The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 1984
Filed:
Jul. 19, 1982
James M Boozer, Asheville, NC (US);
Terry E Franks, Leicester, NC (US);
Richard C Rothweiler, Asheville, NC (US);
Square D Company, Palatine, IL (US);
Abstract
An intrinsically safe or an explosion proof pilot light having a cluster of light emitting diodes arranged in a pattern and visible through a lense cap located in a hazardous area. The pilot light has terminals connected through a rectifying bridge and a current regulator to the diodes to optimize the light output of the diodes and make the pilot light insensitive to the polarity or variations in the voltage of the A.C. or D.C. electrical supply to the pilot light and limiting the current to the diodes to a constant value in event one or more of the diodes is destroyed or shorted. A pair of printed circuit boards are spaced by a plurality of conductive supports with one of the boards mounted on a base of the pilot light and carrying the rectifier and current limiting components which are connected to the terminals. The other printed circuit board provides a support for the diodes and has a printed circuit thereon, portions of which provide a reflective surface for light emitted by the diodes. The pilot light includes a translucent lense cap formed of material that transmits light frequencies matching the light frequencies emitted by the light emitting diodes and optionally may include a fuse that replaces one of the conductive supports and limits current to the hazardous area.