AU2015216636A1

AU2015216636A1 - Cable bolt

Info

Publication number: AU2015216636A1
Application number: AU2015216636A
Authority: AU
Inventors: Jason Matthews; Richard Zhu
Original assignee: Minova International Ltd
Current assignee: Minova International Ltd
Priority date: 2014-02-17
Filing date: 2015-02-17
Publication date: 2016-08-25
Also published as: CA2939414A1; US20170107816A1; WO2015121748A1; CL2016002058A1; PE20161140A1; MX2016010712A

Abstract

A cable bolt for anchoring, by a curable product, in a hole formed in strata, the cable bolt has a drive head that defines a face end of the cable bolt that, when the cable bolt is inserted into the hole, is to protrude from the hole; an end termination that defines a toe end of the cable bolt at the opposing end to the face end; a first coupling member, and a second coupling member that is configured to be coupled to the first coupling member. The cable bolt further has a first segment that includes the drive head and the first coupling member, and a first set of wire strands that are each secured at one end to the drive head and at the opposing end to the first coupling member; and a second segment that includes the second coupling member and the end termination, and a second set of wire strands that are each secured at one end to the second coupling member and at the opposing end are bound by, and/or secured together at, the end termination. In use, the first and second coupling members are coupled together such that tensile loads in the cable bolt are transferred through the coupled first and second coupling members.

Description

Cable bolt

Field of the invention

The present invention relates to a cable bolt for use in reinforcing rock in areas of actual or potential strata movement.

Background

Various excavation and mining works can reduce the stability of strata that remains after completion of the works, leading to actual or potential strata movement. For instance, in underground mining and tunnelling situations, rock faces that surround the tunnel can be under significant internal pressures and stresses. As a part of reinforcing and stabilizing the rock against movement, cable bolts are often installed in the rock wall. With appropriate complementary equipment, such as plates and/or mesh sheets, the cable bolts minimize strata movement.

Cable bolts are installed by drilling a hole from the rock face into the strata. The cable bolt is then inserted into the hole, and voids between the cable bolt and the rock are filled with a curable product, which is typically grout or resin. The cable bolt can be pre-or post-tensioned to provide the required support to the rock wall.

The length of a cable bolt is dependent on the particular application. Flowever, typical cable bolts are at least 4 metres long, and can be up to 10 metres or even longer. Cable bolts are transported to the site in bundles, either in a straight configuration, or a coiled configuration. The minimum bend radius of a cable bolt depends on the cable size and structure. In many cases, the minimum bend radius exceeds 1.5 metres. The weight of a cable bolt is dependent on its construction and length.

Due to these geometric and weight properties, cable bolts can be difficult to transport. Furthermore, in confined spaces, such as in tunnels, there can be difficulties in manual handling of cable bolts during insertion into a wall. There are also various safety issues surrounding the use of cable bolts.

There is a need to address or improve the above, and/or at least provide a useful alternative.

Summary of the invention

The present invention provides a cable bolt for anchoring, by a curable product, in a hole formed in strata, the cable bolt including: a drive head that defines a face end of the cable bolt that, when the cable bolt is inserted into the hole, is to protrude from the hole; an end termination that defines a toe end of the cable bolt at the opposing end to the face end; a first coupling member, and a second coupling member that is configured to be coupled to the first coupling member; a first segment that includes the drive head and the first coupling member, and a first set of wire strands that are each secured at one end to the drive head and at the opposing end to the first coupling member; and a second segment that includes the second coupling member and the end termination, and a second set of wire strands that are each secured at one end to the second coupling member and at the opposing end are bound by, and/or secured together at, the end termination, whereby, in use, the first and second coupling members are coupled together such that tensile loads in the cable bolt are transferred through the coupled first and second coupling members.

The present invention provides a cable bolt for anchoring, by a curable product, in a hole formed in strata, the cable bolt including: a drive head that defines a face end of the cable bolt that, when the cable bolt is inserted into the hole, is to protrude from the hole; an end termination that defines a toe end of the cable bolt at the opposing end to the face end; a plurality of first coupling members, and a plurality of second coupling members that are each configured to be coupled to one of the first coupling members; a first segment that includes the drive head and one of the first coupling members, and a first set of wire strands that are each secured at one end to the drive head and at the opposing end to the respective first coupling member; a second segment that includes one of the second coupling members and the end termination, and a second set of wire strands that are each secured at one end to the respective second coupling member and at the opposing end are bound by, and/or secured together at, the end termination; and at least one intermediate segment that includes one of the first coupling members and one of the second coupling members, and an additional set of wire strands that are each secured at one end to the respective first coupling member and at the opposing end to the respective second coupling member, whereby, in use, the first and second coupling members are coupled together with the or each intermediate segment being connected within the cable bolt between the first and second segments, such that tensile loads in the cable bolt are transferred through the coupled first and second coupling members.

