The present invention relates to wear-resistant armour for protecting mining machinery parts subject to high wear and relates particularly, though not exclusively, to such a wear-resistant armour for buckets, ground-engaging tools provided on the buckets, and the track pads of excavators of the kind used at mine sites.

Background to the Invention

In the mining industry large excavators are used for digging ore out of the ground at open-cut mine sites. Mining excavators have one or more buckets for excavating the ore out of the ground and lifting it onto a transport vehicle, such as a dump truck or conveyor system. The buckets are typically provided with a plurality of Ground-Engaging Tools (GETs) or teeth on a cutting edge of the bucket. Both the GETs and the surfaces of the bucket shell are prone to severe wear. The GETs are prone to severe wear and need to be regularly replaced to maintain the digging efficiency of the excavator. In one mine site surveyed, the GETs on the excavator buckets only lasted 12 hours (one shift) before needing to be replaced.

There are several disadvantages of frequently having to replace the GETs. Firstly, the higher operating costs for the mine site; the cost of one replacement GET or bucket tooth can be as high as $1000 each. Secondly, the loss in productivity due to excavator downtime, while the worn GET is replaced with a new one. Thirdly the increased risk in safety to personnel involved in the changeover of GET components. The GET parts are heavy and therefore the more frequently they need to be handled the greater the risk of injury or accidents. One prior art solution to the problem of high wear of GET components is to apply a coating of suitably wear-resistant material to the whole exterior surface of the GET component. However, in practice, such a coating is relatively brittle and easily cracks or chips, significantly reducing its ability to provide improved resistance to wear for the GET component.

In order to protect the bucket shell all the surfaces exposed to high wear are typically protected by heavy metal wear products welded to both the inside and outside of the bucket shell. Such wear products include wear plates, chocky bars, buttons and a variety of other metal components welded to the bucket.

There are several disadvantages with using the prior art wear products; Lower productivity because the wear products add to the overall weight of the bucket. A machine can only lift a certain gross weight, so by adding 2-3 tonnes of wear products to the bucket it means the machine can lift less weight of ground material or ore, i.e. 2-3 tonnes less ore can be extracted and lifted during each excavation. There is also an increased cost in both time and labour due to the wear products having to be repaired, and or supplemented. Finally, there is also an increased risk of injury caused by the need to perform this maintenance and repair work, which is traditionally carried out by boiler makers using welders and grinders.

The present invention was developed with a view to providing wear-resistant armour for GET components and buckets on mining excavators. It will be apparent that the same wear-resistant armour may also be employed on similar parts of other types of mining machinery which are subject to high wear, such as track pads on a continuous tracked vehicle.

References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere. Summary of the Invention

According to one aspect of the present invention there is provided a mining machinery component with wear-resistant armour, the component comprising: a main body made of metal material; and a plurality of armour pieces made of a suitably wear-resistant material embedded in a surface of the main body whereby, in use, the armour pieces improve the wear resistance of the component while it is engaging ground material and significantly extend its service life. Preferably the plurality of armour pieces is arranged in a pattern adapted to promote the rolling of the ground material over the surface of the main body rather than gouging into the surface.

Typically a series of recesses are formed in the surface of the main body, the recesses being shaped to receive the respective armour pieces therein in a close fit. Optionally each armour piece may be temporarily secured in its recess by an adhesive or bead of weld material designed to hold it in place while the armour piece beds-in during use.

In one embodiment the armour pieces are in the form of strips of the suitably wear-resistant material. In another the armour pieces are in the form of disks or buttons of the suitably wear-resistant material.

Preferably the plurality of armour pieces is arranged in a pattern so as to lie substantially transverse to the direction of ground material movement. Preferably the plurality of armour pieces is arranged in a chevron or herringbone pattern. In one embodiment the mining machinery component is a GET component.

In another embodiment the mining machinery component is an excavator bucket. Preferably the plurality of armour pieces is arranged on the walls and floor of the bucket. In a still further embodiment the mining machinery component is a track pad for a continuous track. Preferably the plurality of armour pieces is arranged so as to lie substantially transverse to the direction of travel of the track over the ground. In a preferred embodiment the suitably wear-resistant material is tungsten carbide.

