GB2098257A

GB2098257A - Tools and tool holders

Info

Publication number: GB2098257A
Application number: GB8135493A
Authority: GB
Original assignee: Mining Supplies Minsup Pty Ltd; Mining Supplies Ltd
Current assignee: Mining Supplies Minsup Pty Ltd; Mining Supplies Ltd
Priority date: 1981-05-09
Filing date: 1981-11-25
Publication date: 1982-11-17
Also published as: GB2098257B

Abstract

A forward attack mineral winning tool 1 releasably retained by a tool holder 2, has the tool 1 comprising a body member 3, a leading end thereof being provided with a full width, hard material insert 5 capable of cutting clearance for the remainder of the tool 1, a generally "V"-shaped mounting slot 6 (not shown) provided in the body member 3 and defined by mutually inclined abutment faces comprising a forward face 7 (not shown) and an upward face 8 (not shown), opposite, lateral sides of the slot 6 being defined by a pair spaced apart cheeks 10 (not shown), and aligned apertures 11 (not shown) provided in each cheek 10, the tool holder 2 comprising a base portion 18 adapted to be welded to an outer edge 19 of a vane 20 of a spiral vane shearer drum and a male, generally "V"-shaped projection 23 also defined by mutually inclined abutment faces and located at a leading end 26 of the tool holder 2, with respect to the cutting direction 27, the projection 23 being provided with a through hole 29 (not shown) also aligned, or generally aligned, with the aligned apertures 11 in the cheeks 10 of the tool 1, the aligned through hole 29 and aperture 11 receiving a common, resilient latching means 30 comprising a central pin 31 not shown surrounded by, and bonded to, resilient material 32 not shown. <IMAGE>

Description

SPECIFICATION Tools and tool holders This invention relates to forward attack mineral cutter tools and tool holders as are commonly provided on spiral vane shearer drums used extensively in mineral winning operations, particularly in coal mining, with the drums rotatably carried by a mining machine. The tool holders are secured by welding, at various locations, to the vanes and the tools are releasably retained, so as to be readily replaceable, by the tool holders. Forward attack tools are, like point attack tools generally tangentially mounted with respect to the axis of rotation of the drum, but are contrasted with point attack tools by having a leading cutting edge capable of cutting clearance for the remainder of the tool.

Conventionally, tool holders have taken the form of a female apertured box, the aperture receiving an integral shank of a tool, with a latching means engaging the shank. This arrangement has proved satisfactory over many years but due to the need for frequent tool replacements, e.g. at every shift during coal mining, the dimensions and hence weight of the tool has resulted in substantial underground transportation and tool handling problems.

Furthermore, it has only been possible for practical reasons to provide in the backface region of a shearer drum, remote from the machine, relatively small size picks, which have not often provided optimum cutting conditions and this has led to premature failure.

Attempts to reverse this conventional arrangement by providing a female tool to be received by a male tool holder (U.K. Patent Specification 1,142,141) have not in practice found acceptance, although this configuration does have advantages if a practical design can be evolved and in fact is used extensively in ploughing devices, particularly for coal winning (U.K. Patent Specification 997,458) although ploughing devices have had no influence on tool and tool holder designs for shearer drums over the last twenty years, presumably because of the completely different cutting and breaking out techniques involved, for in simple terms, ploughing is a fly cutting operation whereas shearing is a deep cutting operation. In another industry, civil engineering, the same female/male tool/tool holder configuration has been used for many years (U.K.Patent Specification 899,344) but again the relatively low technology involved -- robustness being the prime requirement -- has had no influence on tool and tool holder designs for the mining industry.

