A cable anchor securing device

Abstract

A cable anchor securing device is provided. The device includes a tubular body defining an open- ended internal passage. The body operatively receives a wedge assembly which is inserted into the passage from the rear end and locates over a cable extending, in use, through the passage. The wedge assembly is movable between an unlocked condition in which part thereof extends from a rear end of the body with the cable capable of sliding or moving between it, and a locked condition in which the wedge assembly moves within the passage towards the front end and is biased by the sides of the passage into engagement with the cable. In the locked condition the wedge assembly prevents axial movement of the cable in the passage in the direction of, or towards, the front end.

Description

[0001] A CABLE ANCHOR SECURING DEVICE

[0002] FIELD

[0003] This disclosure relates to cable anchors for high tensile cables used in mining and related applications.

[0004] BACKGROUND

[0005] The use of cable anchor systems is widely known in the mining environment. These systems are critical for the safety of the mine workers as they secure the rock roof or hanging wall to ensure a safe working environment. The mechanical components of the cable anchor system are fitted to a cable to make up the mechanical cable anchor and to secure the cable into the rock by allowing pre-tensioning of the cable and then maintaining tension on the cable by locking it in place.

[0006] Barrel and wedge systems are well-known and widely used for the tensioning and locking cable in cable anchor systems. Such cable systems are popular due to their superior load capacity and flexibility compared to solid bar or bolt anchors. Barrel and wedge systems are known to have ‘live end’ components at the excavated tunnel / rock hole interface. A barrel is provided through which the cable runs from a front, rock facing end, to a rear end. Wedges are provided at the rear end through which the cable also runs and against which it abuts. Movement of the cable from the rear end towards the front end, or tension which causes force in the direction of the front end, is prevented by the wedges after the correct tension is applied by a cable tensioning apparatus, such as a tensioning jack, and the wedges moved in the direction of the front end and into closer proximity with the cable by the apparatus. At their fullest insertion into the barrel, the wedges form a strong friction fit over the cable and prevent its further movement.

[0007] Typical cable anchors usually require an extended section of cable protruding beyond the rock face and through the barrel and wedges into the excavated area, to allow a tensioning jack to grip and tension the cable.

[0008] To date, barrels have been provided by machining or forging a metal component as the required strength against excessive radial expansion caused by lateral loading, which leads to failure of the anchor, has not been obtainable through other construction or manufacturing methods. The present invention aims to provide a more cost-effective construction of the live end barrel.

[0009] The preceding discussion of the background is intended only to facilitate an understanding of the present disclosure. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

[0010] SUMMARY

[0011] In accordance with an aspect of the disclosure there is provided a cable anchor securing device which includes a tubular body having a front end and a rear end and which defines an internal passage which tapers inwardly from the rear end towards the front end, and which operatively receives a wedge assembly which operatively locates over a cable extending through the passage, the wedge assembly shaped to be movable between an unlocked condition in which part thereof extends from the rear end of the body and between which the cable can slide, and a locked condition in which the wedge assembly is biased by the sides of the passage into engagement with the cable and prevents axial movement of the cable in the passage in the direction from the rear end towards the front end, and characterised in that the body is provided by a coiled metal rod.

[0012] A nose may be provided at the front end, the nose having a central bore coaxial with the passage. The bore may be radially inwardly stepped adjacent the front end of the body to provide a shoulder against which an inner end of the wedge assembly abuts in the locked condition preventing further inward movement thereof in the passage.

[0013] A first sleeve may be provided over the body. The first sleeve may be made from a plastics material. The first sleeve may be moulded over the body.

[0014] A second sleeve may be provided around the first sleeve. The second sleeve may be made from a metal.

[0015] A cable tensioner interface may be provided at the rear end of the body and may include a squat cylinder having a central opening coaxial with the passage through which the cable can slide, and wherein an inner end of the cylinder abuts the body and a free end provides an abutment surface for a cable tensioner in use.

[0016] The metal rod may be made of mild steel or spring steel. The metal rod may be cross-sectionally round, square, triangular or oblong.

[0017] Cable tension indicators may be provided in the nose or cable tensioner interface.

[0018] The wedge assembly may include a plurality of wedge segments, each wedge segment having an inner surface which operatively abuts the cable, and an outer surface which operatively abuts the surface of the body defining the passage. The inner surface of the wedge segments may be textured or provided with a gripping formation. The outer surface may be substantially smooth to facilitate sliding within the passage.

