[0001] The invention relates to a push-or locking mechanism that engages with a pre-mstalled rock anchor system to support post installation safety installations or utility cabling

[0002] In mine safety installations, typically a rock anchor array is installed inlo a rocx face by drilling holes into the rock face and installing, into each, an appropriately configured rock anchor. The rook face is supported by a faceplate that is engaged wilhthe rock anchor and installed againsl tne rock face, kept in place by a nut or the like,

[0003] Hereinafter reference to a rock anchor includes a rock bolt or a cable anchor,

[0004] Often, after the installation of the rock anchors, it is necessary tc introduce a safety installation to secure the excavation against the possibility of rock fail fron the rock face. The safety installation may be, for example, a mesh panel system wherein a plurality of mesh panels are installed against the rock face.

[0005] Also, it may oe necessary, post installation of the rock anchors, to install utility cabling.

[0006] To do either of this, typically a sscond plurality of rock anchors or the like is instated into or on the rock face. It would, however, be beneficial to use the pre- instalfed rock anchors. [0007] To use a pre-insfalled rock bolt array to support a mesh panel, it is known to use a second "mesh" washer, ln this method, an aperture of the mesh washer is passed over a projecting end of the rock boit and moved along the rock bolt to abut the pre-engaged mesh panel and sandwich the mesh panel between the faceplate and the rock wait.

[0008] The washer is kept in place, and prevented from siding off, by the friction grip between a perimeter edge of the washer aperture and the outer surface of the rock anchor. The problem is thai often this factional force is insufficient to keep the mesh washer in load support of the mesh. Moreover, in the case of a cable anchor made of steei strands of high tensile strength, the steei is too hard for the washer to grip into the material,

SUMMARY OF INVENTION

[0009] The invention provides a push-on locking device which includes a barrel which has a leading end and a traiiing end with a tapered passage which extends at least partially between the ends, a gripping means within the passage, a cylindrical aperture within the gripping means for receiving a rock anchor in use, a retaining formation in the passage between the gripping means and the trailing end which has a hole which is in register with the aperture, wherein a perimeter of the hole is adapted to frictionaiiy engage the rock anchor when the device is pushed onto the anchor from the leading end and wherein the gripping means is adapted to grip the rock anchor when the rock anchor moves relatively to the barrel.

[0010] The gripping means may include a plurality of wedge elements which are positioned in the passage in a circumferential array. [0011] Each wedge element has an inner aperture facing surface and an outer facing surface which is obliquely angled to the inner surface.

[0012] The inner surface of each wedge element may be formed with ridges, teeth or threads. The ridges or teeth may be angied towards the trailing end.

[0013] The thread may be complementary to the thread on a threaded end of 3 rock anchor.

[0014] The device may include a holding means for holding the wedge elements in the circumferential array within the passage.

[0015] The holding means may be a frame into which each of the wedge elements engage to hold them in the array.

[0016] The frame may include first and second spaced concentric ring members and a plurality of interlink elements which connect the ring members and between which arcuate windows are defined, each of which receives a respective wedge element.

[0017] Alternatively, the holding means may be a lug which is adapted to be inserted in the aperture to hold the wedge elements in the anay.

[0018] The lug may be inserted into the aperture from the trailing end of the barrel such that, when the device ss pushed onto the anchor from the leading end, the lug is pushed from the aperture at the trailing end.

[0019] The retaining formation may be a washer and the washer may include a plurality of teeth integrally formed around the perimeter of a hole of the washer, which teeth resiliently deform to accommodate passage of the rock anchor when the locking device is pushed onto the rock anchor end. The teeth may be angled towards the trailing end.

[0020] The invention extends to a post installation support assembly which includes the push-on locking device described above, a faceplate and a faceplate seat which connects the locking device to the faceplate, which includes a body which is internally adapted to receive the locking device and which is externally adapted to engage with the faceplate about a central opening of the faceplate.

[0021] The body of the faceplate seat may be adapted with a passage through or in which the locking device is received.

[0022] The body may include at an abutment formation on an exterior surface of the body against which the faceplate engages about the central opening.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is further described by way of example with reference to the accompanying drawing in which:

Figure 1 diagrammatically illustrates s rock anchor installation with a push-on fastener in accordance with the invention;

Figure 2 is a view in perspective from below of the rock anchor installation of Figure 1 ;

Figure 3 is a view in perspective of the push-on fastener of Figure 1 ;

Figure 4 is a sectioned view in perspective of the push-on fastener of Figure 1 ;

Figure 5 is an exploded view of the push-on fastener of Figure 1 and an associated faceplate; Figure 8 is an explodec view in perspective of a push-on fastener in accordance with a second embodiment of the invention; and

Figure 7 is a sectioned view in perspective of the push-on fastener of Figure 6. DESCRIPTION OF PREFERRED EMBODIMENT

[0024] in describing the context of the invention, reference is made to Figure 1 which illustrates a rock anchor system which includes a rock anchor 10 having, in the case of a bolt, a rigid elongate boil body (not shown) or, in the case of s cable anchor, a flexible elongate cable body 12. in this particular non limiting example, the rock anchor is a cable anchor.

[0025] The body 12 extends, in a rock hole 14 into which it is installed, between a first end 16 and a second projecting end 18. The anchor 10 is secured within the hole by any suitable means, for example, with a mechanical anchor or grout

[0026] A first faceplate 20 is placed in bad support, on the anchor, against a rock face 22, secured in piace with a trailing barrel and wedge assembly 24.

[0027] What has been described above would comprise a pre-installed rock anchor, with a projecting length 28 of the rock anchor projecting from the hole, past the barrel and wedge assembly 24, This projecting part provides support and structure for a post installation application which, in this example, is a safety installation comprising a mesh barrier 30 to arrest rock fall from the rock face 22, The mesh can be applied as a plurality of mesh panels or from a roll of flexible mesh.

[0028] Application of the mesh 30 to the rack face 22 wilt make use of the projecting part 26 of one or more pre-instaHed rock anchors 10. This is done firstly by placing the mesh against the wall 22, passing respective mesh apertures 32 between mesh members 34 over the projecting length 26 until the mesh contacts the first faceplate 20. Then, to secure the mesh in this position a second faceplate 36 is passed over the second end 18 of the anchor 10 and pushed against the mesh 30, A push-on fastener 40A, in accordance with a first embodiment of the invention, is pushed onto the anchor from the second end 18 and moved up the anchor until it abuts the faceplate, thereby fixing the position of the faceplate 36 against the mesh 30.

[0029] Referring to Figures 3 to 5, the push-on fastener 40A includes a barrel-like body 42 which has a truncated conical shape, which body extends in the longitudinal direction between a leading end 44 and a trailing end 46. At the trailing end, the wail 47 of the body is lipped to create a laterally projecting skirl 48 (see Figure 4). A tapered passage 50 passes through the body between its ends.

[0030] A gripping assemblage 52 is iocated in the passage 50, With particular reference to Figure 5, the gripping assemblage comprises a frame 54 and a plurality of wedge elements respectively designed 56A, 588 and 58C, The frame consists of a pair of concentric yet diametrically different rings, respectively designated 5SA and 58B, longitudinally spaaed and attached by means of obliquely angled interlinking members 59. Arcuate spaces are defined between the rings and the members in which a respective wedge element 56 is mounted,

[0031] Each wedge element 56 is arcuate in cross section and, in longitudinal section (as illustrated in Figure 4), in situ, tapers towards the leading end 44 of the fastener body 42 to complement the shape of the tapered passage 50 such that the inner walls 58 of the elements 66 define a cylindrical aperture 60. The inner walls are formed with a plurality of circumferential ridges 61 , each of which is angled towards the trailing end 46.

[0032] To complete the fastener 4GA0 a washer 62 is provided which has a hole 64, the perimeter of which is integrally formed with a plurality of teeth 66 (see Figure 5) that, like the ridges, are angled towards the trailing end.

[0033] A cap 68 is used to mount the washer 62 to the barrel 42. The cap 68 is a disc of sheet metal that ts centrally holed an inner perimeter of which is turned up to define a lip 70. It is on a rim 72 of this lip that the washer 62 Is placed. The diameter of the rim 72 complements the diameter of a down turned edge 74 of the washer such that the washer friction fits onto the rim.

[0034] To attach the washer to the barrel 42, the skirt 48 of the barrel is placed on the cap 68 over the lip 70 to present the washer to the passage 50 with the hole 64 in register with the aperture 60. To fix this position, an edge 76 of the cap is turned up and in to crimp the skirt 48 within the overturned portion. This is illustrated in Figure 4. Along with its principle function of providing a means to attach the fastener 40A to the anchor 10, the washer also functions as a base upon which the gripping assemblage 52 rests.

[0035] In use, as briefly described above, the leading end 46 of the push-on fastener 40 is presented to the second end 18 and positioned to receive the anchor body 12 through the cylindrical aperture 60. The fastener 40A is pushed along the anchor body until it abuts the faceplate 36 Passage of the anchor body through the aperture 80 is not resisted as the ridges 61 of the elements 56 and the teeth 68 of the washer 62 are angled towards the trailing end 46 of the fastener. Also enough circumferential clearance is provided between the aperture and the anchor body. However, the hole 84 of the washer is slightly smaller in circumference to the aperture and thus there is resistive ratcheted passage of the anchor body through the hole, with the teeth resiliency outwardly biasing to accommodate this passage. Once the fastener 40A comes to rest on the anchor body, against the second faceplate 36, the teeth of the washer move inwardly to grip the anchor body and to hold the fastener in this position, supporting the second faceplate 36 and the mesh 30.

[0038] How the fastener 40A engages the second faceplate 38 depends upon ihe shape and configuration of the faceplate itself, In this first example, the faceplate has a deep dome 78 leading to central mouth 80, the circumference of which is such that it allows a leading end 44 portion of the fastener to penetrate the dome 78 through the mouth. To prevent complete egress of the fastener through the mouth and to maintain load support of the faceplate 38 and the supported mesh 30 with the fastener, a load seat 84 is provided which is received over the fastener 40 to rest upon the overturned portion of the cap 68 before it is engaged with the rock anchor 10. When the fastener is fully engaged, a circumferential edge 86 of the mouth 80 abuts an outer sloping surface 86 of the load seat 84.

[0037] The invention extends to a second embodiment of the push-on fastener 408 which is illustrated in Figure 8 and 7.

[0038] In describing this embodiment, like or analogous features bear like designations. Also, description of this embodiment will be confined to the differences between this embodiment (40B) and this first embodiment (40A). [0039] The fundamental difference between second embodiment and the first embodiment is that the tastener 408, the faceplate seat 84 (which hereinafter will be referred to as a connector) and the second faceplate 36 are pre-assembled into a unitary post installation support assembly as illustrated in Figure 7.

[0040] What connects the fastener 40B to the faceplate 36 is the connector 84 which has a tubular body 92 extending between opposed first and second ends, respectively designated 94 and 96. The body defines a passageway 98 extending between the ends. The passageway 98 is divided between a narrow section 100 which opens on the second end 96 and a wider section 102 which opens on the first end 94. The sections are separated by a step 103. The narrow section 100 is complementary sized to receive, in friction fit, the fastener 40B.

[0041] An outer surface 105 of the body S2 is circumferentially ridged with a load seat 104. The ridging of the load seat is comprised of the coming together of an under and upper sloping surface, respectively designated 106 and 108,

[0042] Between the load seat 104 and the first end 94, the outer surface is recessed to provide a locating collar 1 10. The faceplate 36 is engaged with the connector 84, with the mouth 80 of the faceplate received over a lip 1 12 of the first end 94 into the locating collar 110 in snap lock engagement. The edge 86 of the mouth now abuts against the upper sloping surface 108 of the load seat 104.

[0043] The assembly 90 can be engaged with the second end 18 of the body 12 of a pre-installed rock anchor 10 as a unitary whole with the wider section 102 of the passageway 98 of the connector 64 leading. [0042] The gripping assemblage has a higher load bearing capacity to the washer 62 which is the functional component that provides initial attachment of the fastener (40A and 40B) to the anchor 10. If there is movement in the rock face 22, the forces are such that in the absence of the gripping assemblage, the grip of the washer on the anchor would fail and the fastener would come off the anchor, leaving the mesh 30 unsupported at this locality. However, the movement of the rock face has the effect of actuating the wedge etements 58 to pivotally move radially Inwardly to grip the anchor along the length of each element, aided by the ridges 81.