Patent GB-920359-A (GB)
Title: Improvements in or relating to photographic or kinematographic cameras
IPC: G03B7/12
Filed: 1960-02-10
Abstract: 920,359. Photographic cameras. KODAK Ltd. Feb. 10, 1960 [Feb. 14, 1959], No. 4651/60. Class 98 (1). A photographic or kinematographic camera having exposure control means includes an exposure meter which is bodily adjustable in accordance with the setting of one exposure factor and which has a pointer positioned as a function of incident light and exposure meter adjustment, means for automatically setting another exposure factor as a function of the pointer position, and locking means associated with the pointer and co-operating therewith to prevent actuation of the shutter release member when the pointer is in its zero position relative to the exposure meter. As shown, an exposure meter galvanometer 2, rotatably mounted on a shaft 2a in a camera housing 1, carries a toothed wheel 3 geared (by means not shown) to a shutter setting member, and has a pointer 4 which is clamped and scanned (in known manner) by a feeler number when the shutter is released for the purpose of setting the diaphragm automatically. Locking means for preventing release of the shutter, when pointer 4 is in its zero position, comprises a disc 5 which is rotatably and slidably mounted on the shaft 2a and is so loaded by a spring 6 that it is urged both against the housing 1 and in a direction to maintain an arm 5c thereof in contact with a stop 7 on the galvanometer 2. When lighting is sufficient for proper exposure, on adjustment of a release member 13 in the direction of the arrow A (Fig. 4), an arm 10a of a lever 10 pivoted at 11 is urged by a strong spring 12 to slide down an inclined surface 13b disc 5 is moved axially on the shaft 2a by the lever arm 10b, and arm 10c moves out of the viewfinder field 14 to indicate that conditions are satisfactory for exposure. When lighting is weak, however, and the pointer 4 is in its zero position, then a stepped recess 5e on the arm 5c engages with the pointer 4, lever 10 is then unable to pivot under tension of spring 12, and projection 13d of release 13 comes against lever arm 10a thereby preventing the completion of the shutter release operation. In order also to lock the release mechanism when the pointer reaches either limit of the range of adjustment of the automatic diaphragm setting mechanism, a pin 9 for one limit, and a stop 8 for the other limit are provided. The pin 9 is slidably mounted in the housing 1, has a reduced portion 9a engaging the disc 5 so as to slide therewith and has an end portion 9b co-operable with the pointer 4 for locking the same in a manner similar to that described for recess 5e. The pin 8 is fixed in the housing 1 and co-operates with an arm 5f of the disc 5 for limiting rotation thereof under loading of the spring 6. Depending on the shutter speed setting, the pointer 4 may thus become locked (if 5f and 8 engage) before it has reached its zero position. In a modification, the diaphragm setting member may be coupled to gear 3 and the shutter speed be set automatically. Also, the arm 10c may actuate some other form of signal arrangement. Film sensitivities and/or filter factors may be allowed for in the transmission to the gear 3.