[0019] Embodiments of the technology will now be described, by way of example only, with reference to the accompanying drawings.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the drawings:

[0022] Figure 1 is a side perspective partial section view of a first exemplary embodiment of a cable anchor securing device including a coiled tubular body;

[0023] Figure 2 is a side section view of the cable anchor securing device of Figure 1 ;

[0024] Figure 3 is a side perspective partial section view of the cable anchor device of Figure

[0025] 1 , including a wedge assembly in an unlocked condition;

[0026] Figure 4 is a side perspective partial section view of the cable anchor device of Figure 1 , including a wedge assembly in a locked condition;

[0027] Figure 5 is a side section view of the cable anchor device of Figure 1 including a wedge assembly in an unlocked condition;

[0028] Figure 6 is a side section view of the cable anchor device of Figure 1 including a wedge assembly in a locked condition;

[0029] Figure 7 is a front perspective view of the coiled tubular body of the cable anchor securing device of Figure 1 ; Figure 8 is a side view of the body of the cable anchor securing device of Figure 1 ;

[0030] Figure 9 is a side section view of the body of the cable anchor securing device of Figure 1 ;

[0031] Figure 10 is a front perspective view of a wedge assembly of the cable anchor securing device of Figure 3;

[0032] Figure 11 is a rear perspective view of the wedge assembly of the cable anchor securing device of Figure 3;

[0033] Figure 12 is a front view of the wedge assembly of the cable anchor securing device of Figure 3;

[0034] Figure 13 is a side view of the wedge assembly of the cable anchor securing device of Figure 3;

[0035] Figure 14 is a front perspective view of the wedge assembly of the cable anchor securing device of Figure 3 including a wedge spring;

[0036] Figure 15 is a rear perspective view of the wedge assembly of Figure 14;

[0037] Figure 16 is a side view of the wedge assembly of Figure 14;

[0038] Figure 17 is a side section view of the cable anchor securing device of Figure 3 in use with a cable tensioner apparatus;

[0039] Figure 17A is an enlarged side section view of the cable anchor securing device of Figure 17 in the unlocked condition;

[0040] Figure 17B is an enlarged side section view of the cable anchor securing device of Figure 17 in the locked condition;

[0041] Figure 18 is a side perspective partial section view of a second exemplary embodiment of a cable anchor securing device including a sleeve;

[0042] Figure 19 is a side perspective partial section view of the cable anchor securing device of Figure 18;

[0043] Figure 20 is a side perspective partial section view of the cable anchor device of Figure 18, including a wedge assembly in an unlocked condition;

[0044] Figure 21 is a side perspective partial section view of the cable anchor device of Figure 18, including a wedge assembly in a locked condition;

[0045] Figure 22 is a side section view of the cable anchor device of Figure 20;

[0046] Figure 23 is a side section view of the cable anchor device of Figure 21 ;

[0047] Figure 24 is a front perspective view of a further exemplary embodiment of a cable anchor device including a sleeve having a tapered inner surface, with the position of the tubular body shown in broken lines;

[0048] Figure 25 is a front perspective partial section view of the cable anchor device of Figure 24;

[0049] Figure 26 is a front perspective view of the sleeve of the cable anchor securing device of Figure 24;

[0050] Figure 27 is a front perspective view of the sleeve of the cable anchor securing device of Figure 24 with the position of the tubular body shown in broken lines;

[0051] Figure 28 is a side section view of a third exemplary embodiment of a cable anchor securing device including a first and a second sleeve in an unlocked condition;

[0052] Figure 29 is a side section view of the cable anchor securing device of Figure 28 in a locked condition;

[0053] Figure 30 is a side view of a further exemplary embodiment of a cable anchor securing device including a front indicator formation with the body shown in broken lines;

[0054] Figure 31 is a side view of a further exemplary embodiment of a cable anchor securing device including a rear indicator formation with the body shown in broken lines; Figure 32 is a side view of an even further exemplary embodiment of a cable anchor securing device including front and rear indicator formations with the body shown in broken lines;

[0055] Figure 33 is a side section view of the further exemplary embodiment of the cable anchor securing device of Figure 31 in use with a cable tensioner apparatus;

[0056] Figure 33A is an enlarged side section view of the cable anchor securing device of Figure 33 in the unlocked condition;

[0057] Figure 33B is an enlarged side section view of the cable anchor securing device of Figure 33 in the locked condition;

[0058] Figure 34 is a front perspective view of a further exemplary embodiment of a cable anchor securing device including a metal-pressing tubular body shown in broken lines;

[0059] Figure 35 is a front perspective partial section view of the cable anchor securing device of Figure 34;

[0060] Figure 36 is a side view of the cable anchor securing device of Figure 34, with the body shown in broken lines;

[0061] Figure 37 is a side section view of the cable anchor securing device of Figure 34;

[0062] Figure 38 is a side view of a further exemplary embodiment of a cable anchor securing device including a tubular body comprising a single metal pressing, the body shown in broken lines;

[0063] Figure 39 is a section view of the cable anchor securing device of Figure 38; and

[0064] Figure 40 is a front perspective partial section view of the cable anchor securing device of Figure 38.

[0065] DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

[0066] A cable anchor securing device is provided which includes a tubular body having a front end and a rear end. An open-ended internal passage, which extends between the front end and the rear end, is defined by the body. The body operatively receives a wedge assembly which is inserted into the passage from the rear end and locates over a cable extending, in use, through the passage.

[0067] The wedge assembly is movable between an unlocked condition in which part thereof extends from a rear end of the body with the cable capable of sliding or moving between it, and a locked condition in which the wedge assembly moves within the passage towards the front end and is biased by the sides of the passage into engagement with the cable. In the locked condition the wedge assembly prevents axial movement of the cable in the passage in the direction of, or towards, the front end.

