AU2015362088B2

AU2015362088B2 - Tool holder assembly and mounting system

Info

Publication number: AU2015362088B2
Application number: AU2015362088A
Authority: AU
Inventors: Lincoln Kuiper; Matthew Ross
Original assignee: Idim Pty Ltd
Current assignee: Idim Pty Ltd
Priority date: 2014-12-10
Filing date: 2015-12-10
Publication date: 2020-02-27
Anticipated expiration: 2035-12-10
Also published as: WO2016090433A1; AU2015362088A1

Abstract

A tool holder assembly (60) is provided for mounting a cutting tool (14) to a cutter drum (10). The tool holder assembly (60) includes a base block (62) adapted to be secured to the cutter drum (10) and a mounting block (64) releasably engageable with the base block (62). The base block (62) has a front end (73) and a rear end (75) defining a forward direction (F) and a generally perpendicular lateral direction (L). The tool holder assembly (60) also includes a tool holder (66) secured to, or integral with, the mounting block (64), the tool holder (66) being adapted to hold a cutting tool. The mounting block (64) is insertable into and removeable from the base block (62) in a direction that is generally lateral to the vane (50) of the cutter drum.

Description

Tool holder assembly and mounting system

Technical Field [0001] The present disclosure relates to tunnelling machines, mining machines, and road excavators that have a rotating cutter drum. In particular, the present invention relates to apparatus and methods of mounting cutting tools and tool holders to the cutter drum.

Background of the Invention [0002] Tunnelling, road excavation and mining machines, such as roadheaders, road planing machines, continuous miners, longwall shearers and other excavation machines, typically employ a rotating cutter drum to which an array of cutting tools is fixed. As the rotating cutter drum is pressed into the surface, the cutting tools tear or cut into the surface dislodging rock or ore which is then collected and conveyed away from the cutting face. During use, the cutting tools, which are commonly tungsten carbide tipped, wear or chip away, or shear off and need to be replaced.

[0003] The cutting tools are typically mounted in tool holders, with or without an interposed sleeve, which are in turn welded to spiralling vanes on the cutter drum. The cutting tools are usually releasably secured in the tool holders so that the cutting tools can be replaced as they wear.

[0004] As the cutter drum is pressed into the surface, the tool holders are subjected to high loads of shear stress, bending moments, compression stress, vibrations, etc.

Furthermore, as the cutting tools become worn and blunt, the forces placed on the tool and the tool holder increase significantly and commonly cause damage to the tool holders. Damaged tool holders often fail to retain the cutting tools during operation and the cutting tools can become dislodged. Empty tool holders are further damaged during operation of the cutter drum and, in underground mining operations, can result in frictional ignition of flammable gases in the mine, causing an explosion and leading to damaged equipment, the collapse or shutdown of the mine and potential loss of life.

[0005] Further, in underground mining operations, it may not be possible to use welding or grinding equipment to repair damaged tool holders due to flammable gases in the mine.

This means that when tool holders become damaged, the entire cutter drum needs to be removed and returned to the surface, where it can be repaired. This process requires the

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PCT/AU2015/050781 mining operation to cease while the cutter drum is removed and repaired, or at least while the cutter drum is removed and replaced with a substitute cutter drum.

[0006] The cutter drum and spiralling vanes are typically formed from mild steel, while the tool holders are typically formed from an alloy steel, such as 34CrNiMo6 steel. In order to weld such alloy steel components, they need to be heated to a much higher temperature (200°C to 350°C) than mild steel components. In order to avoid extreme temperature differentials in the cutter drum and resultant cracking, the entire cutter drum needs to be pre-heated to around 100°C prior to welding and gradually cooled after welding. This requires a large and custom designed heating device to enable the drum to be pre-heated before the tool holders are welded in place at high temperature and the drum is then gradually cooled again. This pre-heating process is both energy intensive and time consuming.

