Emergency lighting device
US5336977A · kind A · utility
Inventor
Key dates
| Filing date | May 18, 1993 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | May 18, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An emergency lighting device includes a hollow casing, a magnetic field detecting unit, a lamp unit and a driving unit. The casing is positioned adjacent to an electric outlet. The magnetic field detecting unit is disposed inside the casing and detects the absence of a magnetic field from the electric outlet. The lamp unit is mounted operatively on the casing. The driving unit is disposed inside the casing and is connected electrically to the lamp unit and to the detecting unit. The driving unit includes a light-sensitive switch unit and is responsive to the detecting unit so as to activate the lamp unit only when the magnetic field from the electric outlet is absent and there is weak surrounding light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.