AU2005203348A1

AU2005203348A1 - Mesh Sheeting

Info

Publication number: AU2005203348A1
Application number: AU2005203348A
Authority: AU
Inventors: Trevor Sivewright
Original assignee: SOUTHERN WIRE Pty Ltd
Current assignee: SOUTHERN WIRE Pty Ltd
Priority date: 2004-07-29
Filing date: 2005-07-29
Publication date: 2006-02-16

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Actual Inventor Address for service is: Southern Wire Pty Ltd Trevor Sivewright WRAY ASSOCIATES Level 4, The Quadrant 1 William Street Perth, WA 6000 Attorney code: WR Invention Title: Mesh Sheeting The following statement is a full description of this invention, including the best method of performing it known to me:- -2- SMesh Sheeting Field of the Invention The present invention relates to a mesh sheeting. More particularly, the mesh sheeting of the present invention is in one form intended for use in mining applications requiring surface support.

SBackground Art Presently, welded mesh products are utilised in underground mining applications in which it is required to prevent rock falls, for example underground passages or drives. A typical installation involves placing a series of sheets of welded steel mesh arranged to overlap at their edges, against the walls and roof of a drive using the lifting frame of a rock-bolting machine, rock-bolting the sheets into position and spraying thereover with "shotcrete", a sprayable concrete product.

The above described process requires the mesh sheet to be relatively stiff. This stiffness allows the sheet to retain its shape on the lifting frame during lifting and rock-bolting. However, this stiffness and the subsequent lack of flexibility results in increased likelihood of failure of the sheet in the event of rock falls or the collapse of a roof or wall, especially at the welds of the sheet. Further, the sheets are too heavy to be installed by hand and require expensive equipment to support them during installation.

The mesh sheeting of the present invention has as one object thereof to overcome the above problems associated with the prior art or at least provide an effective alternative thereto.

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

It is to be understood that reference to mesh sheeting or the like is intended to be interpreted inclusively and to encompass discrete mesh panels or sheets as well as rolls of mesh sheeting.

Disclosure of the Invention 00 M 5 In accordance with the present invention there is provided a mesh sheeting for supporting a surface, the mesh sheeting including a plurality of line wires and a plurality of stay wires extending substantially transversely across the plurality of line wires to provide a plurality of intersections, the line wire and the stay wire being fastened together at each intersection, and at least one of the line wires and/or the stay wires being provided with a tension crimp adapted to absorb loads.

The mesh sheeting of the present invention has particular application in underground mining drives and tunnels, where support of the roof and wall surfaces is required to reduce the likelihood of their collapse and reduce the likelihood of dislodged rocks and stones falling onto miners and machinery below.

Preferably, the intersecting line wire and stay wire are fastened by means of a knot. Preferably, the knot is provided in the form of a separate piece of wire, wrapped around the intersection.

The use of knots prepared from a separate piece of wire is believed to increase the strength of each intersection and the overall strength of the mesh sheeting compared to mesh sheeting in which the knots are prepared from the stay wires requiring the stay wires be cut and tied at every line wire intersection. Further, the use of knots prepared from a separate piece of wire also avoids the need to weld the wire, those welds being particularly unreliable if a high carbon wire is utilised.

Preferably, the tension crimp is provided in the lines wires. More preferably, each line wire is provided with a plurality of tension crimps. More preferably still, each line wire is provided with a tension crimp between every intersection.

-4- Preferably, the line wires are substantially parallel to each other and the stay wires are substantially parallel to each other.

c-I In one form of the invention, the line wires and the stay wires intersect at right angles.

00 M 5 Preferably, each line wire and each stay wire is provided with two free ends.

Preferably the line wires are secured at their free ends to the stay wires and (Ni preferably the stay wires are secured at their free ends to the line wires.

Where a free end of a line wire is secured to a stay wire, preferably the line wire is wrapped around the stay wire at least once. More preferably, the line wire is wrapped around the stay wire more than once. Where the free end of the line wire is wrapped around the stay wire at least once and preferably more than once, the line wire may also be wrapped around the line wire at least once and preferably, more than once.

Where a free end of a line wire is secured to a stay wire, a knot may be provided.

Preferably, the knot is provided in the form of a separate piece of wire.

Conveniently, the knot may be provided in the same form as the knot provided at the intersection of a stay wire and a line wire.

Where a free end of a stay wire is secured to a line wire, preferably the stay wire is wrapped around the line wire at least once. More preferably, the stay wire is wrapped around the line wire more than once. Where the free end of the stay wire is wrapped around the line wire at least once and preferably more than once, the stay wire may also be wrapped around the stay wire at least once and preferably, more than once.

