GB2045832A - Stilts - Google Patents

Abstract

A mine-roof support includes at least one extendable stilt (14). The stilt contains load-bearing dry solid fluent material (16) and extension is facilitated by flow thereof between two of its parts in one direction only. Specifically, inner and outer (20) cylinders contain sand with a one-way piston valve washer (26, 28) between them to allow the sand to drop past it as an arch or other support is raised but will then block it to prevent retraction of the stilt. <IMAGE>

Description

SPECIFICATION Strata support The invention relates to strata support particularly, but not necessarily exclusively, in mining and in relation to tunnels, such as mine roadways.

According to the invention there is provided a mine-roof support including an extension device connected to or between a part or parts of the support to allow height adjustment of the support, the extension device utilising load-bearing dry fluent material and having means controlling selective flowing and substantially locking said dry fluent material in extension of the device.

In mining, roadways providing access for personnel and equipment to mine faces, and transfer out of mineral or debris, are usually supported against strata collapse by arches, typically of multi-part reinforcing steel joist construction. Component parts, e.g. side and crown parts are usually connected together end-to-end by fishplates. The conflicting requirements of height adjustability and high resistance to strata coilapse are usually met by so-called "slow-yield" telescopic seatings employing steel plate formed to a generally M-shaped section that, centrally, receives and locates the end of a side component part and, to each side, straddles edges of a hollow base so as to require drawing of side walls of the plate over those latter edges on yielding.In-filling between arches has most often been by way of metal or wood plates, slats, boards, plants, or the like.

Several disadvantages arise from such arched support provisions, notably siow erection times and susceptibility to inevitable deterioration of parts, particularly in respect of the telescopic parts and their slow-yield ratings, and the infilling between arches. This invention and that of a companion application are directed to alleviating these disadvantages to obtain substantial practical benefit.

Specifically, herein, attention is directed to the adjustable side-seating of the arches. Hydraulic fluid is normally present and used in mine workings for a wide variety of purposes, including powering of "active" equipment such as mine face mineral winning machinery and self-advancing supports, and also passive equipment such as so-called rapid yield props relying on trapped hydraulic fluid after powered setting. However, it is obviously impractical to use hydraulic fluid for arch supports of roadways as the latter are required to have long life, often virtually permanent, in their position of initial erection. That life is much longer than required of the so-called rapid-yield props that are most often used as a temporary measure prior to installation of slow-yield support arches and/or to further assist face supports in rearward strata control.The costs of maintenance and checking for leaks on roadway supports would be extremely undesirably, if not completely unacceptable.

What we therefore propose herein is the use of a load-bearing dry particulate, powdery, or otherwise comminuted fluent material as a selectively flowed and substantially locked medium in an adjustable extension device connected to or between support parts, such as arch side component parts, usually and preferably as a base or seating extension device.

In referring to arches, we have, of course, in mind any shape conforming to what is to be supported.

As a preferred embodiment, we have in mind an extension device comprised of an outer tubular part closed at its lower end and containing said dry fluent material, and an inner part movable away from the closed end of the outer tubular part and at the same time permitting said dry fluent material to fall therepast but then substantially preventing or at least presenting a very high resistance to reverse flow of the dry fluent material even under loading of that inner part via an arch to which it is connected. A suitable inner part comprises a piston or washer having one-way flow permitting or favouring means, for example a stiff central part and a peripheral flexible or articulated part or parts constructed or otherwise restrained to deflect in one direction only out of contact with the outer tubular part.

Conveniently, such a device is made for delivery in situ on the end of a support part, typically a roadway arch side part, which then forms a piston rod coupled in manufacture to said piston orwasher.

Preferably a cap or cover is fitted over the open end of the outer tubular part, for example by pinning the cap or cover through both the outer tubular part and the arch side part a maximum mutual retraction thereof. The cap or cover may, at that time, seal-in requisite dry fluent material, such as sand. Alternatively, that material may be introduced on site after unpinning or even removal of the cap or cover.

On installation at a roadway for supporting purposes, at least arch side and crown parts will be assembled, outer tubular parts of our extension devices located on the floor, even anchored permanently or temporarily if desired, and the arch crowns raised to the roof with extension of the outer tubular parts to fill the lower portions thereof with load bearing dry fluent material to whatever extent is necessary. Subsequently, leakage problems are very much less than would be the case for hydraulic fluids.

Substantial further advantages accrue if bottom ends of the outer tubular parts of our extension devices are flexibly coupled to a floor engager, say by hinging, preferably universally, for example by a ball-and-socket arrangement. Thus, the outer tubular parts preferably have at least a flexible coupling component part, if not an entire flexible coupling and floor engager. This is of particular value on installation as the arch side parts will, at assembly, be inclined more towards each other, with their crown parts well below roof level to ease assembiy work, which may including cladding, see our said companion application.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawing, in which: Figure 1 shows one side of an arch fitted with an extension device, Figure 2 shows a section through a preferred extension device of Figure 1; and Figures 3, 4 and 5 show details of infilling sheeting.

Referring to Figure 1, ain arch comprises a crown part 10 and two side parts only one 12 of which is shown. These crown and side parts are of conventional I-section reinforcing steel joist preformed to desired shape. Each side part, such as 12, has at its lower end an extension device 14 employing loadbearing dry fluent material for support purposes, e.g. sand 16, see Figure 2.

