Patents by Inventor Donald R. Armstrong

Donald R. Armstrong 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).

  • Treadle control
    Patent number: 4570777
    Abstract: A control for a treadle activated machine tool having a driving power and a mechanical treadle linkage connecting the treadle to the driving power. The control comprises at least one sensor for sensing the presence of an operator's hand remote from a work area of the machine tool and an interrupt for selectively interrupting the treadle linkage in response to a signal indicating the absence of the operator's hand from the sensor.
    Type: Grant
    Filed: October 5, 1983
    Date of Patent: February 18, 1986
    Assignee: Hugh J. Baker and Company
    Inventor: Donald R. Armstrong
  • 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