GB2030614A

GB2030614A - Yielding Mine Roof Stilts

Info

Publication number: GB2030614A
Application number: GB7931328A
Authority: GB
Original assignee: Hayden Nilos Conflow Ltd
Current assignee: Hayden Nilos Conflow Ltd
Priority date: 1978-09-08
Filing date: 1979-09-10
Publication date: 1980-04-10
Also published as: GB2030614B

Abstract

A stilt 1 for a mine roof support comprises an elongate, rectangular or square-section metal sleeve 2 provided internally with at least two longitudinally extending, deformable and/or displaceable elements 12 secured to a portion 5 of the sleeve 2, a shoe 8 having a central member 7 and two pairs of cylindrical projections 9 each pair extending rigidly from opposite sides of the central member 7, with the projections 9 of each pair spaced with respect to one another by an amount less than the corresponding dimension of an element 12 so that each pair embraces at least one element 12, and, in use, progressively deforms the embraced element(s) upon displacement of the shoe 8 resulting from convergence of the mine roof. The elements 12 may be in the form of splayed flanges (as shown), returned loops Fig. 5 (not shown), ribs Fig. 8 (not shown), tubes Fig. 11 (not shown), or semicircular channel sections, Fig. 14 (not shown). <IMAGE>

Description

SPECIFICATION Mine Roof Supports This invention relates to stilts for mine roof supports, and more particularly to box stilts for pit props or mine arch legs of H or I section and comprising an elongate, rectangular or square section metal sleeve with one or more longitudinally extending internally located elements which are deformed, displaced etc. as a pit prop or mine arch leg inserted in one end of the stilt is pressed progressively into the stilt upon roof convergence forces exceeding the designed yield load of the stilt.

In some instances the pit prop or mine arch leg engages directly with the internal elements, whilst in others engagement is via a shoe.

However, with previous constructions the forces on the internal elements is such as to tend to burst the stilt outwards and one object of the invention is to provide a stilt which in use is not subject to forces tending to burst it outwards.

According to the present invention, a stilt for a mine roof support comprises an elongate, rectangular or square section metal sleeve provided internally with at least two longitudinally extending detormable and/or displaceable elements secured to a portion of the sleeve, a shoe having a central member and two pairs of projections extending rigidly from opposite sides of the central member, with the projections of each pair spaced with respect to one another by an amount less than the corresponding dimension of an element so that each pair embraces at least one element and, in use, progressively deforms the embraced element(s) upon displacement of the shoe resulting from roof convergence.

Thus, the stilt in accordance with the invention ensures that all forces are inward and hence the sleeve may be manufactured from relatively thin gauge material. Apart from reducing material costs, this also reduces the weight of the stilt.

The sleeve may be formed by securing together two channel-section half sleeves having mutually inturned flanges, with the flanges of one half sleeve abutting the corresponding flanges of the other half sleeve. The half sleeves may be secured together by spot welding at suitable locations.

Furthermore the deformable and/or displaceable elements are also preferably secured by welding to an adjacent wall or flange of the sleeve.

Thus, in a first embodiment, each deformable and/or displaceable element may take the form of a pair of splayed apart, terminal flanges which, in use, are progressively urged together by displacement of the shoe upon roof convergence.

Conveniently, one such terminal flange is integral with, and bent from, each mutually inturned flange, so that the sleeve contains four terminal flanges.

In a second embodiment each mutually inturned flange terminates in a returned loop which constitutes a deformable and/or displaceable element, the loops being progressively flattened by displacement of the shoe upon roof convergence.

In a third embodiment a rib is formed by displacing a portion of each flange from the general plane of each flange, the ribs extending parallel to the longitudinal axis of the sleeve and being progressively flattened by displacement of the shoe upon roof convergence.

In a fourth embodiment the deformable and/or displaceable elements are constituted by four circular section tubes, each secured by welding to a mutually inturned flange, the tubes being progressively flattened by displacement of the shoe upon roof convergence.

