Patents by Inventor Phillip F. Bolf

Phillip F. Bolf 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).

  • Ladder step extender
    Patent number: D390669
    Type: Grant
    Filed: May 30, 1997
    Date of Patent: February 10, 1998
    Inventors: Donald R. Armstrong, Phillip F. Bolf
  • Ladder step extender
    Patent number: D409765
    Type: Grant
    Filed: April 3, 1998
    Date of Patent: May 11, 1999
    Inventors: Donald R. Armstrong, Phillip F. Bolf
  • Ladder step extender
    Patent number: D434158
    Type: Grant
    Filed: February 7, 2000
    Date of Patent: November 21, 2000
    Inventors: Donald R. Armstrong, Phillip F. Bolf