According to the present invention, there is provided a forward attack mineral winning tool releasably retained by a tool holder, the tool comprising a body member, a leading end thereof being provided with a full width, hard material insert capable of cutting clearance for the remainder of the tool, a generally "V"-shaped mounting slot provided in the body member and defined by mutually inclined abutment faces comprising a forward face and an upward face, opposite, lateral sides of the slot being defined by a pair of spaced apart cheeks, and aligned apertures provided in each cheek, and the tool holder comprising a base portion adapted to be welded to an outer edge of a vane of a spiral vane shearer drum and a male generally "V"-shaped projection also defined by mutually inclined abutment faces and located at a leading end of the tool holder, with respect to the cutting direction, the projection being provided with a through hole also aligned, or generally aligned, with the aligned apertures of the cheeks of the tool, the aligned through hole and aligned apertures receiving a common, resilient latching means comprising a central pin surrounded by, and bonded to, resilient material.

Thus, in use, the tool is fitted to a holder firstly by being located on the projection and secondly by inserting the latching means.

Preferably, the projection hole and cheek apertures are circular and it is further preferred for the projection hole to be oversize with respect to the cheek holes. It is also preferred for the cheek holes to be imperfectly aligned with the projection hole after the tool has been engaged on the holder. The resilient material of the latching means may comprise rubber, neoprene etc. or any resilient material acceptable for underground use.

Preferably, the mutually inclined abutment faces of both the tool and the tool holder consist of a forward face (with respect to the direction of cutting) and an upper face. It is also preferred for the male projection to have "V"-shaped side faces, tapering towards the terminal end of the projection, and in this case the cheeks would have similarly tapering faces. The "V" shapes of the mounting slot and the male projection may terminate in a radiussed corner or nose respectively or may The tool holders are attached to the vane by a base portion which is arcuate, matching the curvature of the vane edge, while the base portion may additionally be provided with chamfered edges to receive weld metal.Preferably, the arcuate length of the base portion of each tool holder is approximately twice the maximum radial height of the tool holder, which maximum height is preferably at a leading end (with respect to the cutting direction) of the tool holder, the height graduaily decreasing towards a trailing end. This arrangement has the advantage of providing not only a base portion length sufficient to accept adequate weld metal for adequate service life but also provides a minimum gap between the trailing end of one tool holder and the leading end of the next succeeding tool holder on the same vane edge.

Preferably, the location of the tool on the projection is such as to leave a gap between a portion of the tool and a shoulder of the holder, whereby a drift etc., may be engaged for tool release. Also for this purpose, the projection may be provided with a through hole for engagement by a drift.

The hard material insert of the tool may be tungsten carbide for instance.

It is also preferred for the tool holder (at least for the majority of applications) to be cranked so as to comprise a vane attachment portion locatable in the plane of the vane and a tool support portion extending radially, or generally so, with respect to the axis of rotation of the shearer drum. For less numerous applications in the backface region of a shearer drum, the tool holders are not located on a spiral vane but usually on an end plate mounted in a plane at right angles to the axis of rotation of the drum.

According to another aspect of the present invention, there is provided a forward attack mineral cutter tool comprising a body member, a leading end thereof being provided with a full width, hard material insert capable of cutting clearance for the remainder of the tool, the insert having an apex co-incident with a central plane of the tool, from which apex sidewalls diverge, a generally "V"-shaped mounting slot provided in the body member and bounded by a pair of spaced apart cheeks having aligned apertures.

Preferably, opposed internal walls of the cheeks diverge in a direction away from the insert. It is also preferred for the front face of the insert to have a negative rake angle of 100--140 preferably 120 and for the top face of the insert to have a negative rake angle of 80--120 preferably 100. Beyond these initial rake angles, the front face and top face of the tool may be raked at 250, while side faces of the insert may be angled at 270 with respect to a line normal to the direction of advance, in use, of the tool.

