Patents by Inventor William C. Grindstaff

William C. Grindstaff 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).

  • Apparatus for unscrewing drill pipe sections
    Patent number: 5996444
    Abstract: Pipe sections of a drill string are unscrewed by holding one pipe section stationary in a clamping arm, and rotating another pipe section by a turning wrench. The clamping arm includes an adapter that can be replaced by similar adapters sized for different pipe diameter. The turning wrench includes a lug arranged to be contacted by a piston rod and rotated thereby for breaking the bond between the pipe sections.
    Type: Grant
    Filed: October 30, 1997
    Date of Patent: December 7, 1999
    Assignee: Driltech Inc.
    Inventors: Richard J. Pearce, William C. Grindstaff, James D. Madden