Where a free end of a stay wire is secured to a line wire, a knot may be provided.

Preferably, the knot is provided in the form of a separate piece of wire.

QThe mesh apertures may be provided as squares, rectangles or rhomboids, or a

(N

Scombination thereof. Where the mesh apertures are square, the apertures are preferably about 75 mm -100 mm wide.

(-i In one form of the invention, the line wires and the stay wires may be made from (3O 0 5 the same type of wire. In an alternate form of the invention, the stay wires may be Cc, Cc thinner than the line wires.

Preferably, the line wires and the stay wires are between about 2 mm 4 mm in diameter. Still preferably, the line wires and stay wires are between about 3.55 and 3.60 mm.

In accordance with the present invention there is further provided a method for supporting a surface, the method comprising the steps of: a. preparing a mesh sheeting by overlaying a plurality of line wires and stay wires to provide a plurality of intersections, the line wires and the stay wires being fastened together at each intersection, at least one of the plurality of line wires and a plurality of stay wires being provided with a tension crimp adapted to absorb loads; b. positioning the mesh sheeting against a surface to be supported; c. fastening the mesh sheeting to the surface; and d. coating the surface with a sprayable binding product.

Brief Description of the Drawings The present invention will now be described, by way of example only, with reference to five embodiments thereof and the accompanying drawing, in which:- Figure 1 is a partial plan view of a mesh sheeting in accordance with a first embodiment the present invention; -6- Figure 2 is a partial plan view of a mesh sheeting in accordance with a second embodiment the present invention; ci Figure 3 is a partial plan view of a mesh sheeting in accordance with a third embodiment the present invention; 00 M 5 Figure 4 is a partial plan view of a mesh sheeting in accordance with a fourth embodiment the present invention; and (Ni Figure 5 is a partial plan view of a mesh sheeting in accordance with a fifth embodiment the present invention; Best Mode(s) for Carrying Out the Invention In Figure 1 there is shown a portion of a mesh sheeting 10 in accordance with a first embodiment of the present invention. The mesh sheeting 10 includes a plurality of line wires 12 and a plurality of cross or stay wires 14 extending transversely across the plurality of line wires 12 to provide a plurality of intersections 16. The line wire 12 and the stay wire 14 are fastened together at each intersection 16 by a knot 18. The knot 18 is prepared from a separate piece of wire 20, wrapped around the intersection 16.

The use of knots prepared from separate pieces of wire is believed to provide greater holding strength than 'hinge joint knots' in which the knot is formed from either the stay wire or the line wire.

Each line wire 12 is provided with a plurality of tension crimps 22, a tension crimp 22 being provided between each intersection 16. The tension crimps 22 are adapted to absorb loads created by rock falls or the collapse of a surface (not shown), against which the mesh sheeting 10 may be positioned in use.

It will be appreciated that the stay wires 14 will be wrapped around the end line wires 24 in the completed mesh sheeting. This is achieved by means of twisting the stay wire 14 about the end line wire 24 in a known manner.

-7- The line wires 12 are substantially parallel to each other and equally spaced from each other. The stay wires 14 are substantially parallel to each other and equally spaced from each other. The line wires 12 and the stay wires 14 intersect at right 1 angles thereby defining square apertures 26, about 100 mm wide.

0 5 The use of high tensile wire enables the wires of thinner diameter than those of C the prior art to be used without compromising sheet strength. The line wires and

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the stay wires are between about 2 mm 4 mm in diameter. The applicant has (Ni Sdetermined that a high tensile strength wire of about 3.55 mm diameter, providing N a tensile strength of about 12 kN is sufficient. This can be compared with a low tensile wire of 5.60 mm diameter that provides a tensile strength of about 12.6 kN.

In use as a surface support, the mesh sheeting 10 may be provided in a roll 50 m long and 2.5 m wide. Mesh sheeting of this dimension will include 25 line wires 12, 100 mm apart. At least a portion of the mesh sheeting is unrolled and positioned against the surface to be supported (not shown). Rock bolting is then conducted in known manner to positively locate the mesh sheeting 10 against the surface. Shotcrete or its equivalent is then applied, by spraying, over the laminated mesh sheets. The whole process may be completed by hand without the need for expensive machinery to hold the mesh sheeting against the surface.

