GB2129851A - Mining machine - Google Patents

Abstract

A stable hole machine comprises a frame having a pair of arms (12) pivotally mounted thereon and carrying at their ends a drum shaft (22) supporting a cutter drum (20) between the arms and further cutter drums (26, 28) cantilevered on the outside of each arm. One of the cantilevered drums and the drum between the arms have scrolls thereon to progress excavated material towards the other cantilevered drum and shields are provided behind the drums provided with scrolls. <IMAGE>

Description

SPECIFICATION Improvements in or relating to mining The invention concerns a machine for forming stable holes in a face of mineral material, especially coal, to be excavated.

The invention is applicable to longwall coal mining, in particular to the provision of stable holes so that the main coal production machine can commence a new cut along the wall without the need to make a series of short cuts by being moved directly into the buttock provided by the stable hole machine.

Most longwall mining operations provide stables for the main production machine in the form of pre-driven roadways such as advance headings, and gate roads pre-driven for retreat longwall excavation. The stable hole machine of the present invention is intended to operate on advanced longwall installations where it is not possible to use the advanced heading technique, the stable hole machine providing space at the ends of the face for the main production machine to pick up its new cut on the buttock the stable hole machine provides.

The present invention provides a stable hole machine comprising a frame having at least one arm pivotally mounted thereon, the or each arm carrying at or near its free end at least one cutter drum rotatable about a first axis substantially perpendicular to the arm.

Preferably the machine includes two arms which support a first rotary cutter drum therebetween and, cantilevered from the outer side of each arm a shorter rotary cutter drum rotatable about the same axis as the first drum.

Preferably the or each cutter drum is driven by a drive assembly mounted on the frame and connectable with the drum(s) by a chain carried on an arm. The drive assembly may include a motor, a gear box and a drive sprocket at the output shaft of the gear box.

Preferably a driven sprocket is mounted on a shaft carrying said cutter drums in a space between said first drum and one of said shorter drums, said chain is provided with excavating picks and the diameter of said driven sprocket is such that the external diameter of the chain and pick assembly is equal to the external diameter of said drums.

The first drum preferably has scroll vanes thereon to direct material removed by the drum to one end thereof and one of said cantilevered shorter cutter drums has scrolls thereon to direct material moved by the said drum towards the first drum. The other shorter cutter drum is provided with means to discharge material towards conveyor means arranged adjacent to the machine.

Preferably material guide means are provided behind the first drum and one of the shorter drums, said guide means comprising two plates, one intended to rest on the floor of the stable hole being excavated, the other moving with said arm(s), with one plate always overlapping the other.

Preferably an hydraulic piston and cylinder device is arranged between the arm(s) and the frame to cause pivotal movement of said arm(s).

A further sprocket may be mounted on said shaft carrying the cutter drums in the space between the first cutter drum and the other shorter cutter drums, said further sprocket mounting a chain provided with paddles for removing excavated material to the rear of the machine and passing over a further sprocket freely rotatable on the other arm. Alternatively the arm adjacent the second shorter cutter drum is cranked to provide clearance behind the said drum to facilitate material discharge.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a plan view of part of a stable hole machine, and Fig. 2 is an end view taken in the direction of arrow A.

The apparatus shown in Fig. 1 comprises a stationary main frame 10 (Fig. 2) upon which is pivotally mounted, for movement about a horizontal axis, a pair of arms 12 and horizontal bracing member 14. The arms are movable about a horizontal axis 1 6 by a pair of piston and cylinder assemblies one end of each of which is fixed to the main frame, another end of each being fixed at points 1 8 of the bracing member 14. The arms 12 between them mount a first cutter drum 20 mounted for rotation about a horizontal axis. The cutter drum is provided with a plurality of picks 22 for excavating coal for the coal face C and a plurality of scrolls which, in the operational rotational direction of the drum, progress excavated coal to the left as shown in the drawing.

The cutter drum 20 is mounted against rotation on two stub shafts 22 each of which is journalled in a bearing 24 at the outer end of each arm 12, each shaft 22 extending beyond the arm 12 away from the cutter drum 20 and having mounted on these cantilevered arms outer cantilevered shorter cutter drums 26, 28. The cutter drum 28 is of greater axial length than the cutter drum 26, each is provided with excavating picks and the latter (26) is provided with scroll vanes which progress excavated coal towards and into the first cutter drum 20.

The stub shaft 22 carrying the cutter drum 26 is driven by a chain and sprocket drive, the drive sprocket 30 of which is mounted on one of the arms 12 to which is mounted a drive assembly comprising a motor 32 and a gear box 34, the output shaft of which carries the sprocket 30. A chain which is shown diagrammatically in the drawing is carried by the drive sprocket 30 and extends over a driven sprocket 36 fixed to the said shaft 22. The driven sprocket 36 and the portion of chain carried by it is accommodated between the first shorter cutter drum 26 and the first cutter drum 20 and is provided with excavating picks shown diagrammatically at 38 for excavating material not touched by the drums 20 and 26.