In at least some embodiments, the first segment includes a central elongate tube defining a throughway through which to pass the curable product, wherein the tube is secured to the drive head and the respective first coupling member, and wherein the wire strands in the first set of wire strands extend along the central tube. Preferably, the wire strands extend spiroidally around the central tube of the first segment.

In such embodiments, the or each intermediate segment preferably also includes a central elongate tube defining a throughway through which to pass the curable product, wherein the tube is secured to the respective first and second coupling members, and wherein the wire strands in the respective additional set of wire strands extend along the respective central tube. Preferably, the respective wire strands extend spiroidally around the respective central tube of the respective intermediate segment.

Further, in such embodiments, the second segment preferably also includes a central elongate tube defining a throughway through which to pass the curable product, wherein the tube is secured to the respective second coupling member and to the end termination, and wherein the wire strands in the respective additional set of wire strands extend along the respective central tube. Preferably, the wire strands extend spiroidally around the central tube of the second segment.

The end termination can further include an end plug that closes the central tube of the second segment at the toe end.

Preferably, one or more of the first, intermediate and second segments have a port formed in the wall of the respective central tube, through which curable product can be discharged.

Preferably, the drive head includes engagement surfaces that a tool can engage to rotate the cable bolt. In certain embodiments, the drive head includes a nut that provides the engagement surfaces.

In some embodiments, the wire strands may be secured directly to the nut. In such embodiments, the cable bolt is to be tensioned with a separate tensioning device. In one example, the separate tensioning device may include a barrel and wedges.

In certain embodiments, each of the wire strands in the first set has an externally threaded portion, and the drive head has a plurality of internally threaded holes, each threaded hole receiving a respective one of the threaded portions of the wire strands.

Preferably, the drive head further includes a cylindrical body, and the plurality of threaded holes are formed at one end of the body, and the body further has an external thread that complements an internal thread on the nut.

The drive head can also include a pin that passes through transverse holes in the nut and body to inhibit rotation of the nut relative to the body. The pin may be removable to allow the nut to rotate on the body. Alternatively, the pin can be sheared on application of torque that exceeds a predetermined limit. Thus, the nut can be released for use in tensioning the cable bolt.

In embodiments in which the first segment includes a central tube, the body of the drive head also includes a connector throughway that mates with the central tube of the first segment such that curable product can be passed through the connector throughway and into the throughway in the central tube.

The or each first coupling member can have a first coupling threaded portion that engages with a complementary second coupling threaded portion provided on a respective one of the second coupling members to couple the first and second coupling members.

Preferably, one of the first and second coupling members includes a seal to prevent curable product discharging from the interface between the coupled first and second coupling members. One of the second and first coupling members can include a projection that is received within a complementary shaped recess in the other of the first and second coupling members. Preferably, the projection includes an annular groove within which an O-ring is seated.

In embodiments in which the first and second segments each include a central tube, the or each first coupling member includes a first coupling member throughway, and the or each second coupling member includes a second coupling member throughway, such that curable product can be passed through the cable bolt and into the central tube of the second segment.

The or each first coupling member can include a cylindrical body with a plurality of apertures that each receive one of the wire strands of the respective segment, and each wire strand having an end formation that resists removal of the wire strand from the respective aperture. The end formation may be an enlarged head. The enlarged head may be formed by deformation of the end of the wire strand.

Alternatively, the end formation may be an external thread formed on the end of each wire strand, and the or each first coupling member can include internally threaded nuts that are each mated with the external thread on a respective one of the wire strands. In such embodiments, the nuts may be tapered, and each aperture may be tapered, wherein the nuts located in the apertures.

In certain embodiments, the apertures are in the form of channels formed in the outer circumferential surface of the cylindrical body, and the first coupling further includes an outer sleeve that is secured to the cylindrical body.

The cylindrical body of the first coupling member can include the recess, and the second coupling member includes the projection.

Preferably, the outer sleeve has a first portion with a second internal thread that engages a complementary external thread on the cylindrical body. In at least some embodiments, the outer sleeve also defines the first threaded portion.

