1. Field of the Invention
The present invention relates generally to a mine roof support and, more particularly, to a system and method for creating a mine roof counter bore adapted to receive a crater plate and cable bolt head therein.
2. Description of Related Art
In mine work, such as coal mining, or in underground formations such as tunnels or other excavations, it is necessary to reinforce or support the roof and/or walls of the excavation to prevent rock falls or cave-ins. Among the most common means presently in use for effecting such support are cable bolts or other suitable elongated members, such as rod bolts, which are inserted into bore holes and exposed to a resin mixture or anchored therein to hold a metal support or bearing plate in tight engagement with the roof or wall surface. With respect to cable bolts, a resin system introduces resin capsules or cartridges into the bore hole and then advances the capsules to a blind end of the bore hole by the cable bolt backing the capsules. The spinning of the cable bolt ruptures the capsules and mixes the resin system supplied. Examples of prior art cable bolt arrangements are disclosed in U.S. Pat. Nos. 6,428,243; 5,586,839; and 5,064,311.
Each of the cable or rod bolts in the aforementioned prior art utilizes either a barrel and wedge assembly or a bolt head, respectively, to secure the metal support or bearing plate against the roof. Therefore, for example, the barrels of the cable bolts extend into the usable walk/crawl or transportation space in a mine, as defined by the distance from the floor to the ceiling of a mine tunnel.
Accordingly, there is a need to provide a mine roof support that limits the extent a bolt head protrudes beyond a roofline of a tunnel. Specifically, a system and method are needed for creating a mine roof counter bore adapted to receive a plate to be seated therein and a portion of a mine roof bolt therein. It is to be understood that the term mine roof bolt is to encompass a cable bolt, a rod bolt, a torque tension bolt and the like. Accordingly, either a barrel of a cable bolt or a head of a rod bolt may be sufficiently recessed within a recess of the plate to provide more vertical clearance within the tunnel. The resultant mine roof support should be cost-effective, easily installable and provide sufficient structural support for the roof. The foregoing need for an improved mine roof support is met by the present invention.
The present invention includes a mine roof support for use with a recess formed within a mine roof. The mine roof support includes a plate and a mine roof bolt. The plate includes (a) a raised portion defining a cavity; (b) a planar portion extending from the raised portion, wherein the planar portion is configured to be received adjacent the mine roof surrounding the recess; and (c) an opening within the raised portion. A first side of the raised portion is shaped to substantially correspondingly mate with the portion of the mine roof defining the recess.
The mine roof bolt may be a cable bolt having a barrel and wedge assembly. The mine roof bolt includes a drive end that extends through the opening and is at least partially received within the cavity. Alternatively, the cavity of the plate may be sized to substantially receive the entire barrel and drive end therein. A second side of the raised portion of the plate may include a portion surrounding the opening that accommodates a surface of the barrel thereagainst. A top portion of the barrel and wedge assembly may be planar and may conform to a planar surface of the second side of the raised portion of the plate. In another embodiment, the top portion of the barrel and wedge assembly may be contoured (e.g., curved) to conform to the second side of the raised portion of the plate. In yet another embodiment, a spherical washer may be positioned between a contoured surface of the raised portion of the plate and a planar surface of the barrel and wedge assembly. One end of the barrel may define a socket dimensioned to receive a drive tool to impart rotational force thereon.
A method of positioning a drive end of the mine roof bolt at least partially above a roofline of a mine includes (a) drilling a bore hole into the mine roof, wherein the bore hole is sized to receive the mine roof bolt therein; (b) drilling a recess into the mine roof to produce a recessed roofline, wherein the recess is situated below the bore hole and adjacent the roofline; (c) inserting a plate having a raised portion into the recess, wherein the raised portion defines a cavity within the plate, and wherein the recessed roofline matingly receives a first side of the raised portion; (d) inserting the mine roof bolt through an opening in the plate and into the bore hole and the recess of the mine roof; and (e) positioning the drive end of the mine roof bolt at least partially into the cavity. A drill bit tool may be provided having a first drill bit sized to drill the bore hole and a second drill bit sized to drill the recess.
A method of supporting the mine roof includes the aforementioned steps with respect to positioning the drive end of the mine roof bolt at least partially above the roofline of a mine with the addition of inserting a resin cartridge into the first hole and rotating the mine roof bolt. Accordingly, the resin cartridge is ruptured and resin contained therein is released within the bore hole, whereby the resin secures the mine roof bolt within the bore hole.