The other stub shaft 22 carrying the second shorter cutter drum 28 also carries a chain sprocket 40 which guides a chain 42, the chain being guided also by a freely rotatable sprocket 44 carried on the other arm. This second chain 42 is also provided with excavating picks 46 and material moving paddles (not shown).

The diameter of the driven sprocket 36 and the corresponding sprocket 40 on the other stub shaft 22 are such that the external diameter of the chain and sprocket assemblies are equal to the external diameter of the cutter drums so that the arrangement excavates a substantially flat face and on movement into the face C provides a buttock B into which the main production machine designated generally by the reference numeral T can work.

Material guide means (Fig. 2) are provided on the side of the drums 20 and 26 on the side thereof remote from the coal face C. The guide means comprise a first member 50 which extends substantially from floor level and is carried by the frame 10 and a second movable member 52 carried by the arms 12. It will be appreciated that as the arms 1 2 are moved by the piston and cylinder assemblies to bring the drums from the lowermost position shown in full lines in Fig. 4 to the uppermost position shown in phantom lines, the material guide means will extend over substantially the full height of the excavated hole so that excavated material cannot fall backwards into the machine but must be guided along the second chain 42 and the second shorter cutter drum 28.At this location the excavated material can move rearably onto the connecting pan 54 of the main production machine and be removed from the area of excavation.

In use, the stable hole machine is advanced towards the coal face C and coal is cut away to provide a stable hole for the main production machine. Two machines are provided, one at each end of the face to be excavated. The height of the hole cut is determined by movement of the piston and cylinder assemblies raising and lowering the cutter drums 20, 26, 28. It will be realised that the floor of the stable hole excavated and the roof thereof can be inclined or horizontal in the direction of progression into the coal face.

Various modifications can be made without departing from the scope of the invention. In certain situations it may be possible to dispense with the second chain 42 in which case the arm alongside which said chain is mounted is cranked towards the other arm to provide a clear area for material being ejected by the second cutter drum 28 which, if necessary, may be provided with paddles. The end of the cranked arm may be provided with a wedge-shaped pick to remove coal from the area between the drums 20 and 28.

In a further modification only one cutter drum is provided and this need not be mounted between a pair of arms but could be mounted in a cantilevered manner from a single arm. The various dispositions of the components of the machine may be altered to suit the operating conditions, for example the drive assembly can be mounted such that the axis of the drive sprocket 30 coincides with the pivotal axis of 1 6 of the arm 12.

Claims (15)

1. A stable hole machine comprising a frame having at least one arm pivotally mounted thereon, the or each arm carrying at or near its free end at least one cutter drum rotatable about a first axis substantially perpendicular to the arm.

2. A machine as claimed in claim 1, including two arms which support a first rotary cutter drum therebetween and, cantilevered from the outer side of each arm a shorter rotary cutter drum rotatable about the same axis as the first drum.

3. A machine as claimed in claim 1 or claim 2, in which the or each cutter drum is driven by a drive assembly mounted on the frame and connectable with the drum(s) by a chain carried on an arm.

4. A machine as claimed in claim 3, in which the drive assembly includes a motor, a gear box and a drive sprocket at the output shaft of the gear box.

5. A machine as claimed in claim 3 or claim 4, in which a driven sprocket is mounted on a shaft carrying said cutter drums in a space between said first drum and one of said shorter drums, said chain is provided with excavating picks and the diameter of said driven sprocket is such that the external diameter of the chain and pick assembly is equal to the external diameter of said drums.

6. A machine as claimed in any one of claims 2 to 5, in which the first drum has scroll vanes thereon to direct material removed by the drum to one end thereof.

7. A machine as claimed in any one of claims 2 to 6, in which one of said cantilevered shorter cutter drums has scrolls thereon to direct material moved by the said drum towards the first drum.

8. Apparatus as claimed in claim 7, in which the other shorter cutter drum is provided with means to discharge material towards conveyor means arranged adjacent to the machine.

9. A machine as claimed in any one of claims 2 to 8, in which material guide means are provided behind the first drum and one of the shorter drums.

10. A machine as claimed in claim 9, in which said guide means comprise two plates, one intended to rest on the floor of the stable hole being excavated, the other moving with said arm(s), with one plate always overlapping the other.

11. A machine as claimed in any one of the preceding claims, including an hydraulic piston and cylinder device arranged between the arm(s) and the frame to cause pivotal movement of said arm(s).

12. A machine as claimed in any one of claims 2 to 11, in which the arm adjacent the second shorter cutter drum is cranked to provide clearance behind the said drum to facilitate material discharge.

13. A machine as claimed in any one of claims 2 to 11, in which a further sprocket is mounted on said shaft carrying the cutter drums in the space between the first cutter drum and the other shorter cutter drum, said further sprocket mounting a chain provided with paddles for removing excavated material to the rear of the machine and passing over a further sprocket freely rotatable on the other arm.

14. A machine substantially as hereinbefore described with reference to the accompanying drawings.

15. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.