According to another aspect of the present invention there is provided a GET component, for mining machinery, with wear-resistant armour, the GET component comprising: a main body made of metal material; and a plurality of armour pieces made of a suitably wear-resistant material embedded in a surface of the main body whereby, in use, the armour pieces improve the wear resistance of the GET component while it is engaging ground material and significantly extend its service life. According to a further aspect of the present invention there is provided an excavator bucket, for mining machinery, with wear-resistant armour, the bucket comprising: a main body made of metal material; and a plurality of armour pieces made of a suitably wear-resistant material embedded in a surface of the main body whereby, in use, the armour pieces improve the wear resistance of the bucket while it is engaging ground material and significantly extend its service life.

According to a still further aspect of the present invention there is provided a track pad, for a continuous track, with wear-resistant armour, the track pad comprising: a main body made of metal material; and a plurality of armour pieces made of a suitably wear-resistant material embedded in a surface of the main body whereby, in use, the armour pieces improve the wear resistance of the track pad while it is engaging the ground and significantly extend its service life.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word "preferably" or variations such as "preferred", will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention.

Brief Description of the Drawings

The nature of the invention will be better understood from the following detailed description of preferred embodiments of the mining machinery component with wear-resistant armour, given by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a top plan view of a first embodiment of a mining machinery component according to the present invention, in the form of a GET component, with recesses formed in a surface of its main body ready to receive a plurality of armour pieces therein;

Figure 2 is a top perspective view of the GET component of Figure 1 showing the armour pieces being inserted into the recesses;

Figure 3 is a perspective view of the GET component of Figure 1 with the armour pieces embedded in the surface of the main body;

Figure 4 is a top plan view of a second embodiment of a mining machinery component according to the present invention, in the form of a GET component, with recesses formed in a surface of its main body ready to receive a plurality of armour pieces therein;

Figure 5 is a top perspective view of the GET component of Figure 4 showing the armour pieces being inserted into the recesses;

Figure 6 is a perspective view of the GET component of Figure 4 with the armour pieces embedded in the surface of the main body;

Figures 7a and 7b are a top perspective view and a bottom perspective view respectively of a third embodiment of a mining machinery component according to the present invention, in the form of a GET component, with armour pieces embedded in the surface of the main body;

Figures 8a, 8b and 8c are a top plan view, side view and bottom plan view respectively of the GET component shown in Figure 7;

Figure 9 is a top perspective view of a fourth embodiment of a mining machinery component according to the present invention, in the form of an excavator bucket, with recesses formed in a surface of its main body ready to receive a plurality of armour pieces therein;

Figure 10 is a top perspective view of a fifth embodiment of a mining machinery component according to the present invention, in the form of a track pad, with recesses formed in a surface of its main body ready to receive a plurality of armour pieces therein; and,

Figure 11 is a top perspective view of a sixth embodiment of a mining machinery component according to the present invention, in the form of a track pad, with recesses formed in a surface of its main body ready to receive a plurality of armour pieces therein. Detailed Description of Preferred Embodiments

A first embodiment of a mining machinery component with wear-resistant armour in accordance with the invention, in the form of a GET component 10 as iliustrated in Figures 1-3, comprises a main body 12 made of metal materia!. In the illustrated embodiment the GET component is a tooth 10 for a bucket of an excavator made from cast metal material. This means the tooth 10 is relatively soft compared to other materials used for digging purposes and therefore it has poor wear properties. Other GET components for attachment to buckets, to assist in penetrating the ground, include adapters, iip shrouds, wing shrouds and heel blocks.

A plurality of armour pieces 14 made of a suitably wear-resistant material is embedded in a surface of the main body 12 of the tooth 0. In use, the armour pieces 14 improve the wear resistance of the GET component 10 while it is engaging ground material and significantly extend its service life. In the illustrated embodiments the suitably wear-resistant material is tungsten carbide. However, it will be understood that any suitably wear- resistant material may be employed, for example, a ceramic material.