The drill bit tool for drilling into the mine roof includes a shaft, a first drill bit and a second drill bit. The first drill bit is situated at a first end of the shaft, wherein the first drill bit is sized to drill a bore hole in the mine roof to accommodate a mine roof bolt therein. The second drill bit has a curved cross-section. The second drill bit is positioned on the shaft and is distal from the first end thereof, wherein the second drill bit is sized to drill a recess in the mine roof sized to accommodate the plate therein. The second drill bit is fixedly secured to the shaft. The shaft may include a coupling for removably connecting a portion of the shaft having the first drill bit to a portion of the shaft having the second drill bit. The second drill bit may be movably secured to the shaft by a locking member.
These and other advantages of the present invention will be understood from the description of the preferred embodiments, taken with the accompanying drawings, wherein like reference numerals represent like elements throughout.
a is a side view of a barrel used in connection with the mine roof support of
b is a bottom view of the barrel of
c is an upper perspective view of the barrel of
d is a lower perspective view of the barrel of
The present invention will now be described with reference to the accompanying figures. It is to be understood that the specific apparatus and system illustrated in the attached figures and described in the following specification is simply an exemplary embodiment of the present invention.
With reference to
The crater plate 14 may be sized to accommodate any angled orientations of an axis of the crater sink 13 with respect to the roofline 12. For example, the depth of one side of the raised portion 16 of the crater plate 14 may be greater than another side of the raised portion 16. In the context of a wall (not shown), a recess would be formed into the wall and, desirably, the edges 18 of the crater plate 14 would be situated substantially parallel with respect to the wall; however, it is to be understood that an axis of the crater sink 13 may be formed in an angled orientation with respect to the plane of the wall.
The crater plate 14 defines an opening 20 to accommodate a mine roof bolt therein. It is to be understood herein that the term mine roof bolt is to encompass a cable bolt, a rod bolt, a torque tension bolt or the like. Therefore, all references made to a cable bolt with a barrel and wedge assembly are to be equally applicable to a rod bolt with head or torque tension bolt with nut, unless specifically indicated otherwise. As used herein, a drive end of a mine roof bolt is not meant to be limiting and may refer to (a) a barrel and wedge assembly (or the like) of a cable bolt; (b) a drive head including a threaded end of either a cable bolt or rod bolt with a drive nut (or the like), such as in a torque tension bolt; and (c) a drive head including a forged head (or the like) of either a cable bolt or rod bolt. In addition, the mine roof bolt described herein may be resin anchored or mechanically anchored using an expansion anchor at the distal end thereof or both. The opening 20 may accommodate a cable 21 of a cable bolt 22 therethrough. In an exemplary embodiment, the opening 20 may be one inch in diameter; however, it is to be understood that the opening 20 may be of various sizes depending on the width of the cable 21. As is known in the art, a bore hole 24 is drilled into the roof 11 to accommodate the cable bolt 22 or other securement mechanism, such as any type of mine roof bolt, therein. The opening 20 of the crater plate 14 is substantially aligned with the bore hole 24 such that a central axis of the opening 20 is substantially co-axial with a central axis of the bore hole 24.
With respect to the first embodiment mine roof support 10 incorporating a cable bolt 22, a barrel 26 is adapted to accommodate one or more wedges 28. As is known in the art, the wedges 28 co-act with the barrel 26 to secure the free end of the cable 21 extending downwardly from the opening 20. One embodiment of the barrel 26 is shown in
With continuing reference to
With continuing reference to the aforementioned figures,
The spherical washer 61 includes a surface 62a that corresponds to the inner curve of the curved raised portion 16 of the crater plate 14 and an opposing surface 62b adapted to be seated substantially flush against a surface of a barrel and wedge assembly of a cable bolt. In one desirable embodiment, the top portion of the spherical washer 61 is substantially semi-spherical; however, it is to be understood that the spherical washer 61 may embody any shape that corresponds to the particular shape of the crater plate 14. The spherical washer 61 may be used in connection with either a cable bolt or a rod bolt. For example, as shown in
The depth of the recess associated with each of the crater plates 64, 65, 66, can control the extent to which the drive end of a mine roof bolt (a barrel and wedge assembly 2, bolt head, nut or the like) extends below the roofline 12. With reference to
With reference to
A second embodiment drill bit tool 80 is depicted in
The aforementioned first embodiment drill bit tool 70 and second embodiment drill bit tool 80 are but exemplary embodiments of drill bit tools that may be used to create the crater sink 13. For example, to form a crater sink that accommodates the crater plate 66, a drill bit sized to correspond to the outer dimensions of the curved raised portion 16c of the crater plate 66 may need to be provided. Therefore, it is to be understood that the aforementioned drill bit tools 70, 80 may be modified to provide a correspondingly and suitably sized crater sink to accommodate a correspondingly sized crater plate.
