Patent GB-613531-A (GB)
Title: Improvements in or relating to photographic shutters
IPC: G03B9/22
Filed: 1945-12-31
Abstract: 613,531. Photographic shutters. KODAK, Ltd. Dec. 31, 1945, Nos. 35309 and 35310. Convention dates, Aug. 15, 1944, and May 21, 1945. [Class 98 (i)] The master' member of the shutter is pivoted on a support which is movable to position the striking surface of the master member for engagement, upon release, with the selected surface of an arm having different contact surfaces, which is carried by one of a pair of interconnected concentric blade rings to which the shutter blades are pivotally connected, the selection of said surface depending upon the required exposure time. For an exposure at normal speeds, the contact surfaces on the arm are engaged in turn while, for an exposure at the highest speed, namely 1/800 second, the master member support is moved during the setting operation so that the striking surface will engage, upon release, only one of the contact surfaces. The shutter may be provided with a flash synchronizing mechanism, and may also incorporate means allowing'of bulb exposures. The whole of the mechanism is enclosed in a casing which supports a lens at each end thereof and carries internally a plate on one side of which lie the blade rings, shutter blades and diaphragm leaves while, on the other side, is mounted the shutter mechanism proper. The shutter casing. The cylindrical casing, Figs. 1 and 8, has a flange 2 terminated by a wall 4 supporting a lens at 7. Supported in the casing is a plate 10 from which projects a cylindrical flange 11 ending in a tubular lens, support 12 defining the exposure aperture EA, Fig. 1. Fixed at 24 to the support 12 is a plate 23 which, together with the flange 2, supports a cam ring 16 so that it may be rotated to bring a pointer 26 thereon opposite the graduation 27 on plate 23 which indicates the desired exposure time. A pointer 166 connected to diaphragm leaves 130, Fig. 8, may also be registered with a graduation 16 indicating the desired diaphragm opening. The stud 195, Fig. 1, connected to a flashlamp synchronizing mechanism, may also be moved in slot 196 in the plate to indicate the desired exposure delay. Blade rings and shutter blades. In Fig. 2, the blade rings 31, 34 are shown in their set position. Pivoted at 30 to blade ring 31 are double-ended blades 29, each of which also has a pin-and-slot connection with the blade ring 34, the blade rings having a connecting link 37 pivoted at 38 to the plate 10. A latching arrangement 50, 51 retains the blade, rings in their set position while blade ring 34 has an ear 250 with a shoulder 251 which, in an exposure at normal speeds, temporarily engages a pivoted latch 53. Blade ring 31 is formed with an arm 43 having stepped surfaces 45, 44 and a cam surface 156 which, upon release, are respectively to be engaged by the master member striking surface and a latch for a diaphragm mechanism whereby the leaves thereof are closed after an exposure. Master member. Fig. 9 shows the master member in its set position for a normal speed exposure. This member is carried by a lever 57, pivoted at 58 on plate 10 and urged clockwise by spring 59, and comprises a plate having a flange 98, lug 63 and a part 64 with a striking surface 65 and a lug 66, which is pivoted at 56 on the lever 57. The head of the stud 56 rests as at 70, Fig. 22, on the periphery 71 of an aperture in the cam ring 16. One end of the main spring 60, Fig. 14, is secured to the master member at 61, the other end being fixed to a stud 62 on the shutter casing, Fig. 14. Diaphragm mechanism. Fig. 20 shows the diaphragm mechanism which comprises three leaves 130, each pivoted at 131 to a fixed diaphragm ring 132, Figs. 8 and 20, and having pin-and-slot connection with an adjustable diaphragm 135, Figs. 8 and 20, recessed at 136 and having pin-and-slot connection with a lever 139 pivoted at 140 on plate 10. An arm 141 of this lever carries a leaf spring 145 which is also fixed to a lever 147, which is pivoted at 140 and has a flange 148, which is engaged by the striking surface 65 of the master member when it is moved to its set position to open the diaphragm leaves, Fig. 14. A lever 152 pivoted at 153 and urged anticlockwise by a spring 154, has a lug 151 which holds fast the lever 147 until a lug 155 on lever 152 is struck by cam surface 156 on blade ring arm 43, whereby spring 157 operates the lever 139 to close the diaphragm leaves. A hook 160 on the adjustable ring 135 and a pin 161, Figs. 8 and 20, carried as at 164 control the diaphragm opening, the position of this pin being determined by the position of the pointer 166, Figs. 1 and 8. Setting mechanism. When the exposure time, diaphragm opening and flashlamp exposure time delay have been selected, the shutter is set and for this purpose there is provided a lever 74, the handle of which projects from the casing in a slot therein, Fig. 14. The lever is slotted at 78, 77 to clear the studs 58, 79 respectively and is normally spring