In some embodiments, the first coupling threaded portion is an internal thread, and the second coupling threaded portion is an external thread that is formed on the second coupling member. The second coupling member can include engagement surfaces to facilitate engaging the second coupling threaded portion within the first coupling threaded portion.

Each of the wire strands in the second and intermediate sets has an externally threaded end portion, and the second coupling member has a plurality of internally threaded holes, each threaded hole receiving a respective one of the threaded portions of the wire strands of the respective second and intermediate sets.

The first segment preferably includes a band surrounding the first set of wire strands adjacent the drive head, and another band surrounding the first set of wire strands adjacent the first coupling member, wherein the bands bind the first set of wire strands together. Alternatively or additionally, bands can bind the first set of wire strands to the central tube of the first segment.

The second segment preferably includes a band surrounding the second set of wire strands adjacent the second coupling member, wherein the band hold the wire strands against the central tube. The end termination may also include an end band surrounding the second set of wire strands that binds the second set of wire strands together. Alternatively or additionally, the end band can bind the second set of wire strands to the central tube of the second segment.

The or each intermediate segment preferably include a band surrounding the respective additional set of wire strands adjacent the respective first coupling member, and another band surrounding the respective additional set of wire strands adjacent the respective second coupling member, wherein the bands bind the respective additional set of wire strands together. Alternatively or additionally, the bands can bind the respective additional set of wire strands to the central tube of the respective intermediate segment.

Any one or more of the first, intermediate and second segments can include a bulb or birdcage formation formed in the respective set of wire strands. Alternatively, any one or more of the first, intermediate and second segments can include one or more spacers that each surround the respective central tube, wherein each spacer spaces the respective set of wire strands radially outwardly of the central tube in a portion of the cable bolt that includes the respective spacer. Preferably, at least the second segment includes a bulb or birdcage formation formed in the second set of wire strands.

The wire strands can have an outer surface that is plain, or is shaped to enhance engagement with the curable product. The wire strands within each set can be combinations of strands with plain or shaped outer surfaces. The wire strands within each segment can be combinations of strands with plain or shaped outer surfaces.

In some embodiments, the central tube of the first segment includes a restrictor that is spaced from the drive head such that a static mixing device can be inserted into the central tube, and the restrictor blocks the static mixing device from further travel along the cable bolt. The restrictor can be in the form of one or more indentations in the wall of the central tube that reduce the internal diameter of the central tube. The first segment can include four indentations that are spaced circumferentially around the elongate tube.

The present invention also provides a method of installing a cable bolt in a hole formed in strata, the method involving: providing a cable bolt as previously described; assembling the cable bolt by coupling the first and second coupling members; and inserting the cable bolt into the hole, involving first inserting the second segment.

In one embodiment, the assembling and inserting steps can occur simultaneously. Thus, each of the segments with a second coupling member can be partially inserted into the hole, and the first coupling member of another segment is then coupled to the second coupling member adjacent the face end of the hole, and the coupled first and second coupling members then progressed into the hole.

Brief description of the drawings

In order that the invention may be more easily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1: is a perspective view of a cable bolt according to a first embodiment of the present invention;

Figure 2: is a perspective view of the first segment of the cable bolt of Figure 1;

Figure 3: is a perspective view of one of the intermediate segments of the cable bolt of Figure 1;

Figure 4: is a perspective view of the second segment of the cable bolt of Figure 1;

Figure 5: is an enlarged view of region A in Figure 2;

Figure 6: is an enlarged view of regions B in Figure 1;

Figure 7: is an enlarged view of regions C in Figures 3 and 4;

Figure 8: is a cross section view along the line X-X in Figure 4;

Figure 9: is a cross section view along the line Z-Z in Figure 2;

Figure 10: perspective view of a cable bolt according to a second embodiment of the present invention; and

Figure 11: is a perspective view of a first coupling member of a cable bolt according to a third embodiment of the present invention.

Detailed description

Figure 1 shows a cable bolt 10 according to a first embodiment of the present invention. In use, the cable bolt 10 is to be anchored by a curable product within a hole that is formed in strata. The cable bolt 10 includes a first segment 12, and a second segment 14. In this particular embodiment, the cable bolt 10 also includes two intermediate segments 16.

The cable bolt 10 is assembled for use such that the first segment 12, the two intermediate segments 16, and the second segment 14 are coupled to one another in series. To this end, the couplings are formed by pairs of first coupling members 18 and second coupling members 20 that, when coupled, transfer tensile loads through adjacent segments 12, 14, 16 in the cable bolt 10.

