Patents by Inventor Ralf Sture Frode

Ralf Sture Frode has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Device for automatic diaphragm setting in photographic cameras
    Patent number: 3988749
    Abstract: An automatic diaphragm control for camera lenses having independent diaphragm and shutter speed rings in which a reversible motor is positioned to drive the diaphragm ring, and a gear engaging the diaphragm ring drives a potentiometer. A light-sensor is in circuit with the motor and the potentiometer to drive the diaphragm ring to cause the potentiometer to balance the light-sensor output. The position of the diaphragm ring and the potentiometer is adjustable for film speed and for the selected shutter speed.
    Type: Grant
    Filed: April 21, 1975
    Date of Patent: October 26, 1976
    Assignee: Fritz Victor Hasselblad
    Inventors: Ralf Sture Frode, Anders Engstrom