Patents by Inventor Charles Kupfer

Charles Kupfer 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).

  • Conversion plug
    Patent number: 4222191
    Abstract: Conversion plug having the general shape of a shotgun shell, having a large counterbore formed in the end adjacent the hammer and having a small threaded counterbore to receive a nipple adapted to receive a percussion firing element.
    Type: Grant
    Filed: August 30, 1978
    Date of Patent: September 16, 1980
    Inventors: Thomas M. Lee, Charles Kupfer