US3324756A - Bail-type anchor device for a hollow rock bolt - Google Patents

Bail-type anchor device for a hollow rock bolt Download PDF

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Publication number
US3324756A
US3324756A US466946A US46694665A US3324756A US 3324756 A US3324756 A US 3324756A US 466946 A US466946 A US 466946A US 46694665 A US46694665 A US 46694665A US 3324756 A US3324756 A US 3324756A
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US
United States
Prior art keywords
bolt rod
bail
bolt
anchor device
hole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US466946A
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English (en)
Inventor
Chester I Williams
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Individual
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Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US466946A priority Critical patent/US3324756A/en
Priority to GB16899/66A priority patent/GB1089510A/en
Priority to DEW37351U priority patent/DE1947487U/de
Priority to DE1634668A priority patent/DE1634668C3/de
Application granted granted Critical
Publication of US3324756A publication Critical patent/US3324756A/en
Priority to CA146349A priority patent/CA932997B/xx
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
    • E21D21/008—Anchoring or tensioning means

Definitions

  • This form of anchor usually includes a wedgeshaped or conical member in threaded engagement with the inner end of the bolt, and a pair of separable bearing members on opposite sides of the bolt.
  • the wedge moves axially between the bearing portions and increases the circumscribed diameter around them to generate a clamping action against the wall of a hole drilled in the rock formation.
  • the interconnecting bail will deflect to accommodate this movement.
  • the primary purpose of the bail is to maintain the axial position of the bearing members with respect to the bolt rod at least temporarily so that the wedge can move between them to generate the clamping action.
  • Hollow rock bolts have been a very useful development, and have permitted the interior of the bolt to function either as a vent hole for the withdrawal of air from the hole in the rock formation as grout is injected near the surface; or, alternatively, to function as a conduit for the grout in cases in which the venting must be done near the surface.
  • the latter case corresponds to situations in which the hole is drilled at a downward angle from the surface, and the former corresponds to overhead installations.
  • Bail-type anchor devices have not been practical in conjunction with hollow rock bolts, in view of the tendency for the bail to obstruct the central bore of the rock bolt so that it cannot adequately function either as a vent or as a grout conduit.
  • the present invention constitutes an improvement in the construction of this type of anchor device so that the conduit aspects of a hollow bolt may be maintained without interfering with the functioning or installation of the anchor device.
  • This improvement centers in a modification of the bail portion of the anchor to provide a passage communicating between the hollow interior of the bolt rod and the surrounding space.
  • FIGURE 1 is a sectional elevation showing a rock bolt with a bail-type anchor device installed in a hole in a rock formation, with the components of the device in the unexpanded condition.
  • FIGURE 2 is a section similar to FIGURE 1, showing the actuated condition of the components of the anchor 3,324,756 Patented June 13, 1967 device, with the bearing members forced against the wall of the hole in the rock formation by the wedge member.
  • the hollow rock bolt 10 is shown installed in the hole 11 in the rock formation 12.
  • the passage 13 through the interior of the rock bolt may be used either to vent air out of the hole 11, or as a conduit for grout.
  • the anchor device for securing the bolt with respect to the surrounding rock formation 12 includes the wedge member 14 in threaded engagement with the bolt rod 10, and the bearing members 15 and 16. These members are disposed in opposite sides of the bolt rod, and the Wedge 14 is interposed between them.
  • the inner surfaces 15a and 16a of the bearing members are tapered in conformity with the tapered outer surface of the wedge member to maintain approximate parallelism of the bearing members as expansion proceeds.
  • the bearing members 15 and 16 are interconnected by the bail portion 17.
  • the wedge is provided with grooves on its opposite sides that register with the bail 17 as shown to maintain the rotative alignment of the wedge with respect to the bearing members 15 and 16.
  • the anchor device thus far described is conventional.
  • the bail 17 is provided with shoulders as shown at 18 and 19, and with the central hole 20, The presence of the shoulders 18 and 19 establishes a spaced relationship between the central portion of the bail and the end 21 of the bolt rod, thus establishing a passage extending laterally in opposite directions in communication with the bore 13.
  • the hole 20 supplements this function by providing a coaxial passage, and it is preferable that both of these arrangements be included. Either one of these, however, will serve the purpose.
  • the joint lateral and coaxial passages have a tendency to provide a better discharge of grout, and also minimize the possibility that the passage might become blocked by rock chips or other such material.
  • the hole 20 should be slightly smaller than the bore 13 of the rock bolt to minimize the possibility that a piece of material might enter into the hole 20, and thus operate as a valve closing off the end of the hollow rock bolt.
  • grout may be injected through the bore 13 without obstruction, or the hollow bolt rod may function as a vent tube to withdraw air from the hole 11 as grout is injected from a point near the surface.
  • an assembly including a hollow bolt rod and an anchor device having separable portions on opposite sides of said bolt rod interconnected by a bail member extending over the end of said bolt rod, and also including a wedge in threaded engagement with said bolt rod and interposed between said separable portions, the improvement comprising means forming a pair of internal shoulders on said bail member normally engaging the opposite sides of the end of said bolt rod, respectively, and providing a central portion on said bail member spaced axially from said shoulders beyond the end of said bolt rod, said central portion having a hole therethrough coaXially with said bolt rod, said hole and spaced central portion providing passages communicating with the interior of said bolt rod.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Piles And Underground Anchors (AREA)
  • Joining Of Building Structures In Genera (AREA)
  • Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
  • Dowels (AREA)
US466946A 1965-06-25 1965-06-25 Bail-type anchor device for a hollow rock bolt Expired - Lifetime US3324756A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US466946A US3324756A (en) 1965-06-25 1965-06-25 Bail-type anchor device for a hollow rock bolt
GB16899/66A GB1089510A (en) 1965-06-25 1966-04-18 Anchor device for use with a hollow bolt rod
DEW37351U DE1947487U (de) 1965-06-25 1966-05-13 Gesteinsanker mit hohler bolzenstange.
DE1634668A DE1634668C3 (de) 1965-06-25 1966-05-13 Spreizanker
CA146349A CA932997B (en) 1965-06-25 1972-07-05 Anchor device for use with a hollow bolt rod