[0007] For certain applications or for better performance, the cutting tools are often required to be secured to the vanes of the cutter drum in different positions and/or orientations, with the cutting tools differing in angle of attack, yaw and depth. This requires complicated and difficult welding operations to ensure that each tool holder is welded to the cutter drum in the correct position and orientation and with sufficient pre-heat temperature. Consequently, the welding operation is time consuming and requires a high level of technical expertise, resulting in a very expensive manufacturing process.

Object of the Invention [0008] It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or to provide a useful alternative.

Summary of the Invention [0009] In a first aspect, the present invention provides a tool holder assembly adapted to mount a cutting tool to a cutter drum, the tool holder assembly comprising:

a base block adapted to be secured to the cutter drum, the base block having a front end and a rear end defining a forward direction and a generally perpendicular lateral direction, wherein movement of the tool holder assembly during rotation of the cutter drum is generally in the forward direction;

a mounting block releasably engageable with the base block;

a tool holder secured to, or integral with, the mounting block, the tool holder being adapted to hold a cutting tool;

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PCT/AU2015/050781 wherein the mounting block is insertable into and removeable from the base block in the lateral direction.

[0010] In a preferred embodiment, the base block is adapted to be secured to a vane of the cutter drum and preferably, the base block is shaped to fit into a corresponding recess in the vane of the cutter drum.

[0011] Preferably, an external shape of the mounting block is generally complementary to an interior shape of the base block, such that the mounting block fits snugly within the base block and can only be inserted into and removed from the base block by generally lateral movement of the mounting block relative to the base block.

[0012] In a preferred embodiment:

the base block has an overhanging rearwardly projecting front flange at the front end and a raised seat at the rear end;

the mounting block has a toe projection at a front end and a rearwardly projecting rear flange at a rear end;

when the mounting block is fitted within the base block, the rear flange of the mounting block abuts the raised seat of the base block and the toe projection is retained beneath the front flange of the base block.

[0013] Preferably, the rear flange is releasably secured to the rear seat by way of at least one rear bolt and rear nut and the front flange is releasably secured to the toe projection by way of at least one front bolt and front nut.

[0014] Further preferably, cavities are provided in the base block for receiving the at least one front nut and the at least one rear nut.

[0015] Further preferably, the at least one front nut is received in a channel in the base block and the at least one rear nut is received in an aperture in the base block.

[0016] Further preferably, the cavities are dimensioned to prevent rotation of the front and rear nuts within the cavities.

[0017] In a preferred embodiment, the mounting block is releasably engageable with the base block by way of at least one releasable fastener.

[0018] Preferably, the at least one releasable fastener is a bolt and nut.

[0019] In a preferred embodiment, the base block is adapted to be welded to the vane of the cutter drum.

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PCT/AU2015/050781 [0020] In a preferred embodiment, a line of weakness is provided in the tool holder and/or the mounting block or between the tool holder and the mounting block, the line of weakness adapted to induce failure along the line of weakness in response to excessive forces being applied to the tool holder assembly.

[0021] Preferably, the mounting block is configured to support the tool holder at various orientations relative to the vane of the cutter drum.

[0022] Further preferably, the mounting block has a generally wedge-shaped lateral projection to provide sufficient surface area to support the tool holder in an oblique orientation.

[0023] In a preferred embodiment, the base block is provided with a water conduit extending through the base block from a lower surface to an upper surface.

[0024] Preferably, when the mounting block is engaged with the base block, fluid communication exists between the water conduit and a nozzle on the tool holder.

[0025] In a second aspect, the present invention provides a cutting tool mounting system comprising a cutter drum and a plurality of the tool holder assemblies as defined above in respect of the first aspect.

Brief Description of the Drawings [0026] Preferred embodiments of the invention will now be described by way of specific example with reference to the accompanying drawings, in which:

[0027] Fig. 1 depicts a cutter drum;

[0028] Fig. 2 is a detailed view of a tool holder assembly attached to the cutter drum of Fig. 1; and [0029] Figs. 3A, 3B, 4A, 4B, 5A and 5B depict different examples of the tool holder assembly of Fig. 2.

