ZA200405798B - Pillar support - Google Patents

Description

k*+2004L/5798

BACKGROUND OF THE INVENTION

[0001] This invention relates to a pillar support and more particularly is concerned with a reinforcing structure for use in a pillar support.

[0002] It is known to make use of a pillar support to provide support between opposing surfaces in an underground excavation. This type of pillar support typically includes a reinforcing configuration for example of wire mesh and steel rods which contain a bag into which a settable material is placed. In a general sense the settable material provides support against compressive forces while the mesh and steel rings, which extend circumferentially around the settable material, provide a restraining force against radial expansion of the settable material. : SIE

[0003] The reinforcing structure which is used in a pillar support should, ideally, meet certain requirements. It should be relatively inexpensive, of adequate strength, and be collapsible in an axial direction, and thereafter be 16 extensible, so that it can be transported to and then used at an underground site with relative ease.

SUMMARY OF INVENTION

[0004] The invention provides reinforcing structure for a pillar support which includes a plurality of wire hoops arranged in a tubular mesh configuration with at least a first hoop being connected to at least one adjacent second hoop at each of a plurality of spaced locations by means of a respective joint

P.2037%/es oo © e2004/57658 which allows sections of the first hoop, on opposed sides of the joint, to move towards sections of the second hoop on opposed sides of the joint.

[0005] Each joint may be formed by twisted interengaged respective portions of the first and second hoops which extend in a circumferential sense within the tubular mesh configuration. Co

[0006] The sections of the hoops may be movable towards one another to collapse the tubular mesh configuration in an axial direction and away from one another to extend the tubular mesh configuration in an axial sense.

[0007] Ali the hoops may be interconnected to one another in a similar fashion so that when the tubular mesh configuration is collapsed the plurality of wire hoops are stacked one above the other.

[0008] Each hoop may have a zigzag shape.

[0009] The reinforcing structure may include a plurality of circular rings fixed to the tubular mesh configuration at intervals which are spaced from one another in an axial sense of the tubular configuration.

[0010] The invention further extends to a pillar support which includes reinforcing structure of the aforementioned kind and a bag e.g. made from a suitable plastics material such as woven polypropylene, positioned within the tubular mesh configuration. The bag may be filed with a settable material which may be cementitious-based or include any other appropriate binder.

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£*-2004/5738

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 is a side view of reinforcing structure according to the invention in an extended form;

Figure 2 is a view on an enlarged scale of portion of the reinforcing structure shown in Figure 1;

Figure 3 is a cross sectional view from one side of part of the extended reinforcing structure shown in Figure 1;

Figure 4 is a cross sectional view of the reinforcing structure in a partly collapsed form;

Figure 5 shows the reinforcing structure of Figure 1 from the side in a collapsed form; and

Figure 6 is a side view of part of the collapsed structure shown in Figure 5 on an enlarged scale.

DESCRIPTION OF PREFERRED EMBODIMENT

[0012] Figures 1 and 5 of the accompanying drawings illustrate from one side reinforcing structure 10 according to the invention in an extended form and in a collapsed form respectively.

[0013] The structure 10 includes a tubular mesh configuration 12 and a plurality of steel rings 14, of appropriate diameter, which are engaged with the

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©++2004/5798 tubular mesh configuration at locations which are regularly spaced from each other by a spacing 16.

[0014] Figure 2 illustrates a portion of the tubular mesh configuration 12 on an enlarged scale. The mesh configuration is made from a plurality of circumferentially extending and interconnected hoops 20 each of which is substantially of a zigzag form. In Figure 1 a single hoop is marked in bold to facilitate tracing of the hoop.

[0015] The mesh configuration is formed into a tubular form using the mesh material which is shaped so that ends 21 of each hoop are brought into an abutting relationship with each other. The two ends are then interconnected e.g. by means of a twisting, bending or welding process. The joined ends lie on an axially extending line, marked L, in the mesh configuration, see Figure 1.

[0016] In Figure 2 portions of three hoops 20A, 20B and 20C respectively are distinguished from one another by suitable markings. The hoop 20A is connected to the hoop 20B at circumferentially spaced locations 22A, 22B etc. and the hoop 20A is connected to the hoop 20C at locations 24A, 24B etc. which are staggered relatively to the locations 22A and 22B. :

[0017] At each location the hoop 20A is connected to the hoop 20B by means of twisted interengaged portions of the hoops which form a respective joint 26. The hoop 20A has opposed sections 28A and 28B which extend at angles away from the joint 26 while, similarly, the hoop 20B has sections 30A

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and 30B which extend from the joint 26. In the extended form the joints 26, in each hoop, are successively spaced from each other in a circumferential sense while, in the axial sense, successive joints are alternately axially displaced in one direction and then in an opposing direction.

