Camera aperture setting control - uses electromagnet and photoresistive cell to position aperture lever in one of two possible positions

摘要

The setting control for a camera aperture uses a control lever in conjunction with electromagnets to move the aperture setting between one of two possible positions. The yoke lever of the electromagnets is rotable about the control lever, the latter being spring loaded. The mechanism is arranged so that the weight of the shutter closure device is greater than the difference between the tractive force of the electromagnets and the spring force. The aperture control mechanism is also controlled by a photoresistive cell responsive to brightness of incoming illumination, because the resistance of the cell is incorporated in a battery circuit with a coil working in conjunction with one of the magnets.