Patents by Inventor Richard R. Criswell

Richard R. Criswell 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).

  • Centering adaptor for flat-bladed drill bits
    Patent number: 8348559
    Abstract: The centering adaptor is configured to receive a spade type drill bit. The body of the adaptor has three centering arms to engage in a previously drilled smaller hole so that the spade type drill bit is guided along the same centerline to re-drill the hole to a larger diameter.
    Type: Grant
    Filed: October 20, 2009
    Date of Patent: January 8, 2013
    Inventor: Richard R. Criswell