[0068] Importantly, the body is made from a metal rod or bar which is coiled to form a tubular shape, similar to that of a coil spring. The coils are configured to provide an inward taper to the body from the rear end towards the front end. The diameter of the body, both external and internal, thus decreases from the rear end towards the front end. The body and passage thus have corresponding, generally frusto-conical shapes. The metal rod used for the body may be made from mild steel or spring steel. The metal rod may have any suitable cross-sectional shape. In particular, it may be cross-sectionally round. Alternatively, it may be cross-sectionally rectangular, square, oblong or have an elliptical or triangular shape.

[0069] The wedge assembly may include a plurality of wedge segments, each wedge segment having an inner surface which operatively abuts or engages the cable, and an outer surface which operatively abuts or engages the inner surface of the body within the internal passage. The inner surface of each wedge segment may be textured or provided with a gripping formation to encourage engagement with the cable and limit or eliminate sliding of the cable along the inner surfaces of the wedge segments. The outer surface of the wedge segments may be substantially smooth to promote sliding within the passage.

[0070] A nose having a central bore coaxial with the internal passage of the body may be provided at a front end of the body. The nose may be secured to the body by press fitting it onto the coiled metal body, or the nose may be releasably secured to the body by, for example, a detachable or clip-on formation where the nose is moulded in plastic. The bore may be radially inwardly stepped adjacent the front end of the body to provide a shoulder or step against which an inner or leading end of the wedge assembly abuts in the locked condition to prevent further inward movement thereof, that is movement in the direction of the nose, in the passage. The shoulder thus acts as a stop to prevent further movement of the wedge assembly in the direction from the rear end towards the front end. A first sleeve may be provided over the body and may be made from a plastics material. In particular, the first sleeve may be moulded over the body. This may be achieved through an “over moulding” process in which the sleeve is injection moulded in a die in which the body is held or retained during moulding, with the body in effect forming a surface of the die to prevent escape of the plastics material. Such over moulding processes are well-known to those skilled in the art.

[0071] The plastics material may be any suitable polymer such as polypropylene, nylon, or any other suitable plastics material which may provide the first sleeve and device as a whole rigidity and allow partial deformity under lateral load. A second sleeve, which may be made from a metal, may be provided around the first sleeve, to provide additional rigidity to the device to resist the lateral load of the wedge segments in use.

[0072] A cable tensioner interface may be provided at the rear end of the body. The cable tensioner interface may be secured to the body by press fitting it onto the coiled metal body, or the cable tensioner interface may again be releasably secured to the body by, for example, a clip-on formation. The cable tensioner interface may include a squat cylinder having a central opening or aperture coaxial with the internal passage of the body between which the cable can slide. An inner end of the cylinder abuts or engages with the rear end of the body while the opposite or free end of the cylinder provides an abutment surface for the cable tensioner in use.

[0073] Cable tension indicators or indicator formations may be provided in either or both of the nose and cable tensioner interface. The indicator formations may be provided as front indicator formations on the nose, and rear indicator formations on the cable tensioner interface. Both a front and a rear indicator or indicator formation may be included or incorporated in a single cable anchor securing device. The indicator formation may be provided by a compressible ring seated in a circumferential groove in the nose or cable tensioner interface respectively. Sufficient tension on the cable causes compression of the groove which in turn compresses the ring and causes it to visibly bulge or project out of the groove.

[0074] An example of a cable anchor securing device 1 is illustrated in Figures 1 to 6 and includes a tubular body 3, having a front end 5 and a rear end 7, as shown more clearly in Figures 7 to 9. Importantly, the body 3 is formed from a metal rod or bar which is coiled into a tubular shape with, in this embodiment, the coils 3a abutting each other.

[0075] The body 3 defines an internal passage 9 which tapers inwardly from the rear end 7 towards the front end 5. A wedge assembly 1 1 extends into the passage 9 from the rear end 7, as shown in Figures 3 to 6. The wedge assembly 1 1 locates over a cable 13, for example a high tensile cable, extending, in use, through the internal passage 9 between the cable 13 and an inner surface 39 of the body.

[0076] In the example embodiment 1 of Figures 1 to 9, the metal rod or bar used to form the body 3 is cross-sectionally round. In this embodiment, mild steel or spring steel is used for the construction of the body 3. It should be appreciated, however, that any suitable metal capable of providing malleability, elasticity and tensile strength to the coiled body can be used.

[0077] A process similar to that for making coil springs is used to bend and coil the metal rod into the desired shape using a suitably shaped mandrel. The process will be familiar to a person skilled in the art of making coil springs.

[0078] In this embodiment 1 , the body 3 has six coils 3a. The coil at either end 5, 7 has material removed to provide substantially flat ends 5, 7 to the body 3. It should be appreciated that the body may comprise any suitable number of coils, and these may depend on the dimensions of the rod or bar used.

