GB2205876A

GB2205876A - Strut

Info

Publication number: GB2205876A
Application number: GB08713675A
Authority: GB
Inventors: Brian George Davidson Smart
Original assignee: Coal Industry Patents Ltd
Current assignee: Coal Industry Patents Ltd
Priority date: 1987-06-11
Filing date: 1987-06-11
Publication date: 1988-12-21
Also published as: GB8713675D0

Abstract

A strut has a hollow elongate tubular member 1 and fixing plates 2, 3 for securing the strut to adjacent members or a wall. The tubular member 1 is wholly or partially filled with a reinforcing material such as concrete. <IMAGE>

Description

' WRUT ' This invention relates to a strut of the kind comprising a hollow elongated tubular member.

In civil and construction engineering struts are used for a variety of support and strengthening purposes and normally these are made of metal or reinforced concrete and placed in positions of support. Many metal stuts are of I section but often in order to give added strength a box section of square or rectangular cross section is used. Alternatively circular cross section struts may also be used.

In the mining industry struts are used particularly underground to support the roof of a tunnel or a roadway when this tunnel or roadway is held up by circular or semi-circular arches. The arches are spaced from each other by struts which assist in bearing the load pressures put on them from the surrounding strata.

In tunnels there is usually a limited amount of space and if the struts are not sufficiently strong it is difficult to put in a stronger one as this usually means that a larger cross section strut is necessary.

The consequence of this is that there is a restriction of space in the tunnel or alternatively extra excavation work has to be undertaken to ensure that the free tunnel space is of the desired size.

It is an object of the present invention to provide a strut which can be given extra strength in its resistance to bending and which makes it particularly suitable for areas where space is limited.

According to the present invention in a strut including a hollow elongated tubular member having fixing means for securing the strut to adjacent members the tubular member is wholly or partially filled with a reinforcing material.

The reinforcing material may be of a homogeneous nature such as cement or a resin or it may comprise a mixture of materials such as a resin with an appropriate amount of filler material.

The tubular member of the strut may be provided with a plurality of holes to enable it to be filled with reinforcing material in situ.

The tubular member may include at least two tubular parts adapted to slide one within the other to enable the strut to be adjusted in length.

Conveniently the fixing means includes plates at the end of the tubular member and support fillets secured between the tubular member and the plates.

In order that the invention may be readily understood one example of a strut in accordance therewith and a modification thereof would now be described with reference to the accompanying drawings.

In the drawings Figure 1 shows a side view of a strut in accordance with the invention, Figure 2 shows a fragmented view of one end of the strut and Figure 3 shows a section part of a telescopic form of strut.

Referring now to Figures 1 and 2 of the drawings the strut comrises a square cross section tubular member 1 having end plates 2 and 3 welded across its open ends and fillet plates 4, 5 welded between the underside of the tubular member 1 and the plates 2 and 3 respectively.

The plates 2 and 3 have fixing bolt holes 6 in their lower portions on either side of the fillet plates.

A filling hole 7 is formed in one embodiment of the invention in one of the end plates 3 and concrete filling material can be injected into the centre of the elongate member 1 as at 8. This is allowed to set and the resulting filled strut is made stronger in bending strength than the empty strut. The only disadvantage with this is that the weight of the concrete makes the strut heavy to move and unless suitable tackle is available for lifting an alternative form of filling the strut has to be found. This can be achieved by securing the empty strut in position and by providing filling holes 9 and 10 in the bottom and top of the elongate member 1. Concrete can then be injected into the hole 9 and air can escape through the top hole 10. The hole 10 will also serve as a guide to show how full the member 1 is. Normally the hole of the tubular section of the member 1 will be filled.Concrete is a very suitable filler material since it is relatively cheap, it is pumpable and it has a high compressive strength. However, if there is much flexing of the beam likely it may be better to have a filling material such as a resin with a suitable filler, if necessary, which is able to flex without any risk of cracking Referring now to Figure 3 this shows a modification of the tubular member which makes it adaptable for fitting in areas where arches or the like to be secured by struts have not been precisely placed and some degree of variation can occur in the position of the mountings. In Figure 3 the tubular member 1 comprises an inner section 11 which will be able to slide in a close fit within an outer section 12. Suitable holes 13 in the inner section 11 can be aligned with an outer hole 14 in the section 12 so that a number of locations are possible and different lengths of strut usually able to be produced. When the hole 13 and 14 are aligned a securing bolt can be fitted through them and tightened to hold the two sections 11, 12 in position. The sections 11, 12 can then be filled with a suitable filling material as described before.

It will be seen that an invention enables a strut of improved strength to be produced without in any way altering the physical size of the strut and also enabling an adjustable strut to be equally available to a user.

Claims

1. A strut including a hollow elongated tubular member and having fixing means for securing the strut to adjacent members, in which the tubular member is wholly or partially filled with a reinforcing material.

2. A strut as claimed in claim 1 in which the reinforcing material is of a homogeneous nature.

3. A strut as claimed in claim 1 in which the reinforcing material is a mixture of materials.

4. A strut as claimed in claims 1 and 2 in which the reinforcing material is cement.

5. A strut as claimed in claims 1 and 2 wherein the material is a resin

6. A strut as claimed in claims 1 and 3 wherein the reinforcing material is a cemintitious mixture.

7. A strut as claimed in claims 1 and 3 wherein the reinforcing material is a resin loaded with a filler material.

8. A strut as claimed in any preceding claim wherein the tubular member is provided with a hole or a plurality of holes to enable it to be filled with reinforcing material in situ.

9. A strut as claimed in any preceding claim wherein the tubular member includes at least two tubular sections one adapted to slide relative to the other to enable the strut to be adjusted in length.

10. A strut as claimed in a preceding claim and including plates at the end of the tubular member with support fillets secured between the member and the plates.

11. A strut substantially as herein before described with reference to Figures 1 and 2 or, as modified, with reference to Figure 3 of the accompanying drawings.