The cable bolt 10 has the significant advantage that the cable bolt can be transported from the manufacture site to the drilled hole in a disassembled state. Furthermore, long cable bolts can be used in confined spaces.

The cable bolt 10 has a drive head 22 at one end of the first segment 12. The drive head 22 defines a face end of the cable bolt that, when the cable bolt 10 is inserted into the hole, is to protrude from the hole. The cable bolt 10 also has an end termination 24 at one end of the second segment 14. The end termination 24 defines a toe end of the cable bolt 10, which is at the opposing end to the face end. When the cable bolt 10 is inserted into the hole, the toe end is the closest portion of the cable bolt 10 to the toe of the hole formed in the strata.

Figure 2 shows the first segment 12 in further detail. The first segment 12 includes one of the first coupling members 18, and a first set of wire strands 26. Each of the wire strands 26 is secured at one end to the drive head 22, and at the other end to the first coupling member 18. The manner in which the wire strands 26 are secured to the drive head 22 is described in further detail below in reference to Figure 5. Further, the manner in which wire strands are secured to the first coupling members 18 is described below in reference to Figure 6.

Figure 3 shows one of the intermediate segments 18 in further detail. Each intermediate segment 16 includes an additional set of wire strands 28. Each of the wire strands 28 is secured at one end to one of the first coupling members 18, and at the opposing end to one of the second coupling members 20. The manner in which wire strands are secured to the second coupling members is described below in reference to Figure 6, which is an enlarged view of coupled first and second coupling members 18, 20 (regions B in Figure 1), and also Figure 7, which is an enlarged view of one of the second coupling member 20 (region C in each of Figures 3 and 4).

Figure 4 shows the second segment 14 in further detail. The second segment 14 includes one of the second coupling member 20, and a second set of wire strands 30. One end of each of the wire strands 30 is secured to the second coupling member 20 of the second segment 14. At the opposing end, the wire strands are bound by, and/or secured together at, the end termination 24, as will be described in further detail in reference to Figure 8.

In the particular cable bolt 10 as illustrated in Figures 1 to 4, the first segment 12 has a central elongate tube 32, which is secured to the drive head 22 and the respective first coupling member 18. Similarly, each of the intermediate segments 16 has a central elongate tube 34 that is secured to the respective first and second coupling members 18, 20; and second segment 14 has a central elongate tube 36 that is secured to the respective second coupling member 20. Each central tube 32, 34, 36 defines a throughway through which to pass curable product for anchoring the cable bolt 10 within the hole.

The wire strands 26, 28, 30 of the segments 12, 16, 14 extend generally spiroidally around the respective central tube 32, 34, 36. The direction of the spiral of each set of wire strands 26, 28, 30 in the segments 12, 16, 14 are all the same within the cable bolt 10. Further, the direction of the spiral can be either left-hand, or right-hand, although it will be appreciated that the direction is to correspond with the rotational direction that the cable bolt 10 is to be driven during installation and fixing procedures.

The end termination 24 includes an end plug 38 that closes the central tube 36 of the second segment 14 at the toe end of the cable bolt 10, as is shown most clearly in Figure 8. In this embodiment, at least the second segment 14 has a port 40 formed in the wall of the central tube 36, through which curable product can be discharged. It will be appreciated that similar ports can be formed in the walls of central tubes 32, 34, such that curable product can be discharged from the first and intermediate segments 12, 16 during installation of the cable bolt 10.

Figure 5 is an enlarged view of the drive head 22. The drive head 22 has engagement surfaces 42 that a tool can engage to rotate the cable bolt 10 during installation procedures. To this end, the drive head 22 includes a nut 44 on which the engagement surfaces 42 are formed (the nut 44 is omitted from Figure 2). Further, the drive head 22 has a cylindrical body 46 with an external thread that receives an internal thread on the nut 44.

Each of the wire strands 26 has an external thread (not shown) formed on an end portion, and the cylindrical body 46 further has internally threaded holes (also not shown). The threaded ends of the wire strands 26 each engage with one of the internally threaded holes to secure the wire strands 26 to the drive head 22.

The drive head 22 can also include a pin (not shown) that passes through a transverse hole 48 in the nut 44, and another transverse hole in the body 46. The pin inhibits rotation of the nut 44 relative to the body 46. Flowever, the pin can be removable or can be sheared to free the nut 44 for rotation on the body 46. Thus, the nut 44 can then be used, in combination with another component (for example, a dome or plate), to tension the cable bolt 10.