[0079] The wedge assembly 1 1 is movable between an unlocked condition, as shown in Figures 3 and 5, and a locked condition, as shown in Figures 4 and 6. In the unlocked condition, a rear part of the wedge assembly 1 1 extends from the rear end of the body 7 and the cable 13 can slide freely between the wedges or wedge segments 11 a. In the locked condition, the wedge assembly 11 extends fully within the passage 9. In the locked condition, the taper of the passage 9 causes radial inward movement of the wedge segments 1 1 a, constricting them about the cable 13 and preventing movement of the cable 13 in the direction of the front end 5 of the body 3.

[0080] The wedge assembly 11 , in this embodiment of the device 1 , includes three wedge segments 1 1 a located between the rear end portion of the body 3 and the cable 13 when the device 1 is in an unlocked condition, as shown in Figures 3 and 5. In the locked condition, as shown in Figure 4 and 6, the wedge segments 1 1 a of the wedge assembly 11 locate between the front end portion of the body 3 and the cable 13.

[0081] An example embodiment of the wedge assembly 11 is shown in Figures 10 to 16. The wedge segments 11 a of the wedge assembly 1 1 include a circumferentially extending groove or recess 45 at their outermost or rear ends 23. A spring or spring clip 57 extends in the grooves 45 with the wedge segments 11 a arranged in a circular pattern to form a tube-like shape and operates to hold the wedge segments together in known fashion. Each wedge segment 11 a of the wedge assembly 11 has an inner surface 35 which operatively abuts the cable 13, and an outer surface 37 which operatively abuts an inner surface 39 of the body 3 and passage 9. The inner surface 35 of the wedge assembly 11 includes a gripping formation such as teeth, grooves, ridges, texture, rubberised texture, knurling, or the like, on substantially the entire or a part of the inner surface 35. The outer surface 37 of each wedge segment 11 a is substantially smooth to facilitate sliding along the surface of the body 3 defining the passage 9.

[0082] A nose 15, having a central bore 17 which is coaxial with the internal passage 9 of body 3, is provided at the front end 5 of the body 3. The bore 17 has an entrance 17a distal to the front end 5 of the body 3, and an exit 17b proximal to the front end 5 of the body 3, as best shown in Figures 2, 5 and 6. The nose 15 operatively locates over the cable 13 extending though the internal passage 9.

[0083] The nose 15 has a generally domed or hemispherical shape. The rounded surface provides the front end 15a and is located distal to the front end 5 of the body 3, while the flat rear 15b is secured to the front end 5 of the body 3 by press fitting the rear 15b to the coiled metal body 3, or by releasably securing the nose 15 to the body 3 where the nose is moulded in plastic, for example using a detachable or clip-on formation.

[0084] The bore 17, in this embodiment 1 , is radially inwardly stepped adjacent the front end 5 of the body 3 to provide a shoulder 19 or step against which the inner or leading end 21 of the wedge assembly 1 1 abuts in the locked condition, as best shown in Figures 4 and 6. This provides a stop which prevents further inward movement of the wedge assembly 1 1 in the passage 9, that is movement of the wedge assembly 1 1 towards the front end 5 of the body 3. This arrangement operatively prevents the wedge segments 11 a from further compressing about the cable 13 creating a pinching point at the inner end 21 of the wedge segments 1 1 a and prevents a stress point on the cable 13 which can cause premature cable failure.

[0085] The nose 15 is made from mild steel in this embodiment, however other suitable materials may also be used.

[0086] A cable tensioner interface 31 is provided at the rear end 7 of the body 3. The cable tensioner interface 31 is provided by a squat cylinder having a central opening 33 coaxial with the passage 9 through which the cable 13 can slide. The cable tensioner interface 31 thus has a washer-like shape in this embodiment 1. As best shown in Figure 5, the front 31 a of the cable tensioner interface or front cable tensioner interface surface is secured by press fitting or through a releasable formation, such as a clip-on formation, it to the rear end 7 of the body 3, and the opposite rear 31 b of the cable tensioner interface or rear cable tensioner interface surface provides an abutment surface for a cable tensioner or cable tensioner apparatus (not shown). The abutment surface 31 b interfaces, in use, with, for example, a hydraulic tensioner or tensioning apparatus that is used to pull the cable 13 through the device 1 and in so doing apply tension to it while keeping the device 1 in position.

[0087] In use, as shown in Figures 17 to 17B, a cable 13 having a rock anchor 61 at its end 63 is inserted, anchor first, into a hole 65 drilled into a rock body or wall 67. The anchor 61 is of a conventional construction, for example a taper barrel and expansion shell construction, and does not form part of the invention. A domed washer or base plate 69 is inserted, convex side out, in a conventional fashion, over the free end 71 of the cable 13, that is the end extending from the hole 65. A cable anchor securing device 1 is then inserted, nose 15 first, over the free end 71 of the cable 13 until the nose 15 abuts the domed washer 69. The cable 13 is urged or pushed into the device 1 first through the bore 17 of the nose 15, then through the front end 5 of the body 3, through the passage 9 between the wedge segments 11 a of the wedge assembly 1 1 , to then exits the device 1 at the rear end 7 of the body 3 through the central opening 33 of the cable tensioner interface 31 . A conventional cable tensioner or cable tensioning apparatus 53 is then attached to the free end 71 of the cable 13 and the apparatus 53 moved until it engages the abutment surface or rear surface 31 b of the cable tensioner interface 31 . Operation of the cable tensioner 53 causes it to pull the cable 13 in the direction of the rear end 7 of the device 1. Movement of the cable 13 towards the rear end of the device 1 is resisted by the rock anchor 61 attached to the end 63 of the cable 13 in the hole 65. This results in tension in the cable 13. Once a predetermined tension is achieved in the cable 13, the wedge segments 1 1 a of the wedge assembly 11 are pushed inwards, in known fashion, into the internal passage 9 by a piston in the cable tensioning apparatus 53. The wedge segments 1 1 a are thus moved from the unlocked condition, shown in Figures 3, 5 and 17A, to the locked condition, shown in Figures 4, 6 and 17B. In this manner the cable 13 is secured under tension in the hole 65.

