Patent GB-957784-A (GB)
Title: Photographic camera
IPC: G03B7/00
Filed: 1960-11-21
Abstract: 957,784. Photographic cameras with built in exposure meters. AGFA A. G. Nov. 21, 1960 [Nov. 21, 1959], No. 40005/60. Heading G2A. A photographic camera with a built-in exposure meter comprises setting means for taking into account the film sensitivity, locking means for said setting means controlled by a part of the camera requiring to be moved on insertion of a film. In the camera shown in Fig. 2, the shutter diaphragm aperture is controlled by a rotatable ring 34 which comprises a slot through which a rod 49, which is part of the exposure time control mechanism, passes. The value of the exposure time is controlled by a cam 41 on a ring 36 connected to a ring 35 by a spring 47a and urged away from it by spring 47. The exposure setting means are connected through gearing and levers 50-55 to a pointer 56 which follows up a pointer 57 of an exposuremeter galvanometer 58. Rings 35, 36 can be rotated relative to each other to indicate the film sensitivity and a projection 46 on ring 35 can engage one of a series of projections 40 on ring 36. When this happens a plate 60 can be moved in direction W through levers 59, 61 by the insertion of the film 62 to lock the rings 35, 36 together. Until these rings are set the projection 46 cannot enter a hole 40 and the film 62 cannot be inserted. In the embodiment shown in Fig. 3, the diaphragm is set according to the exposure meter by rotation of ring 71 and the film sensitivity reading is set by rotation of ring 74 which at the same time sets the exposure time through cam 77. This ring is locked in position by a rod 80a engaging recesses 79, but is urged by spring 93 in a direction in which rod 80a would engage a cam edge 90. The rod 80a is connected to a pin 86 which is urged by spring 87 against a film advancing shaft comprising two parts 89, 88 of different diameters. When the shaft is moved in the direction t to insert the film spool, pin 86 engages part 88 of the shaft so that the rod 80a is moved out of recesses 79 and the ring rotates until cam 94a abuts pin 80a. When the film spool is inserted the shaft 88-89 cannot be depressed so that the pin 86 abuts part 89 until ring 74 is rotated and the rod 80a can engage one of the recesses 79. In another embodiment the rod 80a is movable axially instead of radially by the back of the camera to effect the locking. In this case a plate is movable in front of the recesses when the back is opened and is only removable when the ring 74 is set. In the embodiment shown in Fig. 4 the film sensitivity indicating knob 101 is connected to a galvanometer 106 of an exposure meter and a plate 105 with recesses 126 engageable by a projection 111 on a lever 110 but urged by a spring 107 in a direction p in which projection 111 rides on a cam 105a. The other end of lever 110 has a projection 115 which can engage a recess in a sleeve 125 which surrounds a film rewinding shaft 116, 117 comprising two parts of different diameters. For rewinding, the film lever 120 is moved in a direction opposite to S by means of a knob 122 which moves projection 115 out of the recess in sleeve 125 and from the flange 117a so that a spring 123 can move the rewinding knob 119 on shaft 116 in the direction n and on to an operable position. On inserting the new film the knob 119 cannot be depressed and locked in this position until the film sensitivity reading is set and projection 111 engages a projection 126 to lock this film sensitivity setting.