Patents by Inventor Mark O. Thelin

Mark O. Thelin 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).

  • Duplex trailer hitch
    Patent number: 3963266
    Abstract: A duplex trailer hitch which provides a hook and a pivotable closure to receive a lunette, and a ball on the end of the end of the hook to receive a coupler.
    Type: Grant
    Filed: September 9, 1975
    Date of Patent: June 15, 1976
    Inventor: Mark O. Thelin