[0088] Once the tension load or desired load is reached and the cable anchor securing device is correctly installed and tensioned, the cable tensioner is released from the cable and removed.

[0089] The cable anchor securing device 1 is capable of securing a cable anchor at a load of up to 25 tons. The device may provide between 80% and 95% Ultimate Tensile Strength (UTS) of the cable. For example, when using a 15.24mm cable the UTS required is 25 tons, therefore the device 1 may achieve 23.75 tons. Cable failure may occur in two ways primarily, shear wherein a cut or point load on the surface when the cable is under tension causes failure, and tensile wherein the cable breaks purely because of material strength failure. The most common cable failure is shear on one or two of the cable strands due to the wedges or wedge segments applying point load on to the cable or pinching at the cable.

[0090] As described above, the shoulder 19 in the bore 17 provides a stop which limits inward movement of the wedge assembly 1 1 in the passage 9 and operatively prevents the wedge segments 11 a from further compressing about the cable 13 and creating a pinching point at the inner end 21 of the wedge segments 11 a. This prevents a stress point on the cable 13 which can cause premature cable failure.

[0091] When using a tapered body without the step or shoulder to prevent over travelling of the wedge assembly the wedge segments may pinch the cable and cause cable failure sooner and at lower loads. The inclusion of the stop prevents the wedge segments from moving deeper into the taper or towards the front end of the device which in turn has the advantage of creating a larger pinch force about the cable along the length of the wedge segments and securing the cable. This provides a further important advantage of the device 1 .

[0092] The operation described above is known in the art and will be apparent to the skilled person. It is the construction of the body that forms the advantage over known cable anchor securing devices. It is surprising that a coiled body as described above has sufficient strength to function at loads of up to 25 tons. The body, however, offers substantial savings in manufacturing time and cost over devices known in the art.

[0093] It will be appreciated that many other embodiments of a cable anchor securing device exist. The coiled metal rod of the tubular body 3 may include a wire and may have any suitable cross- sectional shape. It may, for example, be cross-sectionally rectangular or square, or triangular, or any other suitable shape.

[0094] The coiled metal rod may be a cylindrical stack of rings. The stack of rings may be welded together. Also, the diameter of the rod may vary along its length so that the outer diameter remains substantially constant while the diameter of the passage decreases or tapers from the rear end towards the front end.

[0095] The cable tensioner interface may be provided by a metal interface ring or washer capable of carrying and distributing the load generated by the tensioner apparatus.

[0096] Any suitable method of securing the body to the nose and interface can be used. Also, the ends of the tubular body or metal coil may not be fixed at the front and rear ends thereby enabling or allowing the body to expand as the wedge segments move within the internal passage.

[0097] A further embodiment 101 of a cable anchor securing device 101 is shown in Figures 18 to 23. This embodiment shares features with that described with reference to Figures 1 to 17B and these are indicated by similar numerals in the drawings.

[0098] The device 101 has a body 103, wedge assembly 11 1 , nose 1 15 and cable tensioner interface 131 which are the same as those described with reference to Figures 1 to 17B.

[0099] In this embodiment, however, a first sleeve 125 is provided over the body 103. The sleeve 125 is made from a plastics material and is internally shaped to conform, or provide a complementary fit, to the outer surface 141 of the body 103. The sleeve 125 has a front end 127 and a rear end 129, as best shown in Figures 18 to 23, which correspond to the front end 105 and rear end 107 of the body 103. The front end 127 of the sleeve 125 abuts the rear end 115b of the nose 115.

[0100] The sleeve 125 is, in this embodiment, moulded over the body 103 using an over moulding process or an injection moulding process. The body 3 is thus encapsulated along its length by the sleeve 125. The plastics material is polycarbonate but any suitable polymer such as polypropylene, or nylon may be used. A glass fill may be added to the plastics material to add additional rigidity to the sleeve 125.

[0101] The sleeve 125 provides additional strength to the device 101 to resist lateral load when the wedge assembly 1 11 moves from the unlocked condition, shown in Figures 20 and 22, to the locked condition, shown in Figures 21 and 23. The sleeve 125 further provides corrosion protection or resistance to the body 103. Such corrosion or degradation may be caused by chemical or electrochemical reactions with its environment, particularly involving moisture, air, chemicals, or other corrosive agents.