The invention will now be further described, by way of example, with reference to the accompanying drawing in which: Figure 1 is a side elevation of a tool and tool holder in accordance with the present invention mounted in a vane of a spiral vane shearer drum; Figure 2 is a plan view of Figure 1; Figure 3 is a side elevation, to a larger scale of the tool of Figures 1 and 2; Figure 4 is a view in the direction of arrow A of Figure 3; Figure 5 is a plan view of Figure 3; Figure 6 is a section on the VI-VI of Figure 3: and Figure 7 shows to an even larger scale, the resilient latching means.

in the drawings, a forward attack mineral cutter tool is indicated at 1 and a tool holder, on which the tool 1 is to be releasably retained, is indicated at 2. In Figures 1 and 2, the left hand tool holder 2 is shown, for clarity, with its tool 1 removed.

The tool 1 comprises a body member 3 with a leading end 4 thereof provided with a full width hard material insert 5 e.g. of tungsten carbide, capable of cutting clearance for the remainder of the tool 1. A generally "V"-shaped mounting slot 6 is provided in the body member 3 and is defined by mutually inclined abutment faces comprising a forward face 7 and an upward face 8, opposite lateral sides of the slot 6 being defined by diverging, opposed internal walls 9 a pair of spaced apart cheeks 10, while aligned circular apertures 11 are provided in each cheek 10. A face 12 of the insert 5 has a negative rake angle of 120, while a top face 13 of the insert 5 has a negative rake angle of 100. In addition, side walls 14 of the insert 5 are angled at 270 with respect to a line 1 5 normal to the direction of advance, in use, of the tool 1.Also, front face 1 6 and top face 17 of the tool 1 each have a 250 negative rake.

The tool holder 2 comprises an arcuate base portion 18 to match the curvature of an edge 19 of a vane 20 welded to an inner support barrel, which may be cylindrical or frusto-conical, in the well-known manner and is mounted on a drive arbor of a mining machine. The base portion 18 is chamfered at 21 to receive weld metal 22 by which the holder 2 is attached to the vane 20. The tool holder 2 is provided with a male, generally "V"-shaped projection 23 also defined by mutually inclined abutment faces being a forward face 24 and an upward face 25, the projection 23 being located at a leading end 26 of the tool holder 2 with respect to the cutting direction, which is indicated by the arrow 27.The projection 23 also has "V"-shaped or mutually inclined side faces 36 tapering towards a radiussed terminal end 37 of the projection 23 to match the divergence of the walls 9 of the tool 1.

Furthermore, as indicated in Figure 2, the tool holders 2 are cranked such that their leading ends 26 are angled with respect to their trailing ends 28. The projection 23 is provided with a circular through hole 29, of slightly larger diameter than the apertures 11, adapted to be co-axially aligned, or generally aligned, with the apertures 11 in the cheeks 10, the aligned aperture 11 and hole 29, as shown to the right hand side of Figures 1 and 2, subsequently receiving a common, resilient latching means 30 comprising a central steel pin 31 surrounded by, and bonded to, a sleeve 32 of resilient material e.g. rubber or neoprene, the pin 31 having a terminal collar 33 at each end.

As indicated to the right hand side of Figure 1, the location of the tool 1 on the projection 23 is such as to leave a gap 34 between a portion of the tool and a shoulder 35 of the holder 2 whereby a drift may be engaged to remove a worn tool from a holder

Claims

1. A forward attack mineral winning tool releasably retained by a tool holder, the tool comprising a body member, a leading end thereof being provided with a full width, hard material insert capable of cutting clearance for the remainder of the tool, a generally "V"-shaped mounting slot provided in the body member and defined by mutually inclined abutment faces comprising a forward face and an upward face, opposite, lateral sides of the slot being defined by a pair of spaced apart cheeks, and aligned apertures provided in each cheek, and the tool holder comprising a base portion adapted to be welded to an outer edge of a vane of a spiral vane shearer drum and a male generally "V"-shaped projection also defined by mutually inclined abutment faces and located at a leading end of the tool holder, with respect to the cutting direction, the projection being provided with a through hole also aligned, or generally aligned, with the aligned apertures of the cheeks of the tool, the aligned through hole and aligned apertures receiving a common, resilient latching means comprising a central pin surrounded by, and bonded to, resilient material.

