US3695045A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rock bolts
Assignee: WILLIAMS FORM ENGINEERING Corp A MI CORP
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Filing: 1970-02-03
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Granted: 1972-10-03
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Expires: 1990-02-03
Abstract
Abstract A method of reinforcing a rock formation with rock bolts establishing a lock-in pre-stress condition inhibiting the initiation of movement of the formation, and structural features of a rock bolt assembly capable of use in the practice of the method.
Inventors
- 👤 Chester I Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:03
CPC Classifications
E; E21; E21D; E21D20/00; E21D21/00; E21D21/0026; E21D21/0093; F; F16; F16B; F16B13/00; F16B13/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
174 words
A method of securing a rock formation in position, the said method including drilling a hole in said formation an installing a rock bolt assembly equipped with an anchor device in said hole, wherein the improvement comprises the following operations in sequence: setting said anchor device; steps for tensioning the said rock bolt assembly substantially up to a predetermined work load tension below the yield point of the bolt rod of said rock bolt assembly, said steps comprising, concomitantly applying tension to said bolt rod and elongating the same as a substantially linear function of the applied tension, increasing the applied tension and elongation of said bolt rod as a substantially linear function of increasing tension substantially to said work load tension, terminating the application of tension at a point short of and representing a substantial fraction of the yield point of said bolt rod, maintaining said last named tension on said bolt rod; and grouting said rock bolt assembly in said hole to substantially fill said hole with grout around said bolt rod.
Claim 2
Independent Claim
174 words
A method of securing a rock formation in position, the said method including drilling a hole in said formation an installing a rock bolt assembly equipped with an anchor device in said hole, wherein the improvement comprises the following operations in sequence: setting said anchor device; steps for tensioning the said rock bolt assembly substantially up to a predetermined work load tension below the yield point of the bolt rod of said rock bolt assembly, said steps comprising, concomitantly applying tension to said bolt rod and elongating the same as a substantially linear function of the applied tension, increasing the applied tension and elongation of said bolt rod as a substantially linear function of increasing tension substantially to said work load tension, terminating the application of tension at a point short of and representing a substantial fraction of the yield point of said bolt rod, maintaining said last named tension on said bolt rod; and grouting said rock bolt assembly in said hole to substantially fill said hole with grout around said bolt rod.
Claim 3
Dependent Claim
42 words
A method as defined in claim 1, wherein said grouting is delivered into said hole at the low end thereof via a conduit, and continued under pressure until grout is recirculated in said hole throughout the length of said rock bolt assembly.
Claim 4
Dependent Claim
31 words
A method as defined in claim 2, wherein the flow of liquid grout is subsequently plugged while in liquid form to permit the same to set under pressure in said hole.
Claim 5
Dependent Claim
24 words
A method as defined in claim 1, wherein said anchor device is set initially to an intensity sufficient to sustain said last named tension.
References Cited (Backward Citations)
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Cited
US3222873A
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US3234742A
Cited
US3379016A
Cited
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Cited
US3301123A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |