GB2227780A - Roof support assembly - Google Patents

Abstract

A roof support assembly comprises a roof plate (122) which is hollow, and is provided on its underside, at a forward position thereof with a slot or opening (126), and on a rearward portion thereof with an extraction opening (127). An extractor unit is connected by a flexible duct (136) to the extraction opening (127) enabling air to be drawn through the inlet opening (126), together with dust entrained thereon, through a hollow duct provided by the hollow roof plate (122), and conveyed from the face of the working. <IMAGE>

Description

Title: "Mining machinery', Description of Invention This invention is concerned with improvements relating to mining machinery, and will be described hereinafter in relation to the mining of coal.

It is however to be appreciated that the invention is applicable to the mining of other materials.

A conventional mine working involves the use of a cutting machine operative to cut mineral material from a region being worked, and at least one roof support assembly extending at least in part over the cutting machine, to protect the cutting machine and mine working personel.

In most mining operations, large quantities of dust are created, which can be hazardous to the health of the personel, and at times constitute a safety hazard.

Considerable attention has been given over the years to providing a convenient and reliable method of removing dust created by the cutting machine.

According to this invention there is provided a mining system comprising a cutting machine and at least one roof supporting assembly behind the cutting machine and comprising a roof plate extending from a position above the machine, generally rearwardly thereof, wherein the roof plate provides an extraction duct through which air, and hence dust produced by the cutting machine, may be drawn from a position above the machine rearwardly thereof.

Preferably the system comprises impeller means to draw the air through the extraction duct, a flexible hose conveniently 'being provided extending between the extraction duct and the impeller means.

Advantageously the roof plate is hollow, and the extraction duct is provided by the hollow roof plate.

Where the system comprises two roof support assemblies, impeller means may be connected to the extraction duct of each of the roof support assemblies, to extract air from the working, and to convey the dust entrained thereon rearwardly of the working.

Conveniently however, the impeller means is connected to the extraction duct of one of the roof support assemblies, and an intermediate duct, preferably flexible, extends between said one roof support assembly and the other roof assembly.

According to this invention there is also provided a roof support assembly of the kind comprising a base, a roof-engaging superstructure, and a plurality of hydraulic rams extending between the base and the superstructure (such an assembly hereinafter being referred to as being of the kind specified), wherein the superstructure comprises a hollow roof support member, an opening being provided in said roof support member on a forward region thereof, and an extraction opening being provided therein on a rearward region thereof.

Preferably the opening is provided on the underside of the roof support member, so that air drawn into the roof support member through the opening is drawn from the region of highest dust creation.

Preferably the extraction opening is provided at a rearward region thereof, and is connected to a flexible duct.

There will now be given a detailed description, of a mining system and a roof support assembly for use in such mining system, which are illustrative of the invention, and which have been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings FIGURE I is a side elevation of the mining system which is the preferred embodiment of this invention, showing the illustrative cutting machine, together with roof support assemblies which are also illustrative of certain aspects of the invention; FIGURE 2 is a plan view taken on Figure l; FIGURE 3 is a rear elevation of the system; FIGURE 4 is a plan view of the illustrative cutting machine; FIGURE 5 is a rear elevation of the cutting machine; FIGURE 6 is a plan view of the cutting machine with a carriage thereof removed; FIGURE 7 is an underneath plan view of the cutting machine; FIGURE 8 is a vertical sectional view, taken on the line 8-8 of Figure 4, FIGURE 9 is a vertical sectional view, taken on the line 9-9 of Figure 4;; FIGURE 10 is a vertical sectional view, taken on the line 10-10 of Figure 4; FIGURE II is a vertical sectional view, viewed from the opposite side, showing an intermediate conveyor assembly; FIGURES 12, 13 and 14 are schematic front elevation, side elevation and plan view of a slide block and slide assembly of the machine; FIGURE 15 is schematic view illustrating the operation of a cutter disc of the machine in cutting mineral material from a face being worked; and FIGURES 16 to 19 are respectively face, side, rear and underneath views of a roof supporting structure of the embodiment.

The machine which is the preferred embodiment of this invention is adapted for use in cutting coal in ar; underground seam, and is designed specifically for operation on a relatively narrow front, typically between 5 metres and 10 metres. It is however to be appreciated that the principles of construction and operation of the machine may be utilised in the cutting of other mineral materials, in relation to narrower, or wider faces.

