GB2121087A

GB2121087A - Mineral mining machines

Info

Publication number: GB2121087A
Application number: GB08312967A
Authority: GB
Inventors: Henry Mcgaw Brown
Original assignee: Anderson Strathclyde PLC
Current assignee: Anderson Strathclyde PLC
Priority date: 1982-06-01
Filing date: 1983-05-11
Publication date: 1983-12-14
Also published as: GB8312967D0

Abstract

A mineral mining machine comprising a shearer disc or drum on which is mounted a plurality of cutter picks some of which are arranged to overhang the face side of the disc or drum to cut top and side clearance, and all of which are identical in shape and are mounted to have an identical angle of attack which lies in the range 20 to 35 DEG . <IMAGE>

Description

SPECIFICATION Mineral mining machines The invention relates to mineral mining machines of the nature of shearer disc or drum machines. Conventionally such machines employ a plurality of mineral mining picks each of which comprises a shank adapted for reception in a correspondingly shaped socket in a holder and a portion extending from the shank which portion is formed with a cutting edge or tip usually of a hard material such as tungsten carbide. The holders for such picks may be secured by welding to the helical vanes of a shearer drum. In such an arrangement it is conventional to mount some of the picks on the periphery of the drum so that they project axially beyond one end of the drum to provide top and side clearance on the face side of the drum.It is known to provide coal cutter picks which project more or less radially from the drum and it is also known to provide so-called forward attack picks which are forwardly inclined, considered in the direction of rotation of the drum, so that the cutting forces acting on the pick are absorbed more favourably as compared with radial picks. Although it is preferred to use such forward attack picks it is not practical to do so to provide top and side clearance on the face side of the drum since when such picks are inclined axially of the drum their axial length is insufficient to provide the necessary working clearance. It is thus necessary to use radial picks with their inherently greater effective gauge to provide top and side clearance.It is obviously undesirable to use two different types of pick and holder on one machine especially where the working load of one pick is different from that of the other pick and the present invention seeks to avoid this disadvantage of known arrangements.

We provide an arrangement in which it is possible for all of the picks and holders on the shearer drum to be of identical construction, this being achieved by selecting an angle of inclination for the picks which angle is intermediate that of a radial pick and that of a forward attack pick. This can be achieved by suitably angling the pick holders on the drum and/or by angling the working portions of the picks with respect to the pick shanks.

According to the invention the is provided a mineral mining machine comprising a shearer disc or drum on which is mounted a plurality of cutter picks some of which are arranged to overhang the face side of the disc or drum to cut top and side clearance, and all of which are identical in shape and are mounted to have an identical angle of attack which lies in the range 20 to 350.

A mineral cutter pick adapted to be mounted on the mineral mining machine described above may comprise a body having a frusto-conical shank for accommodation in a correspondingly shaped recess on a support on the mineral mining machine to mount the pick on the machine, said shank being adjacent its inner end not substantially less in diameter than at its outer end, and the body having a forward end carrying a cutting tip. Preferably said body has a passage therethrough for liquid which passage leads from an inlet in the side wall of the shank to at least one liquid outlet adjacent to the cutting tip.

A holder for the mineral cutter pick described above may have a base shaped as a part cylinder, the axis of the part cylinder being aligned with the cutting direction of the cutter pick to be mounted in the holder, whereby the holder can be rotated about the axis into a suitable position on the shearer disc or drum before being finally secured thereto, e.g by welding. If desired a water passage may extend from a position substantially on the said axis in a face of the holder which is perpendicular to the said axis to the interior of the recess for accommodating the shank of the cutter pick.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which: Figures 1 to 3 illustrate a conventional radial pick positioned on the vane of a shearer drum; Figures 4 to 6 illustrate a conventional forward attack pick mounted on the vane of a shearer drum: Figure 7 is a side view of a semi forward attack pick in accordance with the invention mounted in a holder attached to the vane of a shearer drum; Figure 8 is an end elevation of a vane of a shearer drum showing a pick and pick holder in accordance with Figure 7 mounted in various different positions between the normal upright position and the "rolled over" axially projecting position in which the pick cuts top and side clearance for the face side of the shearer drum; Figure 9 is a side view of a modified form of mineral cutter pick mounted in a holder on the vane of a shearer drum; and Figure 10 is an end elevation of the combination shown in Fig. 9 and with the holder "rolled over" to provide clearance at the face side of the drum.

With reference to Figures 1 to 3 of the drawings there is shown a conventional radial coal cutter pick 1 which comprises a forward part or blade 2 having a hard cutting tip 3 and a shank 4 arranged for reception in the correspondingly shaped recess 6 of a holder or box 5 which is secured, e.g. by welding, to the vane 7 of the rotary shearer drum of a mineral mining machine.

It will be seen that the pick gauge indicated by dimension A in Figure 2 is reduced to dimension a when the pick and holder are "rolled over" (so that the pick can cut top and side clearance at the face side of the drum) but that in this position an adequate side clearance indicated by dimension B in Figure 3 is provided.

In Figures 4 to 6 there is shown a forward attack coal cutter pick and holder which is generally similar to the radial pick of Figures 1 to 3 except that the axis of the pick is forwardly inclined, relative to the upright or radial at an angle in the region of 50 .

