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:
Jul. 24, 2012
Filed:
Apr. 29, 2009
Bao Liu, Cupertino, CA (US);
Lien Ouyang, Los Altos, CA (US);
Shawn J. Beard, Livermore, CA (US);
Irene LI, Stanford, CA (US);
Fu-kuo Chang, Stanford, CA (US);
Bao Liu, Cupertino, CA (US);
Lien Ouyang, Los Altos, CA (US);
Shawn J. Beard, Livermore, CA (US);
Irene Li, Stanford, CA (US);
Fu-Kuo Chang, Stanford, CA (US);
Acellent Technologies, Inc., Sunnyvale, CA (US);
Abstract
Methods and apparatuses for detecting fastener loosening. Sensors query a structure at a baseline value of an environment variable, such as temperature, and this baseline signal is stored for later use. Subsequently, users can query the structure remotely and at any time, and the signals from these queries are compared to the stored baseline signal. In some embodiments, an index is calculated, and the system determines that one or more fasteners have come loose if the calculated index exceeds a predetermined threshold value. It is desirable to select a time window within which the query signal is most sensitive to fastener loosening but least sensitive to variations in the environment variable. Accordingly, embodiments of the invention include methods and apparatuses for determining an optimal time window for use in calculating the above described index.