The body 46 of the drive head 22 also includes a connector throughway 50. The central tube 32 of the first segment 12 mates with the connector throughway 50 such that curable product can be passed through the connector throughway 50 and into the throughway in the central tube 32. A portion of the connector throughway 50 is internally threaded, such that a nozzle (not shown) with a complementary external thread can engage the drive head 22 whilst introducing curable product. The nozzle forms part of a delivery system for supplying curable product (such as grout or resin) to the cable bolt 10.

Figure 7 is an enlarged view of a second coupling member 20. In this particular embodiment, each second coupling member 20 has an externally threaded coupling portion 52, which engages with a complementary internally threaded coupling portion (not shown) formed in the first coupling member 18. The threaded coupling portions engage one another to couple the first and second coupling members 18, 20 to one another.

As is also shown in Figure 7, the second coupling members 20 include a seal to prevent curable product discharging from the interface between the coupled first and second coupling members 18, 20. To this end, the second coupling members 20 each have a projection 54 that is received within a complementary shaped recess (not shown) in one of the first coupling members 18, when the first and second coupling members 18, 20 are joined. The projection 54 includes an annular groove within which an O-ring 56 is seated.

The second coupling members 20 have engagement surfaces 58 to facilitate engaging the second coupling threaded portion 20 within the first coupling threaded portion 18, using an appropriately shaped tool.

Each first coupling member 18 has a first coupling member throughway (not shown). Similarly, each second coupling member 20 also has a second coupling member throughway (not shown). Thus, curable product can be passed through the cable bolt 10, and in particular through to the central tube of the second segment via the second coupling member throughway.

Figure 6 is an enlarged view of a first coupling member 18 that is coupled to a second coupling member 20. The wire strands secured to the first coupling member 18 can be those of the first or intermediate segments 12, 16. Further, the wire strands secured to the second coupling member 20 can be those of the intermediate or second segments 16, 14. In Figure 6, selected components of the first coupling member have been illustrated in a partially transparent format for clarity.

Each first coupling member 18 has a generally cylindrical shaped body 60 that defines the recess into which the projection 54 of the second coupling member 20 is to be received. Channels 62 are formed in the outer circumferential surface of body 60, with lands formed between adjacent channels 62. The wire strands 26, 28 of the respective first or intermediate segment 12, 16 are each received in one of the channels 62. Each wire strand has an end formation 66 that resists removal of the wire strand from the respective channel 62. In this particular embodiment, the end formation 66 is an enlarged head, which may be formed by a cold working technique (for example, by cold heading, or cold forging) that deforms the end portion of the wire strand.

The first coupling member 18 also has an outer sleeve 68 (which is partially transparent in Figure 6) that extends over the body 60. The sleeve 68 incorporates the internally threaded coupling portion (not shown) that, as previously described, couples the first coupling member 18 to a second coupling member 20. The sleeve 68 also has a portion with a second internal thread (not shown) that engages a complementary external thread 64 formed on the lands of the cylindrical body 60.

As will be appreciated, the body 60 and outer sleeve 68 co-operate such that the channels 62 are covered by the outer sleeve 68 to effectively form apertures that each receive one of the wire strands 26, 28 of the respective segment. The end formation 66 at the end of each wire strand 26, 28 is larger than the apertures, which inhibits the strand being pulled out of the first coupling member 18.

The thread handedness of these complementary threads is selected such that rotation of the cable bolt 10 during installation procedures urges the threads on the respective components into further engagement.

As will be appreciated, tensile loads in the cable bolt 10 are transferred through the outer sleeve 68, by virtue of the engagement of the threads in the externally threaded coupling portion 52 and the internally threaded coupling portion, and also by the engagement of the threads 64 formed on the lands and the second internal thread.

Bands 70 are provided on each of the first, intermediate and second segments 12, 16, 14 surrounding the respective set of wire strands 26, 28, 30. The bands 70 serve to contract the wire strands in the respective set, and bind the wire strands to the central tube. In the first segment 12, bands 70 are provided adjacent the drive head 22 and the first coupling member 18. In the intermediate segments 16, bands 70 are provided adjacent the first and second coupling members 18, 20. Further, in the second segment 14, one band 70 is adjacent the second coupling member 20. The end termination 24 also includes an end band 72 surrounding the second set of wire strands 30 to bind the second set of wire strands 30 together, and also to the central tube 36.