Finally, in a fifth embodiment the deformable and/or displaceable elements are constituted by four semi-circular strips, again secured by welding along their two edges to a mutually inturned flange, these semicircular strips again being progressively flattened by displacement of the shoe upon roof convergence.

With all the above described embodiments, it is desirable to provide, over a relatively short length of the stilt and extending from one end thereof a lead-in portion incorporating no deformable and/or displaceable element. The lead-in portion, in use, will be located at the upper end of the stilt and serves to accommodate readily the shoe and the lower end of a pit prop or mine arch leg.

The shoe may be formed of a plate with two round bars passing through two spaced holes in the plate, with the bars welded to the plate.

Alternatively, an elongate slot with arcuate ends may accommodate both bars, one being welded to the plate at each end of the slot. Yet again, to avoid a welding operation, the bars may be a press fit in each of two suitably dimensioned holes.

The stilt may be provided with a baseplate at its lower end, i.e. that remote from the leadin portion, which baseplate may be welded thereto or may be provided with a socket or spigot (or spigots) to suite the end of the hollow metal section.

The invention will now be further described, by way of examples, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a first embodiment of stilt in accordance with the present invention; Figure 2 is a view in the direction of arrow A of Figure 1; Figure 3 is a view in the direction of arrow B of Figure 1; Figure 4 is a side elevation of a second embodiment of stilt in accordance with the present invention; Figure 5 is a view in the direction of arrow A of Figure 4; Figure 6 is a view in the direction of arrow B of Figure 4; Figure 7 is a side elevation of a third embodiment of stilt in accordance with the present-invention; Figure 8 is a view in the direction of arrow A of Figure 7;; Figure 9 is a side elevation of a fourth embodiment of stilt in accordance with the present invention; Figure 10 is a view in the direction of arrow A of Figure 9; Figure 11 is a view in the direction of arrow B of Figure 9; Figure 12 is a side elevation of a fifth embodiment of stilt in accordance with the present invention; Figure 13 is a view in the direction of arrow A of Figure 12; and Figure 14 is a view in the direction of arrow B of Figure 12.

In all the Figures, like reference numerals are used for like components.

In the drawings, a stilt 1 comprises an elongate, square section metal sleeve 2 formed by securing together at welds 3 a pair of identical, channel-section half sleeves 4, the sleeves having mutually inturnsd and abutting flanges 5. In a gap 6 between the mutually inturned flanges 5 is located a central plate 7 of a shoe 8, the central plate 7 being provided with two pairs of projections 9 extending rigidly from opposite sides of the central plate 7, adjacent peripheries 10 of each pair of projections to each side of the central plate 7 being spaced apart by a distance that will accommodate the combined thickness of the abutting, mutually inturned flange s 5. The position, in use, of a four inch by four inch mine arch strut is shown in dotted line at 11 in Figure 3.

In the embodiment of Figures 1 to 3 a pair of splayed apart, terminal flanges 12 are bent from the abutting and mutually inturned flanges 5 over the majority of the length of the stilt 1, with the exception of a relatively short lead-in length 13 (Figure 1) provided at what, in use, is to be the upper end of the stilt. In the conventional manner, the mine arch strut seats on the shoe 8 urging the latter downwardly but displacement of the shoe 8 is resisted by the splayed apart terminal flanges 1 2 which are progressively urged together as the shoe 8 is displaced downwardly in the direction of arrow 14 (Figure 1) upon convergence of the roof supported by the mine arch.

In the second embodiment of Figures 4 to 6, the same effect is achieved by having each inturned flange 5 terminating in a return loop 15, while in this embodiment the adjacent peripheries 10 of each pair of projections 8 to each side of the central member 6 are spaced apart by a greater distance than the shoe 8 of the first embodiment.

In the third embodiment of Figures 7 and 8, a rib 16 is formed by displacing a portion of each inturned flange 5, the ribs 16 extending along the lengths of the flanges 5 with the exception of the lead-in portion 13.

In the fourth embodiment of Figures 9 to 11, a circular section tube 1 7 is welded at 18 to each of the mutually inturned flanges 5, the tubes 1 7 being flattened by displacement of the shoe 8 upon roof convergence.