Typically a series of recesses 16 are formed in the surface of the main body 12, the recesses 16 being shaped to receive the respective armour pieces 14 therein in a close fit. Figure 1 shows a series of grooves 16 formed in the surface of the main body 12 of the tooth 0 ready to receive a plurality of armour pieces 14 therein. In this embodiment the armour pieces are in the form of linear strips 14 of tungsten carbide. The grooves 16 are typically about 5mm wide and 10mm deep.

Preferably the plurality of armour pieces 14 (and hence also the series of recesses 16) is arranged in a pattern adapted to promote the rolling of the ground material over the surface of the main body 12 rather than sliding and gouging into the surface of the main body 12. The spacing and angled arrangement of the strips 14 encourages this rolling movement of the soil and rock material over the surface of the tooth 10, further reducing the abrasive wear of this surface. In this embodiment the strips 14 of tungsten carbide are arranged in a herringbone pattern. Figure 2 illustrates the strips 14 of tungsten carbide being inserted into their respective recesses 16 on both the upper and lower surfaces of the tooth 10.

As ground material begins to wear down the main body 12 of the apparatus, the harder or wear-resistant inserts 14 start to sit slightly proud of the main body 12. As material passes over these slightly raised armour pieces 14 the material is lifted up / deflected from the surface of the main body 12, reducing contact with the main body and reducing the abrasion / gouging energy absorbed by the main body 12. Ground material, e.g. rock, which has a large particle size relative to the spacing between wear the armour pieces 14 tends to rollover the armour pieces without making significant sliding contact with the main body 12. Ground material with a smaller particle size relative to the spacing between the armour pieces will re- contact the main body 12 resulting in some abrasion but at a reduced rate. The spacing between the armour pieces 14, where possible, may be tuned to the particle size of the material passing over the surface of the main body 14 of the machine. With regard to the arrangement of the wear elements or armour pieces 14 on the main body 12, they are preferably positioned so as to lie substantially transverse to the direction of ground material movement. A chevron or herringbone pattern may be employed depending on the original shape of the main body 14 of the apparatus. This has the effect of maintaining a penetrating point shape. The angle of the armour pieces 14 relative to the direction of ground movement will vary from apparatus to apparatus.

Further testing has shown that arrangement of the wear elements or armour pieces 14 substantially parallel to the direction of ground movement does not yield a satisfactory improvement in wear reduction. This is either because the wear elements have been dislodged / levered out of their recesses 16, removing protection from the entire length of the main body 12, or because ground material is able to slide and gouge along the entire length of the main body 12 between the parallel wear elements without being interrupted.

Where the original shape of the main body 12 does not easily lend itself to the use of armour pieces in the form of strips 14, round wear buttons may be employed. As with the strips, these are recessed into the main body 12 of the apparatus.

Optionally each strip 14 of tungsten carbide may be temporarily secured in its recess 16 using an adhesive or by a bead 18 of weld material, as shown in Figure 3. The weld material 18 is designed to hold the armour piece 14 in place while it beds-in during use.

Figures 4 to 6 illustrate a second embodiment of a GET component 20 with wear-resistant armour in accordance with the invention. This embodiment is similar to the first embodiment, and hence the similar parts will not be described again in detail. The main difference is that in this embodiment the armour pieces, embedded in a main body 22 of the tooth 20, are in the form of disks or buttons 24 of a suitably wear-resistant material. In this embodiment the disks or buttons 24 are also made of tungsten carbide.

As in the first embodiment, the disks or buttons 24 are arranged in a pattern adapted to promote the rolling of the ground material over the surface of the main body 22 rather than gouging into the surface. As with the first embodiment, the disks or buttons 24 of tungsten carbide are arranged in a herringbone pattern, as can be seen most clearly in Figure 4. The armour pieces, in the form of disks or buttons 24, can also be embedded in the side walls of the tooth 20, as shown in Figures 5 and 6, to improve the wear- resistance of these surfaces.

