[0002] The provision of support in an underground excavation is subject to a large number of factors such as cost, ease of erection, degree of support required, ability to yield with closure, and the like. In certain excavations a support which covers a relatively large area is required but the ability to yield, although being important, is not decisive. Also, in some situations, the overall load-bearing capability need not be significantly high provided, of course, it is above a predetermined and known yield point.

[0003] A further factor which comes into play when constructing a pack which is effective over a large area is that it should be possible to construct the pack from components which are relatively easy to transport and position, particularly in the arduous conditions which are encountered underground.

SUMMARY OF INVENTION [0004] The invention provides a component for a support pack which includes a first elongate element of a first length, a second elongate element of a second length, the second element being parallel to and spaced from the first element, and at least one intermediate member which is positioned between, and secured to, the first and second elements.

[0005] The elements and members may be made from the same or different materials and these materials may be of any appropriate kind. It is preferred however that the elements and the members are made from timber. Each element, and each member, may be of substantially rectangular or square cross section.

0006] The first length may be greater than the second length.

[0007] The second element may be positioned, relatively to the first element, so that it is centrally positioned, ie. when viewed from a side, portions of the first element which are more or less of the same length extend outwardly beyond opposed respective ends of the second element.

[0008] In a preferred embodiment of the invention the intermediate members are regularly positioned from each other and are located between, and secured to, the first and second elements.

[0009] As used herein"elongate"in relation to an element means that the element has a length which is greater than its transverse dimensions i. e. its width and thickness.

[0010] The invention also provides a support pack which includes a plurality of components, each component being of the aforementioned kind, the components being arranged in a plurality of overlying layers wherein, in a first group of layers, each layer has at least two of the components which are substantially co-planar and which are positioned with the respective second elongate elements adjacent each other and with the elongate elements extending in a first direction and, in a second group of layers, each layer is positioned between two layers of the first group with the respective second elongate elements adjacent each other and extending in a second direction which is at a right angle to the first direction, so that, in plan, the plurality of components have a substantially rectangular or square outline with at least two sides thereof each having a length which is approximately equal to the first length.

BRIEF DESCRIPTION OF THE DRAWINGS [0011] The invention is further described by way of examples with reference to the accompanying drawings in which: Figure 1 is a plan view of a component for a support pack according to the invention; Figure 2 is a plan view of a support pack which is constructed from a plurality of the components shown in Figure 1; Figure 3 is a side view of the support pack shown in Figure 2; Figure 4 is a plan view of a modified component; Figure 5 illustrates in plan a pack made from a plurality of components each of the type shown in Figure 4; Figures 6 and 7 show a modified pack in different stages of construction; and Figures 8 and 9 show a further modification.

DESCRIPTION OF PREFERRED EMBODIMENTS [0012] Figure 1 of the accompanying drawings illustrates a component 10 for a support pack which is made from timber and which includes a first elongate element 12 of square cross section which has a first length 14, a second elongate element 16 of square cross section which has a second length which is shorter than the first length, and three elongate intermediate members 20,22 and 24, which are also made from timber of a square cross section, and which are positioned at regular intervals transversely between the elongate elements which are substantially parallel to each other.

[0013] The element 16 is positioned more or less centrally relatively to the member 12 so that, when the component 10 is viewed from one side, portions of the elongate element 12, at opposed ends, project more or less equally outwardly relatively to corresponding ends of the element 16.

[0014] The members 20 to 24 are secured to the elements 12 and 16 in any appropriate way. In one technique indicated schematically in dotted lines only wire ties 26 are passed through registering holes in the elements and the members and are twisted or linked to one another to secure the members and elements together.

[0015] In one example of the invention the length 14 is 900mm and the length 18 is 600mm. The elements and the members are made from timber which is square in cross section with each side having a width of 100mm. Each member has a length of 200mm, although it could be shorter, which means that a distance 28 between an outer side of the element 16 and an inner side of the element 12 is 400mm. Each intermediate member could vary in length, according to requirement and could be a 1/4, or less, of the length of the length 18.

[0016] In a different version of the invention timber which is square in cross section with a side of 100mm is used for the construction of the elements and the members.

The length 14 is 750mm while the length 18 is 450mm. The length 28 is 225mm.

10017] It is to be understood that these values are given only by way of examples and are non-limiting.

[0018] Figure 2 illustrates, in plan, a support pack 30 which is constructed from a ,, plurality of components 10 each of the kind shown in Figure 1. The support pack is more or less square in cross section with sides 32 and 34 each being 900mm long.

[0019] The uppermost components 10A and 10B are positioned so that the corresponding shorter elongate elements designated 16A and 16B respectively are adjacent each other and parallel to each other extending in a first direction 36, and form a first layer 38 in the pack, see Figure 3. An underlying pair of components 10C and 10D respectively form an underlying layer 40 in the pack. The shorter elements 16C and 16D are adjacent each other and extend in a direction 42 which is a right angle to the direction 36.

[0020] Figure 3 illustrates the support pack 30 from the side. It is apparent that the pack comprises a plurality of layers of support components with each layer being formed by two support components. The layers are divided into two groups of layers with the elongate elements in one group extending in the direction 36 while the elongate elements in the other group which are intercalated with the first group extend in the direction 42.

[0021] A support pack of the invention is constructed from the components 10 which are relatively light and not unduly difficult to transport and install, particularly in arduous underground conditions. Also, the overall area projected by an assembled pack is substantial-in the illustrated example of the order of 900mm by 900mm. On other hand the quantity of timber used in the pack is reduced compared to certain other packs of which the applicant is aware.

[0022] The aforementioned principles can be used, with modifications, to produce components and support packs of different configurations.

[0023] Figure 4 illustrates a modified component 10X formed from a first elongate element 12, a second elongate element 16, and a single intermediate member 44 which, in this instance, is parallel to, positioned between and in contact with, the elements 12 and 16. The member 44 is approximately equal in length to the length of the second element 16, but it could be shorter than the second element about 50%, or less, of the length of the second element. Also two or more intermediate members could be positioned between the elements 12 and 16.

[0024] A plurality of the components 10X can be used in a manner similar to what has been described in connection with Figures 2 and 3 to produce a support pack 50 of the type shown in plan in Figure 5.

[0025] Figures 6 and 7 show a modified pack 50A wherein each layer 52 in the pack has three components 10 of the type shown in Figure 4 except that the central timber element 22 is omitted. Each layer is essentially a mirror image of an adjacent layer.

The pack is rectangular in outline with a greater area (in plan) than the pack 50, and is strong for it has a high timber density. The pack has a substantially solid inner core made up of the timber pieces 16,20 and 24 with three elements 12 per layer.

The pack can however be made with any other components 10, which fall inside the scope of the invention, to reduce the quantity of timber required while providing support over an extended area.

[0026] Figures 8 and 9 show another modified pack 50B made from components 10 of the type shown in Figure 1, but also optionally without the central member 22.

Each layer 52 has four components arranged to enclose a veritcal hollow space 56.

Extended areal coverage is achieved with a relatively low timber density although there are four of the timber elements 12 per layer.