Patent GB-709460-A (GB)
Title: Improvements in or relating to photographic roll film cameras
IPC: G03B1/66
Filed: 1952-03-07
Abstract: 709,460. Photographic roll-film cameras. KODAK, Ltd. March 7, 1952 [March 10. 1951], No. 6047/52. Class 98(1) In a camera wherein a perforated spring metal tape forms part of a film metering device which also includes a tape-engaging lever pivotally carried by a shutter tensioning lever and engaged during movement of the tape with the film in a film feeding direction by one of the tape perforations which thereby moves the levers towards the shutter trigger and tensions the shutter, said film feeding movement is interrupted when a fresh area of film has been fed due to one of the levers engaging a part of the shutter trigger, and after exposure operation of the trigger the tape-engaging lever is releasable from the tape for spring return to a position at which a further film winding operation may be carried out. As shown, a spool S having an eccentric channel in its core is slid through an opening in the camera bottom closed by a door 11 on to a windirig shaft 20 having a complementary key and carrying a sheave 19<SP>1</SP> on which is wound a metal tape T which extends across the camera in a guideway above the exposure gate into a chamber 17 in which its free end is retained by a projection on it engaging a lip of the guideway. After drawing outwardly the knob 21 and with it the shaft 20 so as to disengage from fixed slots 24 the arm 22 of a spring brake 23 opposing clockwise rotation of the shaft, the tape and film F are fed across the camera into coils in the receiving chambers 17, 15. This movement, is arrested when the film is fully unwound by the operation of the means described in Specification 709,458. The knob is then pressed inwardly reengaging the spring brake so preventing further clockwise rotation. The tape and film are then wound back towards the supply chambers. The parts are initially in the Fig. 14 position and the trigger is latched to prevent its fully rising to the Fig. 5 position under its return spring 90. Rewinding of the tape and film then presents an aperture 70 in the tape to a finger 69 on a lever 68 urged anticlockwise by an extension 77 of a spring 76 about a pivot 71 on a lever 58 pivoted at 75 on a base plate 37 and so moves the levers 68, 58 to the left, tensioning the shutter driving spring 55 between the lug 60 on a shutter timing sector, pivoted at 48 and comprising a spring plate 49 fixed to a rigid plate 47, and a pin 57 on the lever 58. When the downwardly-stepped arm 79 of the lever 58 approaches the shutter trigger 65, it strikes a lateral arm 89 on the lever 86 pivoting the latter anticlockwise against an extension 123 of spring 76 to remove the arm 87 on said lever from a channel 84 in the trigger which rises to the Fig. 5 position. The film rewinding is then arrested by the arm 79 of lever 58 striking the trigger. To make an instantaneous exposure, the trigger is depressed so that the bevel 66 engages on arm 67 on a lever 62 and the lever clockwise releasing the shutter timing sector which is driven by its spring 55 so that a pin 51 on an arm 44 pivoted at 45 rides up a ramp 50 on the springy plate 49 turning the arm anticlockwise, whereby a pin 43 on it engaging in slots 42 in the pivoted shutter blades 38, 39 opens the shutter. The shutter remains open as the pin travels along the plate 49 and during this travel the lug 61 freely rocks a lever 102 provided for making bulb exposures to move an arm 104 on it out of the path of the lug, the shutter closing when the pin drops off the plate at 52. On release of the trigger, the lever arm 67 which is urged against it moves into the channel 84 and locks the trigger against rising fully. Further winding of the film and tape then allows further leftward movements of the levers 58, 68 since the arm 79 too can move into the channel. When an arm 81 fixed to the lever 68 strikes a stop 82 and is pivoted clockwise withdrawing the finger 69 from the tape aperture 70, a return spring 72 moves the levers 58, 68 until the pin 57 on the lever 58 engages the right-hand end of. a slot 74 in the plate 37, the pin engaging and carrying with it an arm 73 on the shutter timing sector the lever 62 being pivoted clockwise by the lug 61 on the sector which is then latched by a projection 63 on the lever 62. The movement of the lever 62 removes the arm 67 from the channel 84 in the trigger but this is held depressed by engagement in the trigger channel of the arm 87. The parts are then again in the Fig. 14 position and further rewinding by causing engagement of finger 69 and a tape aperture 70 again sets the shutter and brings an exposed length of film into the exposure gate. To make a bulb exposure, the trigger is rotated through 180 degrees from the Fig. 5 position, when a long shoulder 100 on the trigger engages a finger 106 on the lever 102 and so holds the arm 104 in the path of the lug 61 on the timing sector so that the shutter is open until the trigger is released when the trigger rises sufficiently to allow the lug 61 to rock the lever anticlockwise and thus the shutter to close.