Patents by Inventor W. David Calhoun

W. David Calhoun 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).

  • Yielding column
    Patent number: 6655877
    Abstract: A yielding column for support mine roofs or the like includes a tube provided with one or more circumferential rows of slots which provide a preferred locus for buckling. A reinforcing sleeve within the tube prevents inward buckling, so that the buckled portions are easily seen.
    Type: Grant
    Filed: April 16, 2002
    Date of Patent: December 2, 2003
    Inventor: W. David Calhoun
  • YIELDING COLUMN
    Publication number: 20030194280
    Abstract: A yielding column for support mine roofs or the like includes a tube provided with one or more circumferential rows of slots which provide a preferred locus for buckling. A reinforcing sleeve within the tube prevents inward buckling, so that the buckled portions are easily seen.
    Type: Application
    Filed: April 16, 2002
    Publication date: October 16, 2003
    Inventor: W. David Calhoun