GB2093515A - Improvements in or relating to mine roof supports - Google Patents

Abstract

A mine roof support, for use in the roadhead area of a road or gate, comprises a roof-engaging member 10, shaped as an arch to conform approximately to the arched roof of a road or gate of the underground mine working. The roof-engaging surface of the roof member is formed by a curved steel plate 12, which is braced by I-section girders 14, 16 extending across the member, one at each end. The lowermost lateral edge portions 26, 28 of the roof-engaging member are straight and are supported by base members 30, 32 respectively. Each base member is coupled to the roof-member by two hydraulic props 34, 36 pivotally secured to the base member. Each base member 30, 32 is coupled to the roof-engaging member by sliding guide means 50 which restrict their relative movement in directions other than the direction of action of the hydraulic props 34, 36. <IMAGE>

Description

SPECIFICATION Improvements in or relating to mine roof supports The invention relates to mine roof supports, particularly for use in supporting roadways or gates in underground mine workings.

The invention is concerned especially with roadway roof supports for use in or adjacent the roadhead area of roads or gates of advancing longwall workings.

As the face advances, the roads or gates, which extend away from the face to provide access to and from the face for men and materials, must be extended by removing material in the roadhead area. Quite often part of the material in the gate end area, usually the material being worked, for example coal, is removed by the mining machine, leaving a so-called ripping lip above the worked-out volume which is then removed to the required height of the road or gate. The roof of the road or gate is then supported by installing, manually, spaced arches connected together by horizontal struts, with lagging, for example cover boards, steel sheets or mesh panels, to prevent material or debris falling between the arches from the roof and sides into the roadway.

Immediately after removal of the ripping lip the road or gate roof is particularly unstable due to strata settlement following caving of the roof behind the face roof supports as they are advanced. To avoid the need for men to work under this unstable roof area, it is desirable to provide one or more powered roof supports to provide temporary support for some distance along the road or gate from the roadhead or ripping lip. Then manual installation of the permanent arch supports can be done at a position of relative safety and where initial settlement has taken place. These powered supports must straddle the road or gate, to leave the middle clear for conveyors, power lines, access and so on.Problems arise in providing a support with sufficient adjustment to take account of the roof and floor not being parallel and to instability when the support is being moved, as is necessary as the roadway advances.

This will apply particularly when moving supports on uneven floors obstruction of the support base member may cause lateral loading resulting in damage to the props and consequent malfunctioning of the support.

According to the present invention there is provided a mine roadway roof support, for use at the roadhead of a road or gate, comprising a roofengaging member adapted to straddle the road or gate, and supported at each side by hydraulic prop means acting between the member and a respective base member, each base member being coupled to the roof-engaging member by sliding guide means serving to restrict their relative movement in directions other than the direction of action of the hydraulic prop means.

Usually the prop means will act substantially directly floor-to-roof i.w. substantially vertically for a horizontal floor.

The restriction of relative movement is preferably relative to directions parallel to and transversely of the direction of the road or gate, with preferred embodiments of the invention providing for angular relative movement of the base so that the latter can rock at least fore-and-aft.

Such a road roof-support can be moved by pushing against either of the roof-engaging and base members, for example by rams acting against permanent arches, and the load will be borne by the guide means rather than the prop means, reducing the risk of damage if the other member catches against an obstruction on an uneven floor. Viewed generally, the restriction of relative movement ensures that the guide means rather than the prop means takes forces applied other than floor-to-roof.

Moreover, preferred roadway roof supports hereof are advanceable in contact with the roof often under light load conditions that result from tendencies of strata to settle behind the face proper.

Each guide means may comprise a substantially vertically slotted part of, or secured to, the roofengaging member, slidingly cooperating with a part upstanding from the associated base member.

In a preferred embodiment, the slotted part comprises a channel open at both ends and having its mouth, directed inwardly of the support, provided with inturned lips or flanges. The upstanding part comprises an elongate member dimensioned so as to be insertable laterally into the channel i.e. via the mouth. The slide memberthen comprises at least one retaining piece, inserted into the channel from the end to fit between the elongate member and the channel interior. The retaining piece prevents removal of the elongate member and constrains it to sliding vertical movement in the channel.

Such an arrangement advantageously facilitates assembly of the roof support in the restricted headroom of the roadway.