[0018] Figure 3 is a view in cross section through part of the tubular mesh configuration shown in Figure 1 i.e. in an extended form. Figure 4 illustrates that portion of the tubular mesh configuration which is in Figure 3 in a collapsed form. If an axially directed force, represented by opposing arrows 36 and 38, is applied to the extended mesh configuration, either due to gravity force or to a manually applied force or to a combination thereof, then the twisted joints 26 in each hoop act as pivots or hinges and allow the sections 28 of the hoop 20A to fold over onto the sections 30 of the hoop 20B. The tubular mesh configuration is, in the process, collapsed, in an axial sense, and the various hoops are stacked or superimposed one above the other, as is shown on an enlarged scale in Figure 4.

[0019] Figure 5 shows the tubular mesh configuration 12 in a collapsed form while Figure 6 illustrates a portion of the collapsed tubular mesh configuration on an enlarged scale.

[0020] It has been found that the mesh configuration 12 can be collapsed or extended, in an axial sense, with relative ease. Each joint 26 is formed from wires which are loosely twisted with each other, with a shallow helix angle.

The wires do therefore not bind tightly to one another and one wire can pivot

P.20379/jes . : | = . I ro Tag FN R dq around the other with ease. This hinged action coupled with the zigzag shape ~ of each hoop means that the hoops can be collapsed one over the other with an axially aligned outer series of joints designated 26X and an inner axially aligned series of joints designated 26Y, see Figure 4.

[0021] Figure 1 illustrates, in dotted outline, a bag 40 which is made from a suitable plastics material such as woven polypropylene. The bag is inserted into the tubular mesh configuration 12 and forms a liner inside the configuration. As is known in the art a settable material, which can be cementitious-based can be pumped or otherwise introduced into the bag and then allowed to set to form a permanent support between opposing surfaces in an excavation. These aspects are known in the art and therefore have not been described.

[0022] The wire hoops, although of zigzag form, provide substantial reinforcement, in a circumferential sense, to the column which is formed by the settable material inside the bag 40 with the reinforcement being such that it provides a restraining force against expansion of the column in a radial sense when the column is loaded in a compressive way.

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Claims (11)

1. Reinforcing structure for a pillar support which includes a plurality of wire hoops arranged in a tubular mesh configuration with at least a first hoop being connected to at least one adjacent second hoop at each of a S plurality of spaced locations by means of a respective joint which aliows sections of the first hoop, on opposed sides of the joint, to move towards sections of the second hoop on opposed sides of the joint.

2. Reinforcing structure according to claim 1 wherein each joint is formed by twisted interengaged respective portions of the first and second hoops which extend in a circumferential sense within the tubular mesh configuration.

3. Reinforcing structure according to claim 1 or 2 wherein the sections of the hoops are movable towards one another to collapse the tubular mesh configuration in an axial sense and away from one another to extend the tubular mesh configuration in an axial sense.

4. Reinforcing structure according to claim 3 wherein all the hoops are interconnected to one another in a similar fashion so that when the tubular mesh configuration is collapsed the plurality of wire hoops are stacked one above the other.

5. Reinforcing structure according to any one of claims 1 to 4 wherein each hoop has a zigzag shape.

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6. Reinforcing structure according to any one of claims 1 to 5 which includes a plurality of circular rings fixed to the tubular mesh configuration at intervals which are spaced from one another in an axial sense of the tubular configuration.

7. Reinforcing structure for a pillar support which includes a tubular mesh configuration formed from a plurality of wire hoops each of which extends circumferentially within the tubular configuration, and wherein each hoop is connected to an adjacent hoop at each of a plurality of circumferentially spaced locations by means of a respective joint formed by twisted interengaged portions of the hoops which permit relative movement of the hoops from first positions in which the tubular configuration is extended to second positions at which the tubular configuration is collapsed.

8. Reinforcing structure according to claim 7 wherein, at the second positions, the plurality of wire hoops are stacked one above the other.

9. Reinforcing structure according to claim 7 or 8 wherein, when the plurality of wire hoops are at the first positions, the joints in each hoop are alternately displaced from one another circumferentially and axially.

10. Reinforcing structure according to any one of claims 7 to 9 which includes a plurality of circular steel rings fixed to the tubular configuration at axially displaced intervals.

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11. A pillar support which includes reinforcing structure according to any one of claims 1 to 10, a bag which is positioned within the tubular mesh configuration and a settable material inside the bag. Dated this 20™ day of July 2004. N\ McCALLUM, RADEMEYER & FREIMOND Patent Agents for the Applicant

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