Patent GB-870317-A (GB)
Title: Single lens reflex photographic camera
IPC: G03B19/12
Filed: 1959-06-02
Abstract: 870,317. Photographic reflex cameras. AGFA A. G. June 2, 1959 [June 18, 1958]; No. 18877/59. Class 98(1) A photographic single-lens reflex camera has a common setting means for a roller blind shutter and a spring-loaded mirror, means for retaining the mirror in its set position against the spring and separate means operable by the shutter release for disengaging the shutter from said setting means and for releasing the mirror from said retaining means, the said setting means including a setting spindle, the axis of which is perpendicular to a plane including the axis of rotation of the mirror, and a spiral cam extending around the setting spindle, by means of which cam the mirror can be pivoted into its set position through rotation of the spindle, the arrangement being such that on the mirror reaching said set position the setting spindle becomes disengaged therefrom. On rotation of pinion 9 and associated setting spindle 7 (Figs. 1 and 2), by a setting knob or rapid setting lever (not shown), pin 23 carried by a lever 24 p:voted at 25 is displaced by the spiral cam 22, rigid with spindle 7, causing mirror 30 in housing 29 to pivot downwardly about spindle 44 and against the loading of spring 45, due to the mirror housing 29 being engaged by a pin 27 also carried by lever 24 and penetrating through a slot 28 in camera wall 4. Just before pin 23 reaches the end of cam surface 22a, and is disengaged therefrom, the mirror 30 becomes locked in its viewing position by a latch 31 on spring-held lever 33 pivotable about pin 34. During the setting of mirror 30, rotation of spindle 7 is also transmitted by coupling means 10-17 to pinions 18, 19, which pinions are coupled to the shutter blinds (not shown) for setting thereof, and pinion 19 of which is rotatably mounted on shutter spindle 16 and is coupled thereto during setting by way of dogs 20, 21. In the set position, blade springs 60, 61 respectively engage lugs 18a, 19a on pinions 18, 19. On depression of release 41, conical surface 40 displaces abutment edge 39 of the lever 33, latch 31 is thereby moved out of engagement with housing 29, and mirror 30 returns to its idle position (Fig. 2) under spring tension, taking with it pin 23 and lever 24 against the tension of weak spring 46. At the same time, fork members 43 carried by the lower end (not shown) of release 41 axially displace a disc 13, which is non-rotatably mounted on setting spindle 7, until pin 12 disengages from pin 11 on rotatably mounted coupling disc 10, thereby freeing the shutter from the setting means. Also at the same time, the lower end of release 41 disengages spring 60 from pinion 18, thereby allowing the first shutter blind to run down for starting the exposure, and after a short delay, lug 62 comes against end 63a of leaf-spring 63 and by way of slidable pin 66 disengages spring 61 from lug 19a, thereby allowing the second shutter blind to run down for ending the exposure. A series of lugs 62 are arranged in the form of a spiral on pinion 18, and spring 63 is pivotally mounted at 64 so as to be adjustable by means, not shown, for varying the exposure time. In a modification (Fig. 4) setting knob 48 is fixed directly on to spindle 7, the spiral cam 49a is cut out of a solid boss 49 and the pin 50 engaging this cam is directly connected to the mirror housing 29. There is also a modified coupling (shown disengaged in Fig. 4) between setting spindle 7a and shutter spindle 16a. On rotation of spindle 7a, a cam member 68b disengages spring 76 from an axially movable coupling element 74 which is non-rotatably mounted on spindle 16a and which is thereupon urged by spring 75 for establishment of the coupling between dog 74a and recess 68a, for setting of the shutter. At shutter release the element 74 is moved downwards to its original position, thereby freeing the shutter from the setting means prior to its release. In an alternative embodiment (Fig. 5), a pin 52, attached to a sleeve 51 on spindle 7b, engages during rotation of the spindle with the spiral cam surface 56 formed by one arm 53b of a bell-crank lever 53, which is pivoted at 54 and has a second arm 53a engaging a pin 55 for displacing the mirror 30 against the tension of its spring, not shown. In a modification of the embodiment shown in Fig. 5, the cam surface is formed by a member directly attached to the mirror housing.