GB777401A - Improvements in or relating to photographic cameras - Google Patents

Abstract

777,401. Photographic cameras. DECKEL, H., and DECKEL, F. W. June 10, 1955 [June 16, 1954], No. 16807/55. Class 98(1) In a photographic camera with a focal plane shutter, the shutter speed and diaphragm adjusting members are mounted for rotation about the optical axis, a graduated scale indicates their relative position and the members may. be adjustably coupled to maintain a constant exposure value. As shown in Fig. 1 a rotatable spindle 12 is fast with two rollers 14 carrying the leading blind of a roller-blind shutter. A further roller 16, loosely mounted on the shaft 12, carries the following blind of the shutter. Both blinds are wound against spring action by means of a film feed roller 18 carrying a pin 20 which engages a pin 22 on a gear wheel 24 which drives the rollers 14 through gears 30, 32. When a spindle 26, on which the feed roller 18 is loosely mounted, is depressed against the action of a spring 28, the engagement between the pins 20, 22, is released, and the blinds run down to make an exposure. At the end of the winding of the shutter and of the film, the film feed roller 18, and consequently the rollers 14, are locked in position. The roller 16 is engaged by a detent lever 42 pivoted at 44, see also Fig. 2. The lever 42 engages a cam 38 fixed to roller 16 by a pin 34 passing through a slot 36 in the upper roller 14. A bevel wheel 52 is fast on the spindle 12, and engages a planet wheel 50 mounted on an arm 46 loosely mounted on the spindle 12. The planet wheel 50 also engages a bevel wheel 54 loosely mounted on the spindle 12 but held in position by means to be described. When the shutter is released, the leading blind begins to run down, the rollers 14 and the spindle 12 rotating. Bevel 52 turns with spindle 12, causing rotation of the bevel 50. The spindle 48 of bevel 50 engages a stop 56 on the lever 42, thereby releasing cam 38 and allowing the following blind, wound on roller 16, to run down. The width of the slit between the blinds and hence the time of exposure, depends on the distance through which the pin 48 has to move before striking the stop 56. The initial position of this pin is determined by the initial positon of bevel 54. Bevel 54 is pinned to a gear wheel 58, which is connected through gears 60, 62 to a gear sector of a lever 64 pivoted at 66 to the camera body, and having a pin 68 sliding in a cam slot 70 in a sector 72 rotatable with the diaphragm exposure time setting ring. The exposure time setting ring 80 forms part of an interchangeable lens mount, and is releasably connected to a diaphragm setting ring 106 in the manner described in Specification 769,070.. The coupling of the rings is adjusted in accordance with the light value, and thereafter any equivalent combination of shutter speed and diaphragm aperture may be set, the shutter being set automatically to the required speed by means of the sector 72.