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US466946A US3324756A (en) 1965-06-25 1965-06-25 Bail-type anchor device for a hollow rock bolt

Publications (1)

Publication Number Publication Date
US3324756A true US3324756A (en) 1967-06-13

Family

ID=23853686

Family Applications (1)

Application Number Title Priority Date Filing Date
US466946A Expired - Lifetime US3324756A (en) 1965-06-25 1965-06-25 Bail-type anchor device for a hollow rock bolt

Country Status (4)

Country Link
US (1) US3324756A (de)
CA (1) CA932997B (de)
DE (2) DE1634668C3 (de)
GB (1) GB1089510A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4195952A (en) * 1978-03-27 1980-04-01 Swanson Roger I Means for anchoring to rock

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3012498A1 (de) * 1980-03-31 1981-10-08 Hilti AG, 9494 Schaan Spreizduebel
US6829871B1 (en) 1998-12-01 2004-12-14 Cobra Fixations Cie Ltee-Cobra Anchors Co., Ltd. Wedge anchor for concrete
WO2000032946A1 (en) * 1998-12-01 2000-06-08 Cobra Fixations Cie Ltee - Cobra Anchors Co. Ltd. Wedge anchor for concrete
CN107524463A (zh) * 2017-09-11 2017-12-29 李顺良 一种涨壳式中空锚杆

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1050345A (en) * 1912-04-19 1913-01-14 U S Expansion Bolt Co Expansion-bolt.
US2667037A (en) * 1949-08-24 1954-01-26 Edward M Thomas Suspension roof support
US3065659A (en) * 1959-09-28 1962-11-27 Superior Concrete Accessories Expansion bolt
FR1327260A (fr) * 1962-04-06 1963-05-17 Dispositif d'ancrage, notamment pour la stabilisation des toits de mines
US3200693A (en) * 1963-10-17 1965-08-17 Eastern Co Expansion shell
US3247754A (en) * 1963-08-08 1966-04-26 Dennis W Bieser Self-drilling anchor bolt

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1050345A (en) * 1912-04-19 1913-01-14 U S Expansion Bolt Co Expansion-bolt.
US2667037A (en) * 1949-08-24 1954-01-26 Edward M Thomas Suspension roof support
US3065659A (en) * 1959-09-28 1962-11-27 Superior Concrete Accessories Expansion bolt
FR1327260A (fr) * 1962-04-06 1963-05-17 Dispositif d'ancrage, notamment pour la stabilisation des toits de mines
US3247754A (en) * 1963-08-08 1966-04-26 Dennis W Bieser Self-drilling anchor bolt
US3200693A (en) * 1963-10-17 1965-08-17 Eastern Co Expansion shell

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4195952A (en) * 1978-03-27 1980-04-01 Swanson Roger I Means for anchoring to rock

Also Published As

Publication number Publication date
CA932997B (en) 1973-09-04
DE1634668B2 (de) 1979-03-08
DE1634668A1 (de) 1970-09-17
DE1947487U (de) 1966-10-06
DE1634668C3 (de) 1979-10-31
GB1089510A (en) 1967-11-01

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