The machine which is the preferred embodiment of this invention is specifically for use in a mining system, also illustrative of certain aspects of this invention, comprising a plurality (e.g. three) self-advancing roof support structures, and conveying mechanism for conveying cut mineral material from the face being worked.

THE FRAME The machine comprises a frame 4 comprising a base plate 6 from which extends parallel side rails 8, 10, the rail 8 on the forward or face side of the frame being at a lower level than that of the rail 10, on the rear or goaf side of the working. The two rails 8 and 10 together provide a track way.

THE CARRIAGE Mounted on the track way is a carriage 20, comprising a single forward wheel 22 and a pair of rearward wheels 24 adapted to seat on the rails 8, 10 respectively. Mounted on either side of the wheels 24 are guide plates 26, secured to the underside at each of which is a stop plate 28, said stop plates as the wheel 24 travels along the rail, engaging the sides of the rail to retain the carriage centrally on the rail.

The carriage carries cutting mechansim comprising hydraulic drive mechanism, comprising a motor 30, and gear boxes 32, for twin cutting discs 34, 36. Each cutting disc 34 and 36 comprises two circumferential arrays of picks 38 and 40, the picks 38 extending a short distance axially forwardly of the picks 40, whilst the picks 40 extend radially slightly outwardly. Each cutting disc is mounted on one of two parallel axes, fixed in relation to the carriage, which extend at right angles to the direction of movement of the carriage on the track way.

Unlike larger shearer drums, which are intended to take relative deep cuts into the mineral wall being mined, the cutter discs of the subject machine are intended to take only a relatively shallow cut at each pass, typically between 50 mm and 200 mm, conveniently about 100 mm.

The cutter discs 34 and 36 are driven in opposite rotary directions, so as to enable torque loading to be balanced in the gear boxes.

On traverse of the face being cut, the foce is first attacked by the radially outer picks 38, which lift a first layer LI from the face (see Figure 15), typically of about 50 mm. The picks 38 act more as ploughs than conventional picks, whilst the radially inner but axially more advanced picks 40 following in the direction of traverse lift a second layer L2 from the face.

It has been found that, by utilising a cutter disc which acts primarily to lift the layer of mineral material from the face rather than simply breaking into the face, the power which is required is significantly reduced, in addition to achieving a reduction in the amount of noise and dust created.

CARRIAGE DRIVE Mounted on the frame above the base plate and between the rails are spaced sprockets 50, 52 around which an endless, round-link chain 54 extends.

One of the sprockets 50 is driven, through an hydraulic motor 56 and gearing 58, the other sprocket being idle. Secured to the underside of the carriage is a slide block 60, provided with a slot or channel 62, and slidable in slot 62 is a slide member 64 secured to one link of the chain 54 by a pin 66 (see Figures 6, 12, 13 and 14.) Thus as the chain is driven between and around the sprockets 50, 52, the slide member 64 moves along one reach of chain, carrying the carriage in one direction, and as the pin 66 travels around the sprocket at the end of said reach the carriage decelerates as the slide member 64 travels in said slot 62, and the carriage is then accelerated as the pin 66 moves along the opposite reach of the chain.

In the preferred embodiment the slot 62 is angled in the direction of travel of of the carriage, conveniently at an angle of between 350 and 800, conveniently about 600. In this manner reaction forces between the pin, the slide plate and the block, which cause linear movement of the carriage, may be reduced as the pin passes through the top dead centre position in relation to the sprocket.

In relation to the diameter of the two cutter discs, the distance between top dead centre of the two sprockets 50, 52, is such that, at each of the extreme positions of the carriage on the track way, a vertical centreline of one of the cutter discs occupies a vertical central position of the machine, to ensure that, during successive traverses of the machine across the face, a cut of mineral material is taken which extends the full height (and depth) of the working. In fact, desirably the machine is set up such that there is some overlap between the vertical centreline positions of the two cutter discs, to allow scope for (e.g.) chain stretch.

STEERING MECHANISM The machine comprises a supporting means for the frame, whereby the frame, and thus the bulk of the machine, are retained at a position raised slightly above the ground.

