Patents Represented by Law Firm Armstronc, Westerman, Hattori, McLeland & Naughton
  • Varying apparent mass accelerometer
    Patent number: 5604313
    Abstract: A varying apparent mass accelerometer 1 for detecting earthquake vibrations includes a frame 2 vibrating with an earthquake wave, a mass 51 supported on the frame 2 via a spring 52, electrodes 6 and 7 disposed above and below the mass 51, power sources 8 each applying a voltage across the electrodes 6 and 7, and a capacitance detector 9 for detecting changes in capacitance between the electrodes. The accelerometer 1 exerts a signal only when an acceleration exceeds a threshold.
    Type: Grant
    Filed: November 23, 1994
    Date of Patent: February 18, 1997
    Assignee: Tokyo Gas Co., Ltd.
    Inventors: Sean S. Cahill, Kenichi Nakamura