Patents by Inventor Robert H. Mathews

Robert H. Mathews 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).

  • Torque measuring apparatus and method employing a crystal oscillator
    Patent number: 6581478
    Abstract: Torque in a torsion member, such as a rotating shaft, is sensed by a piezoelectric element that is attached to the torsion member. The piezoelectric element has a resonant frequency that varies with changes in the torque and is part of a transducer oscillator that produces a first signal. A reference oscillator has a similar piezoelectric element and produces a second signal having a frequency that varies in response to environmental parameters. The first and second signals are heterodyned, thereby cancelling the effects due to environmental parameters acting on both piezoelectric elements and producing a resultant signal that has a frequency which corresponds to the torque applied to the torsion member.
    Type: Grant
    Filed: July 5, 2001
    Date of Patent: June 24, 2003
    Assignee: Eaton Corporation
    Inventors: Birger Pahl, James E. Hansen, Matthew F. Planning, Robert H. Mathews
  • Torque measuring apparatus and method employing a crystal oscillator
    Publication number: 20030005780
    Abstract: Torque in a torsion member, such as a rotating shaft, is sensed by a piezoelectric element that is attached to the torsion member. The piezoelectric element has a resonant frequency that varies with changes in the torque and is part of a transducer oscillator that produces a first signal. A reference oscillator has a similar piezoelectric element and produces a second signal having a frequency that varies in response to environmental parameters. The first and second signals are heterodyned, thereby cancelling the effects due to environmental parameters acting on both piezoelectric elements and producing a resultant signal that has a frequency which corresponds to the torque applied to the torsion member.
    Type: Application
    Filed: July 5, 2001
    Publication date: January 9, 2003
    Inventors: Birger Pahl, James E. Hansen, Matthew F. Planning, Robert H. Mathews