The roof-engaging member may comprise a curved steel plate supported by a plurality of similarly curved girders, preferably of Section, attached to its underside. The slotted channel part of the guide means may then conveniently comprise the lower end part of one of the girders.

Preferably the guide means comprises pairs of channels, elongate members and retaining pieces.

The hydraulic prop means may comprise a pair of props, conveniently spaced apart longitudinally of the support, one each side of a central guide means.

Advantageously the lower end of the upstanding part is carried by a self-aligning bearing block, which bearing block may be pivotal relative to the base member about a transverse axis to allow relative pivotting of the base member and the bearing block thereby accommodating to unevennesss of the floor.

We further prefer that each base member has a forward formation or attachment which, during support advance serves to clear debris inwardly of the roadway and thereby facilitate arch-setting subsequent to the support advance. A suitable base front portion is raked ortaperedfrom outside to inside usually in conjunction with raking or tapering from top to bottom to afford a plough-like action on support advance.

The roof engaging member and/or base members may have advancing rams attached at one end thereto, to extend behind the roof support to engage an abutment such as a fixed arch.

Two or more roof supports may be coupled together, either by advancing rams so that they are self-advancing or by fixed couplings.

Advantageously a mine roof support system comprises a series of the aforesaid mine roof supports arranged end-to-end, preferably with their respective roof-engaging members fixedly interconnected to form a continous arch. The respective base members are advantageously unconnected or only pivotably connected, to permit their relative flexing to clear floor obstacles.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is an end view of a mine roof support shown installed in the roadway of a mine working; Figure 2 is a side view, from the roadway, of one lateral edge part of the roof-engaging member of the support and the associated base member; Figure 3 is a detail end view of the base member of Figure 2 and prop means coupling it to the roofengaging member; Figure 4 is a detail part-sectional view of guide means of the support;; Figure 5 is a section on the line AA of Figure 2, through the guide means Figure 6 is a detail sectional view on the line BB of Figure 2 Figure 7 is a side view showing advancing rams attached to the roof-engaging member of the support Figure 8 is a plan view of an advancing ram attached to a base member of the support Figure 9 is a detail sectional view on the line ZZ of Figure 2.

The mine roof support shown in the drawings comprises a roof-engaging member 10, shaped as an arch to conform approximately to the arched roof of a road or gate of the underground mine working.

The roof-engaging surface ofthe roof member is formed by a curved steel plate 12, which is braced by I-section girders, 14 and 16, extending across the member, one at each end. The middle of the plate 12 is braced buy a pairofl-section girders 18 and 20, secured side-by-side with their flanges 22 and 24, respectively, abutting, as shown in Figure 5.

The lowermost lateral edge portions, 26 and 28, of the roof-engaging member (Figure 1) are straight and are supported by base members, 30 and 32, respectively. Each of the base members 30 and 32 comprises an elongate box-section skid substantially equal in length to the roof-engaging member 10.

As the two base members 30 and 32, and their couplings to the roof member 10, are the same, for convenience only one will be described hereafter.

Each base member is coupled to the roof-member by two hydraulic props, 34 and 36, pivotally secured to the base member by devises 38 and 40, respectively, spaced apart along the uppermost surface of the base member, and to the roof-engaging member 10 of the devises 42 and 44, respectively. The clevises 42 and 44 are each secured to the plate 12 at a position approximately midway between the spaced I-sections girders 14 and 18, or 16 and 20, and spaced from the lower edge of the roof-engaging member by a distance approximately equal to the stroke of the props 34 and 36.

Midway between the two props 34 and 36, guide means 50 is provided to constrain relative move rent of the roof-engaging member 10 and basemember 32 so as to be substantially parallel to the extension axes of the props 34 and 36shown as vertical. The guide means 50 comprises end portions 52 and 54 of the central I-section girders 18 and 20, respectively. L-section guide members 56 and 58 extend parallel to, and spaced from, the girder end portions 52 and 54, respectively. Each guide member is secured to the plate 12 by the edge of one flange 60,62 so that the other flange 64,66 projects towards the web 68,70 of the associated girder end portion, forming a slot 72,74 of generally rectangular cross-section open at both ends and along its length.