Optionally each of the disks or buttons 24 of tungsten carbide may be temporarily secured in its recess 26 by a bead 28 of weld material, as shown in Figure 6. The weld material 28 is designed to hold the armour piece 24 in place while it beds-in during use. Figures 7 and 8 illustrate a third embodiment of a GET component 30 with wear-resistant armour in accordance with the invention. This embodiment is similar to the first embodiment, and hence the similar parts will not be described again in detail. In the illustrated embodiment the GET component is a tooth 30 for a bucket of an excavator. As with the first embodiment, a plurality of armour pieces 34 made of a suitably wear-resistant material is embedded in a surface of a main body 32 of the tooth 30.

Typically a series of recesses 36 are formed in the surface of the main body 32, the recesses 36 being shaped to receive the respective armour pieces 34 therein in a close fit. 3 In this embodiment the armour pieces are in the form of linear strips 34 of tungsten carbide, again arranged in a herringbone pattern. The spacing and angled arrangement of the strips 34 encourages a rolling movement of the soil and rock material over the surface of the tooth 30, further reducing the abrasive wear of this surface. A similar arrangement of the linear strips 34 is provided on both the upper and lower surfaces of the body 32 of the tooth 30.

A fourth embodiment of a mining machinery component with wear-resistant armour in accordance with the invention, in the form of an excavator bucket 40 as illustrated in Figure 9, comprises a main body 42 made of metal material. In the illustrated embodiment the bucket 40 is for an excavator, and is main body or shell 42 is made from hardened stee! plate material. However since the plates the bucket is made of have to be welded together and the plates also need to have a certain degree of flexibility whilst the bucket is in use, there is a limit to the hardness of the steel plate that can be used. This means that the steel plate is significantly softer than other harder wear-resistant materials available.

The present invention overcomes the weight problems caused by adding extra wear products to the exterior surfaces of the bucket shell 42, by modifying the surface of the main body of the bucket shell 42 itself to form a light armour for the bucket 40. A plurality of armour pieces 44 made of a suitably wear-resistant material is embedded in a surface of the main body 42 of the bucket 40. In use, the armour pieces 44 improve the wear resistance of the bucket 40 while it is engaging ground material and significantly extend its service life.

In the illustrated embodiment the suitably wear-resistant material is tungsten carbide. However, it will be understood that any suitably wear-resistant material may be employed, for example, a ceramic material. Because of the relatively small size of the armour pieces 44, the additional weight carried by the bucket 40 is in the order of only a few hundred kilograms, as opposed to the increased weight of 2-3 tonnes with conventional wear products. This represents a massive improvement in productivity.

Typically a series of recesses 46 are formed in the surface of the main body 42, the recesses 46 being shaped to receive the respective armour pieces 44 therein in a close fit. Figure 9 shows series of slots 46 formed in the surface of the shell 42 of the bucket 40 in which a plurality of armour pieces 14 have been inserted. The slots are cut into the walls and floor of the bucket shell 42. The depth and spacing of the slots is determined by the type and size of the bucket 40. In this embodiment the armour pieces are in the form of linear strips 44 of tungsten carbide. The slots 46 are typically about 5mm wide and 10mm deep. Preferably the plurality of armour pieces 44 (and hence also the series of recesses 46) is arranged in a pattern adapted to promote the rolling of the ground material over the surface of the main body 42 rather than gouging into the surface of the bucket 40. The spacing and angled arrangement of the strips 44 encourages this rolling movement of the soil and rock material over the surface of the bucket 40, further reducing the abrasive wear of the bucket surfaces. In this embodiment the strips 44 of tungsten carbide are arranged in parallel lines substantially transverse to the direction of travel of the bucket 40 as it excavates the ground material.

Optionally each strip 44 of tungsten carbide may be temporarily secured in its recess 46 by a bead 48 of weld material (not visible). The weld material 48 is designed to hold the armour piece 44 in place while it beds-in during use.

In some cases discs or buttons of a suitably wear-resistant material may be used in place of, or in addition to, the strip armour pieces. The discs or buttons are received in recesses formed in the surface of the main body 42 of the bucket 40, the recesses being shaped to receive the respective armour pieces therein in a close fit. in the case of refurbishing an existing bucket, sheets of thin stee! plate e.g. 8mm thick Biz 80 can be pre-slotted or have recesses pre-drilied, then cut and welded onto the surface of an existing bucket and the slots then filled with the hardened material strips or the holes filled with hardened material buttons or disks.

