GB2062736A

GB2062736A - Movable Mine Roof Supports

Info

Publication number: GB2062736A
Application number: GB8033245A
Authority: GB
Original assignee: Dobson Park Industries Ltd
Current assignee: Joy Global Industries Ltd
Priority date: 1979-11-09
Filing date: 1980-10-15
Publication date: 1981-05-28
Also published as: GB2062736B

Abstract

A large mine roof support (10) for use with high coal seams (14), and having an elevated platform (13) disposed between its base (11) and a roofing bar structure (12), is provided with caterpillar tracks (22) in order that it may be advanced whilst supporting the roof. The tracks (22) are mounted on the base (11) for vertical movement relative thereto by means of rams so that the weight of the support (10) is taken by the base (11) whilst stationary but by the tracks (22) during the advance movement. A safety valve maintains the extension of the rams if the supply of pressure fluid thereto fails. The roofing bar structure (12) is supported from the base (11) and platform (13) by extendible props (18, 19) and coal face support sprags (20, 21) are pivotally mounted on the roofing bar structure (12) and the platform (13). <IMAGE>

Description

SPECIFICATION Movable Mine Roof Supports This invention relates to mine roof supports, and in particular to self advancing roof supports used along a coal face. More particularly the invention relates to mine roof supports for use with high coal faces and which have an elevated forwardly extending platform. Such a platform may extend over the coal conveyor and coal cutting machine and may also provide a mounting for a forwardly located roof supporting prop or props. Such arrangements are described in British Patent No. 1,114,472.

One of the problems associated with the use of such mine roof supports is that of moving the supports forward towards the coal face as the seam is progressively cut away. In the case of the relatively much smaller mine roof supports used with low and medium height coal seams such supports having a base and a roofing bar structure supported by props from the base, but not having an intermediate elevated platform, it is known to have caterpillar tracks mounted on the base and on the roofing bar structure to facilitate the advancement of the support. For reasons of stability and maximum loading such an arrangement has been envisaged only in connection with supports of height of the order of, or at least not significantly greater than, the length of the base. Such devices are disclosed in, for example, U.K.Patent Specifications 706088, 1552258, 1572534 and 2031494.

In the case of the type of mine roof supports to which the present invention relates their weight is of the order of 25 tons, and in consequence of their large size and weight they are difficult to move in the conventional manner. It is an object of the present invention to provide a mine roof support of the type having an intermediate elevated platform, which support is easier to move than are previously known supports of this type, and which may be moved under load.

The invention provides a mine roof support having in combination a base, a roofing bar structure supported from said base, an elevated forwardly extending platform intermediate the base and the roofing bar structure and caterpillar tracks provided on said base whereby the support may be advanced.

It has been found that by means of the arrangement of the present invention, the mine roof support may be advanced under load, and in such circumstances the stability of the support is maintained.

Drive means may be provided whereby the tracks are driven to advance the support.

Alternatively the tracks may be mounted on the base by means of extendible rams, whereby the tracks and the base may be advanced one relative to the other alternately during advancement of the support. The rams may be extendible by means of fluid under pressure fed to the support along feed and return lines from a remote source of pressure fluid.

Preferably in the latter case, the support is provided with an automatic safety valve to maintain the extension of the rams in the eventuality of failure of the supply of the fluid under pressure.

The invention will now be further described with reference to the accompanying drawing, the single figure of which illustrates one embodiment of mine roof support according to the invention.

The mine roof support 10 comprises a base 11, a roofing bar structure 12 and an elevated forwardly extending platform 13. The support 10 is positioned near to and facing a coal face 14, and a coal cutting machine 15 and a coal conveyor 1 6 are located at the foot of the coal face 14. The elevated platform 1 3 extends over the conveyor 1 6 and cutting machine 1 5. To aid stability of the support 10, the base 11 may be extended forwardly at the toe 17. The roofing bar structure 12 is supported from the base 11 by extendible props 18 and also at the forward end by a further extendible prop or props 19 which is or are mounted on the elevated platform 13.As an alternative arrangement the support may be constructed so that the height of the elevated platform 1 3 is adjustable relative to the base 11 in the manner disclosed in copending Application No. 7938880. Coal face supporting sprags 20 and 21 are mounted on the elevated platform 13 and the roofing bar structure 12 respectively as is disclosed in copending Application No. 7938879; alternatively a second coal cutting machine and conveyor may be mounted on the elevated platform as is disclosed in copending Patent Applications Nos. 7938878 and 7938881.

The base 11 is mounted on caterpillar tracks 22, one on each side of the base 11. Drive means 23 may be provided for driving the tracks 22 so as to advance the support 10. Alternatively the mounting may be by means of a plurality of hydraulically actuated rams 24, for example four such rams, one at the forward end and one at the rearward end of each track 22. The rams are supplied by fluid under pressure from a remote source thereof (not shown) when required to advance the roof support 10 towards the coal face 14. During this operation the rams are extended or retracted so that the base 11 and the tracks 22 may be advanced one relative to the other. Whilst the support 10 is stationary during the coal cutting operation and whilst the support is being advanced towards the coal face 14, the base 11 is supported by the floor of the coal mine, and the roofing bar structure 12 supports the roof.

The latter provides stability for the support 10 during such advancement.

Surprisingly, it has been found that the support 10 of the present invention can be advanced towards the coal face 14 whilst under load, i.e.

whilst still giving a measure of support to the roof of the coal mine. An automatic safety valve may be provided in the hydraulic circuit connecting the pump to the rams, whereby pressure in the rams is maintained if the supply of pressure fluid fails.

Claims

1. A mine roof support having in combination a base, a roofing bar structure supported from said base, an elevated platform intermediate said base and said roofing bar structure, and caterpillar tracks provided on said base whereby the support may be advanced.

2. A support according to claim 1 wherein drive means are provided whereby said tracks may be driven to advance said support.

3. A support according to claim 1 , wherein said tracks are mounted on said base for horizontal movement relative thereto.

4. A support according to claim 3 comprising a plurality of extendible rams adapted to move said tracks horizontally relative to said base.

5. A support according to claim 4 wherein said rams are extendible by means of fluid under pressure fed thereto from a supply tereof.

6. A support according to claim 5 comprising valve means adapted to maintain the pressure of fluid in said rams upon faiiure of said supply.

7. A support according to any one of claims 1 to 6, wherein said roofing bar structure is supported from said base by extendible props.

8. A support according to claim 7 wherein said roofing bar structure is supported from said platform by an extendible prop or props.

9. A support according to any one of claims 1 to 8, comprising a coal face support sprag pivotally mounted on said roofing bar structure to depend therefrom.

10. A support according to any one of claims 1 to 9, comprising a coal face support sprag pivotally mounted on said platform to extend upwardly thereof.

11. A support according to claim 9 or claim 10 comprising jack means adapted to adjust the inclination of said sprag or sprags.

12. A mine roof support substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.