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:
Sep. 06, 2005
Filed:
Nov. 13, 2002
Shigeru Muramatsu, Hamamatsu, JP;
Tsutomu Sasaki, Hamamatsu, JP;
Tadaharu Kato, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
A hammer sensor includes a photo-filter plate movable together with a hammer assembly and having a base plate fixed to the hammer shank and an arc pattern formed on the base plate and different in transparency from the base plate, a photo radiating element radiating a light beam toward the arc pattern and a photo detecting element disposed on the optical path of the light beam for converting the amount of transmitted light to an electric signal, wherein the photo-filter plate converts the rotational angle of the hammer assembly to the amount of light incident on the photo detecting element, and makes the photo radiating element and the photo detecting element stationary so that a suitable photo-shield case prevents the photo elements from environmental light.