GB2126639A

GB2126639A - Mine roof support forepoling beam

Info

Publication number: GB2126639A
Application number: GB08311696A
Authority: GB
Inventors: George Albert Parrott
Original assignee: Dresser Europe SPRL
Current assignee: Dresser Europe SPRL
Priority date: 1982-09-09
Filing date: 1983-04-28
Publication date: 1984-03-28
Also published as: GB8311696D0

Abstract

A hydraulically powered, self- advancing mine roof support (1 Fig. 1) comprises an elongate base means (2 Fig. 1) adapted to seat on a mine floor (3 Fig. 1), an elongate roof beam 4 adapted to engage a mine roof 5 and supported by displacement means (9 Fig. 1) from the base means (2 Fig. 1), a forepoling beam 14 carried by the roof beam 4 and adjustable in position with respect to the roof beam 4 from a rearward, retracted position to a forward, projecting position, and at least one inflatable bag 18 operable on the forepoling beam 14 at least when the latter is in a projecting position, to urge the forepoling beam 14 upwardly into a roof engaging condition. <IMAGE>

Description

SPECIFICATION Mine roof support This invention relates to a hydraulically powered, self-advancing mine roof support.

Conventionally, such supports are employed in the longwall mining of coal and other minerals, by being located, side by side along the goaf side of an armoured, scraper chain conveyor extending along the mineral face, each support comprising a roof beam, to engage the mine roof, supported in space relationship from a base means, seating on the mine floor, by a plurality of hydraulically extensible chock legs. It is also conventional to provide the roof beam with a forepoling beam, which is extendable from, and retractable into, the roof beam, by means of a double-acting hydraulic ram.However, once extended, it is necessary, for the forepoling beam to have any beneficial roofsupporting effect, to urge the beam upwardly into engagement with the mine roof, and many different arrangements have been proposed to achieve this, but most arrangements have embodied additional equipment in the form of a ram and/or bell crank and/or lever/toggle mechanism, but this additional equipment inevitably takes up additional space in the limited confines available and furthermore may present an obstruction to the unhindered passage to and fro along the face of a mineral winning device e.g.

a shearer type mining machine or a plough.

According to the present invention, there is provided a hydraulically powered, self-advancing mine roof support comprising an elongate base means adapted to seat on a mine floor, an elongate roof beam adapted to engage a mine roof and supported by displacement means from the base means, a forepoling beam carried by the roof beam and being adjustable in position with respect to the roof beam from a rearward, retracted position to a forward projecting position, and at least one inflatable bag operable on the forepoling beam at least when the latter is in a projecting position, to urge the forepoling beam upwardly into a roof engaging condition.

The invention, by employing an inflatable bag, thus obviates the need for conventional ancillary equipment to urge the forepoling beam upwardly, producing several consequential advantages, among which are: there is less obstruction than with a conventional arrangement, giving more clearance for the mineral winning device to pass under the support in this critical position; a cheaper construction is possible in this area of the support; easier maintanance and replacement is possible for a bag can be simply located; lower maintenance costs; and no point loading is effected on the forepoling beam due to the cross-sectional area of a bag being much larger than that of any conventional arrangement hence the bag may be inflated at lower pressure than required by a ram.

The forepoling beam may be retractable beneath, or within, the roof beam. With the latter arrangement, the bag may be inserted between an underside of the forepoling beam and an upper side of a portion of the roof beam.

The bags may be of any suitable flexible yet abrasion resistant material, e.g. a reinforced synthetic plastics, although a flameproof material would be required for use on a coal face.

Conveniently, the bag(s) is filled with conventional 95/5 water/oil emulsion normally available on a mineral face.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which :- Figure 1 is a diagrammatic side elevation of a mine roof support in accordance with the invention; and Figures 2 to 4 are diagrammatic sectional views of the forward end of the roof beam of Figure 1 , to an enlarged scale.