The forward attack pick shown in Figures 4 to 6 is inherently better situated to receive the cutting forces generated during use of the mineral mining machine as compared with the radial pick of Figures 1 to 3 whilst still retaining an adequate clearance or effective gauge as shown by dimension C in Figure 4 that is to say when used upright. If however the pick and holder are rolled over as shown in Figure 6 the top and side clearances indicated by dimensions c and D respectively are insufficient for normal cutting operations. Consequently where forward attack picks are fitted to a shearer drum or other cutting head, these can only be positioned upright thus making it necessary to use conventional radial picks of the kind illustrated in Figures 1 to 3 for the purposes of providing top and side clearance at the face side of the drum.

A semi forward attack pick and holder generally similar to those described above but in accordance with the present invention is shown in Figure 7.

The purpose of the semi forward attack arrangement is to provide a pick and holder that will be capable of use in alt positions on the drum whether vertical or anguiar. As can be seen from Figure 8 of the drawings adequate side and top clearance is provided when the pick and holder are rolled over. The angle of attack of a pick in accordance with the invention measured from the vertical or radial will be in the range of 20 to 350 and advantageously is in the range 28 to 30". The preferred angle of attack is 300.

In Figures 9 and 10 of the drawings there is shown a coal cutter pick 1 comprising a body 2 formed at its forward end with a cutting tip 3 of a hard material such as tungsten carbide the body being formed with a frusto-conical shank 4 arranged for reception with a tight wedging fit in a correspondingly shaped socket 6 in a support 5 welded to the vane 7 of a mineral shearer drum not shown.

The inner end of the socket 6 of the holder 5 is terminated by a transverse slot 8 which extends through the holder to expose the rearward end of the shank 4 of a pick mounted in a holder. In this manner removal of the pick from the holder is facilitated since a tool, e.g. a wedge, may be engaged with the rear end of the pick to force it from the holder.

A water conduit 9 is provided extending through the vane of the mineral shearer drum which conduit connects with a conduit 10 which extends through the holder 5 and emerges into the socket 6. The mineral cutter pick 1 is formed with a radially extending bore 11 in its shank 4 which bore communicates with the passage 10 in the holder and the radial bore 11 connects with a longitudinally extending bore 1 2 which extends forwardly into the vicinity of the cutting tip 3 and which communicates with bores 1 4 and 1 3 which emerge from the body of the pick near the front face and rear face respectively of the cutting tip 2.

The rearward end of the bore 12 which may be formed by drilling is plugged as shown at 1 5.

It will be seen that the base of the holder 5 is radiused as shown at 1 9 and comprises a semi circle. The face 1 6 of the holder through which the water conduit 10 emerges is disposed at 900 to the curved base of the holder and the end of the water passage 10 which emerges through the face 1 6 of the holder 5 is disposed substantially on the axis of the curved base 1 9 of the holder.

As shown in Fig. 9 the vane 7 of the shearer drum may be flame cut to shape to receive the holder 5 and a stepped portion 17 is formed in the vane to allow for the water passing 9 to be drilled through the vane and into the hub of the shearer drum.

If desired a secondary water passage 1 8 can be provided in the holder so that apart from water emission at or near the tip of the tool water can be sprayed directly from the holder.

Fig. 1 0 illustrates the rolled over attitude of the holder in order to achieve adequate side clearance as illustrated by dimension M.

Claims

1. A mineral mining machine comprising a shearer disc or drum on which is mounted a plurality of cutter picks some of which are arranged to overhang the face side of the disc or drum to cut top and side clearance, and all of which are identical in shape and are mounted to have an identical angle of attack which lies in the range 20 to 350.

2. A mineral mining machine according to claim 1, wherein the angle of attack is in the range 28 to 300.

3. A mineral mining machine according to claim 1, wherein the angle of attack is around 300.

4. A mineral mining machine substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

5. A mineral cutter pick adapted to be mounted on the mineral mining machine according to any preceding claim comprising a bcJy having a frusto-conical shank for accommodation in a correspondingly shaped recess for a support on the mineral mining machine to mount the pick on the machine, said shank being adjacent its inner end not substantially less in diameter than at its outer end, and the body having a forward end carrying a cutting tip.

6. A mineral cutter pick according to claim 5, wherein the body has a passage therethrough for liquid which passage leads from an inlet in the side wall of the shank to at least one liquid outlet adjacent to the cutting tip.

7. A mineral cutter pick substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

8. A holder for the mineral cutter pick as claimed in any one of claims 5 to 7, comprising a base shaped as a part cylinder, the axis of the part cylinder being aligned with the cutting direction of the cutter pick to be mounted in the holder, whereby the holder can be rotated about the axis into a suitable position on the shearer disc or drum before being finally secured thereto.

9. A holder as claimed in claim 8 when dependent on claim 6 or claim 7, comprising a water passage extending from a position substantially on the said axis in a face of the holder which is perpendicular to the said axis to the interior of the recess for accommodating the shank of the cutter pick.

10. A holder for a mineral cutter pick substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.