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:
Apr. 13, 1993
Filed:
Jun. 24, 1991
Steven M Hamer, Willernie, MN (US);
Thomas J Lunn, Hudson, WI (US);
David L Wortman, St. Paul, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
An optical traffic preemption detector detects pulses of light emitted by an approaching emergency vehicle and provides an output signal which is processed by a phase selector. The phase selector can request a traffic signal controller to preempt a normal traffic signal sequence to give priority to the emergency vehicle. A detector assembly is mounted in proximity to an intersection and can have multiple detector channels. A detector channel can have multiple photocells. A detector housing includes a base, at least one detector turret and a cap. A detector channel circuit includes a circuit board, a photocell with a lens placed over the photocell, and circuitry to produce an output signal.