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. 31, 1994
Filed:
Oct. 22, 1992
Applicant:
Inventors:
William J Hanson, Bolton, MA (US);
Peter R Teare, Westborough, MA (US);
Assignee:
Liberty Mutual, Boston, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R / ;
U.S. Cl.
CPC ...
324616 ; 324602 ; 73646 ; 381 58 ;
Abstract
A portable hearing protection device evaluation apparatus which can be taken into the field to measure noise attenuation of a muff type hearing protection device under actual working conditions is provided. The apparatus includes two miniature microphones, one positioned inside a muff near the ear, the other positioned outside the muff to detect the noise in the environment. These two microphones simultaneously receive input signals which are provided to circuitry which determines and displays a single number output representing the noise attenuation.