GB2072126A - Improvements in and relating to face conveyors - Google Patents

Abstract

A combined face conveyor and stage loader for use in longwall coal mining methods consists of a continuous length of chain comprising alternate sections of chain links and blocks (20), each block (20) having two flight bars hingedly attached to it, teeth (25) of sprocket wheels (5) driving the conveyor engaging the chain blocks (20) to supply motive power to the chain while the flight bars adjacent to each wheel (5) are pivoted out of engagement with the wheel. The return chain path can be either located under the haulage chain path or adjacent to the haulage chain path in which case the flight bars of the return chain are kept in a vertical position. <IMAGE>

Description

SPECIFICATION Improvements in and relating to face conveyors The present invention relates to an improved face conveyor and in particular to a combined face conveyor and stage loader for use in longwall coal mining methods to remove coal from the coal face.

One prior art transportation system used in longwall mining for removing mined products from the face to the main roadway generally comprises a face conveyor installed at the face, a separate stage loader, and a belt conveyor in the maingate roadway.

The face conveyor and the belt conveyor in the maingate roadway are substantially at right angles to each other with the stage loader transferring mined material from the face conveyor to the belt conveyor. With this transportation system, when materials are mined in large lumps, there frequently occurs tie-ups or jamming at a transfer point where the stage loader and the face conveyor overlap, as the face conveyor and the stage loader are arranged at right angles to each other at the maingate junction of the maingate roadway and the face. The jamming thereby disrupts smooth transportation of the mined products. It is therefore necessary to stop the conveyor and remove the lumps. This is both time consuming and requires unproductive use of labour.Furthermore extra power is needed for the conveyor drive as the return chain is often jammed by fines not discharged to the stage loader because of the lumps.

The present invention ameliorates these problems at the maingate junction by integrating the face conveyor and the stage loader. This also results in reduced maintenance owing to the simplification of the system.

In other prior art there is a combined face conveyor and stage loader, however, it requires sprocket wheels of comparatively large diameter to curve the conveyor at the maingate junction. In this arrangement the conveyor consists of a continuous chain with fixed flight bars extending therefrom the end of the flight bars being engaged by the sprocket wheel to move the chain along the surface to transport the mined material.

Accordingly, in a retreating longwall system, the large wheel obstructs a mining machine from cutting into the maingate junction particularly at the floor level. Thus the prior art combined face conveyor and stage loaders is not suitable for efficient use in a retreating longwall mining operation.

The present invention overcomes the previously mentioned problem by providing a combined face conveyor and stage loader comprising: a continuous length of chain comprising alternate sections of chain links and blocks, each block having two flight bars hingedly attached thereto; and sprocket wheels, at least one of which is a drive wheel, said wheels being adapted to rotate in a horizontal plane, the teeth of the sprocket wheels engaging the blocks of the chain or the chain to supply motive power thereto while the flight bars adjacent the wheel are pivoted out of engagement with the wheel.

Therefore the diameter of the wheels at the maingate junction in the present invention can be made smaller than in the prior art thus the conveyor of the present invention is suitable for use in retreating longwall mining as well as in advancing longwall mining.

It is a general tendency with face conveyors that the diameters of the drive wheels increase as the pitch of the chain, together with its thickness, increases. This continuous increase in size of drive wheels in the existing vertical arrangement produces problems in mining design because of the necessity to increase the height of drive frame accordingly within a limited ceiling. Since the said invention utilizes a horizontal arrangement of sprocket wheels, there is no appreciable change on the ceiling limit when it is necessary to size up a chain. Moreover, the chain used in the invention can also be elliptical when reinforcing is necessary so that there is no necessity to alter the chain height.

It is desirable to have a low conveyor pan to operate with the continuous mining machine in order for the mined ore or coal to be loaded smoothly onto the conveyor. However in existing conveyor pans two chain paths are used, one for hauling materials and the other being the returning chain; these being arranged one above the other.

In one embodiment of the present invention the two paths can be arranged so that the returning chain runs along the side of the conveyor pan with the flight bars in a folding state. Therefore, the total height of the conveyor pan is reduced by about half the height of the conventional conveyor pan if the size of the chains of both conveyors are the same. This arrangement improves the effectiveness of loading and also, is a great advantage in a thin longwall mining seam where the height of each machine is critical.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 illustrates a layout of the conveyor according to an embodiment of the present invention; Fig. 2 is a sectional view taken along the lines Il-Il of Fig. 1; Fig. 3 illustrates another layout of the conveyor according to another embodiment of the present invention; Fig. 4 is a sectional view taken along the lines IV--IV of Fig. 3; Fig. 5 illustrates a detailed view of a section of the chain in the embodiment illustrated in Fig. 1; Fig. 6 is a sectional view taken along the line VI-VI of Fig. 5; Fig. 7 is a sectional view taken along the line VIl-VIl of Fig. 5;; Fig. 8 is a plan view of the engagement of a sprocket wheel and the chain of the embodiment illustrated in Fig. 1; Fig. 9 is a sectional view taken along the lines IX-IX of Fig. 8; Fig. 10 is a sectional view taken along the line X-X of Fig. 8; Fig. 11 is a sectional view taken along the line Xl-Xl of Fig. 8; and Figs. 12 and 13 illustrate two other types of chains suitable for use with the present invention.

