Glass break detector
US4837558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1987 |
| Grant date | Jun 6, 1989 |
| Priority date | — |
| Expiry date | Oct 13, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/04
- WIPO fieldControl
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.