A fifth embodiment of a mining machinery component with wear-resistant armour in accordance with the invention, in the form of a track pad 50 for a continuous track (not shown) as illustrated in Figure 10, comprises a main body 52 made of metal material. In the illustrated embodiment the track pad 50 is a steel tread plate for a continuous track of an excavator. A plurality of such track pads 50 are joined together, end to end, in a continuous band to form the track for an excavator. A plurality of armour pieces 54 made of a suitably wear-resistant material is embedded in a surface of the main body 52 of the track pad 50. In use, the armour pieces 54 improve the wear resistance of the track pad 50 while it is engaging the ground and significantly extend its service life. In the illustrated embodiments the suitably wear-resistant material is tungsten carbide. However, it will be understood that any suitably wear-resistant material may be employed, for example, a ceramic material.

Typically a series of recesses 56 are formed in the surface of the main body 52, the recesses 56 being shaped to receive the respective armour pieces 54 therein in a close fit. Figure 10 shows series of grooves 56 formed in the surface of the main body 52 of the track pad 50 ready to receive a plurality of armour pieces 54 therein. In this embodiment the armour pieces are in the form of linear strips 54 of tungsten carbide. The grooves 56 are typically about 5mm wide and 10mm deep.

Preferably the plurality of armour pieces 54 (and hence also the series of recesses 56) is arranged in a pattern adapted to promote the rolling of the ground material under the surface of the main body 52 rather than gouging into the surface of the main body 52. The spacing and angled arrangement of the strips 54 encourages this rolling movement of the soil and rock material over the surface of the track pad 50, further reducing the abrasive wear of this surface. In this embodiment the strips 54 of tungsten carbide are arranged substantially transverse to the direction of travel.

Optionally each strip 54 of tungsten carbide may be temporarily secured in its recess 56 by a bead 58 of weld material. The weld material 58 is designed to hold the armour piece 54 in place while it beds-in during use. Figure 11 illustrates a sixth embodiment of a track pad 60 with wear- resistant armour in accordance with the invention. This embodiment is similar to the fifth embodiment, and hence the similar parts will not be described again in detail. The main difference is that in this embodiment the armour pieces, embedded in a main body 52 of the pad 60, are in the form of disks or buttons 64 of a suitably wear-resistant material. In this embodiment the disks or buttons 64 are also made of tungsten carbide.

As in the first embodiment, the disks or buttons 64 are arranged in a pattern adapted to promote the rolling of the ground material over the surface of the main body 52 rather than gouging into the surface. As with the first embodiment, the disks or buttons 64 of tungsten carbide are arranged in a line substantially transverse to the direction of travel, as can be clearly seen in Figure 1.

Optionally each of the disks or buttons 64 of tungsten carbide may be temporarily secured in its recess 66 by a bead 68 of weld material. The weld material 68 is designed to hold the armour piece 64 in place while it beds-in during use.

Now that preferred embodiments of the mining machinery component with wear-resistant armour have been described in detail, it will be apparent that the described embodiments provide a number of advantages over the prior art, including the following:

(i) The service life of the mining machinery components is significantly extended due to the presence of the armour pieces.

(ii) The spacing and angled arrangement of the armour pieces in a pattern adapted to promote the rolling of the ground material over the surface of the main body of the component, rather than gouging into the surface, also reduces the rate of wear,

(iii) The GET component and the track pad with wear-resistant armour can be used as a replacement part for a worn standard GET component without any modification required to the mining machine.

(iv) The reduced weight of the armour pieces compared to conventional wear products, results in a huge improvement in productivity, as considerably more ore can be extracted and lifted during each excavation.

(v) Also by removing the need for maintenance, there is a significant reduction in risk and improvement in safety for workers.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, in both the described embodiments the armour pieces are embedded in the main body of the component after the main body has already been manufactured. However it will be apparent that the armour pieces can also be embedded in the main body of the component during manufacture of the main body, for example, during casting, or cutting and welding of the steel plate. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described and is to be determined from the appended claims.