[0102] As shown in Figures 24 to 27, in some embodiments of the device 201 , the outer surface of the sleeve 225 may be tapered inwardly partway along its length between the rear end 229 and the front end 227. The taper assists in decreasing the volume or amount of plastics material required for the sleeve 225. This embodiment shares features with that described with reference to Figures 18 to 23 and like numerals are used to indicate like features for convenience. The thickness of the first sleeve varies between 3mm and 8mm.

[0103] The cable tensioner interface functions to prevent the cable tensioner nose cone from pushing directly on the plastic first sleeve of the device and may assist in distributing forces over a larger area.

[0104] A further embodiment of a cable anchor securing device 301 is shown in Figures 28 and 29. The device 301 shares the features of the embodiment shown in Figures 17 to 22. In this embodiment, a second sleeve 343 is provided over the first sleeve 325. The second sleeve 343 is made from a metal, such as stainless steel or mild steel, and increases the strength and add impact resistance of the device 301 .

[0105] As illustrated, in this embodiment 301 , the second sleeve 343 extends between the front end of the first sleeve 327 and the cable tensioner interface 331 .

[0106] In this embodiment, the second sleeve has a thickness of about 1 ,6mm to 3mm. In preferred embodiments, the thickness of the second sleeve is about 2mm.

[0107] The first sleeve may also be recessed partway along its length to provide a shoulder at the front end and at the rear end between which the second sleeve can locate.

[0108] Further embodiments of a cable anchor securing device 401 ,501 ,601 are shown in Figures 30 to 33B. The devices in these embodiments are substantially as described with reference to Figures 1 to 29 but further include cable tension indicators 449, 551 , 649, 651 which provide an indication that a desired load or predefined preload or tension load has been reached on the cable or cable anchor securing device.

[0109] Such indicators may be provided at or extend from the nose 415 or cable tensioner interface 531 . Figure 30 shows an embodiment of the cable anchor securing device 401 including an elongated nose 415 which includes a front indicator or indicator formation 449. Figures 31 and 33, 33A and 33B show an embodiment of the cable anchor securing device 501 including a cable tensioner interface 531 provided by a squat cylinder and comprising a rear indicator or indicator formation 551 . Figure 32 shows an embodiment of the cable anchor securing device 601 including both a front indicator or indicator formation 649 provided at a nose 615 and a rear indicator or indicator formation 651 provided at a cable tensioner interface 631 . The indicators or indicator formations may be provided as, for example, a deformable insert secured in a recess such as a hole or groove. Tension applied through the device causes the recess to collapse and so apply pressure to the deformable insert. This results in the insert being partially extruded or pushed out of the recess and becoming more visible. In so doing, a visual indication of the desired tension having been reached is provided. The deformable insert may be a rubber insert and may be provided as a colour insert different to the colour of the device.

[0110] Figure 33 shows the cable anchor securing device 501 in use and engaged with a cable tensioner apparatus 553 which tensions the cable 513 and device 501 . Before the tension load is reached the indicator 551 has not activated, as shown in Figure 33A. Whereas, as shown in Figure 33B, after the tension load is reached the indicator 551 is activated.

[0111] In use, in the embodiment 501 shown in Figures 33 to 33B, once a desired load or predefined preload or tension load has been reached on the cable 513 or cable anchor securing device 501 , the indicator 551 activates by deforming and the rubber material forming part of the indicator 551 pushes out of the recess and becomes more visible. This provides a visual indication that the desired tension has been achieved and remains visible during the life of the device.

[0112] A further cable anchor securing device 701 is shown in Figures 34 to 37 and has a tubular body 703 provided by, in this embodiment, three, complementarily shaped metal pressings 703a nested one within the other. Any suitable number of pressings may be used to form the body, including a single pressing as shown in the embodiment of Figures 38 to 40.

[0113] Each pressing 703a has a generally frusto-conical shape and is inwardly lipped 719 at the front, narrower end 705. The body 703 defines an internal passage 709 which tapers inwardly from a rear, wider end 707 toward the front end 705.

[0114] In this embodiment the lips 719 of the pressings 703a act as a stop for the wedge segments to prevent further inward movement into the passage which may result in a cable being pinched as described with reference to the previous embodiments.

[0115] The pressings 703a are produced by a multi-stage metal pressing process in which a series of dies are used to progressively from the final shape from a metal plate. Such a process will be apparent to the person skilled in the art of metal pressing.

[0116] Each pressing 703a is made from mild steel and has a thickness of 1 ,2mm. It will be appreciated that any suitable metal used and that the thickness of the material used may determine the number of pressings required to make the body.

[0117] An advantage of using a metal pressing for the body is fast, relatively inexpensive and high- volume production and considerably less material waste than conventional methods. Any suitable number of pressings may be used to form the body, including a single pressing.

[0118] The device 701 , 801 shown in Figures 34 to 40 has a body 703, 803, wedge 711 , 81 1 , nose 715, 815 and cable tensioner interface 731 , 831 which are substantially similar to those described with reference to Figures 1 to 27 and are described below.

