Method and apparatus for loosening of fasteners on structures
US8229680B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 2009 |
| Grant date | Jul 24, 2012 |
| Priority date | — |
| Expiry date | Jul 3, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01H1/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.