Margin test switch for photoelectric intruder detection devices
US3974488A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 14, 1975 |
| Grant date | Aug 10, 1976 |
| Priority date | — |
| Expiry date | Mar 14, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/14
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A switch incorporated in a photoelectric intruder detection system provides a simple means for testing the system for a predetermined margin of safety from false alarm producing sources. Upon actuation of the switch, the sensitivity of the system is reduced by a predetermined factor, such factor representing a predesired margin of safety from false alarms. During installation of the system, the switch is actuated to reduce system sensitivity. Upon positioning the system components to provide a desired catch capability, the switch is deactuated, thereby increasing the system sensitivity to a level which provides a margin of safety equal to or greater than the amount of gain reduction effected by the switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.