Patents by Inventor Donald J. Dufour

Donald J. Dufour 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).

  • Rotary valve
    Patent number: 4406442
    Abstract: A rotary valve having a hollow spool with a metering notch rotatable on a sleeve which is pressed into a valve body, the sleeve having an opening selectively and progressively alignable with said notch. A thrust needle bearing is trapped between a shoulder on the spool and a cap threaded into the valve body. A passage freely transmits pressure inside said hollow spool to the side of the bearing opposite said shoulders to reduce the thrust force imposed on said bearing.
    Type: Grant
    Filed: November 6, 1981
    Date of Patent: September 27, 1983
    Assignee: International Harvester Co.
    Inventors: Leonard A. Bettin, Imre Galos, Donald J. Dufour