Patent GB-527498-A (GB)
Title: Improvements in or relating to roll film photographic cameras
IPC: G03B19/04
Filed: 1939-03-27
Abstract: 527,498. Roll-film cameras. KODAK, Ltd. (Eastman Kodak Co.). March 27, 1939, No. 9476. [Class 98 (i)] A roll-film photographic camera of the type having a pair of spool chambers arranged one at each end of the camera body, the film passing from a supply spool in one chamber across an exposure frame to a take-up spool in the other, is provided with masking means for varying the size of the exposure opening, together with film feed locking means operated, after the correct amount of film has been fed, by film measuring means which is actuated by the movement of the film and is pre-adjusted according to the selected size of the exposure opening, the film feed locking means being rendered inoperative on actuation of the shutter release so that a fresh length of film may be fed. In the camera shown in Figs. 1, 2, 7 and 8, slidably mounted L-shaped masking plates 77, 78 are given equal and opposite movements by a pinion 82 which engages racks 80, 81 formed on the edges of apertures in them. They are moved between the position shown in Fig. 8 and a position in whi ch they form an exposure opening of smaller width B between them by the rotation of an external disc 9 having pin 91 which engages in a slot in a lug 92 extending up from the masking plate 77. A snap-over spring 89 acting on the pin 91 retains the masking plates at either end of their movement. Simultaneously with the movement of the masking plates, masks 101 are adjusted in front of the view-finder in order that the field of view may correspond to that included on the film. The masks 101 are carried by pivoted bell-crank levers 98 urged towards one another by a spring 102 and caused to have equal movements by a pin and slot connection 100, the levers being positioned by one or other of two lugs 103, 108 carried by a sliding plate 104 which is moved by a bracket 106 extending from it and having a slotted end engaging the pin 91. The film is wound, and the focal-plane shutter (which may be of the kind described in Specification 529,297) is set, by a knob 6, through differential planetary gearing of the kind described in Specification 527,449. The knob 6 rotates through a crown gear 19 and gear 21 a pinion 24 loosely mounted on a stub shaft 25, which drives the film spool and has integral with it a disc 26 carrying planetary pinions 2 7. These pinions mesh with the pinion 24 and with internal teeth 28 on a gear ring, the external teeth 30 of which drive a gear train 31, 38, 42, 43, 44 for rotating the shutter spool 45. The pinions 27 either drive the gear ring and wind the shutter, or roll on the gear ring and rotate the disc 26 and shaft 25 to wind the film, according to which operation offers the least resistance. When either operation is completed the driving means for it become locked, the further action of the planetary drive then completing the other. In order to lock the film feed, the film passes over a measuring roller 51 of the kind described in Specification 492,874 carrying a sharp-toothed wheel 52 which is rotated by contact with the moving film and drives two gears 53, 54 of different diameters. proportionate to the two sizes of picture. Either of the gears 53, 54 may be caused to drive a gear 59 through one of two gears 55, 56 carried between pivotally mounted yokes 57 which are rocked by a link 58 operated from the mask 77 to engage one or other of the gears 55, 56 with the gear 59. During winding of the film the gear 59 is turned through one revolution, driving a notched disc 61 until the notch 62 engages a hook 65 of a lever 63, having a slotted end in which engages a pivot pin 64. The subsequent movement of the disc moves the lever bodily until a notch 72 in it clears a lug 67 on a pawl 66, which then engages a ratchet 29 on the shaft 25 and so prevents further feed of the film. The parts are then in the position shown in Figure 1. When the shutter release is operated a bell-crank lever 69, 70 is swung counterclockwise, the arm 70 engaging the lug 67 on the pawl 66 and disengaging the pawl from the ratchet 29. The lug 67 engages the lever 63 and moves the hook 65 from the notch 62. A spring 68 then moves the lever bodily so that the hook bears on the periphery of the disc 61 and the slot 72 engages the lug 67 on the pawl and prevents the pawl re-engaging the ratchet, so that the film may be wound. In order to allow the backing-paper of the film to be wound, a button 109, when depressed engages an extension 110 of the pawl 66 and moves it to release the ratchet 29. The disc 61 remains locked by nose 65 of the lever 63, the necessary rotation of the gear 59 being permitted by a friction clutch between it and the disc. Fig. 17 shows a camera in which the picture opening is reduced to half size by masks 149, 150 which are wound on shafts 151, 154, the latter being rotated by a crossed belt 153 from the former. A cam 159 on the shaft 151 engages between discs 146, 155 keyed to but slidable on a shaft 157 to which is secured a toothed wheel 158, which is rotated by the passage of the film F over it. Adjustment of the masks for a large or small picture causes the cam to move the discs 146, 155 vertically in order to bring one of them into operative relation to a locking arm 139, which is adapted to enter a single notch formed in the upper disc, or one of two oppositely-disposed notches 156 in the lower disc, which latter is in operation when the masks are set to give a half-size picture. The locking arm is formed on a plate 137 slidably and pivotably mounted on pin 138, and carrying a pawl 135 which, when the arm 139 falls into a notch in the selected locking-disc 146 or 155 engages a pinion 133 and prevents further feed of the film. Depression of the shutter release 129 rocks a shaft 128 and causes the arm 144 of a bell-crank lever 143 carried by it to engage a lug 145 on the plate 137, which is thus rocked about the pin 138 to disengage the arm 139 and the pawl 135. The plate 137 is then moved to the left by a spring (not shown) so that the arm 139 engages the periphery of the disc, and does not lock it until the end of the next filmwinding operation. During this movement a cam edge 160 on the plate 137 engages a pin depending from a mutilated gear 140 and turns the latter into engagement with the gear 133. The gear 140 is eccentrically - pivoted on an arm 142 having a slotted end engaging round the shaft 128. During the winding of the film the gear 140 is turned until stopped by the mutilated portion, this causing a single reciprocation of the arm 142. While moving to the right a projection 148 on the arm 142 engages a pin 147 on the bell-crank lever 143, which rocks the shaft 128 in a clockwise direction and causes a U-form member 127 carried by it to move a slide 123 to the right. A check 122 on the slide engages a lug 121 on a rotary sleeve 119 carried by the lens mount, thus turning the sleeve and causing a lug 120 at the front end to operate the setting arm 118 of a betweenlens shutter. When the release 129 is depressed the slide 123 is similarly moved to the left, a check 122a on it causing rotation of the sleeve 119 in the opposite direction so that the lug 120 operates the shutter release 117. This form of shutter-operating device is described in Specification 532,610.