Door status detector apparatus
US4278968A · kind A · utility
Inventors
Key dates
| Filing date | Nov 13, 1979 |
| Grant date | Jul 14, 1981 |
| Priority date | — |
| Expiry date | Nov 13, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B21/18
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus is disclosed which creates a signal that indicates when a door has remained open for a predetermined amount of time. The apparatus includes a switch element responsive to the opening of the door and the closing of the door for monitoring the positional status of the door. The apparatus further includes electrical circuit components responsive to the monitoring switch for detecting when the door has been open for the predetermined period of time. The apparatus also includes electrical circuit components responsive to the detecting components for generating the signal indicating that the door has been open for the predetermined period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.