Patent GB-724079-A (GB)
Title: Improvements in or relating to combined winding and shutter mechanisms for photographic roll film cameras
IPC: G03B17/42
Filed: 1950-07-17
Abstract: 724,079. Photographic roll-film cameras; Shutters. GILBERT, G. July 17, 1951 [July 17, 1950], No. 17825/50. Class 98 (1). In a combined film winding and shutter mechanism for a camera having a take-up spool rotated by a winder unit and a reciprocable shutter-setting member moved in one direction to the set position by operation of the winder unit, the setting member is retained in the set position during continued winding of the film and the shutter-releasing means includes an element which on actuation of said means first disengages the setting member from the shutter prior to exposure of the film and then causes the setting member to be locked against return movement to its initial position until after the exposure is complete. As shown, on rotating the take-up spool knob 26, one or other of arms 24 integral with the winding shaft engages a lug 23 on a plate 1 having a flange 1a and pin- and-slot mounted at 20, 21 to slide adjacent the flange 18 of the base plate 14 against the action of a spring 11. A lever 2 pivoted at 19 on the plate 1 and urged clockwise by a spring is provided with a slot 31 in which engages, a lug 4 integral with the shaft 17 of a shutter disc 9 disposed to the front of the base plate. As the plate 1. moves'upwards, the lever 2 rotates the disc 9 clockwise tensioning the shutter-driving hairpin spring 8 secured at 42 to the disc and at 44 to a lever 7 which is adjustable to produce different exposure times, and the shutter is latched in the set position by a notch 37 in a clockwise-urged lever 3 pivoted at 35. Since in setting the shutter an aperture 16 therein crosses the, exposure aperture 15 in the base plate a cover blade 5 is provided to cover the aperture 15 during setting. The cover blade is pivoted at 34 and a pin 32 fixed to a link 10 and passing through a slot 33 in the base-plate is pivoted to the blale, a spring 12 fixed to this pin and to a lug on the base plate holding the blade in the position shown. On depressing the shutter-release lever (not shown), the link 10 moves downwardly rotating the cover blade clockwise to uncover the aperture 15 and successively a pin 40 on the blade 5 moves the lever 2 anticlockwise clear of the lug 4 against a stop 6 and a lug 39 on the blade trips the latch 37 for the shutter disc lug 4, so that the disc rotates td effect an exposure. The lobes of the shutter disc on opposite sides of the aperture 16 visible through the lens in the exposed and set positions may carry the words " exposed " and " set " respectively. Until the release lever is let go, the lever 2 is held against the stop 6 so that the spring 11 cannot influence the instantaneous exposure times, as might occur if the lever 2 were allowed to follow and overtake -the lug 4 and so that the exposure aperture remains open for the period of a bulb exposure for which a lug on the shutter blade 9 engages a lug on a release lever which is moved to a different position for a bulb exposure. Upon release of the lever Z, the plate 1 is returned towards the position shown in Fig. 2. In order to set the shutter it is necessary to wind on the film by rotating the knob 26. If one of the arms 24 prevents the return of the lever Z, the first part of the film winding merely effects an idle movement of the lever, but after this arm has moved past the lug 23'the lever returns to the Fig. 2 position so that on continued winding the shutter is set. If the winding means is such that less than one complete revolution of the shaft 25 winds on a fresh exposure frame, three or more arms 24 may be provided.