In the region of each segment 12, 14, 16 that is between each band 70, and the respective adjacent first coupling member 18, or second coupling member 20, the wire strands 26, 30, 28 are spaced radially outwardly from the respective central tube 30, 36, 34. This radial spacing of the strands 26, 30, 28 forms voids into which curable product can flow. The curable product curing through the strands 26, 30, 28 at these locations and into these voids enhances engagement between the cable bolt 10 with the cured product. As will be appreciated, this improves the performance of the cable bolt 10.

In the cable bolt 10, each of the segments 12, 14, 16 may be in the range of 1 to 3 metres long. In one example, the cable bolt may have two intermediate segments, and each of the first, intermediate and second segments may be 2 metres long. In such an example, the overall length of the assembled cable bolt would be 8 metres.

Figure 9 shows a cross section view of the first segment 12. As shown in this Figure, the central elongate tube 32 includes a restrictor that is spaced from the drive head 22. A static mixing device can be inserted into the throughway defined by the central tube 32, and the restrictor blocks the static mixing device from further travel along the central tube 32. In this embodiment, the restrictor is in the form of indentations 74 in the wall of the central tube 32 that reduce the internal diameter of the central tube 32. The first segment 12 has four indentations 74 that are spaced circumferentially around the central tube 32.

The static mixing device (not shown) that is to be used with the cable bolt 10 has a central body, and a plurality of projections that each project outwardly from the mixing device body. The largest diameter of the static mixing device is less than the internal diameter of the elongate tube 32. The projections space the mixing device body from the internal wall of the central tube 32, which forms an annular cavity between the mixing device body and the central tube 32.

In use, the mixing device is inserted through the drive head 22, and into the throughway in the central tube 32. Passage of the mixing device through the throughway is limited by the restrictor. In particular, passage of the mixing device is blocked by the abutment of projections against the indentations 74. Further, curable product flowing through the throughway must flow around the mixing device, and through the annular cavity. The projections cause curable product to flow at least partially circumferentially as it progresses through the annular cavity, and this enhances mixing of the curable product. This is particularly advantageous because a homogeneous curable product is likely to cure with maximum engagement with the cable bolt and surrounding strata.

In some alternative embodiments, the second segment can include one or more bulbs or birdcage formations formed in the second set of wire strands. In one example, the second segment can include spacers that surround the central tube of the second segment, and space the wire strands radially outwardly of that tube. This causes the wire strands to spread radially to form a "bulb" (also known as a "bird cage") in a portion of the second segment that includes each spacer. In such embodiments, the spacers are provided between the bands at either end of the second segment. Each spacer can be in the form of a ring with radially projecting ribs that define channels. Each wire strand in the second segment sits within a channel, and between two ribs.

Bulbs provided in the second segment are particularly useful in applications where the assembled cable bolt is to be point anchored at the toe end, pre- tensioned, and then fixed in place with a curable product, such as grout.

In some further alternative embodiments, the first and/or intermediate segments can include one or more bulbs / birdcage formations, as previously described.

Figure 10 shows a cable bolt 110 according to a second embodiment. The cable bolt 110 is substantially similar to the cable bolt 10 of Figure 1. In Figure 10, the features of the cable bolt 110 that are substantially similar to those of the cable bolt 10 have the same reference numeral with the prefix "1".

The principal difference between the cable bolt 110 and the cable bolt 10 is that the cable bolt 110 only has a first segment 112 and a second segment 114.

In the illustrated embodiments, the wire strands all have plain (in other words, smooth) outer surfaces. However, the wire strands may be shaped to enhance engagement with the curable product (herein referred to as a "shaped wire strand"). To this end, the wire strands may have indentations and/or projecting formations, for example spiroidal ribs.

Figure 11 shows a first coupling member 218 on the end of the wire strands 226 of a first segment 212 of a cable bolt according to a third embodiment of the present invention. The cable bolt of the third embodiment is substantially similar to the cable bolts 10, 110, and thus has a first segment, and may have one or more intermediate segments. The first segment, and each of the intermediate segments (if provided) have one of the first coupling members 218.

The first coupling member 218 has a generally cylindrical shaped body 260, and an outer sleeve (which is omitted from Figure 11 for clarity) that has an internal thread. The body 260 has an external thread, onto which the outer sleeve can be mated. The first coupling member 218 defines the recess into which the projection of the second coupling member is to be received, as previously described in connection with the cable bolt 10.