[0030] Fig. 6 depicts an alternative tool holder assembly mounted on a vane of a cutter drum;

[0031] Fig. 7 is a further view of the tool holder assembly of Fig. 6;

[0032] Fig. 8 is a side view of a the tool holder assembly of Fig. 6;

[0033] Fig. 9 is an exploded view of the tool holder assembly of Fig. 6;

[0034] Fig. 10 is a plan view of the tool holder assembly of Fig. 6;

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PCT/AU2015/050781 [0035] Fig. 11 depicts a base block of the tool holder assembly of Fig. 6; and [0036] Fig. 12 is a side view with hidden detail of the base block of Fig. 11.

Detailed Description of the Preferred Embodiments [0037] Fig. 1 depicts a cutter drum 10 for a longwall shearer mining machine used in underground coal mining. The cutter drum 10 has a number of radially projecting helical vanes 12, which each support a plurality of cutting tools 14. Each of the cutting tools 14 is mounted in a corresponding tool holder 16 that is secured to a peripheral edge of the vane 12. In certain embodiments, the cutting tools 14 may be mounted in the tool holder 16 via an interposed sleeve. The cutting tools 14 are mounted to project outwardly and generally forward in the direction of rotation of the cutter drum 10. During mining operations, the cutting tools 14 cut into the coalface and the dislodged coal is directed away from the coalface between the vanes 12 and is then collected and conveyed away.

[0038] As depicted in detail in Fig. 2, the helical vanes 12 each have a series of generally U-shaped recesses 18 spaced along an edge of each vane 12. Each recess 18 has a pair of generally parallel sidewalls 20 and an end portion comprising an end surface 22, which is generally perpendicular to the sidewalls 20 and two chamfer surfaces 24 joining the two side walls 20 to the end surface 22. Each recess 18 has the same shaped end portion, with some recesses 18 having different length sidewalls 20, resulting in some recesses 18 extending deeper into the vane 12 than other recesses 18. In other embodiments, different shaped recesses may be used.

[0039] Each recess 18 is designed to receive a tool holder assembly 15, comprising a mounting block 30 and a tool holder 16, which is secured, usually by welding, to a support surface 32 of the mounting block 30. The tool holder 16 is adapted to releasably hold a cutting tool 14, either with or without an interposed sleeve. The size and shape of each mounting block 30 determines the angle of attack and relative depth of the cutting tool 14 relative to the vane 12. Three examples of different tool holder assemblies 15 are depicted in Figs.3A, 3B; Figs. 4A, 4B; and Figs. 5A, 5B. Each of the different tool holder assemblies 15 has a mounting block 30 with a common base shape but a different body shape, which determines the different positions and orientations of the tool holders 16 relative to the vane 12.

[0040] The mounting block 30 of each tool holder assembly 15 has a base portion 33 corresponding to the end portion of the recesses 18. The base portion 33 has a base

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PCT/AU2015/050781 surface 34 and two chamfer surfaces 36 joining the base surface 34 to a pair of generally parallel side walls 38 that are generally perpendicular to the base surface 34. By varying the length of the side walls 38 and the angular orientation of the support surface 32 relative to the base surface 34, the position and orientation of the tool holder 16 can be accurately controlled.

[0041] The different recesses 18 and their respective tool holder assemblies 15 are specifically designed to provide a specific array of cutting tools 14 on each vane 12, with each cutting tool 14 being arranged in a predetermined position and orientation, specifically determined by the depth of the recesses 18 and the shape of the mounting block 30.

[0042] The orientation and angle of attack of the cutting tool 14 is determined by the angle of the support surface 32 relative to the base surface 34 and the position and relative depth of the cutting tool 14 is determined by the distance between the support surface 32 and the base surface 34 and the depth of the recess into which the tool holder assembly 15 is secured. The position of the tool holder 16 on the support surface 32 can also be varied, from one tool holder assembly 15 to another, to add a further variable in determining the position of the tool holder 16.

[0043] When assembling a cutter drum 10, the tool holder assemblies 15 are inserted into the corresponding recesses 18 and the mounting block 30 is secured in the recess 18. The mounting block 30 is preferably releasably secured in the recess 18, such as by bolting, dowel connectors, or other releasable connection. This releasable connection allows the tool holder assemblies 15 to be removed from the vanes 12 when damaged and replaced by a new tool holder assembly 15.

