Patent GB-748394-A (GB)
Title: Improvements in or relating to shutters for photographic cameras
IPC: G03B9/20
Filed: 1952-03-28
Abstract: 748,394. Photographic shutters. JUNGHANS, H., and JUNGHANS AKT.-GES., GEB. March 28, 1952 [March 30, 1951], No. 8031/62. Class 98 (1). A multiple pivoted blade shutter having symmetrical blades of the double-ended type, which open and close the aperture by rotary movements in a single direction and are controlled by a blade ring and which move in alternate directions at successive exposures, is characterized by two guided spring-driven slides each of which extends into the operating range of a driving lug provided on the blade ring, a tensioning member comprising a single pivotally mounted tensioning lever to which two pushrods are linked, each of which can be brought into operative engagement with one of the spring-driven slides which are retained in the set position after tensioning, and a rocker with an abutment for each of the slides, spring fingers being provided on the rocker and extending into the working range of a lug provided on the blade ring so that said lug tensions one of the fingers whereby the rocker is prepared to release the subsequently-acting spring- driven slide and to block the previously-acting slide when the shutter has been set anew. As shown, double-ended symmetrical blades 2 pivoted at 3 are rotated in the same direction to open and close the shutter by pins 5 on a rotatable blade ring 4 engaging in slots 2a in the blades, the ring 4 moving in opposite directions for alternate exposures and being latched at the end of its movement, which is limited by lugs 101, 4c engaging in recesses 102, 1a in the supporting plate, by a latch 6a which may be tripped by the release lever 10. The shutter is set by clockwise rotation of a lever 18 pivoted at 17, links 21, 22 pivoted to said lever moving pins 23, 24 (Fig. 3, not shown) at the free ends of the links in opposite directions along a rectilinear guide 1d in which are movable slides 12, 13 bearing pins 14, 15 connected by a tension spring 16. In Fig. 1, the slide 12 is held at the outer end of the guide by a shoulder 27a on a rocking lever 27 on the pivot 17. On rotating the lever 18, the link 22 engages the pin 15 on the slide 13 and moves it to the outer end of the guide while the link 21 idles. At the end of the setting movement, the link 21 moves the slide 12 further outwardly clear of the shoulder 27a whereupon the lever 27 is tilted over by a tensioned spring 28a and 28b to bring the shoulder 27b into the path of the slide 13. On letting go the setting lever 18 which is then returned by a spring 25 to its original position, the slide 13 is latched by the shoulder 27b while the slide 12 bears against the lug 4c on the blade ring which is latched by the lug 6a on a latch 6. Thus on operating the release lever 10 to trip the latch, the ring 4 rotates clockwise to effect an exposure. During this movement, a pin 11 on the lug 4c engages the limb 28b of the spring 28a and 28b, tensioning it without releasing the latch 27b. On again operating the setting lever 18, the actions of the links are reversed, link 21 moving the slide 12 to the outer end of the guide while link 22 serves only to allow the rocking lever 27 to tilt, whereupon the shutter is set again as in Fig. 5. Release of the ring 4 this time causes anticlockwise movement of the ring, so that after the exposure the shutter is again in the Fig. 1 position. Additional leaf-springs 30, 31 secured to arms pivoted at 32, 33 may be caused to bear on the pins 14, 15 to increase the speed of movement of the ring 4, these springs being brought into action as shown by cam means on an exposure time setting ring (not shown) engaging pins 34, 35 on the arms. In a modification, Fig. 8, the spring 16 is replaced by two springs 50, 51 secured at 52, 53 to similarly-controlled arms 54, 55 pivoted at 56, 57. To prevent operation of the release 10 when the shutter is not set, a lever 60 pivoted at 61 is forked to engage a pin 10a on the release and has an upstanding lug 60c at its opposite end. Levers 64, 65 are pivoted at 63 and urged respectively anticlockwise and clockwise by a spring 66 surrounding the pivot 63 so as to cover the ends of the guide 1d whereby when either of the pins 14, 15 is not in its extreme outer position, one or other of the levers 64, 65 obstructs the lug 60c.