Fig. 1 shows an embodiment of the present invention being used in coal mining method in which (1) is the maingate roadway, (2) is the coal face and (3) is the tailgate roadway. In this case, the said face conveyor (4) has a drive at the maingate side and tailgate side respectively, but it can use only a maingate drive depending on the length of coal face. At the maingate drive, the sprocket wheel (5) fixed to the shaft (6) is driven in a horizontal plane through the reducing gear box (7) by an electric or hydraulic motor (8). At the tailgate drive, the sprocket wheel (10) fixed to the shaft (9) is driven in its horizontal plane through the reducing gear box (11) by an electric or hydraulic motor (12).The guide sprocket wheel (13) changes the direction of travel of the chain through approximately 90 guiding the chain units (14) at the junction of maingate roadway (1) and face (2). Coal mined from the face (2) miner (not shown) and loaded to the face conveyor (4) from the coal face (2) will be transported in the direction of the arrow (15) by the chain units (14) to the maingate driving wheel (5). At the maingate driving wheel (5), the coal is discharged to the belt conveyor (17) located under the maingate driving wheel (5) where the plate (16), over which the chain units travel, terminates, while any coal carried on the sprocket is released to the belt conveyor ( 17) forcibly by the separator board (1 8).

The arrangements of the hauling conveyor chains path (14') and the returning chains path (14") are as shown in Fig. 2.

In Figs. 3 and 4 are illustrated another embodiment of the combined face conveyor and stage loader of the present invention. In this embodiment the hauling conveyor chains path (14') and the returning chain path (14"') are located in a side to side relationship as compared to the one being on top of the other as is illustrated in Figs. 1 to 2.

The returning chain path (14"') brings the chain (14) against a guide plate (24) similar to that illustrated in Fig. 9 adjacent the wheel (5) to raise the flight bars (21) clear of engagement with the wheel (5). A continuation (40) of this guide plate together with a guide plate (39) located on the other side of the chain urges the flight bars (21 ) to a vertical position as shown by the returning chain in Fig. 4. The flight bars are then kept in the vertical position until the returning chain approaches the sprocket wheel (10) where the flight bars (21) are lowered to the haulage position.

A chain unit (14) as shown in Figs. 5 to 7, comprise of a chain link (1 9), a pair of flight bars (21), and connecting block (20). The block (20) has an upper member (26) and bottom member (27) fixed together by a bolt and a nut at the hole (28). The chain link (19) is held between the two members of the connecting block (20), the projection (22) of the lower member (27) limiting the links movement but allowing some play horizontally and vertically.

The flight bars (21) is connected to the connecting block (22) by the pin (23) to allow for pivotal upward movement. When sprocket wheels (5) engage the chain as shown in Fig. 8, the flight bars (21) slide up by the guide plate (24) so as not to come into contact with the wheel (5).

In the embodiment illustrated in Fig. 9 the chamfered shoulder (30) slides along the face (31) of the guide plate (24) lifting the flight bar (21) clear of engagement with the wheel (5).

The sprocket tooth (25) engages the block (20) and (20') between upper sprocket wheel radial projection (32) and lower sprocket wheel radial projection (33). Each of these radial projections contain respective small projections (34) and (35) which fit between the blocks (20) and (20'). These small projections are preferably shaped as shown in Fig. 8 on tooth (36) where the top radial projection (32) has been cut away to show the engagement of the projection 34 and the two blocks (20") and (20'). It is therefore quite clear that the motive force of the drive wheels are transmitted by the sprockets to the blocks (20) of the haulage chain. No force being directly exerted onto the chain links or the flight bars themselves.

Another embodiment of the chain unit of the conveyor is illustrated in Fig. 12. The unit comprises chain links (19) joining each one piece connecting block (37) to adjacent blocks, with the flight bars (21) being pivotally connected to the connecting blocks (37) by pins (38).

A further embodiment of the chain unit is illustrated in Fig. 13, wherein the block is in essence identical to that illustrated in Fig. 12 with two separate chain arrangements 41 joining adjacent blocks 37 together.

The present invention therefore produces a novel face conveyor which discharges the mined products directly into the maingate conveyor and which is driven by a horizontally rotating drive wheel, the diameter of which is smaller than existing drive wheels for the same size chain, due to the motive force being applied from the wheel to the connecting blocks or the chain and not to the ends of the flight bars.

It is obvious to people skilled in the art that the embodiments discussed in the foregoing could be modified without departing from the spirit of the invention.

Claims (4)

1. A combined face conveyor and stage loader comprising: a continuous length of chain comprising alternate sections of chain links and blocks, each block having two flight bars hingedly attached thereto; and sprocket wheels, at least one of which is a drive wheel, said wheels being adapted to rotate in a horizontal plane, the teeth of the sprocket wheels engaging the blocks of the chain or the chain to supply motive power thereto while the flight bars adjacent the wheel are pivoted out of engagement with the wheel.

2. A combined face conveyor and stage loader according to claim 1 wherein said blocks are joined by two separate chain sections to adjacent blocks.

3. A combined face conveyor and stage loader according to claim 1 or claim 2 wherein the return chain path in the face conveyor section is located adjacent the haulage path of the chain remote from the face, with the flightbars in a substantial vertical position.

4. A combined face conveyor and stage loader substantially as hereinbefore described with reference to the accompanying drawings.