Patent US4318302A successfully refreshed from Google Patents.
US4318302A
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Method of determining mine roof stability
Assignee: Consolidation Coal Co
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Filing: 1978-12-13
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Granted: 1982-03-09
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Expires: 1998-12-13
Abstract
Abstract A method and apparatus for determining the tension of mine roof bolts and/or mine roof stability which utilizes the natural vibration frequency of the seated roof bolt and/or roof structure to provide indication of bolt tension and/or roof stability.
Inventors
- 👤 Dai-Shik Choi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:23
CPC Classifications
E; E21; E21C; E21C39/00; E21D; E21D21/00; E21D21/02; G; G01; G01L; G01L1/00; G01L1/25; G01L1/255; F; F16; F16B; F16B31/00; F16B31/02; F16B2031/022; G01N; G01N2291/00; G01N2291/02; G01N2291/028; G01N2291/02827
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
75 words
A method of testing mine roof stability, comprising the steps of: exciting the mine roof bolt to vibration at the natural occurring frequencies by normal tightening of the roof bolt; detecting the natural occurring frequency vibrations; and analyzing spectrally to determine the predominance of frequency distribution within the range of natural occurring frequencies between zero and 1,000 Hz. to provide an indication of roof bolt tension thereby to derive an indicator of mine roof stability.
Claim 2
Independent Claim
75 words
A method of testing mine roof stability, comprising the steps of: exciting the mine roof bolt to vibration at the natural occurring frequencies by normal tightening of the roof bolt; detecting the natural occurring frequency vibrations; and analyzing spectrally to determine the predominance of frequency distribution within the range of natural occurring frequencies between zero and 1,000 Hz. to provide an indication of roof bolt tension thereby to derive an indicator of mine roof stability.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |