AU2012209052B2

AU2012209052B2 - Friction Stabiliser and Pull Collar for Same

Info

Publication number: AU2012209052B2
Application number: AU2012209052A
Authority: AU
Inventors: Michael Franco
Original assignee: DSI Underground Australia Pty Ltd
Current assignee: DSI Underground Australia Pty Ltd
Priority date: 2011-08-02
Filing date: 2012-08-02
Publication date: 2017-09-07
Anticipated expiration: 2032-08-02
Also published as: AU2012209052A1

Abstract

-11 A friction stabiliser 10 comprises an elongated member 12 having a first end 14 in an opposite second end 16, a first stop 18 fixed to the elongated member 12 5 near the first end 14, and a second stop 20 fixed to the elongated member 12 and disposed near, but spaced from, the stop 18. 3573853_1 (GHMarm ) P87709.AU-1

Description

-1 - 2012209052 17 Aug 2017

FRICTION STABILISER AND PULL COLLAR FOR SAME

Field of the Invention 5 The present invention relates to a friction stabiliser and to a pull collar incorporated in or used with a friction stabiliser.

Background of the Invention 10 Friction stabilisers are used in the mining industry to assist in stabilising the free face of rock walls. One type of friction stabiliser is formed from high tensile steel which is coiled or rolled into a tubular member having a C shaped cross section thereby creating a continuous slot or opening along its entire length. A ring is welded to the end of the tubular member. This ring engages a stabiliser 15 plate which either bears directly against the rock face or holds a mesh against the rock face. An opposite leading end of the tubular member is usually tapered to enable easy installation into a hole drilled in the rock face.

In order to ensure compliance with safety standards it is required to test the pull 20 out strength of installed friction stabilisers. One method of doing this involves placing a sliding pull collar on a friction stabiliser during installation. The pull collar has the effect of spacing the ring a fixed distance from the rock face and enabling a pull testing machine or tool to engage the friction stabiliser between the ring and the rock face. 25

Summary of the Invention

Disclosed is a friction stabiliser comprising: an elongated member having first and second opposite ends; 30 a first stop fixed to the elongated member near the first end; a second stop fixed to the elongated member and disposed at a location near but spaced from the second stop, the second stop configured to enable engagement with a stabiliser plate. 35 In one embodiment the friction stabiliser comprises a spacer extending between and joining the first stop and the second stop. 9395168_1 (GHMatters) P87709.AU.1 -2 - 2012209052 17 Aug 2017

In one embodiment the second stop has an abutment surface which is in the configuration of a dome having an axial hole through which the member passes. 5 In one embodiment the first stop is in the form of a ring.

In one embodiment the first stop extends radially outward from an end of the spacer distant the second stop. 10 In one embodiment the first stop, the second stop and the spacer are integrally formed as a single unitary device.

In one embodiment the first stop and the second stop each comprise separate rings fixed to the elongated member. 15

Also disclosed is a pull collar for friction stabiliser or ground bolt, the pull collar comprising: an abutment face for engaging with a stabiliser plate, the abutment face being convexly curved; and, 20 a coaxial spacer extended from the abutment face, the pull collar, having an axially extending through hole to enable to pull collar, to be seated on the friction stabiliser or ground bolt.

In one embodiment the spacer is formed integrally with the abutment face. 25

In one embodiment the pull collar comprises a stop which extends in a radial outward direction from an end of the spacer distant the abutment face.

In one embodiment the stop is formed integrally with the spacer. 30

In one embodiment the stop comprises a ring.

Also disclosed is a friction stabiliser or ground bolt comprising: an elongated member provided at one end with a stop; and 35 a pull collar in accordance with the second aspect of the invention, the pull collar of being seated on and fixed to the elongated member with the spacer in abutment with the stop. 9395168_1 (GHMatters) P87709.AU.1 -3 - 2012209052 17 Aug 2017

The present invention provides a friction stabiliser or ground bolt comprising: an elongated member having first and second opposite ends, for insertion into a rock face or ground; a first stop fixed to the elongated member near the first end; 5 a second stop fixed to the elongated member and disposed at a location near but spaced from the first stop along the elongated member, the second stop configured to enable engagement with a stabiliser plate, wherein the first stop and the second stop spaced from the first stop are fixed to the elongated member to a sufficient degree to enable a pull test 10 machine or tool to: (a) grip the elongated member between the first and second stops, and (b) apply a force along an axis of the elongated member, to test a pull out strength of the friction stabiliser or ground bolt, when inserted into the rock face or ground. 15 Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which; 20 Figure 1 is a sight view of one embodiment of a friction stabiliser in accordance with a present invention;

Figure 2 is an end view of the friction stabiliser as shown in Figure 1;

Figure 3 is a side view of a second embodiment of the friction stabiliser;

Figure 4 is an end view of the friction stabiliser shown in Figure 3; 25 Figure 5a is a representation of one end of a point anchored friction stabiliser incorporating an embodiment of the present invention;

Figure 5b is a representation of the portion of the point anchored friction stabiliser shown in Figure 5a, but in a disassembled state;

Figure 6a is a representation of an opposite end of the point anchored friction 30 stabiliser shown in Figure 5a; and,

Figure 6b is a representation of the portion of the point anchored friction stabiliser shown in Figure 6a, but in a disassembled state.

Detailed Description of Preferred Embodiments 35

With reference to the accompanying drawings in particular Figures 1 and 2, a friction stabiliser 10 is disclosed which comprises an elongated member 12 9395168 1 (GHMatters) P87709.AU.1 -4- 2012209052 17 Aug 2017 having a first end 14 in an opposite second end 16, a first stop 18 fixed to the elongated member 12 near the first end 14, and a second stop 20 fixed to the elongated member 12 and disposed near, but spaced from, the stop 18. 5 The elongated member 12 is in a general from of a tube. In one embodiment the member 12 can be made by rolling a sheet of high tensile steel so that opposite edges 22 and 24 of the sheet are spaced apart to create a longitudinal slot 26 extending between the first and second ends 14 and 16. A leading portion 28 of the elongated member 12 near end 16 is tapered to progressively 10 reduce in outer diameter with the smallest diameter being at the second end 16. A further smaller slot 30 is formed in the leading portion 28 diagonally opposite the slot 26. The slot 30 opens onto the end 16.

In this embodiment both stops 18 and 20 are in the form of rings. Further, each 15 of the stops 18 and 20 is welded or otherwise fixed to the elongated member 12. The stops 18 and 20 are separated by a distance D along the length 12 elongated members 12. This distance is sufficient to enable a machine or tool to on grip or otherwise engage the elongated member 12 between the stops 18 and 20. The machine or tool is then operated to apply a force along an axis of 20 the elongated member 12 in a direction to pull the friction stabiliser 10 from a hole in which it is inserted. This enables a pull test to be conducted on a friction stabiliser 10.

When the friction stabiliser 10 is being installed, a stabiliser plate is passed onto 25 the elongated member 12 from end 16. The friction stabiliser 10 is then pushed into a hole with end 16 first. Usually the hole is formed with an inner diameter smaller than the outer diameter of the elongated member 12 causing hoop compression of the elongated member 12 resulting in a reduction in the width of the slot 26. The friction stabiliser 10 is pushed into the rock face until the stop 30 20 forces the stabiliser plate against the rock face. In the event that a reinforcing mesh is also being used, the plate will hold the mesh against the rock face. In its configuration, it will be appreciated that the first stop 18 is now spaced by at least the distance D from the stabiliser plate and the rock face. In order to complete the application of the friction stabiliser 10, grout is injected 35 from the first end 14 and allowed to set.

With a rock face stabilised using a plurality of friction stabilisers 10 one is now 9395168 1 (GHMatters) P87709.AU.1 -5 - 2012209052 17 Aug 2017 able to test any one of the friction stabilisers as the tool or machine for a applying a pulling force to the stabiliser is able to grip each stabiliser 10 between the stops 18 and 20. In practice it is envisaged the pull test will only be applied to a small percentage of the installed stabiliser 10. However 5 embodiments of the friction stabilisers enable persons conducting the pull test to select any installed stabiliser and to vary the percentage of stabilisers to be tested.

Figure 3 illustrates a second embodiment of a friction stabiliser 10’. In this 10 embodiment, features which are identical to those of the first embodiment are denoted with the same reference numbers. The features which are similar but are not identical to those of the first embodiment are denoted with the same reference numbers but with the addition of the prime symbol, (’). 15 The substantive difference between the friction stabilisers 10 and 10’ resides in the use of a pull collar 34 to perform the same function as the stops 18 and 20 of the first embodiment. The pull collar 34 comprises a first stop 18’, a second stop 20’, and a spacer 36 extending between and joining the first and second stops 18’ and 20’. The pull collar 34 is, or can be, fixed to the elongated 20 member 12 near the first end 14 with the stops 18’ and 20’ in substantially the same location as stops 18 and 20 of the first embodiment shown in Figure 1. The spacer 36 has an axial length substantially equal to the distance D shown in Figure 1. In one embodiment, the pull collar 34 is integrally formed, with the stops 18’, 20’ and spacer 36 being a single unitary device. 25

The stop 18’ extends radially outward from an end of the spacer 36 distant the second stop 20’. More particularly, the stop 18’ is in a form of a ring having a substantially square or rectangular shaped section. This is to the contrast with the stop 18 of friction stabiliser 10 in Figure 1 which is in the form of a ring 30 having a circular cross section.

The second stop 20’ is the general shape or configuration of a ring having convexly curved or tapered abutment face 38 which in use engages or can engage a stabiliser plate. The second stop 20’ may alternately be viewed or 35 considered to be in the general from of a dome provided with an axial through hole. Configuring the stop 20’ in this manner assist in maintaining engagement between the stop 20’ and the stabiliser plate particularly when the stabiliser 9395168_1 (GHMatters) P87709.AU.1 -6 - 2012209052 17 Aug 2017 plate does not lie perpendicular to the elongated member 12. In such circumstances, the entirety of an opening of the stabiliser plate can still be in contact with the face 38 of stop 20’ to provide better and uniform force application via the stabiliser plate against the rock face and/or reinforcing mesh. 5

The stop 20’ is configured to increase in outer diameter in a direction toward the stop 18’. The maximum outer diameter of stop 20’ is greater than the outer diameter of the spacer 36. Similarly, the outer diameter of stop 18’ is greater than the outer diameter of spacer 36. This difference in outer diameters 10 creates a space or region about the spacer 36 between the stops 18’ and 20’ that can be engaged by a machine or tool for conducting a pull test on the friction stabiliser 10’.

An axial through hole is formed through the pull collar 34 through which the 15 elongated member 12 passes. In manufacture, it is envisaged that the elongated member 12 and the pull collar 34 are formed separately and then fixed together for example by welding once the pull collar 34 has been placed at the require location on the elongated member 12 near end 14. 20 Figures 5a to 6b illustrate an embodiment of a point anchored friction stabiliser 10p. The point anchored friction stabiliser 10p differs for the friction stabilisers 10 and 10’ describe above by the addition of a central bolt 90 having a wedge 92 that threaded onto a screw thread formed at a distal end 91 of the bolt 90. The wedge 92 is located inside of the leading portion 28 near end 16. An 25 expandable split sleeve 94 sits over the wedge 92. A nut 95 screwed onto bolt 90 at its distal end 91 and acts as stop for the sleeve 94.

An opposite end 93 of the bolt 90 extends past end 14 of the member 12 and through a bush 96. The bush 96 locates in the end 14 and is otherwise stopped 30 from sliding along bolt 90 by a stop nut 97 threaded onto bolt 90. An end nut 98 threads onto the bolt 90 on a opposite side of the bush 96. A washer 100 is located between the end nut 98 and bush 96. The point anchored friction stabiliser 10p incorporates a pull collar 34 identical to that shown in Figures 3. 35 After insertion of the point anchored friction stabiliser 10p into a hole, applying torque to the end nut 98 caused the bolt 90 to rotate within the member 12.

This in turn causes the wedge 92 to travel toward first end 14 expanding the 9395168 1 (GHMatters) P87709.AU.1 -7 - 2012209052 17 Aug 2017 sleeve 94 which in turn expands the leading ending 28 to apply a compression force against the surrounding rock in the hole. It will appreciate that due to the provision of the bolt 90 there is no need or indeed ability to grout the point anchored friction stabiliser 10p. The pull collar 34 enables pull testing of the 5 point anchored friction stabiliser 10p.

Now that embodiments of a pull collar and friction stabiliser have been described in detail, it will be apparent to those skilled in the relevant arts the numerous modifications and variations may be made without departing from the 10 basic inventive concepts. For example, in one variation, the friction stabiliser may be formed which comprises the combination of: a modified friction stabiliser 10 having a configuration as shown in Figure 1 but with the omission of the stop 20; and, a modified pull collar, 34 which with reference to Figure 3, comprises only the spacer 36 and the second stop 20’. In such an 15 embodiment, the modified pull collar is seated on the elongated member 12 with the spacer 36 in abutment with or close proximity to the stop 18. The above embodiments are described in relation to friction stabilisers comprising an elongated member 12 having a longitudinal slot 26 extending between each opposite ends. However in the invention may be practiced in relation to other 20 forms ground/rock bolts to enable pull testing. In yet further embodiments of the present invention the elongated member 12 may be in the form of a rib bolt or cable bolt.

The above modifications and variations together with others that would be 25 obvious to person of ordinary skill in the art are deemed to be within the scope of the present invention the nature of which is to be determined form the above description and the appended claims. 9395168_1 (GHMatters) P87709.AU.1

Claims

The claims defining the invention are as follows:

1. A friction stabiliser or ground bolt comprising: an elongated member having first and second opposite ends, for 5 insertion into a rock face or ground; a first stop fixed to the elongated member near the first end; a second stop fixed to the elongated member and disposed at a location near but spaced from the first stop along the elongated member, the second stop configured to enable engagement with a stabiliser plate, 10 wherein the first stop and the second stop spaced from the first stop are fixed to the elongated member to a sufficient degree to enable a pull test machine or tool to: (a) grip the elongated member between the first and second stops, and (b) apply a force along an axis of the elongated member, to test a pull out strength of the friction stabiliser or ground bolt, when inserted into the 15 rock face or ground.
2. The friction stabiliser according to claim 1 comprising a spacer extending between and joining the first stop and the second stop.
3. The friction stabiliser according to claim 1 or 2 wherein the second stop has an abutment surface which is in the configuration of a dome having an axial hole through which the member passes.
4. The friction stabiliser according any one of claims 1 to 3 wherein the first 25 stop is in the form of a ring.
5. A friction stabiliser according to any one of claims 2 to 4 wherein the first stop extends radially outward from an end of the spacer distant the second stop. 30
6. The friction stabiliser according to any one of the claims 2 to 5 wherein the first stop, the second stop and the spacer are integrally formed as a single unitary device.
7. The friction stabiliser according to claim 1 wherein the first stop and the second stop each comprise separate rings fixed to the elongated member.
8. The friction stabiliser according to any one of the preceding claims, wherein the first stop and the second stop are welded to the elongated member.