The supporting means comprises two support members afforded by toe plates 80 (see Figure 9) which are pivotally mounted at spaced positions on the forward side of the machine so as to extend generally downwardly, and generally towards the face being worked. Slightly rearwardly of a longitudinal centreline, and generally midway between the ends, there is provided on the underside of the frame a third, goaf-side support member 28 which provides an arcuate surface about which the machine as a whole may tilt. Specifically, the support member 82 is afforded by a shoe to which the frame is pivotally mounted, as shown at 83 (see Figure 10.) The forward support members 80 are each pivotally mounted at 86 on the forward frame rail 8, and are each connected, by a link 88, to the piston 89 of an hydraulic ram 90.By the application of hydraulic fluid to the ram 19, the forward support member 80 may individually be moved about its fulcrum, adjusting its heightwise position in relation to the system.

Thus by simultaneous movement of the two toe plates 80 in the same direction, the machine may be tilted about a horizontal axis extending parallel to the direction of movement of traverse of the cutting mechanism over the frame, whilst by disparate adjustment of the two toe plates 80, the machine as a whole may be tilted about an axis extending at right angles to the direction of traverse.

In this manner the machine may be "steered" to follow the inclination of the seam being worked.

Control of the two hydraulic rams 90 may be exercised by a control panel (not shown) whereby the toe plates may be moved to desired positions.

However to compensate for leakage of hydraulic fluid over a prolonged period of use, each of the rams is connected by an adjustment rod 92 to a manuallyoperable control member 94, in the form of a cam which bears against the rear face of the rail 10. With the hydraulic pump inoperative, the position of the piston may be adjusted by rotation of the control member 94 to set the ram (and hence the toe plate) to a datum position prior to activation of the hydraulic control.

CONVEYOR MECHANISM Mounted above the base plate 6 of the frame is a deck plate 12, providing the bed of a scraper conveyor, the deck plate 12 being provided with an outlet hole 14 for exit of cut mineral material. Extending through the deck plate, and spaced apart in the longitudinal direction, are spindles 15, one of which being driven by an hydraulic drive motor 57, carrying sprockets 16 around and between which a round-link chain 17 extends, upon which at spaced intervals flights or vanes 18 extends, said vanes travelling over the top plate and engaging the inside faces of the rails 8 and 10 to provide a conveyor 11.

Extending forwardly from the inner rail 8, and passing beneath the toe plate, is an inclined ramp 19, up which cut mineral material is pushed by operation of the cutter discs, to fall onto the deck plate to be conveyed by the conveyor through the outlet hole 14.

ROOF SUPPORT STRUCTURE Mounted behind the machines are three self-advancing support assemblies 100 each comprising a base 120, and a roof supporting member or roof plate 122, between which extend a plurality of hydraulic rams 124. Each assembly comprises, in conventional manner, an inner assembly and an outer assembly. In use, the roof plate 122 may be urged against the roof by either said inner or soid outer assembly. Thus, when the roof plate is clamped in position by the outer assembly, the rams of the inner assembly may be relaxed, and the inner assembly may be advanced by horizontally-operating rams. The roof plate is then clamped against the roof by the inner assembly, and the rams at the outer assembly may be relaxed, and the outer assembly may be moved forwardly by said horizontal rams.

The roof plate 122 of each assembly 100 is provided with an elongate slot 104, which opens to the rear edge of the roof plate. In this manner a mine worker may support the roof of the working by inserting into the roof through the slot 104, a number of roof bolts, whilst remaining fully protected by the roof support assembly. Subsequent to advance of the roof support assembly, girders 106 (which are conveniently carried on brackets 108 provided on the rear of the support assembly) may be secured to the roof.

Provided on a forward region of the base 120 of each roof support assembly is an hydraulic ram 109, which may be operated to urge the frame of the cutting machine forwardly, as will hereinafter be explained.

Secured to the rear of one roof supporting assembly is a primary conveyor 110, operative to remove cut mineral material from the mine working, which is pulled forwardly as said roof support assembly advances.

Thus, an intermediate conveyor 112, secured to the underside frame 4 and extending beneath the outlet 14, extends rearwardly to deposit mineral material on said primary conveyor 110.

DUST EXTRACTION SYSTEM The roof plate 122 of each support assembly 100 is hollow, and is provided, on its underside at a forward portion thereof, with a slot or opening 126 (see Figure 19.) Provided on the underside of each roof plate 122, on a rearward portion thereof, is an extraction opening 127, enabling air to be drawn through the extraction duct provided by the hollow roof plate from a position above the working generally rearwardly.

If desired each opening 127 may be connected directly to a dust extractor unit, conveniently being connected to said opening 127 by an elongate flexible duct extending rearwardly of the working.

