clear of the end of the member 83 by an inclined ramp 100 during a slight over-travel of the setting member. On depressing the trigger 87 from D to E, a pro. jection 110 thereon releases the diaphragm ring latch 105, 108 so that the diaphragm leaves close to an aperture determined by an arm 93 on the ring engaging an adjustable stop member 95. On further depressing the release to F, the master-member 78 is released to make an exposure by the lever 75 oscillating the blade ring 73 to open and close the blades 72. Specification 554,076 also is referred to.