[0119] A wedge assembly 711 extends into the passage 709 from the rear end 707, as shown in Figures 34 to 39. The wedge assembly 71 1 locates over a cable 713, extending, in use, through the internal passage 709 between the cable 713 and an inner surface 739 of the body.

[0120] As with the previously described embodiments, the wedge assembly 71 1 is movable between an unlocked condition, as shown in Figures 34 to 39, and a locked condition (not shown). In the unlocked condition, a rear part of the wedge assembly 711 extends from the rear end of the body 707 and the cable 713 can slide freely between the wedge segments 711 a. In the locked condition, the wedge assembly 71 1 extends fully within the passage 709. In the locked condition, the taper of the passage 709 causes radial inward movement of the wedge segments 71 1 a, constricting them about the cable 713 and preventing movement of the cable 713 in the direction of the front end 705.

[0121] The wedge assembly 71 1 , in this embodiment of the device 701 , again includes three wedge segments 711 a located between the rear end portion of the body 703 and the cable 713 when the device 701 is in an unlocked condition. In the locked condition the wedge segments 71 1 a of the wedge assembly 71 1 locate between the front end portion of the body 703 and the cable 713. It should be appreciated, however, that any suitable number of wedge segments may be used.

[0122] The wedge segments 71 1 a of the wedge assembly 711 include a circumferentially extending groove or recess 745 at their outermost or rear ends 723. A spring or spring clip (not shown) extends in the grooves 745 with the wedge segments 711 a arranged in a circular pattern to form a tube-like shape. The wedge spring or spring clip operates to hold the wedge segments together in known fashion.

[0123] As shown in Figure 35, each wedge segment 71 1 a of the wedge assembly 71 1 has an inner surface 735 which operatively abuts the cable 713, and an outer surface 737 which operatively abuts an inner surface 739 of the body 703 and the passage 709. As with the previously described wedge assemblies, the inner surface 735 of the wedge assembly 711 includes a gripping formation such as teeth, grooves, ridges, texture, rubberised texture, knurling, or the like, on substantially the entire or a part of the inner surface 735. The outer surface 737 of each wedge segment is substantially smooth to facilitate sliding along the surface of the body 703 defining the passage 709.

[0124] As described above, in this embodiment the lips 719 of the pressings 703a act as a stop for the wedge segments 71 1 a to prevent further inward movement of the wedge assembly 711 into the passage 709, that is movement of the wedge assembly 71 1 towards the front end 705 of the body 703, which may result in the cable 713 being pinched as described with reference to the previous embodiments.

[0125] A nose 715, having a central bore 717 which is coaxial with the internal passage 709 of body 703, is provided at the front end 705 of the body 703. The bore 717 has an entrance 717a distal to the front end 705 of the body 703, and an exit 717b proximal to the front end 705 of the body 703, as best shown in Figures 35 and 37. The nose 715 operatively locates over the cable 713 extending through the internal passage 709.

[0126] The nose 715 has a generally domed or hemispherical shape. The rounded surface provides the front end and is located distal to the front end 705 of the body 703, while the flat rear is secured to the front end 705 of the body 703 by press fitting the nose 715 onto the, for example, coiled metal body, or by releasably securing the nose, for example where it is moulded in plastic, to the body through a detachable formation such as a clip-on formation.

[0127] Similar to the previous embodiments described, the nose 715 is made from mild steel in this embodiment, however any other suitable materials may also be used.

[0128] A cable tensioner interface 731 , with like features to the cable tensioner interface of the previously described embodiments in Figures 1 to 29, is provided at the rear end 707 of the body 703. The cable tensioner interface 731 is provided by a squat cylinder, with a washer-like shape in this embodiment 701 , having a central opening 733 coaxial with the passage 709 through which the cable 713 can slide. As best shown in Figure 37, a front of the cable tensioner interface or front cable tensioner interface surface 731 a is secured through a press fitting or a detachable securing means such as a clip-on formation to the rear end 707 of the body 703, and the opposite rear of the cable tensioner interface or rear cable tensioner interface surface 731 b provides an abutment surface for a cable tensioner or cable tensioner apparatus (not shown). The abutment surface 731 b interfaces, in use, with, for example, a hydraulic tensioner or tensioning apparatus that is used to pull the cable 713 through the device 701 while keeping the device 701 in position.

[0129] A first sleeve 725 is provided over the body 703. As with the previous embodiments, the sleeve 725 is made from a plastics material and is internally shaped to conform, or provide a complementary fit, to the outer surface 741 of the body 703. The sleeve 725 is, in this embodiment, moulded over the body 703 using an over moulding process or an injection moulding process to encapsulate the body 703 along its length. The plastics material is polycarbonate but any suitable polymer such as polypropylene, or nylon may be used. Similar to the previously described embodiments, a glass fill may be added to the plastics material to add additional rigidity to the sleeve 725.

[0130] The sleeve 725 has a front end 727 and a rear end 729, as best shown in Figure 35, which correspond to the front end 705 and rear end 707 of the body 703. The front end 727 of the sleeve 725 abuts the rear end 715b of the nose 715.