2. A tool and tool holder as claimed in Claim 1, wherein the projection hole and cheek apertures are circular.

3. A tool and tool holder as claimed in Claim 1 or Claim 2, wherein the projection hole is oversize with respect to the cheek holes.

4. A tool and tool holder as claimed in any preceding Claim, wherein the cheek holes are imperfectly aligned with the projection hole after the tool has been engaged on the holder.

5. A tool and tool holder as claimed in any preceding Claim, wherein the resilient material of the latching means is rubber.

6. A tool and tool holder as claimed in any one of Claims 1 to 4, wherein the resilient material of the latching means is neoprene.

7. A tool and tool holder as claimed in any preceding Claim, wherein the mutually inclined abutment faces of both the tool and the tool holder consist of a forward face (with respect to the direction of cutting) and an upper face.

8. A tool and tool holder as claimed in any preceding Claim, wherein the male projection has "V"-shaped side faces, tapering towards the terminal end of the projection, and the cheeks have similarly tapering faces.

9. A tool and tool holder as claimed in Claim 8, wherein the "V" shapes of the mounting s!ot and the male projection terminate in a radiussed corner or nose respectively.

10. A tool and tool holder as claimed in any one of Claims 1 to 8, wherein the "V" shapes of the mounting slot and the male projection terminate in a flat end.

11. A tool and tool holder as claimed in any preceding Claim, wherein the tool holder has a base which is arcuate.

12. A tool and tool holder as claimed in Claim 11, wherein the base is provided with chamfered edges to receive weld metal.

13. A tool and tool holder as claimed in Claim 11 or Claim 12, wherein the arcuate length of the lower mounting edge is approximately twice the maximum radial height of the support.

14. A tool and tool holder as claimed in Claim 13, wherein the maximum height is at a leading end (with respect to the cutting direction) of the support, the height gradually decreasing towards a trailing end.

1 5. A tool and tool holder as claimed in any preceding Claim, wherein the location of the tool on the projection is such as to leave a gap between a portion of the tool and a shoulder of the holder, whereby a drift etc., may be engaged for tool release.

16. A tool and tool holder as claimed in any preceding Claim, wherein the projection is provided with a through hole for engagement by a drift.

1 7. A tool and tool holder as claimed in any preceding Claim, wherein the tool is tipped with tungsten carbide for instance for enhanced wear resistance.

1 8. A tool and tool holder as claimed in any preceding Claim, wherein the tool holder is cranked so as to comprise a vane attachment portion locatable in the plane of the vane and a tool support portion extending radially, or generally so, with respect to the axis of rotation of the shearer drum.

19. A forward attack mineral cutter tool comprising a body member, a leading end thereof being provided with a full width, hard material insert capable of cutting clearance for the remainder of the tool, the insert having an apex co-incident with a central plane of the tool, from which apex sidewalls diverge, a generally "V"shaped mounting slot provided in the body member and bounded by a pair of spaced apart cheeks having aligned apertures.

20. A tool as claimed in Claim 19, wherein opposed internal -walls of the cheeks diverge in a direction away from the insert.

21. A tool as claimed in Claim 19 or Claim 20, wherein the front face of the insert has a negative rake angle of 100--140.

22. A tool as claimed in Claim 21, wherein the negative rake angle is 120.

23. A tool as claimed in any one of Claims 19 to 22, wherein the top face of the insert has a negative rake angle of 80--120.

24. A tool as claimed in Claim 23, wherein the negative rake angle is 100.

25. A tool as claimed in any one of Claims 1 9 to 24, wherein the front face and top face of the tool are raked at 250.

26. A tool and tool holder substantially as hereinbefore described with reference to the accompanying drawings.

27. A tool substantially as hereinbefore described with reference to Figures 3 to 6 of the accompanying drawings.