Finally, in the fifth embodiment of Figures 12 to 14, a semi-circular strip 1 9 is welded at 20 to each of the mutually inturned flanges 5, the strips 19 being flattened by displacement of the shoe 8 upon roof convergence.

Claims

1. A stilt for a mine roof support comprising an elongate, rectangular or square section metal sleeve provided internally with at least two longitudinally extending, deformable and/or displaceable, mutually spaced elements secured to a portion of the sleeve, a shoe having a central member and two pairs of projections extending rigidly from opposite sides of the central member, with the projections of each pair spaced with respect to one another by an amount less than the corresponding dimension of an element so that each pair embraces at least one element and, in use, progressively deforms the embraced element(s) upon displacement of the shoe resulting from roof convergence.

2. A stilt as claimed in Claim 1, wherein the sleeve is formed by securing together two channel-section half sleeves having mutually inturned flanges, with the flanges of one half sleeve abutting the corresponding flanges af the other half sleeve.

3. A stilt as claimed in Claim 2, wherein the half sleeves are secured together by spot welding at suitable locations.

4. A stilt as claimed in any preceding Claim, wherein the deformable and/or displaceable elements are secured by welding to an adjacent wall or flange of the sleeve.

5. A stilt as claimed in any preceding Claim, wherein each deformable and/or displaceable element takes the form of a pair of splayed apart, terminal flanges which, in use, are progressively urged together by displacement of the shoe upon roof convergence.

6. A stilt as claimed in Claim 5, wherein one such terminal flange is integral with, and bent from, each mutually inturned flange, so that the sleeve contains four terminal flanges.

7. A stilt as claimed in any one af Claims 1 to 4, wherein each mutually inturned flange terminates in a returned loop which constitutes a deformable and/or displaceable element, the loops being progressively flattened by displacement of the shoe upon roof convergence.

8. A stilt as claimed in any one of Claims 1 to 4, wherein a rib is formed by displacing a portion of each flange from the general plane of each flange, the ribs extending parallei to the longitudinal axis of the sleeve and being progressively flattened by displacement of the shoe upon roof convergence.

9. A stilt as claimed in any one of Claims 1 to 4, wherein deformable and/or displaceable elements are constituted by four circular section tubes, each secured by welding to a mutually inturned flange, the tubes being progressively flattened by displacement of the shoe upon roof convergence.

10. A stilt as claimed in any one of Claims 1 to 4, wherein the deformable and/or displaceable elements are constituted by four semi-circular strips, again secured by welding along their two edges to a mutually inturned flange, these semicircular strips again being progressively flattened by displacement of the shoe upon roof convergence.

11. A stilt as claimed in any preceding Claim, wherein there is provided, over a relatively short length of the stilt and extending from one end thereof, a lead-in portion incorporating no deformable and/or displaceable element.

12. A stilt as claimed in any preceding Claim, wherein the shoe is formed of a plate with two round bars passing through two spaced holes in the plate, with the bars welded to the plate.

13. A stilt as claimed in any one of Claims 1 to 1 1, wherein the shoe is formed of a plate having an elongate slot with arcuate ends, the slot accommodating both bars, one being welded to the plate at each end of the slot.

14. A stilt as claimed in any one of Claims 1 to 1 wherein the shoe is formed of a plate with two spaced holes, a bar being press fitted into each hole.

1 5. A stilt as claimed in any preceding Claim, provided with a baseplate at its lower end.

16. A stilt for a mine roof support substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.

17. A stilt for a mine roof support substantially as hereinbefore described with reference to Figures 4 to 6 of the accompanying drawings.

18. A stilt for a mine roof support substantially as hereinbefore described with reference to Figures 7 and 8 of the accompanying drawings.

19. A stilt for a mine roof support substantially as hereinbefore described with reference to Figures 9 to 11 of the accompanying drawings.

20. A stilt for a mine roof support substantially as hereinbefore described with reference to Figures 1 2 to 14 of the accompanying drawings.