Figure 2 shows a typical extension device as comprising an outer tubular part 20 closed at its lower end 22 and an inner part slidable axially thereof, see piston washer 24 which, has a stiff central portion 26 that, taken alone, would be a clearance fit to the interior 26 of outer part 20 and a peripheral flexible portion 28. As shown, the piston washer 24 has an overall dished configuration with the peripheral portion 28 directed towards the closed end 22 of the outer tubular part 20 as well as outwardly towards its interior wall 26 in order readily to permit passage of sand 16 downwards but not upwards.This resistance to upward movement is wholly a characteristic of the construction of the piston washer 24, by the nature of the peripheral flexible portion 28 alone, or by abutment between a stiff part or parts of it and the central stiff portion 26, or by abutment with teeth on the edge of the central portion 26, or in any other desired way.

The piston washer 24 is shown secured to the lower end of arch side part 12, specifically by way of pinning 30 to a reduced arch side extension 32. The main body of the arch side part 12 is a guided and generally mutually supportive fit within the outer part 20 of the extension device.

As supplied to site in situ on the arch side part 12, the extension device 14 will normally be at maximum retraction, and will then have fitted over the open end of the outer part 20 a cap or cover 34 then pinned as at 36 through the outer part 20 and the arch side part 12. This may sealingly retain the sand 12 or other dry fluent material 16. The cap or cover 34 is then removed to permit of extension the device 14, usually after assembly of arch side and crown parts.

At its lower end 22 the outer tubular part has means for flexibly coupling it to a floor engaging shoe or beam 40 (see Figure 1 also showing hinging 42 for the desired flexure) to permit at least varying of its inclination towards and away from a roadway wall. Figure 2 shows a spherical extension 44 to mate with a suitable seat though it could equally well have the seat for mating with an extension, or bearing on an insert between itself and another seat.

Figure 1 demonstrates the desired variable-inclina- tion with primed references to its assembled and unextended condition, but shown offset and without lower hinging.

Installation of arches will thus involve the steps of taking side arch parts equipped with extension devices, as proposed herein, orso equipping such side arch parts; assembling them into arches with arch centre parts, e.g. byfishplating 44; and setting that arch to the roof to be supported, by raising the crown parts and thus extending the extension devices preferably having previously attached the side arch parts flexibly with floor engagers at sides of the tunnel or roadway to be supported.

Setting to the roof is conveniently by way of pressure-fluid, usually hydraulically, operated equipment such as particularly positioned props or some other mechanism that may be at the rear of a heading machine.

A preferred form of arch in-filling is shown in Figures 3 to 5 and, in fact, constitutes external cladding utilising corrugated sheets 50, 52 able to fit overlapped one upon another and pitched to accommodate arch joisting 10, 12 (Figure 3). These sheets 50, 52 are provided in separate parts each corresponding to central crown and side arch parts as indicated in Figure 3. Ends of the separate sheet parts 50, 52 engage one with the other by way of hook-and-eye type apertures and/or protrusions 54, 56 mating one with the other but shown separated in the drawing. This greatly facilitates quick assembly prior to extension as proposed herein, especiaily if, as shown, it allows hanging of the side sheets 52 from crown sheets 50. The preferred overlapping of adjacent sheeting space indicated in Figure 4 provides side-to-side location and reduces arch requirements to one per sheeting span.

It will, of course, be appreciated that our extension devices may be applied to a support in the form of a simple stilt and at any position along such a stilt.

Obviously, such stilts may be parts of more complex support structures.

Claims (14)

1. A mine-roof support including an extension device connected to or between a part or parts of the support to allow height adjustment of the support, the extension device utilising load-bearing dry fluent material and having means controlling selective flowing and substantially locking said dry fluent material in extension of the device.

2. A mine-roof support according to claim 1, wherein the or each extension device comprises an outer tubular part closed at its lower end and containing said dry fluent material, an inner part movable away from the closed end of the outer tubular part and at the same time permitting said dry fluent material to fall therepast but then resisting reverse flow of that material even under loading of the support.

3. A mine-roof support according to claim 2, wherein said inner part comprises a piston or washer having one-way flow favouring means for the dry fluent material.

4. A mine-roof support according to claim 3, wherein said piston or washer has a stiff central part and a peripheral flexible or articulated part or parts to deflect out of contact with the outer tubular part in one direction only.

5. A mine-roof support according to claim 4, wherein the peripheral part or parts is or are of flexible material.

6. A mine-roof support according to any preceding claim, wherein each of two said extension devices comprises a seating device fitted to a different bottom end of side parts of the support.

7. A mine-roof support according to claim 6 with claim 2, wherein said lower end has a coupling means for flexible connection to a floor engager part.

8. A mine-roof support according to claim 7, wherein said coupling means is a spherical extension for a ball-and-socket type said flexible connection.

9. A mine-roof support according to any one of claims 2 to 8, further comprising a cap or cover fitted to the open end of said outer tubular part at least prior to extension.

10. A mine-roof support according to claim 9, wherein said cap or cover overlaps the extension of said outer tubular part and is fixed by pinning through the outer tubular part and a said support part.

11. A mine-roof support according to any one of claims 2 to 10, wherein said outer tubular part fits about an associated said support part in mutual guiding and supporting relationship.

12. Amine-roofsupport according to claim 11, with claim 3, wherein said associated support part is secured as a piston rod to said piston or washer.

13. A mine-roof support arch with extension devices substantially as herein described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

14. A mine-roof support according to any preceding claim with outer cladding as herein described.