[0131] The sleeve 725 provides additional strength to the device 701 to resist lateral load with the wedge assembly 71 1 in the locked condition under load. The sleeve 725 further provides corrosion protection or resistance to the body 703.

[0132] The outer surface of the sleeve 725 is tapered inwardly partway along its length between the rear end 729 and the front end 727. The taper assists in decreasing the volume or amount of plastics material required for the sleeve 725. The thickness of the first sleeve varies between 3mm and 8mm.

[0133] In other embodiments (not shown), a second sleeve, extending between rear end of the nose and the cable tensioner interface, may be provided over the first sleeve. The second sleeve is made from a metal, such as stainless steel or mild steel, and increases the strength and adds impact resistance to the device. The first sleeve may again be recessed partway along its length to provide a shoulder at the front end and at the rear end between which the second sleeve can locate.

[0134] The devices described may be used in the underground mining sector but may also be used in ground stabilization or surface mining operations or applications, as well as in the construction sector for post-tensioned concrete slabs or any other tensioning used in cast concrete applications. The advantages provided by the cable anchor securing device include simplified mass production of the components of the device thereby reducing the manufacturing or production time and costs of the various components. The combination of the tubular metal body with a plastics first sleeve, and optional metal second sleeve, adds additional strength to the tubular body component. Increased blast resistance may be provided when the combination of the metal body, for example made of mild steel, and a plastics sleeve is used.

[0135] Also, encapsulation of the metal body with the plastics material of the sleeve may result in there being less appeal for theft of the device for sale as scrap metal as the removal of the plastics material will be difficult and costly. It may thus not be worthwhile selling the device as scrap metal.

[0136] Both plastic injection moulding and wire coiling processes required for manufacturing the device have very little waste of material making the production of the device more cost effective and reduces the environmental impact.

[0137] The modular design of the cable anchor securing device allows for a number of different configurations of the nose and cable tensioner interface. The advantage being that this design minimises the amount of complete product or the entire cable anchor system required to be held in stock by a supplier or manufacturer but instead separate components can be held in stock and quickly assembled to customer-specific configurations. Furthermore, the encapsulation of the body into a plastic material lessens corrosion over time and has the advantage of a longer storage life with minimal risk of theft.

[0138] The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the technology to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

[0139] The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the present disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope of any accompanying claims. Finally, throughout the specification and any accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

CLAIMS:1 . A cable anchor securing device which includes a tubular body having a front end and a rear end and which defines an internal passage which tapers inwardly from the rear end towards the front end, and which operatively receives a wedge assembly which locates over a cable extending through the passage, the wedge assembly shaped to be movable between an unlocked condition in which part thereof extends from the rear end of the body and between which the cable can slide, and a locked condition in which the wedge assembly is biased by the sides of the passage into engagement with the cable and prevents axial movement of the cable in the passage in the direction of the front end, and characterised in that the body is provided by a coiled metal rod.

2. The cable anchor securing device as claimed in claim 1 , in which a nose is provided at the front end, the nose having a central bore coaxial with the passage.

3. The cable anchor securing device as claimed in claim 1 or claim 2, in which the bore is radially inwardly stepped adjacent the rear end of the body to provide a shoulder against which an inner end of the wedge assembly abuts in the locked condition preventing further inward movement thereof in the passage.

4. The cable anchor securing device as claimed in any one of claims 1 to 3, in which a first sleeve is provided over the body.

5. The cable anchor securing device as claimed in claim 4, in which in which the first sleeve is made from a plastics material.

6. The cable anchor securing device as claimed in claim 4 or claim 5, in which the first sleeve is moulded over the body.

7. The cable anchor securing device as claimed in any one of claims 4 to 6, in which a second sleeve is provided around the first sleeve.

8. The cable anchor securing device as claimed in claim 7, in which the second sleeve is made from a metal.

8. The cable anchor securing device as claimed in any one of the preceding claims, in which a cable tensioner interface is provided at the rear end of the body and includes a squat cylinder having a central opening coaxial with the passage through which the cable can slide, and wherein an inner end of the cylinder abuts the body and a free end and provides an abutment surface for a cable tensioner in use.

9. The cable anchor securing device as claimed in any one of the preceding claims, in which the metal rod is made of mild steel.

10. The cable anchor securing device as claimed in any one of claims 1 to 8, in which the metal rod is made of spring steel.1 1 . The cable anchor securing device as claimed in any one of the preceding claims, in which the metal rod is cross-sectionally round.

12. The cable anchor securing devices as claimed in any one of the preceding claims, in which tension indicators are provided in the nose or cable tensioner interface.

13. The cable anchor securing device as claimed in one of the preceding claims, in which the wedge assembly includes a plurality of wedge segments, each wedge segment having an inner surface which operatively abuts the cable, and an outer surface which operatively abuts the surface of the body defining the passage.

14. The cable anchor securing device as claimed in claim 13, in which the inner surface of the wedge segments is textured or provided with a gripping formation.

15. The cable anchor securing device as claimed in claim 13 or claim 14, in which the outer surface is substantially smooth to facilitate sliding within the passage.

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