[0044] During underground mining operations, if individual tool holders 16 become damaged or worn, then individual tool holder assemblies 15 can be removed and replaced, quickly and efficiently, without any welding and without having to remove the cutter drum 10 from the mining machine.

[0045] Alternatively, in certain applications, the mounting blocks 30 can be welded into the corresponding recesses 18, permanently securing the tool holder assemblies 15 to the vanes 12. In this welding process, both the vanes 12 of the cutter drum 10 and the mounting blocks 30 are typically made of mild steel or other alloys that do not require the very high welding temperature of an alloy steel. This means that the cutter drum 10 does not need to be pre-heated to such an extreme temperature, as it does when welding alloy steel tool holders 16 directly to the vanes 12.

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PCT/AU2015/050781 [0046] Each tool holder assembly 15 is manufactured by securing a tool holder 16 to a mounting block 30. This is typically done by welding. As the tool holders 16 are typically formed from an alloy steel, such as 34CrNiMo6 steel, the mounting block 30 and the tool holder 16 need to be pre-heated to a high temperature (typically 200°C to 350°C for an alloy steel tool holder). The tool holder 16 is then welded to the support surface 32 of the mounting block 30 and the tool holder assembly 15 is then allowed to cool.

[0047] Because the mounting block 30 and the tool holder assembly 15 are much smaller than the cutter drum 10, the pre-heating of the mounting block 30, which can be performed in a heat treatment oven, is much easier, faster and more cost effective than heating an entire cutter drum 10. It also allows the components to be more accurately heated to a specific pre-heat temperature, which results in a higher standard of weld quality. This simpler process allows a large number of tool holder assemblies 15 to be quickly and cheaply manufactured to a high quality standard at a simple workbench. It also allows tool holders 16 made from a wider range of alloys to be used.

[0048] Because the tool holder 16 simply needs to be welded to the support surface 32 in a given orientation relative to the support surface 32, the welding process is a relatively simple welding operation that does not require a high level of technical expertise. The welding operation is also one that a robotic welding machine can be programmed to perform, leading to significant cost savings in labour and increased manufacturing speed and efficiency.

[0049] As the size and shape of the mounting block 30 is used to determine the orientation and depth of the tool holder 16 relative to the vane 12, it is much easier to ensure that the tool holders 16 are correctly positioned and oriented when secured to the vanes 12. The technically difficult operation of welding the tool holder 16 in the correct position and orientation on the vane 12 itself is no longer necessary.

[0050] An alternative embodiment of the tool holder assembly is depicted in Figs. 6 to 12. The tool holder assembly 60 comprises a base block 62, a mounting block 64 and a tool holder 66. The base block 62 is arranged in a correspondingly shaped recess 52 in an edge of a vane 50 of the cutter drum and secured, typically by welding, to the vane 50 in the recess 52. The tool holder 66 may be either formed integrally with, or secured (such as by welding or fastening) to, the mounting block 64.

[0051] As shown in isolation in Figs. 11 and 12, the base block 62 is formed as a unitary product and includes a base portion 72 having a bottom surface 74 and a top surface 76. The base block 62 has a front end 73 and a rear end 75, defining a forward direction Fand a

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PCT/AU2015/050781 lateral direction L The forward direction F corresponds generally to the direction of travel of the tool holder assembly 60 during rotation of the cutter drum. A water conduit 78 extends through the base portion 72 from the bottom surface 74 to the top surface 76.

[0052] At one end, the base block 62 has a front wall 80 and an adjacent rectangular channel 82 that extends laterally across the base portion 72. At a height above the top surface 76 of the base portion 72, a front flange 84 projects rearwardly from the front wall 80 over the channel 82. The front flange 84 includes a pair of countersunk front bolt holes 86 extending therethrough.

[0053] At the other end, the base block 62 has a raised rear seat 88 extending laterally across the base portion 72. Beneath the rear seat 88 an aperture 90 extends laterally through the base portion 72. A pair of rear bolt holes 92 extend through the seat 88 from an upper surface 94 of the seat 88 through to the laterally extending aperture 90.