An exemplary installation utilizing the aforementioned components includes selecting a section of wall or roof into which the crater sink 13 is to be formed. Thereafter, the depth of the drill bit tool 70 or 80 is adjusted to form the desired sized bore hole 24. The drill bit tool 70 is then used to drill the bore hole 24 with the accompanying crater sink 13. It is to be understood that the crater sink 13 and the bore hole 24 may be formed using two separate and distinct drill bits. For example, one drill bit (not shown) may be used to form the crater sink 13, whereas another drill bit (not shown) may be used to form the bore hole 24. These two drill bits may, therefore, be used independently of each other to form the crater sink 13 and the bore hole 24. Thereafter, a scraping tool (not shown) or equivalent may be used to prepare the resultant surface of the crater sink 13 to ensure that the respective surface mating areas will provide the requisite alignment between the crater plate 14 and the crater sink 13. The crater plate 14 is placed within the crater sink 13, such that the opening 20 substantially is co-axially aligned with the bore hole 24. A resin cartridge 90 (as shown in
It is to be understood that the dimensions described herein and in the accompanying drawing are for exemplary purposes only and are not to be construed as limiting the invention. As previously discussed, the present invention may be used in the context of rod bolts, torque tension bolts or cable bolts depending upon the mine roof application. While the present invention has been primarily described in reference to use with a cable bolt, rod bolts having a fixed (e.g., forged) head or threaded head (e.g., torque tension bolt) may likewise be employed.
In still another embodiment of the present invention, the plate may be generally planar with the drive end of the mine roof bolt having a surface for mating with the recessed roofline, wherein the drive head partially extends through the plate opening and has a bearing surface retained by the plate.
The present invention has been described with reference to the preferred embodiments. Modifications, combinations and alterations will occur to others upon reading the preceding detailed description. It is intended that the invention be construed as including all such modifications, combinations and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims the benefit of U.S. Provisional Patent Application No. 60/706,827, filed Aug. 9, 2005, and entitled “System and Method for Mine Roof Counter Bore and Cable Bolt Head Securement Therein,” the contents of which are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
654861 | Tynan | Jul 1900 | A |
3090203 | Durget | May 1963 | A |
3238731 | Seifert et al. | Mar 1966 | A |
4079766 | Conley et al. | Mar 1978 | A |
4523881 | Ringe | Jun 1985 | A |
4708559 | Locotos | Nov 1987 | A |
5064311 | Giroux et al. | Nov 1991 | A |
5259703 | Gillespie | Nov 1993 | A |
5511909 | Calandra, Jr. et al. | Apr 1996 | A |
5586839 | Gillespie | Dec 1996 | A |
5628587 | Lesslie | May 1997 | A |
5769570 | Stankus et al. | Jun 1998 | A |
5791823 | Blakley et al. | Aug 1998 | A |
5791824 | Radtke | Aug 1998 | A |
5791828 | Fergusson | Aug 1998 | A |
5829922 | Calandra et al. | Nov 1998 | A |
5934855 | Osterle et al. | Aug 1999 | A |
5954456 | Bowles | Sep 1999 | A |
6056482 | Calandra, Jr. et al. | May 2000 | A |
6428243 | Hutchins | Aug 2002 | B1 |
6457909 | Xu et al. | Oct 2002 | B1 |
6626610 | Seegmiller | Sep 2003 | B1 |
6648557 | Morrow et al. | Nov 2003 | B1 |
6682268 | Robertson, Jr. et al. | Jan 2004 | B2 |
6881015 | Wallstein et al. | Apr 2005 | B2 |
20030143038 | Babcock | Jul 2003 | A1 |
20040161316 | Locotos et al. | Aug 2004 | A1 |
Number | Date | Country | |
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20070036617 A1 | Feb 2007 | US |
Number | Date | Country | |
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60706827 | Aug 2005 | US |