Patents by Inventor Pieter Hoffman

Pieter Hoffman 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).

  • Drill string apparatus and method of extending the length of a drill string
    Patent number: 6241033
    Abstract: A percussive drilling mechanism includes a percussive hammer and a drill string connected to the hammer. The drill string includes a plurality of identically shaped shank rods interconnected to one another. To extend the drill string, a trailing one of the shank rods is removed from the hammer, and a new shank rod is interposed between the hammer and that removed shank rod.
    Type: Grant
    Filed: July 6, 1999
    Date of Patent: June 5, 2001
    Assignee: Sandvik AB
    Inventor: Pieter Hoffman