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:
Dec. 01, 1992
Filed:
Jul. 06, 1989
Hiroshi Shima, Kodaira, JP;
Masanori Murase, Sayama, JP;
Naotaka Tomita, Sayama, JP;
Kazuyoshi Iida, Yokohama, JP;
Bridgestone Corporation, Tokyo, JP;
Abstract
A noise reducing apparatus comprising a first passageway group consisting of a plurality of first passageways aligned in parallel with each other for forming a first flat wave A by sound waves having a first same phase passed through each first passageway from a sound source, and a second passageway group consisting of a plurality of second passageways aligned in parallel with each other for forming a second flat wave B by sound waves being a second same phase passed through each second passageway from the sound source, said first passageway group having positioned above said second passageway group, and the phase of said first flat wave being advanced by a phase difference of 240.degree..+-.60.degree. with respect to the phase of said second flat wave to thereby reduce noise emitted from the sound source by interference of the first and second flat waves A and B.