Conveniently however transfer ducts 128, 130 are provided between the first and second, and between the second and third assemblies, the opening 127 of the third assembly being connected to an extractor unit 140 by a flexible duct 136. Thus, by the use of a single impeller, air may be drawn directly from the opening 126 of the hollow roof plate of the left-hand roof support assembly (Figure 18), and, by way of the ducts 128 and i30, through the roof plates 122 of the other two roof support assemblies.

Conveniently the dust extraction unit is located a distance rearwardly of the working, and if desired may be connected to one of the roof support assemblies, so as to follow the direction of advancement of the working.

Conveniently an inlet unit 142, for the supply of fresh air, opens at a position between the working and the extractor unit 140.

As will be appreciated from Figure 18, the use of flexible couplings 128, 130, 132 permits for relative movement between the three roof supporting assemblies, as they advance towards the working.

GENERAL OPERATION It is to be appreciated that the various components of the system the subject of this application, included the frame, carriage, drive motors, roof support assemblies and conveyor mechanism, are contained, in the direction of the working, by an envelope E defined by the parallel lines extending between the outer edges of the cutting discs and the outer parts of the circumference of the cutting discs at their extreme positions of travel, as is shown in Figure 3.

With the machine extending generally parallel to the face being worked, the rams 109 of the roof support assemblies are advanced to push the frame forwardly, and the rotary cutter discs into the face, to an advanced position defined by engagement of the toe plates 80 with the wall, in a partial "sumping" operation. The carriage is then fully traversed (back and forth), taking a desired depth of cut from the face, and forces cut mineral material up the ramp 19 onto a conveyor II. On completion of the travserse the rams 109 of the roof support assemblies are advanced, pushing the machine forwardly and the toe plate into engagement with the newly cut face, reciprocation of the carriage being continued.

Coal is pushed onto the conveyor II, and falls through the outlet 14 onto the intermediate conveyor, and is conveyed thereby to and deposited on a primary conveyor, which is pulled forwardly by said one roof support assembly as the mine working advances.

On meeting an upward inclination of the face being worked, the hydraulic ramps 19 may be instoked to lower the toe plate against the floor, raising the frame slightly, the frame tilting about the central shoe, and causes the cut taken by the cutting disc to be elevated slightly.

On meeting a sideway inclination, the toe plate 80 on the higher side is lowered, tilting the machine about the shoe, about an axis extending in the direction of advancement of the face.

In the event of it becoming necessary to withdraw the machine from the working, the picks may be removed from the cutting discs, and the hydraulic ramps 90 fully outstroked, lowering the cutter discs to a level at which the machine as a whole may pass rearwardly beneath the girders utilised in the roof supporting operation.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in termsof a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (12)

CLAIMS:

1. A mining system comprising a cutting machine and at least one roof supporting assembly behind the cutting machine and comprising a roof plate extending from a position above the machine, generally rearwardly thereof, wherein the roof plate provides an extraction duct through which air, and hence dust produced by the cutting machine may be drawn, from a position above the machine rearwardly thereof.

2. A system according to Claim I comprising impeller means to draw the air through the extraction duct.

3. A system according to Claim 2 comprising a flexible hose extending between the extraction duct and the impeller means.

4. A system according to any one of the preceding claims wherein the roof plate is hollow, and the extraction duct is provided by the hollow roof plate.

5. A system according to any one of Claims 2, 3 and 4 comprising two support assemblies, impeller means being connected to the extraction duct of each of the roof support assemblies.

6. A system according to any one of Claims 2, 3 and 4 comprising two roof support assemblies, the impeller means being connected to the extraction duct of one of the roof support assemblies and an intermediate flexible duct extending between said one roof assembly and the other roof assembly.

7. A roof support assembly comprising a base, a roof-engaging superstructure, and a plurality of hydraulic rams extending between the base and the superstructure, wherein the roof-engaging superstructure comprises a hollow roof support member, an opening provided in said roof support member on a forward region thereof, and an extraction opening provided therein on a rearward region thereof.

8. A roof support assembly according to Claim 7 wherein said opening is provided on an underside of the roof support member.

9. A roof support assembly according to one of Claims 7 and 8 wherein the extraction opening provided at the rearward region thereof is connected to a flexible duct.

10. A mining system comprising a cutting machine, at least one roof supporting assembly, and dust extraction system constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

11. A roof support assembly constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

12. Any novel feature or novel combination of features as hereinbefore described and/or as shown in the accompanying drawings.