Alternating lamp flashing system with lamp failure indicator
US4096470A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1977 |
| Grant date | Jun 20, 1978 |
| Priority date | — |
| Expiry date | Apr 21, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C5/0825
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system for alternately flashing two groups of signal lamps, as commonly employed for emergency and police vehicles, school buses, or the like, is provided with a lamp failure indicating circuit comprising two separate relay coils connected, respectively, as parts of current load lines to the lamp groups so that each coil normally will act through a contactor to energize a pilot circuit, thus causing a pilot lamp to be lighted so frequently when all the signal lamps are functional that the pilot lamp appears to be steadily illuminated; yet a relay coil will not so act, and the pilot lamp then will flash intermittantly to indicate a lamp outage, when a signal lamp on the load line of either coil does not function. In one embodiment, each relay coil has a contactor of its own in a separate branch of the pilot lamp circuit; in another, the two relay coils act alternately to displace a common contactor in the pilot lamp circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.