Patent GB-1014362-A (GB)
Title: Photographic camera with exposure regulating device
IPC: G03B7/04
Filed: 1963-04-11
Abstract: 1,014,362. Exposure regulating device for cameras. AGFA A.G. April 11, 1963 [April 19, 1962; July 14, 1962], No. 14673/63. Heading G2A. A camera has a built-in exposure regulating device comprising a bodily rotatable moving-coil galvanometer 2 and manual setting means for shutter speed and/or diaphragm aperture which are adjustable to a position in which, on operation of release mechanism 40 before exposure, shutter speed and/or diaphragm aperture are automatically regulated by the interaction of galvanometer needle 3 and a cam 14 connected to other setting means for shutter and diaphragm, the manual setting means being also adjustable to correspond to desired shutter and/or diaphragm settings, and the cam 14 being immobilised during such manual setting in which movement of the setting means causes the galvanometer 2 to rotate as a whole until the needle 3 reaches a pre-determined position at which the shutter and diaphragm are set for exposure. Manual film sensitivity setting means are provided whose movement also rotates the galvanometer 2 as a whole. Galvanometer 2 is rotated against spring 4 by its peripheral engagement with a Bowden (Registered Trade Mark) cable 5 whose other end is attached to a diaphragm leaf bearing ring 6 with an inner tube-shaped part having pins 7 engaging slots 8 of diaphragm leaves 9. A second leaf bearing ring 10 also has pins 11 entering bores in leaves 9, and has an arm 12 cooperating through pin and slot connection 13, 50 with an exploratory cam 14 for needle 3. Ring 6 is set manually by means 15 to aperture values on a scale 16 using friction catch 17, 18. A setting ring 19 is set by means 21 and catch 22, 23 to a position for automatic exposure regulation and to various shutter speeds on scale 20. In the automatic position pin 24 on ring 19 cannot engage shutter speed ring 25, but on setting to definite shutter speeds a lug 26 is engaged and ring 25 is rotated to the set speed, the shutter mechanism (not shown) being set by cams 27 or 28. Ring 25 is set by arm 12 of diaphragm ring 10 through powerful spring 30 and stop pin 51. Film sensitivity setting ring 33 has a spring-loaded manual control 34 pivoted at 35 whose tooth 37 engages notches 38 on setting ring 19, one end of the Bowden sheath 32 being fixed to ring 33 and the other end to housing 1 at point 1a. Automatic exposure regulation: Means 21 is put in the automatic position, manual diaphragm setting means 15 is put in its initial position, and control 34 is set to the film sensitivity whereby a loop is formed in sheath 32 and hence in cable 5 so that the galvanometer is rotated according to the film speed. Camera release 40 is now depressed and, through spring 41, arm 40a draws cam 14 into contact with needle 3 whose position depends on prevailing light conditions. This motion of cam 14 sets ring 10 and, through spring 30, the ring 25 according to the needle position. Lever arm 40b then actuates shutter release 29. Semi-automatic regulation: Shutter speed is manually set by rotation of means 21 against catch 22, 23 whereby ring 19 is rotated and hence, through pin 24 and lug 26, the ring 25 is set on scale 20. This rotation of ring 25 tensions spring 30 since arm 12 rest against stop 31, and cam 14 is thus held against the action of release 40 whose spring 41 is much weaker than spring 30. Ring 10 is therefore held also. Film sensitivity is set as above, and the diaphragm is then set in accordance with the pre-selected shutter speed by rotation of manual setting means 15 so that ring 6 is rotated until needle 3, under tension by cable 5, is located between index marks 43 seen in viewfinder 42. Alternatively, the aperture may be manually preselected, and the shutter speed set through means 21 using needle 3 and marks 43. In another embodiment, Fig. 3, the end of the Bowden sheath 32 is attached to a carrier 60 pivoted at 61 and having a slot 62b cooperating with a pin 63 on setting ring 19, and also having a projection 64 engaging a lug 66 on an index mark carrier 67 loaded by spring 65 and rotating independently on the galvanometer spindle. On carrier 67 is mounted an uncoloured transparent index field portion 68 with setting mark 69, and a further field 70 with an uncoloured half 71 and a green half 72, the fields being alternatively visible in viewfinder eyepiece 79 by means of semi-transparent mirror 76. On a further galvanometer needle 83 are carried field 80 with setting mark 81 and field 82 coloured red, each being transparent and entering the observation beam 73. Clear field 80 appears in the viewfinder and greenfield 72 is visible if sufficient light is available and the exposure device may be used; red field 82 appears if not. For semi-automatic operation, ring 19 is set as before and also the ring 25 after some lost motion while pin 63 slides in slot 62b and hence causes carried 60 to rotate so that sheath 32 is moved in the same sense as the end attached to ring 33. The slope of slot 62b may be such that no movement of cable 5 occurs, and galvanometer 2 is not moved. Rotation of carrier 60, however, brings field 68 on carrier 67 into the beam 73. When means 21 reaches the first shutter speed on scale 20, pin 63 enters range 62a of the slot in which movement of pin 63 causes no further rotation of carrier 60 and the galvanometer responds to setting means 21 as usual, so that index 81 may be set between marks 69.