Two bars 76 and 78 project upwardly from the base member 32 and into the slots 72 and 74 respectively. The bars 76 and 78 are rectangular in crosssection and siginficantly smaller in width and thickness than the associated slot 72 or 74. Two channelshaped retaining pieces, 80 and 82, their combined length equal to that of the slot 72, fit around the portion of the bar 76 extending in the slot 72. Similar retaining pieces 84 and 86 locate the bar 78 in the slot 74.

As can be seen from Figure 5, each of the retaining pieces 80 to 86 is a close fit in the associated slot with its bight portion engaged by the flange 54, 66 of the associated guide member and its limbs, notched externally at 88, located inside the opposed flanges of the associated girder end portions. The inside surfaces 90,92 and 94 of the limbs and bight portion, respectively of the retaining piece embrace three faces of the bar 74,76, the fourth face 95 abutting the leg of the associated girder end portion. Sufficient clearance is provided for the barto slide relative to the girder.

The lowermost ends of the bars 76 and 78 are supported at the base-member 32 by a bearing block or shoe 96 which is pivotably secured to the base member 32 by a pin 98 extending through aligned holes in the block 96, the side wall 100 of the base member 32, and a vertical flange 102 spaced from the sidewall 100. The bottom of the block 96 has front and rear faces 104 and 106, respectively, inclining upwardly away from the middle of the block. The upper surface of the block 96 has a longitudinal groove 108 which accommodates the ends of the bars 76 and 78, which are primed to the bearing block 96. The arrangement of the bearing block 96 thus permits the base-member to pivot or rock relative to the bars 76,78 in riding over steps or floor obstructions as the roof support advances.

A guard plate 110 extends upwardly between the outer edge of the base member 32 and the lower edge of the plate 12 to prevent debris falling from the roadway wall onto the base member. The guard plate 110 can slide relative to the plate 12 as the roof engaging member is raised or lowered.

An advantage of the configuration of the guide means 50 is that it can be assembled quickly and easily eventhough the headroom is restricted. Thus, with the roof-engaging member 10 supported in the required position above the base member 32, 34 each of the bars 76 and 78 is inserted laterally into the associated slot and twisted slightly until its aforementioned fourth face is flat against the girder.

The bar is then lowered until its lower end engages in the groove 108 in the bearing block 96 and primed as at 112 in Figure 6. The retaining pieces 80-86 are then slid into position from the ends of the slots 72, 74 to locate the bars in position. The props 34 and 36 can then befitted and used to raise and lower the roof-engaging member.

When, in use, the roof support needs to be advanced, the roof-engaging member will usually be lowered only slightly and the roof support pushed by advancing rams. These rams may be separate, but preferably are attached to the roof-engaging member and/or base members.

Figures 1 and 7 show four advancing rams 120, 122,124 and 126 spaced at equal intervals around the roof-engaging member 10. Each ram has a piston rod 128 secured at one end to the plate 12 and a cylinder 130 extending between the end girder 16 and the central girders 18,20. The cylinder 130 is mounted slidably in bearing blocks 132 and 134 attached to the girders 16 and 18, respectively.

An abutment plate 136 at the rearmost end of the cylinder is adapted to abut a fixed arch or other anchorage behind the roof support. Then as the ram extends, causing the cylinder 130 to project beyond the rear of the roof support, the latter is advanced along the roadway.

Figure 8 shows an advancing ram 140 attached to the base member 32 of the roof support. The ram cylinder 142 is pivotally attached at one end to a bracket 144 secured to the inner sidewall 146 of the base member. The end of the piston rod 148 projecting from the cylinder is attached to a floor-mounted bracket 150 by a clevis 152 and pin 153. Extension of the ram 140 causes the base member 32 and hence the roof support lOto advance.

To assist the sliding action of the base member 32 its ends have upwardly inclined faces 154 and 156, respectively. In addition, as can be seen from Figure 8, the ends have inwardly inclined faces 158 (rear only shown) to push any debris from the foot of the walls towards the middle of the roadway so that it does not jam between the base member and the wall.

It is envisaged that, in use, several of the roof supports will be connected together end-to-end. This could be achieved by means of the advancing rams.

Then, using double-acting rams, the set of roof supports could be made self-advancing.

