Patent GB-878081-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B7/00
Filed: 1957-12-04
Abstract: 878,081. Photographic cameras. GAUTHIER G.m.b.H., ALFRED. Dec. 4, 1957 [Dec. 21, 1956], No. 37834/57. Class 98(1) In a photographic camera, the entire diaphragm range is adjustable by means of a single diaphragm aperture and shutter speed adjusting member while the shutter speed cannot be altered from the maximum duration permissible for hand held exposures and the shutter speeds faster than this value can only be paired with the diaphragm values in the range of the smallest apertures while the shutter speeds slower than this value can only be paired with the maximum diaphragm aperture. Thus the whole exposure range which the shutter and diaphragm can command is covered but, for each exposure value, there is only, one combination of shutter speed and diaphragm aperture available. As shown in Fig. 6, in order to enable the drive from the single shutter speed and diaphragm aperture adjusting ring 22 to the shutter speed control ring 23 to be disconnected while the diaphragm aperture is being adjusted, ring 22 carries pivoted pawls 24. When the shutter speed reaches 1/60 sec. (this being taken as the maximum duration for hand held exposures) one pawl 24 strikes a fixed abutment 28 and the other rides out of its notch 23a. The control ring 23 is held stationary during the diaphragm adjustment phase by a resilient click stop arrangement 29, 31. The diaphragm adjustment is performed in Fig. 2 by a lost-motion connection between a diaphragm aperture control ring 2 and the single adjusting ring 3 (previously numbered 22) carrying a pin 7 which restrains a transmission ring 4 urged by tension spring 5 connected to fixed pin 6. The first part of the travel of pin 7 corresponds to the adjustment of slow shutter speeds but, on reaching 1/60 sec. as pawls 24 are disengaged, arm 4b strikes pin 12 to begin the diaphragm adjustment. The diaphragm is held at maximum aperture by tension ,spring 8 and the engagement of fixed pin 10 with one end of slot 2a. Spring 5 overcomes spring 8 to enable arm 4b to follow pin 7 until the other end of slot 2a abuts pin 10 and the diaphragm reaches its minimum aperture. Thereupon pawls 24 engage notches 23a and the shutter speeds faster than 1/60 sec. can be set. The diaphragm adjustment is performed in Fig. 4 by a cam ring 20 driven from the single adjusting ring by pin 21. The construction of the shutter is simplified by the omission of speeds between 1 /60 and 1/500 sec. In order to provide exposuresequivalent to f/22 at 1/125 sec. andf/22 at 1/250 sec., the shutter dwells at 1/500 sec. (as well as at 1/60 sec.) and the diaphragm is adjusted to f/11 and f/16 respectively. Pin 19 is thus held in contact with two successive diaphragm adjusting portions of cam ring 20 by the force of spring 16 transmitted by diaphragm blade ring 14 and pivoted lever 17. Portion 20a of ring 20 is concentric to allow movement to set the slower shutter speeds without altering the diaphragm aperture. In a form (Fig. 7, not shown) in which an exposure meter is,mounted on the camera body, the single adjusting ring drives a ring surrounding the meter dial and having a scale of film speeds marked thereon. A further ring is rotatably mounted within the first ring and has an index for the film speed scale, a follower index for the exposure meter pointer and a scale indicating types of flash bulb. the latter scale co-operates with an index rotatably mounted on the outer ring and reading on a subject distance scale marked on the camera body. The flash bulb sockets may be covered at unsuitable shutter speeds (Figs. 10a, 10b and 11, not shown) or electrically disconnected (Figs. 14 and 15, not shown). The single adjusting ring may be coupled with the lens focusing ring (Figs. 12 and 13, not shown). A pin and slot operated depth of field indicator (Figs. 8 and 9, not shown) may be provided.