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:
May. 12, 1987
Filed:
Dec. 18, 1985
Applicant:
Inventors:
Larry J Eriksson, Madison, WI (US);
Mark C Allie, Oregon, WI (US);
Richard H Hoops, Stoughton, WI (US);
Assignee:
Nelson Industries Inc., Stoughton, WI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E04B / ;
U.S. Cl.
CPC ...
381 71 ; 181222 ;
Abstract
Acoustic attenuation apparatus (2) is provided for a duct (4) guiding an acoustic wave propagating (6) therethrough. A silencer (8) is provided for passively attenuating the acoustic wave in the duct, and a cancelling speaker (32) is provided within the silencer. The combination provides hybrid active/passive combined attenuation. Various rectangular and circular structures are disclosed, together with multi-path and multi-speaker arrangements.