Intrusion alarm system
US4191947A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1978 |
| Grant date | Mar 4, 1980 |
| Priority date | — |
| Expiry date | Sep 6, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B1/08
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An intrusion alarm system and method is provided which includes one or more sound pulse transmitters that are triggered upon the opening of an entryway, such as a door or window, to produce a high-intensity sound pulse having a decibel level above a predetermined minimum. For example, each transmitter may comprise a percussive photoflash unit in combination with a pyrotechnic device which responds to the radiant output of the fired photoflash unit to emit the intense sound pulse. A centralized detector responds to the sound pulse above a predetermined threshold level to produce an alarm signal. Preferably, the detector comprises an electroacoustical transducer arrangement which provides the dual functions of both sound pulse detection and generation of an audible alarm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.