Patents by Inventor John Daniel Madsen

John Daniel Madsen 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).

  • Tower
    Patent number: 6336622
    Abstract: A derrick, especially a drilling rig derrick, including a derrick structure and lifting tackle for a load, for example, a drill string, in the derrick structure.
    Type: Grant
    Filed: October 22, 1999
    Date of Patent: January 8, 2002
    Assignee: Engineering & Drilling Machinery AS
    Inventors: Bjørn Eilertsen, John Daniel Madsen