Patents by Inventor Alfred E. Yarbrough

Alfred E. Yarbrough 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).

  • Portable intrusion alarm
    Patent number: 5109216
    Abstract: An intrusion alarm system, for an enclosed space responsive to first frequencies in the one to two Hertz range for detecting opening of doors or windows; and responsive to second frequencies in the third to four Khz range for detecting breaking glass. A mode selector renders the alarm responsive to a selected one of either the first or the second frequencies, or the concomitant detection of both first and second frequencies.
    Type: Grant
    Filed: July 18, 1990
    Date of Patent: April 28, 1992
    Assignee: Burnett Oil Co., Inc.
    Inventors: Alfred E. Yarbrough, Jerry O. Ball
  • Portable intrusion alarm
    Patent number: 4853677
    Abstract: An intrusion alarm system, for an enclosed space responsive to frequencies in the one to two Hertz range for detecting opening of doors or windows; and responsive to frequencies in the three to four Khz range for detecting breaking glass. A detected frequency in the one to two Hertz range increases the sensitivity required for detecting breaking glass.
    Type: Grant
    Filed: July 20, 1988
    Date of Patent: August 1, 1989
    Inventors: Alfred E. Yarbrough, Jerry O. Ball