held in its rest position. Clockwise movement of the lever sets the shutter, a nose 91 thereon rotating the part 64 of the master member to tension spring 60 and the surface 65 thereon engages flange 148 to open the diaphragm leaves after a flange on the lever has rotated the blade ring arm 43 to open and close the shutter blades. A latch 94, pivoted at 54, is urged clockwise by a spring 255 to engage the flange 98 of the master member and hold it fast. Also a flange 89 on an extension 88 of the lever 74 engages a tooth on a disc 100, pivoted at 101 and urged clockwise by spring 102, to rotate it until a tooth 103 thereon engages at 104 a lever 105 which is pivoted at 79 and spring urged anticlockwise at 106. The setting movement of the lever urges blade ring 31 clockwise, the blade ring 34 thus moving anticlockwise, whereupon it is latched at 50, 51. Releasing mechanism. Movement of lever 74 anticlockwise to release the shutter for an exposure at normal speed, results in a lug 87 thereon, Fig. 14, engaging an arm 107 of the lever 105, which pivots about stud 79 to release the tooth 103. of disc 100, while a shoulder on the lever engages a lug 114 on the latch 50, Fig. 2, to release the blade rings. Disc 100 rotates clockwise so that a tooth thereon engages lever 94, which pivots anticlockwise to release the master member which thereby swings anticlockwise about its pivot 56. The striking surface 65 then hits surface 45, whereupon the blade ring. 34 rotates clockwise so that the shoulder 251 thereon engages the latch 53 to keep the blades open, during which time the surface 65 is riding over the rounded surface 46 of arm 43. Just before contact with the surface 44, which takes place after a time determined by the manual setting of a known gear retard mechanism, the flange 63 of the master member hits the latch 53 to release the blade rings and close the shutter blades. The contact of surfaces 65, 44 is maintained, while the cam surface 156 on the arm 43 strikes the lug 155 on the lever 152 of the diaphragm mechanism to close the leaves thereof. Bulb exposures. In order to allow of a bulb exposure,.in which lever 74 is depressed to open the shutter blades which are closed only on the release thereof, use is made of the latch 53. The latch has thereon a lug 117, Fig. 14, which may be engaged by a hook 118 on a lever 119, pivoted at 58, and spring urged anticlockwise at 120. Such engagement occurs only when a lug 121 on the lever 119 rides in the part 123 of a slot 122 in the cam ring 16, Fig. 22, which is the case only when the pointer 26 registers with the latch " B " on the plate 23, Fig. 1. Flange 63 now cannot open the latch until the handle 75 is released, whereby it is spring urged to its rest position and lug 87 moves away from arm 107 so that the lever 105 pivots anticlockwise to move lug 121 into the narrow part of slot 122. Highest speed exposure. Cam ring 16 is rotated until the pointer 26 registers with numeral " 800 " on the plate 23, Fig. 1, whereupon a cam surface 68 on the ring, Fig. 22, moves the head 70 of the stud 56 away from blade ring 34 to position the surface 65 for direct engagement upon release, with the surface 44 of the arm 43. If desired, an auxiliary spring may be used, this spring 212, Fig. 14, being coiled about the stud 56 and being fixed to a lever 210, freely mounted on the stud and engaged by the cam surface 213 on the ring 16 to rotate and tension the spring when the ring 16 is rotated, Fig. 22. Flashlamp synchronizing mechanism. The shutter casing is provided with a lamp plug 170, Fig. 1, from which run an earthing lead 174 and a lead 172 to a switch element 176 carried by a lever 198, the other switch element 177 being carried by a lever 178, both levers 178, 198 being pivoted at 178<1> on the plate 10, Fig. 24. A latch element 180 is pivoted on lever 178 and is spring urged into contact therewith, the lever 178 having a gear segment 184 engaging a pinion 185 on the plate 10. Upon release of the shutter, a tooth on disc 100 engages latch 180 which, together with the lever 178, controls the movement of the disc by a cam ring 21 having steps 190-192 contacting a pin 193 on lever 198, whereby the time when switch elements 176, 177 contact relative to the position of blades 29 is controlled. A pin 195 on cam ring 21 extends through the slot 196 in plate 23, Fig. 1, and is moved to indicate the required delay so that the flash lamp will achieve full brilliance before the blades are wide open. Escapement mechanism. Fig. 22 shows a stepped cam surface 213 engaging a pin 220 carried by an arm 67 pivoted at 221 and urged anticlockwise by spring 222, Fig. 14. The cam thus varies the position of arm 67 relative to the lug 66 on the master member part 64, a gear segment on the end of arm 67 co-operating with a gear train ending in a star-wheel which may be engaged by a spring-urged pallet, a pin 227 on which engages a slot 230 in the cam ring 16, Fig. 22. Safety arrangement. To provide for full setting of the shutter, a latch may be