Alternatively the roof supports could be connected together fixedly. A particularly advantageous form of connection is shown in Figure 9 which is a section through the juxtaposed leading and trailing end girders 14 and 16. The girders are fastened together by one or more bolts 164 extending through suitably aligned holes in their respective webs. A block 166 fits between the webs. The corners of the block are chamfered as at 168 to provide edges 170 which bear against the inclined inner surfaces of the girder flanges. The width of the block 166, between its faces opposed to the webs of the girders, is slightly greaterthan the depth of the flanges. Then, as the bolts are tightened and the girders drawn together, the edges or corners 170 seat between the inclined inner surfaces of the flanges giving accurate and secure location of the roof-engaging members relative to each other.

Claims (20)

1. A mine roadway roof support, for use at the roadhead of a road or gate, comprising a roofengaging member adapted to straddle the road or gate, and supported at each side by hydraulic prop means acting between the member and a respective base member, each base member being coupled to the roof-engaging member by sliding guide means serving to restrict their relative movement in directions other than the direction of action of the hydraulic prop means.

2. A mine roadway roof support according to claim 1, wherein restriction of relative movement ensures that it is the guide means rather than the prop means that bears loads due to force applied to its roof engaging member or its base members other than floor-to-roof.

3. A mine roadway roof support according to claim 1 or claim 2, wherein said prop mean acts substantially vertically.

4. A mine roadway roof support as claimed in claim 1 or claim 2, wherein each guide means comprises a part slotted in, or parallel to the direction of action ofthe hydraulic prop means said slotted part being of, or secured to the roof-engaging member, and slidingly cooperating with a part upstanding from the associated base member.

5. A mine roadway roof support as claimed in claim 4, wherein the slotted part comprises a channel open at both ends and having its mouth, directed inwardly of the support, provided with inturned lips or flanges.

6. A mine roadway roof support as claimed in claim 5, wherein the upstanding part comprises an elongate member dimensioned so as to be insertable laterally into the channel via its mouth, and at least one retaining piece insertable into the channel from an end thereofto fit between the elongate member and the channel interior and limit sliding to being substantially only in or parallel to the direction of the channel.

7. A mine roadway roof support as claimed in claim 4 or 5 or 6, wherein the lower ends of the upstanding parts are carried by self-aligning bearing blocks.

8. A mine roadway roof support as claimed in claim 7, wherein the bearing blocks are pivotal relative to the base members about transverse axes.

9. A mine roadway roof support as claimed in any preceding claim, wherein the roof-engaging member comprises a curved steel plate supported by a plurality of similarly curved girders attached to its underside.

10. A mine roadway roof support as claimed in claim 9 with claim 5, wherein the curved girders are each of I-section with lower parts of at least some of the girders comprising the slotted channel parts of the guide means.

11. A mine roadway roof support as claimed in any preceding claim, wherein each of the guide means comprises pairs of channels or said channels, elongate members or said elongate member, and retaining pieces or said retaining pieces.

12. A mine roadway roof support as claimed in any preceding claim, wherein the hydraulic prop means comprise a pair of props, conveniently spaced apart longitudinally of the support, one to each side of a central guide means.

13. A mine roadway roof support as claimed in any preceding claim, wherein the hoof-engaging member and/or base members have advancing rams attached at one end thereto, to extend behind the roof support to engage an abutment such as a fixed arch.

14. A mine roadway roof support as claimed in any preceding claim, wherein two or more roof supports are coupled together either by relatively acting advancing rams so that they are self-advancing or by fixed couplings.

15. A mine roadway roof support substantially as herein described with reference to and as illustrated in the accompanying drawings.

16. A mine roadway roof support system comprising a series of mine roof supports as claimed in any one of claims 1 to 15 arranged end-to-end, with their respective roof-engaging members fixedly interconnected to form a continuous arch.

17. A mine roadway roof support system as claimed in claim 16, wherein the respective base members are unconnected or only pivotably connected to permit their relative flexing to clear floor obstacles.

18. A mine roadway roof support system as claimed in any preceding claim, wherein each base member has a forward formation or attachment which, during support advance, serves to clear debris inwardly of the roadway.

19. A mine roadway roof support system as claimed in claim 18, wherein each base member has a front portion that is raked or tapered from outside to inside and also from top to bottom to give a ploughlike-effect during support advance.

20. A mine roadway roof support system substantially as herein described with reference to and as illustrated in the accompanying drawings.