The body 260 has a plurality of apertures 262 that extend parallel to the longitudinal axis of the body 260. An end formation is provided to each of the wire strands 226 of the first segment 212. In this particular embodiment, each end formation is in the form of an external thread (not shown) adjacent the end of the strand. The first coupling member 218 has tapered nuts 266, and the apertures 262 are tapered to complement the shape of the tapered nuts 266. The threaded ends of the wire strands 226 are located within the apertures 262, and the tapered nuts 262 are each threaded onto one of the wire strands 226. The tapered nuts 266 are also located within the apertures 262, and the interference of the tapered nuts 266 and body 260 inhibit the removal of the wire strand from the apertures 262. In this particular embodiment, the tapered nuts are approximately 30 mm to 50 mm in length, and the external threads on the wire strands 262 is of at least the length of the tapered nuts 266.

As will be appreciated, to assemble the first coupling member 218 onto the wire strands 226, each strand 226 is passed through one of the apertures 262. The respective tapered nut 266 is then threaded onto the strand 226, and the tapered but 266 then located in the aperture 262.

As is evident from Figure 11, there are nine strands 226 in the first set, and thus the body 260 has nine apertures 262. Further, the first coupling member 218 has nine tapered nuts 266.

The first coupling member 218 has been described in connection with a first segment 212, but it will be appreciated that the same construction can apply to the first coupling member(s) of the each intermediate segment, as required.

Within any one set of wire strands in one segment of the cable bolt, various combinations of plain and shaped wire strands may be used. Alternatively or additionally, in the segments of a cable bolt, different combinations of plain and/or shaped wire strands may be used.

Further, in the illustrated examples, each set of wire strands contains nine wire strands. Flowever, the sets of strands may have more or less wire strands in some alternative embodiments. Further, a cable bolt may have segments with differing numbers of wire strands in some alternative embodiments.

Claims

CLAIMS:

1. A cable bolt for anchoring, by a curable product, in a hole formed in strata, the cable bolt including: a drive head that defines a face end of the cable bolt that, when the cable bolt is inserted into the hole, is to protrude from the hole; an end termination that defines a toe end of the cable bolt at the opposing end to the face end; a first coupling member, and a second coupling member that is configured to be coupled to the first coupling member; a first segment that includes the drive head and the first coupling member, and a first set of wire strands that are each secured at one end to the drive head and at the opposing end to the first coupling member; and a second segment that includes the second coupling member and the end termination, and a second set of wire strands that are each secured at one end to the second coupling member and at the opposing end are bound by, and/or secured together at, the end termination, whereby, in use, the first and second coupling members are coupled together such that tensile loads in the cable bolt are transferred through the coupled first and second coupling members.
2. A cable bolt for anchoring, by a curable product, in a hole formed in strata, the cable bolt including: a drive head that defines a face end of the cable bolt that, when the cable bolt is inserted into the hole, is to protrude from the hole; an end termination that defines a toe end of the cable bolt at the opposing end to the face end; a plurality of first coupling members, and a plurality of second coupling members that are each configured to be coupled to one of the first coupling members; a first segment that includes the drive head and one of the first coupling members, and a first set of wire strands that are each secured at one end to the drive head and at the opposing end to the respective first coupling member; a second segment that includes one of the second coupling members and the end termination, and a second set of wire strands that are each secured at one end to the respective second coupling member and at the opposing end are bound by, and/or secured together at, the end termination; and at least one intermediate segment that includes one of the first coupling members and one of the second coupling members, and an additional set of wire strands that are each secured at one end to the respective first coupling member and at the opposing end to the respective second coupling member, whereby, in use, the first and second coupling members are coupled together with the or each intermediate segment being connected within the cable bolt between the first and second segments, such that tensile loads in the cable bolt are transferred through the coupled first and second coupling members.
3. A cable bolt according to either claim 1 or 2, wherein the first segment includes a central elongate tube defining a throughway through which to pass the curable product, wherein the central elongate tube is secured to the drive head and the respective first coupling member, and wherein the wire strands in the first set of wire strands extend along the central elongate tube.
4. A cable bolt according to claim 3, wherein the wire strands extend spiroidally around the central elongate tube of the first segment.
5. A cable bolt according to claim 2, wherein the or each intermediate segment includes a central elongate tube defining a throughway through which to pass the curable product, wherein the central elongate tube is secured to the respective first and second coupling members, and wherein the wire strands in the respective additional set of wire strands extend along the respective central tube.
6. A cable bolt according to claim 5, wherein the respective additional set of wire strands extend spiroidally around the respective central elongate tube of the respective intermediate segment.
7. A cable bolt according to either claim 1 or 2, wherein the second segment includes a central elongate tube defining a throughway through which to pass the curable product, wherein the central elongate tube is secured to the respective second coupling member and to the end termination, and wherein the wire strands in the respective additional set of wire strands extend along the respective central elongate tube.
8. A cable bolt according to claim 7, wherein the wire strands extend spiroidally around the central elongate tube of the second segment.
9. A cable bolt according to either claim 7 or 8, wherein the end termination further includes an end plug that closes the central elongate tube of the second segment at the toe end.
10. A cable bolt according to any one of claims 3 to 9, wherein one or more of the segments has a port formed in the wall of the respective central elongate tube, through which curable product can be discharged. 11 A cable bolt according to any one of claims 1 to 10, wherein the drive head includes engagement surfaces that a tool can engage to rotate the cable bolt.
12. A cable bolt according to claim 11, wherein the drive head includes a nut that provides the engagement surfaces.
13. A cable bolt according to claim 12, wherein the drive head further includes a cylindrical body, and the plurality of threaded holes are formed at one end of the body, and the body further has an external thread that complements an internal thread on the nut.
14. A cable bolt according to any one of claims 1 to 12, wherein each of the wire strands in the first set has an externally threaded portion, and the drive head has a plurality of internally threaded holes, each threaded hole receiving a respective one of the threaded portions of the wire strands.
15. A cable bolt according to claim 3 and either claim 13 or 14, wherein the cylindrical body of the drive head includes a connector throughway that mates with the central elongate tube of the first segment such that curable product can be passed through the connector throughway and into the throughway in the central elongate tube.
16. A cable bolt according to any one of claims 1 to 15, wherein the or each first coupling member has a first coupling threaded portion that engages with a complementary second coupling threaded portion provided on a respective one of the second coupling members to couple the first and second coupling members.
17. A cable bolt according to any one of claims 1 to 16, wherein one of the first and second coupling members includes a seal to prevent curable product discharging from the interface between the coupled first and second coupling members.
18. A cable bolt according to any one of claims 1 to 17, wherein one of the second and first coupling members includes a projection that is received within a complementary shaped recess in the other of the first and second coupling members.
19. A cable bolt according to claim 18, wherein the projection includes an annular groove within which an O-ring is seated.
20. A cable bolt according to any one of claims 1 to 19, wherein the or each first coupling member includes a cylindrical body with a plurality of apertures that each receive one of the wire strands of the respective segment, and each wire strand having an end formation that resists removal of the wire strand from the respective aperture.
21. A cable bolt according to claim 20, wherein the end formation is an enlarged head.
22. A cable bolt according to any one of claims 1 to 21, wherein the first and second coupling members have complementary internal and external threads for coupling the first and second coupling members.
23. A cable bolt according to any one of claims 1 to 22, wherein each of the wire strands in the second set has an externally threaded end portion, and the second coupling member of the second segment has a plurality of internally threaded holes, and wherein each threaded hole receives a respective one of the threaded portions of the wire strands of the second set.
24. A cable bolt according to claim 2, or any one of claims 3 to 23 when dependent on claim 2, wherein in each intermediate segment, each of the wire strands in the additional set has an externally threaded end portion, and the second coupling member of the respective intermediate segment has a plurality of internally threaded holes, and wherein each threaded hole receives a respective one of the threaded portions of the wire strands of the respective additional set.
25. A cable bolt according to any one of claims 1 to 24, wherein any one or more of the segments includes a bulb or birdcage formation formed in the respective set of wire strands.
26. A cable bolt according to any one of claims 1 to 25, wherein the wire strands have an outer surface that is plain, and/or is shaped to enhance engagement with the curable product.
27. A cable bolt according to either claim 3 or 4, wherein the central elongate tube of the first segment includes a restrictor that is spaced from the drive head such that a static mixing device can be inserted into the central elongate tube, and the restrictor blocks the static mixing device from further travel along the cable bolt.
28. A method of installing a cable bolt in a hole formed in strata, the method involving: providing a cable bolt as previously described; assembling the cable bolt by coupling the first and second coupling members; and inserting the cable bolt into the hole, involving first inserting the second segment.
29. A method according to claim 28, wherein the assembling and inserting steps occur simultaneously.