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. 14, 1992
Filed:
Feb. 26, 1991
Applicant:
Inventors:
Richard A Miller, Stillwater, MN (US);
Scott G Theirl, St. Paul, MN (US);
Kenneth A Aho, Chisago, MN (US);
Assignee:
Minnesota Mining and Manufacturing Company, Saint Paul, MN (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; E01F / ;
U.S. Cl.
CPC ...
359552 ; 359547 ; 404-9 ;
Abstract
A passive railroad crossing warning device has two input optical windows that receive light from the headlight of an oncoming locomotive. The light is redirected to an output optical window where a combiner causes it to exit at a predetermined angle to make it visible to motorists approaching the railroad crossing.