GB2105764A - Strut - Google Patents

Abstract

A strut designed to provide support between two flanged sections. The strut comprises a central section (3) which may have a channel- shaped cross-section. Two opposite end sections (4, 4a) are integral with the centre section and each comprises a neck (5) tapering outwardly into a tab region which is divided into at least two tabs (7, 8). The overall width of the tab region is equal to the combined width of the centre web (13) and two side webs (14, 15), which make up the central section (3). <IMAGE>

Description

SPECIFICATION Strut This invention relates to a strut designed to provide support between two flanged sections.

Colliery arches are usually formed from Isection girders comprising a centre web and opposite flanges. It is necessary to provide struts between those arches, the struts desirably being designed to have tensile and compressive load figures as near equal as possible. One known form of strut is formed from an integral length of steel bar of rectangular cross-section by cutting away parts at each side at each end of the bar to leave a central projecting tongue. Opposite sides of the centre portion of the bar are then bent out of the plane of the centre section to form a channel section, the width of the centre of which is equal to the width of the projecting tongue. In use the strut is placed between two I-section arches so that at each end of the strut the channel sides bear against one side of the flange of the arch, the central tab passing across the exposed face of that flange.The end of the tab may then be hammered to fold around the opposite web of the flange, so securing the strut in place. In use, it is found that transfer of load to the strut is unsatisfactory due to the limited amount of grip that can be achieved using such a narrow tab.

The object of the present invention is to provide a strut that does not suffer from these disadvantages.

According to the present invention a strut comprises a central section and two opposite end sections extending from the centre section, the centre section having a strength-providing crosssection, and each end section comprising a neck extending from the centre section and substantially equal in width thereto, tapering outwardly into a tab region of greater width than the centre section, the tab region being divided along part of its length by at least one cut extending inwardly from the free end thereof.

Use of a tab region of greater width than the centre section rather than a tab of equal width as in previous constructions improves load transfer onto the strut, particularly when the strut is in tension. However, difficulty is experienced in bending a wide tab around the web of a beam forming the colliery arch; by dividing each tab region into two or more parts by one or more longitudinal cuts this disadvantage is overcome, as each part of the tab region can then be bent separately into position. Moreover, the use of two or more spaced adjacent parts in the tab region significantly improves the centring of the strut relative to the arch and thus further improves load transfer.

The centre section is conveniently of channelshaped cross-section comprising a centre web and two side webs. However, other crosssections, such as hollow square, rectangular, circular or oval section are possible. The end sections may be secured to the centre section, for example by welding, or may be formed integrally therewith. In the case of the aforesaid channelshaped cross-section the overall width of the tab region is conveniently equal to the combined width of the centre web and the two side webs when notionally unfolded into the plane of the centre web.

A preferred strut in this form can be manufactured from a single length of rectangular section strip, for example of mild steel, by making appropriately shaped cut-outs from each side of the strip adjacent each end thereof. After forming the cut-outs the centre section of the bar is bent to form the side webs for the channel section, leaving the end tab regions of the same width as the original strip. The tab regions may be divided into two or more parts at any convenient stage of manufacturing process.

Preferably the ends of the side webs are cut away adjacent the centre web to form recesses into which one web of the flange of an I-section beam may be located.

The invention will be better understood from the following description of a specific embodiment of strut in accordance therewith, given with reference to the accompanying drawings in which: Figure 1 illustrates manufacture of the strut; Figure 2 is a plan view of a strut; Figure 3 is a side elevation of the strut of Figure 1; Figure 4 is an end elevation of the strut of Figure 1; and Figure 5 shows schematically one end of the strut of Figure 1 in engagement with an arch member.

Referring now to Figure 1 this shows a blank 1 in the form of a mild steel bar of rectangular cross-section. The strut is manufactured by making a cut-out indicated by the broken lines 2 from each side of the strip adjacent each end thereof, the cut-outs effectively dividing the strip into a centre section 3 and end sections 4 and 4a.

Each end section comprises a neck 5 which diverges outwardly into an end tab region 6 equal in width to the full width of the strip. The tab region is divided into two tabs 7 and 8 by a cut 9 extending centrally and longitudinally into the end section from the free end thereof. Each tab 7 and 8 is stamped to form a raised projection 10 and 1 Oa respectively from one surface thereof. The centre section 3 is then bent along longitudinally extending lines 11, 12 to form a centre web 13 and side webs 14 and 1 5, together forming a channel-shaped cross-section. The final form of the strut is shown in Figures 2 to 4. It will be understood that the manufacturing steps described can be carried out in a different order after the formation of the cut-outs 2.

Referring to Figures 2 to 4 it will be seen that the strut has the channel-shaped centre section 3 and identical end sections 4 and 4a. The formation of the cut-outs 2 is such that each end of each side web of the channel shaped centre section is formed with a recess 1 6 adjacent to the centre web. The projections 10 and 1 0a extend to the same side of the plane of the centre web as do the side webs 14 and 15.

Figure 5 shows the method by which a strut may be secured in position on an I-section beam, for example forming part of a colliery arch. The strut is positioned so that the recesses 1 6 engage one web 1 7 of the flange 1 8 of the section 19, the end region 4 of the strut extending across the free face of the flange 1 8. When in this position each individual tab 7 and 8 is hammered out of the plane of the end section into the position shown in Figure 5 which engages around the other web 20 of the flange, the projection 10 or 1 Oa engaging as shown to lock the tab in position. The second tab is then similarly hammered into engagement with the flange, the division 9 between the tabs enabling each of them to be bent without the need to use excessive force.

When in position on the strut it will be seen that virtually the full width of the original bar from which the strut is formed is in engagement with the flange of the section 1 9 so materially increasing stress transfer from the arch to the strut. The use of the two centrally divided tabs has an automatic centreing effect during location of the strut on the section, which again improves stress transfer. Furthermore, the strut exhibits substantially equal resistance to tensile and compressive loads.

It will be understood that struts may be made in various lengths as required, and that the particular size and shape of the cut-outs will be designed to suit the particular dimensions of the flanges of the sections with which the strut is to be used. It will also be understood that each end region may be divided not into two, but into three or more individual tabs by making two or more longitudinal cuts into the end region from the free end thereof. The individual tabs may or may not be of equal width.

In alternative constructions end sections having tab regions divided into two or more parts may be integral with or welded or otherwise secured to a centre section of any required strength-providing cross-section.

Claims (7)

Claims

1. A strut designed to provide support between two flanged sections, the strut comprising a centre section and two opposite end sections extending from the centre section, the centre section having a strength-providing cross-section, and each end section comprising a neck extending from the centre section and substantially equal in width thereto tapering outwardly into a tab region of greater width than the centre section, the tab region being divided along part of its length by at least one cut extending inwardly from the free end thereof.

2. A strut according to claim 1 in which the end sections are integral with the centre section.

3. A strut according to claim 1 or claim 2 in which the centre section is of channel-shaped cross-section and comprises a centre web and two side webs.

4. A strut according to claim 3 in which the overall width of the tab region is equal to the combined width of the centre web and two side webs when notionally unfolded into the plane of the centre web.

5. A strut according to claim 4 in which the ends of the side webs are cut away adjacent the centre web to form recesses into which one web of the flange of an I-section beam may be located.

6. A strut according to any one of the preceding claims in which the strut is formed from a mild steel bar of rectangular cross-section.

7. A strut designed to provide support in compression between two flanged sections, the strut being substantially as herein described with reference to Figures 2 to 4 of the accompanying drawings.