The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 06, 1989
Filed:
Oct. 13, 1987
William E Abel, Portland, OR (US);
Douglas H Marman, Ridgefield, WA (US);
Sentrol, Inc., Portland, OR (US);
Abstract
A glass break defection system includes a unidirectional acoustic transducer directed toward an area of glass to be monitored. The transducer is narrowband and has a sharp frequency response peak in the 4 to 8 kHz range. An electronic audio discriminator connected to the transducer output is responsive to signals within this frequency range having a predetermined amplitude thereby eliminating ambient or environmental sounds not characteristic of breaking glass. The transducer is mounted in a rectangular enclosure which is pointed at the area to be monitored and comprises a flat circular metallic disk affixed to the enclosure with a piezo electric element affixed to the rear of the metallic disk. The enclosure is tuned to resonate at a frequency characteristic of the sound of breaking glass.