[0054] As best shown in Figs. 7 to 9, the mounting block 64 has a shape that is generally complimentary to the base block 62, with the mounting block 64 fitting laterally, in a 'keyed' fashion, into the base block 62. The mounting block 64 has a forwardly projecting front toe portion 96, having a pair of front bolt holes 98 extending therethrough, and a rearwardly projecting rear flange 100, having a pair of countersunk rear bolt holes 102 extending therethrough. When the mounting block 64 is mounted in the base block 62, the front toe portion 96 projects beneath the front flange 84 and the rear flange 100 sits on the rear seat 88.

[0055] In order to accommodate the tool holder 66 at an oblique angle to the circumferential direction of the vane 50, the mounting block 64 is flared along its leading side, providing a wedge shaped lateral projection 104, as best depicted in Figs. 9 and 10. This provides a greater surface area on which to support the tool holder 66.

[0056] The mounting block 64 is releasably securable to the base block 62 by way of fasteners, depicted here as bolts 106, 108 and nuts 110, 112. In order to assemble the mounting block 64 to the base block 62, the mounting block 64 must slide laterally into place in a lateral direction (depicted by the arrow L in Fig. 9) that is generally perpendicular to both the radial and circumferential directions of the vane 50.

[0057] Once in place, the mounting block 64 is secured in the base block 62 by inserting the front bolts 106 into the front bolt holes 86 of the front flange 84 and the rear bolts 108 into the rear bolt holes 102 of the rear flange 100. The front bolts 106 extend through the

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PCT/AU2015/050781 front bolt holes 86 of the front flange 84 and the toe portion 96 and are secured by nuts 110 arranged in the channel 82. The rear bolts 108 extend through the rear bolt holes 102 of the rear flange 100 and the rear seat 88 and are secured by nuts 112 arranged in the aperture 90. The channel 82 and the aperture 90 are dimensioned to prevent the nuts 110, 112 from rotating axially, encapsulating the nuts 110, 112 in the channel 82 and aperture 90, as best shown in Fig. 8.

[0058] During operation, the forces exerted on the tool holder 66 push the tool holder rearwardly and inwardly. This has the effect of forcing the rear flange 100 against the rear seat 88 and pulling the toe portion 96 against front flange 84. In both cases, this action does not induce a large tensional force in the bolts 106, 108 and most of the force is absorbed by the base block 62 and the mounting block 64. For this reason, the bolts 106, 108 are unlikely to be over-strained and fail during normal operation.

[0059] Because the base block 62 is permanently secured in a recess 52 of the vane 50, it is desirable that the base block 62 does not fail due to excessive load or fatigue, as the base blocks 62 cannot be easily replaced in situ. In order to avoid failure in the base block 62 due to excessive loading or fatigue, lines of weakness 116 are provided in the mounting block 64 and/or tool holder 66 or between the mounting block 64 and the tool holder 66 to ensure that failure occurs in the mounting block 64 or tool holder 66 before the base block 62.

[0060] In operation, water is supplied through drilled holes in the vane 50 to the tool holder 66 via the water conduit 78 in the base portion 72 of the base block 62. An internal conduit in the mounting block 64 and tool holder 66 delivers water to a water nozzle 120 on the tool holder 66. When the mounting block 64 is engaged with the base block 62, fluid communication exists between the water conduit 78 and the nozzle 120.

[0061] As the base blocks can be welded into the recesses of the cutter drum vanes during construction or maintenance of the cutter drum, replacement of damaged tool holders can be performed on site without the need for welding. The damaged tool holder and mounting block is simply detached (by undoing the bolts) from the corresponding base block and a new mounting block and tool holder mounted to the existing base block.

[0062] The system of lateral insertion and removal the mounting block allows the base block to be recessed into the vane and provides greater durability for the tool holder assembly, as the tool holders are better protected from operational forces. The lateral insertion and removal system also helps prevent unintended disengagement due to

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PCT/AU2015/050781 excessive operational forces as the operational forces do not typically have significant components in the lateral directions.

