Title: Noise control apparatus

What is claimed is:

1. A noise control apparatus for reducing sound volume of noise propagating from a noise source, comprising:

a sound arresting wall separate from the noise source; and

means for shifting in phase and refracting the acoustic wave of the noise to provide a refracted propagating acoustic wave, said means being disposed at substantially the top of said sound arresting wall, said means being hollow and further comprising bent plates vertically disposed within said means, said bent plates having an equal interval therebetween and having front edges aligned in such a manner that a line drawn through the front edges diagonally descends and intersects with said noise source,

whereby said refracted propagating acoustic wave interferes with said acoustic wave directly propagating from the noise source and diffracting over said sound arresting wall.

2. A noise control apparatus as set forth in claim 1, wherein said sound arresting wall comprises a sound absorbing member on the inner side thereof facing the noise source.

3. A noise control apparatus as set forth in claim 1, further comprising a sound insulating member placed behind said means to isolate said refracted propagating sound downwardly propagating from said means.

4. A noise control apparatus as set forth in claim 1 or 3 wherein said means is disposed on the top of said sound arresting wall.

5. A noise control apparatus as set forth in claim 1 or 3 wherein said means is disposed at inner upper side of said sound arresting wall, and said sound insulating member is the upper portion of said sound arresting wall.

6. A noise control apparatus as set forth in claim 1, wherein said means is integrally formed on said sound arresting wall.

7. A noise control apparatus as set forth in claim 1, wherein said sound arresting wall placed about 2.7 m apart from the noise source and extending about 2.8 m from the noise source.


Other info:


Inventors: Yamamoto, Tsuyoshi (Tokyo, JP)
Taniguchi, Norihisa (Tokyo, JP)
Iida, Kazuyoshi (Yokohama, JP)
Kondo, Yoshikazu (Tokyo, JP)

Application Number: 06/335617
Filing Date: 1981-12-30
Publication_date: 1984-03-13
Assignee: JAPAN NATIONAL RAILWAY (JP)
BRIDGESTONE TIRE CO LTD (JP)

Primary Class(es): 181/210 181/288, 105/452, 104/124, 181/286
Other Classes: E01F8/00; G10K11/175; G10K11/00; G10K11/00
US Patent Ref:

3080937	March, 1963	Garbell	181/210	Combined acoustic wall and exhaust gas deflector in operation of jet engines
4069768	January, 1978	Matsumoto et al.	181/210	Device for controlling a propagation direction of noise
4158401	June, 1979	Matsumoto et al.	181/210	Device for controlling a propagation direction of noise

Other Refs: JP54-2006

February, 1979

Primary Examiner: Fuller, Benjamin R.
Assistant Examiner:
Attorney: Parkhurst & Oliff