BACKGROUND OF THE INVENTION

[0001] This invention relates to a mesh support system which is usable in an underground excavation, and to a clip which is used in the mesh support system. [0002] Mesh panels are used for safety reasons in underground locations to intercept material which may fall free from a hanging wall or other rock surface. The mesh panels are normally spanned between rock bolts which are embedded in a body of rock and which are usually spaced apart by substantial distances. The dimensions of the mesh panels are therefore correspondingly large. Often adjacent mesh panels have overlapping sections at their perimeters so that a single rock bolt can be used to secure at least two panels in position.

[0003] The mesh panels are difficult to handle underground due to their dimensions. Each panel is usually transported in a rolled-up configuration to an installation site. A free end of a panel is then fixed to a hanging wall and the panel is progressively unrolled and fixed at intervals to the hanging wall. This method of attachment can call for coordinated cooperation between several miners in an underground environment, a requirement which is not always easily achieved.

[0004] An object of the present invention is to address, at least partly, the aforementioned issues. SUMMARY OF THE INVENTION

[0005] The invention provides a clip which includes a body formed from an elongate rigid member with a first end and an opposed second end, a first hook-shaped formation, which lies in a first plane, at the first end, a second hook-shaped formation, which lies in a second plane, at the second end, and a U-shaped formation which lies in a third plane and which is between the first and second hook-shaped formations, and wherein the first plane is displaced from and is parallel to the second plane, and wherein the first plane and the third plane subtend between them an angle of from 20 to 40 Preferably the said subtended angle is 30

[0006] The clip may be such that when the body is viewed from a first side, the first hook- shaped formation is superimposed over the second hook-shaped formation.

[0007] The invention also provides ajmesh support system which includes at least a first mesh panel with a first perimeter and a second mesh panel with a second perimeter which is adjacent the first perimeter and a plurality of clips which connect the first perimeter to the second perimeter, and wherein each clip includes spaced apart hook-shaped formations which are engaged at spaced apart locations with a first component of the first perimeter and a U-shaped formation positioned between the hook-shaped formations which is engaged with a second component of the second perimeter.

[0008] Preferably the first mesh panel comprises a first mesh section and the said first component comprises a first flexible cable which is engaged with loops of the first mesh section, and the second mesh panel comprises a second mesh section and the said second component comprises a second flexible cable which is engaged with loops of the second mesh section.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 illustrates in perspective a clip according to the invention;

Figure 2 is a view from one side of the clip, in the direction of an arrow marked 2 in Figure 1 ; Figure 3 is a plan view of the dip in the direction of an arrow marked 3 in Figure 2;

Figure 4 is an end view of the clip in the direction of an arrow marked 4 in Figure 2;

Figure 5 illustrates in plan a part of a mesh support system according to the invention; and Figure 6 shows on an enlarged scale a part of the mesh support system in Figure 5 which is enclosed in a circle marked 6.

DESCRIPTION OF PREFERRED EMBODIMENT

[0010] Figure 1 of the accompanying drawings illustrates in perspective a clip 10 according to the invention. Figure 2 shows the clip from one side, Figure 3 shows the clip 10 in the direction of an arrow marked 3 in Figure 2, and Figure 4 is an end view of the clip in the direction of an arrow marked 4 in Figure 2.

[0011] The clip 10 includes a body 12 which is formed from an elongate rigid member 14. Typically the member is made from an appropriate grade of steel. “Rigid” means that the member is not easily deformable by means of a manual force. Thus the body 12 has substantial strength. [0012] The elongate member 14 has a first end 16 and a second opposed end 18. A first hook-shaped formation 20 which extends over a first part 12A of the body is formed at the first end 16. A second hook-shaped formation 22 which extends over a second part 12B of the body is formed at the second end 18. As is indicated in Figure 4 the hook-shaped formation 20 lies in a first plane 20A and the second hook-shaped formation 22 lies in a second plane

22A which is parallel to the first plane and which is displaced therefrom by a distance 24 which is roughly twice the size of the diameter 26 of the elongate member 14.

[0013] A U-shaped formation 30 is formed at a central location between the first end 16 and the second end 18. The U-shaped formation 30 lies in a third plane 30A (see Figure 4). The first plane 20A and the third plane 30A subtend an angle 34 between them. The angle 34 is equal to an angle 36 subtended between the second plane 22A and the third plane 30A.

[0014] The angle 34 lies between 20° and 40°. A preferred value is 30°. In this configuration a gap 40 (Figure 2) is formed between opposing surfaces of the first hook-shaped formation 20 and the second hook-shaped formation 22. The size of this gap is equal to or slightly less than the dimension 26.

[0015] The clip 10 is designed to be used, in the manner shown in Figures 5 and 6, in the construction of a mesh support system 50 in an underground location (not shown). In the construction of the mesh support system 50 use is made of a number of mesh panels two of which, designated 52 and 54, are partly shown in Figure 5. The panels 52, 54 are substantially identical. Each panel includes a respective mesh section 58 with mesh apertures 60, of a chosen size, defined by arrays of wires 62 arranged and secured together in a net configuration in a manner which is known in the art and which for that reason is not further described herein. [0016] The mesh section 58 of the mesh panel 52 is bounded at its perimeter by a first flexible cable 66. Similarly , the mesh section 58 of the second mesh panel 54 is bounded at its perimeter by a second flexible cable 68. Each cable is looped through apertures 60 at a perimeter of the mesh section. Lengths of the cable 66 and of the cable 68 are positioned to be substantially adjacent one another and are then connected together using a plurality of the clips 10 which are positioned at closely spaced locations to ensure that the two mesh sections are firmly fixed together. The mesh apertures 60 of the mesh sections do not overlap one another.

[0017] Figure 6 shows a portion of the arrangement in Figure 5 which is enclosed in a circle marked 6, on an enlarged scale. A clip 10 is positioned so that a part of the cable 68 can pass through the gap 40 between the first hook-shaped formation 20 and the second hook-shaped formation 22. The clip is moved so that the cable 68 is then positioned closely inside the U- shaped formation 30. In the process the orientation of the clip relative to the cable 68 changes through about 90°. [0018] The cable 66 and the clip 10 are then twisted to the extent necessary to enable the cable 66 to pass into the gap 40. The cable 66 is then pushed between the first part 12A and the second part 12B of the body until the cable 66 is moved beyond the first end 16 and the second end 18. At this point the natural resilience of the cable 66 acts to undo the twist with the result that the cable enters each of the hook-shaped formations 20 and 22. The cable 66 is then secured to the cable 68. As the hook-shaped formations face in opposing directions the cable 66 cannot easily be disengaged from the formations. As noted the cable 68 rests in the U-shaped formation 30. [0019] A plurality of mesh panels can be interconnected using a plurality of the clips 10 which secure adjacent perimeters of the panels to one another to form a mesh support system for a hanging wall. The connection technique allows for each mesh panel to be of a manageable size so that the panel can be easily handled. It is possible for the interconnection of adjacent panels to be done by a single miner. An important aspect is that the connection process does not require an overlap of the perimeters of adjacent mesh panels. Consequently there is a saving in the amount of material required to provide support over a given area. The mesh panels come in a standard size which are assembled to cover a larger surface area. Stock holding is simplified as a plurality of standard size panels are the only stock which is required. [0020] If a section of a panel is damaged then it can readily be detached from the mesh support system and replaced with a fresh panel drawn from the available stock. The new panel is connected to the mesh support system in the manner which has been described.