A hydraulically powered, self-advancing mine roof support 1 comprises an elongate base means 2 adapted to seat on a mine floor 3, an elongate roof beam 4 adapted to engage a mine roof 5. The support 1 is provided at its rearward end with a lemniscate linkage 6 comprising an upper link or sheild element 7 having lateral side elements to which are pivotally attached, at each lateral side of the base means 2, upper ends of links 8, lower ends of which are pivotally attached to the base means 2.In the conventional manner the roof beam 4 is supported from the base means 2 by a plurality of hydraulically extensible chock legs 9, opposite ends of which legs are aticulated respectively to the base means 2 and roof beam 4, so that upon extension of the chock legs the roof beam 4 is urged into roof supporting engagement with the roof 5, and upon retraction of the chock legs the roof beam 4 is lowered so the support may be advanced, in the conventional manner, by means of one or more double-acting advancing rams 10, located within the base means 2, and connected between the base means 2 and a line pan 11 of an armoured, scraper chain conveyor 1 2, along the goaf side of which a plurality of support 1 are located side-by-side, a mineral winning machine e.g. of a shearer type being mounted on and/or guided by the conveyor 12 to remove webs of mineral from a mineral face 13.

In order to provide a roof supporting effect above and beyond the conveyor 12, the forward end of the roof beam 4 is provided with an extensible and retractable forepoling beam 1 4 which is displaceable by means of a double-acting ram 1 5 carried by the roof beam 4.

As best seen in Figures 2 to 4, the roof beam 4 comprises, at its forward end, an upper, roof engaging plate 1 6 spaced from a lower plate 17, between which plates the forepoling beam 1 4 is located, and in order to urge the forepoling beam upwardly into a roof-supporting condition when extended from the roof beam 4, a fluid inflatable bag 1 8 is located between the underside of the forepoling beam 14 and the lower plate 1 7.

In Figure 2, the bag 1 8 is shown in a deflated condition, and the forepoling beam 1 4 is shown retracted into the roof beam 4, by retraction of the advancing ram 1 5.

In Figure 3, the advancing ram 1 5 has been extended to displace the forepoling beam to the desired extent, with the bag 1 8 again remaining deflated.

After effecting the operation shown in Figure 3 the bag is then inflated with fluid e.g. water or a water/oil emulsion, by the roof support operator opening an appropriate control valve, the bag inflation urging the forepoling beam upwardly, so that it performs a roof supporting function, as indicated in Figure 4.

It follows that after passage of the mineral winning machine in a mineral cutting run along the conveyor 12, the conveyor 1 2 needs to be advanced to the newly exposed mineral face 1 3 by extension of the rams 10 and thereafter, the support needs to be advanced by retraction of the rams 10, but before this last-mentioned operation can be effected, the bag 1 8 needs to be deflated and the forepoling beam retracted into the roof beam 4 by retraction of the ram 1 5, whereupon the chock legs 9 can be partially retracted so that the support 1 can be pulled forwards. It will be understood that in some mining conditions retraction of the forepoling beams 14 of the roof support 1 may be necessary to allow unimpeded passage of the mineral winning machine, with the forepoling beams being subsequently reextended.

Claims

1. A hydraulically powered, seif-advancing mine roof support comprising an elongate base means adapted to seat on a mine floor, an elongate roof beam adapted to engage a mine roof and supported by displacement means from the base means, a forepoling beam carried by the roof beam and being adjustable in position with respect to the roof beam from a rearward, retracted position to a forward projecting position, and at least one inflatable bag means operable on the forepoling beam at least when the latter is in a projecting position, to urge the forepoling beam upwardly into a roof engaging condition.

2. A support as claimed in Claim 1 , wherein the forepoling beam is retractable beneath the roof beam.

3. A support as claimed in Claim 1, wherein the forepoling beam is retractable within the roof beam.

4. A support as claimed in Claim 3, wherein the bag is inserted between an underside of the forepoling beam and an upper side of a portion of the roof beam.

5. A support as claimed in any preceding Claim, wherein the bag is of a flexible yet abrasion-resistant material.

6. A support as claimed in any preceding Claim, wherein the bag is of a reinforced synthetic plastics material.

7. A support as claimed in any preceding Claim, wherein the bag means is of a flameproof material.

8. A hydraulically powered, self-advancing mine roof support substantially as hereinbefore described with reference to the accompanying drawings.