The mesh sheeting is more easily moulded to conform to the contours of the surface due to its flexible nature when compared with prior art mesh. This is expected to reduce the volume of Shotcrete required, thereby speeding up the process and reducing costs.

It is envisaged that a combination of wires may be used in the mesh sheeting of the present invention. For example, the line wires may be provided in the form of high tensile wire whilst the stay wires are provided in the form of a non-high tensile wire, such as a medium tensile wire. In such form of the present invention it is envisaged that in use the stay wires will be positioned against or immediately adjacent to the surface to be stabilised.

-8- In Figures 2 to 5, there is shown portions of a mesh sheeting 10 in accordance with four further embodiments of the present invention. The embodiments depicted in Figures 2 to 5 differ only from the embodiment shown in Figure 1 by N the manner in which the ends of the stay wires and the ends of the line wires are secured.

o00 Mq In Figure 2, a free end 28 of the stay wire 14 is bent and looped back over the Sknot 18 and wound over the same stay wire 14. In Figure 3, a free end 28 of the stay wire 14 is bent and looped back over the knot 18 and wound over the N adjacent line wire 12. In Figure 4, a free end 28 of the line wire 12 is bent and looped back over the knot 18 and wound over the same line wire 12. In Figure a free end 28 of the line wire 12 is bent and looped back over the knot 18 and wound over the adjacent stay wire 18.

It is envisaged that the manner of securing the ends of the line wires and the stay wires as depicted in Figures 2 to 5 reduces the risk of the line wires 12 pulling free of the stay wires 14 or any of the stay wires 14 pulling free of the line wires 12.

Modifications and variations such as would be apparent to a skilled addresses are considered to fall within the scope of the present invention.

Claims

1. A mesh sheeting for supporting a surface, the mesh sheeting including a plurality of line wires and a plurality of stay wires extending substantially 0 transversely across the plurality of line wires to provide a plurality of intersections, the line wire and the stay wire being fastened together at each intersection, and at least one of the line wires and/or the stay wires being N provided with a tension crimp adapted to absorb loads.

2. A mesh sheeting for supporting a surface according to claim 1, wherein the intersecting line wire and stay wire are fastened by means of a knot.

3. A mesh sheeting for supporting a surface according to claim 2, wherein the knot is provided in the form of a separate piece of wire, wrapped around the intersection.

4. A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein the tension crimp is provided in the lines wires.

5. A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein each line wire is provided with a plurality of tension crimps.

6. A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein each line wire is provided with a tension crimp between every intersection.

7. A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein the line wires are substantially parallel to each other and the stay wires are substantially parallel to each other.

8. A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein the intersection of adjacent lines wires with adjacent stay wires defines mesh apertures, the mesh apertures being provided in the Sform of squares, rectangles or rhomboids, or a combination thereof. C 9. A mesh sheeting for supporting a surface according to claim 8, wherein square mesh apertures are about 75 mm -100 mm wide. 00oO M 5 10.A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein each line wire and each stay wire is provided with two free ends.

11.A mesh sheeting for supporting a surface according to claim 10, wherein the free ends of the line wires are secured to stay wires and the free ends of the stay wires are secured to line wires.

12.A mesh sheeting for supporting a surface according to claim 11, wherein the free end of a line wire is secured to a stay wire by means of a knot.

13.A mesh sheeting for supporting a surface according to claim 12, wherein the knot is provided in the form of a separate piece of wire.

14.A mesh sheeting for supporting a surface according any one of claims 11 to 13, wherein the free end of a stay wire is secured to a line wire by means of a knot. mesh sheeting for supporting a surface according to claim 14, wherein the knot is provided in the form of a separate piece of wire.

16.A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein the stay wires are thinner than the line wires.

17.A mesh sheeting for supporting a surface according to any one of the preceding claims, wherein the line wires and the stay wires are between about 2 mm and about 4 mm in diameter.

18.A method for supporting a surface, the method comprising the steps of: -11- a. preparing a mesh sheeting by overlaying a plurality of line wires and Sstay wires to provide a plurality of intersections, the line wires and the stay wires being fastened together at each intersection, at least one of N the plurality of line wires and a plurality of stay wires being provided with a tension crimp adapted to absorb loads; 00oO M b. positioning the mesh sheeting against a surface to be supported; c. fastening the mesh sheeting to the surface; and d. coating the surface with a sprayable binding product.

19.A mesh sheeting for supporting a surface substantially as hereinbefore described with reference to any one of Figures 1 to Dated this Twenty Ninth day of July 2005. Southern Wire Pty Ltd Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant(s)