[0063] The provision of a flared lateral projection on the mounting block allows tool holders to be supported on the mounting block at various angles oblique to the vane of the cutter drum. This allows the tool holder assemblies to support the different orientations of tool holders necessary for tool older arrays such as depicted in Fig. 1.

[0064] Providing a water conduit through the base block advantageously allows water to be delivered to tool holders that have built-in water nozzles. This allows tool holders with water nozzles to be fitted and interchanged using the present system.

[0065] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

CLAIMS:

1. A tool holder assembly adapted to mount a cutting tool to a cutter drum, the tool holder assembly comprising:

a base block adapted to be secured to the cutter drum, the base block having a front end and a rear end defining a forward direction and a generally perpendicular lateral direction, wherein movement of the tool holder assembly during rotation of the cutter drum is generally in the forward direction;

a mounting block releasably engageable with the base block;

a tool holder secured to, or integral with, the mounting block, the tool holder being adapted to hold a cutting tool;

wherein the mounting block is insertable into and removeable from the base block in the lateral direction.
2. The tool holder assembly of claim 1 wherein the base block is adapted to be secured to a vane of the cutter drum.
3. The tool holder assembly of claim 2 wherein the base block is shaped to fit into a corresponding recess in the vane of the cutter drum.
4. The tool holder assembly of any one of claims 1 to 3 wherein an external shape of the mounting block is generally complementary to an interior shape of the base block, such that the mounting block fits snugly within the base block and can only be inserted into and removed from the base block by generally lateral movement of the mounting block relative to the base block.
5. The tool holder assembly of any one of claims 1 to 4 wherein:

the base block has an overhanging rearwardly projecting front flange at the front end and a raised seat at the rear end;

the mounting block has a toe projection at a front end and a rearwardly projecting rear flange at a rear end;

when the mounting block is fitted within the base block, the rear flange of the

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PCT/AU2015/050781 mounting block abuts the raised seat of the base block and the toe projection is retained beneath the front flange of the base block.
6. The tool holder assembly of claim 5 wherein the rear flange is releasably secured to the rear seat by way of at least one rear bolt and rear nut and the front flange is releasably secured to the toe projection by way of at least one front bolt and front nut.
7. The tool holder assembly of claim 6 wherein cavities are provided in the base block for receiving the at least one front nut and the at least one rear nut.
8. The tool holder assembly of claim 7 wherein the at least one front nut is received in a channel in the base block and the at least one rear nut is received in an aperture in the base block.
9. The tool holder assembly of claim 7 or 8 wherein the cavities are dimensioned to prevent rotation of the front and rear nuts within the cavities.
10. The tool holder assembly of any one of claims 1 to 5 wherein the mounting block is releasably engageable with the base block by way of at least one releasable fastener.
11. The tool holder assembly of claim 10 wherein the at least one releasable fastener is a bolt and nut.
12. The tool holder assembly of any one of claims 1 to 11 wherein the base block is adapted to be welded to the vane of the cutter drum.
13. The tool holder assembly of any one of claims 1 to 12 wherein a line of weakness is provided in the tool holder and/or the mounting block or between the tool holder and the mounting block, the line of weakness adapted to induce failure along the line of weakness in response to excessive forces being applied to the tool holder assembly.

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PCT/AU2015/050781
14. The tool holder assembly of any one of claims 1 to 13 wherein the mounting block is configured to support the tool holder at various orientations relative to the vane of the cutter drum.
15. The tool holder assembly of claim 14 wherein the mounting block has a generally wedge-shaped lateral projection to provide sufficient surface area to support the tool holder in an oblique orientation.
16. The tool holder assembly of any one of claims 1 to 15 wherein the base block is provided with a water conduit extending through the base block from a lower surface to an upper surface.
17. The tool holder assembly of claim 16, wherein, when the mounting block is engaged with the base block, fluid communication exists between the water conduit and a nozzle on the tool holder.
18. A cutting tool mounting system comprising a cutter drum and a plurality of the tool holder assemblies as defined in any one of claims 1 to 17.