Ultrasonic transmitter for burglar alarm system
US4117462A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1976 |
| Grant date | Sep 26, 1978 |
| Priority date | — |
| Expiry date | Jun 1, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B1/08
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An ultrasonic transmitter for apprising a central burglar alarm system of an unauthorized event includes a transmitting diaphragm which is repeatedly struck by a metal ball driven by a lever. The lever is actuated by a toothed wheel which is rotated by a motor spring, the rotation being governed to maintain constant speed and constant ultrasonic pulse rate. The rotation of the wheel is stopped by a striker interfering therewith, the striker being spring biased to the non-interference position. Thus the striker must be retained in the interference position by a door, window, trip wire, or the like, and any disruption of these structures will trip the striker and cause the transmitter to generate an ultrasonic pulse train and sound an alarm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.