Soil-engaging wear part

Abstract

There is described a soil-engaging wear part 100 configured to disturb topsoil, the soil-engaging wear part including a wing 102 comprising a leading edge 104 and a trailing edge 106, wherein the wing comprises: a first portion 108 having a first durability; a second portion 110 having a second durability; and a third portion 112 having a third durability; wherein the first portion is disposed substantially at the leading edge; the second portion is disposed substantially between the leading edge and the trailing edge; and the third portion is disposed substantially between the first portion and the second portion; and wherein the first durability and the second durability are substantially greater than the third durability. The first and / or the second portions may comprise a tile having a first or second durability respectively. Further, there is described a wing configured for use in the soil-engaging wear part, and a kit of parts operable to be assembled into the soil-engaging wear part. The wing maybe replaceable on the wear part. A long-life wear part is provided through strategic and economical use of durable portions.

Description

Field of the Invention The present invention relates to wear parts. In particular, the present invention relates to soilengaging wear parts. Background of the Invention Wear parts are parts of equipment designed to wear during use and eventually to be replaced under preventative maintenance. Wear parts are commonly used in agricultural machinery and particularly in applications relating to soil preparation, improvement and seed placement. As wear parts wear, they may gradually change size and shape. As a result, the performance of the part may degrade as the original size and / or shape may have been key to the efficacy of the part. In addition, as wear parts change shape due to wear the protection they offer to nearby features may be reduced. Further, should a wear part wear out to failure during use, the task in progress may be compromised, e.g., the task may need to be halted to replace the part. When a wear part wears out, it must be replaced, which incurs costs. Extending a service life of the wear part reduces the frequency at which those costs are incurred and can make the wear part more cost effective. Summary of the Invention At its most general, the present invention provides a soil-engaging wear part, such as a subsoiler point. The soil-engaging wear part is configured to disturb topsoil and comprises an arrangement of portions configured to deliver increased durability of the wear part and thereby long service life. The wear part comprises a pair of wings, each wing comprising at least three portions arranged substantially parallel to the leading edge across a span of the wing. A first portion, arranged at the leading edge, and a third portion, arranged between the leading edge and the trailing edge, have a greater durability than a second portion, which is disposed between the first and third portions. In this way, the wings each comprise two highly durable strips separated by a less durable strip. Accordingly, a durability of the wear part is increased through strategic and economical use of high durability portions. According to a first aspect of the invention, there is provided a soil-engaging wear part configured to disturb topsoil, the soil-engaging wear part including a wing comprising a leading edge and a trailing edge, wherein the wing comprises: a first portion having a first durability; a second portion having a second durability; and a third portion having a third durability; wherein the first portion is disposed substantially at the leading edge; the second portion is disposed substantially between the leading edge and the trailing edge; and the third portion is disposed substantially between the first portion and the second portion; and wherein the first durability and the second durability are substantially greater than the third durability. In use, the soil-engaging wear part is driven into and through topsoil, e.g., by a subsoiler machine. Soil may be prepared using the soil-engaging wear part, e.g., before drilling, to aerate the soil and improve rainwater absorption. As the wear part is driven through the soil, the wing passes through the soil such that soil passes over and under the wing. As a result, the topsoil is disturbed; combatting effects of soil compaction. On a machine, the wear part may be arranged such that the leading edge of the wing penetrates deeper into the topsoil than the trailing edge of the wing. For example, the wing may be tilted or inclined downwards so that the leading edge is disposed lower than the trailing edge. In this way, as the wing of the wear part passes through the topsoil, the leading edge of the wing of the wear part impacts a deep portion of topsoil. As the wing continues forwards, some of the soil impacted by the leading edge of the wing is urged up and over the wing. The wing lifts this soil as it is driven along until the soil reaches the trailing edge of the wing, where it passes off the wing and is deposited behind the wing onto the ground. In this way, in use, the wear part disturbs topsoil. By providing a wing comprising a first portion at a leading edge and a second portion between the leading edge and a trailing edge and separated from the first portion by a third portion, wherein the first and second portions are more durable than the third portion, a durable wing is provided. Such a wing may be resilient to impact during use such that it wears slowly and has a long service life. In particular, where a wing is arranged such that the leading edge of the wing penetrates deeper into the topsoil than the trailing edge of the wing, a durable leading edge may not provide sufficient impact protection for the whole wing. Indeed, as the trailing edge does not directly follow the leading edge through the soil, instead being disposed above the leading edge in use, the rear of the wing is exposed to significant soil impact. As such, by providing the third portion disposed between the leading edge and the trailing edge and having a greater durability than the second portion, a durability of a rear of the wing is increased. Improving a durability of a rear of the wing may increase a service life of the wing as an original profile of the wing may be preserved, and the wear part’s soil lifting and disturbing properties may be maintained, even as the wear part wears such that the wear part may be used for a long life without loss of performance. By providing the first and second portion separated by the third portion, a front and a rear of the wing may wear at a similar rate such that replacement of the wear part may coincide with the end of the useful life of both the front and rear of the wing. In other words, no ‘life’ may be left in one part while the other is worn out, which may be an inefficient use of resources. Increasing service life decreases costs associated with replacing parts by decreasing the frequency at which such costs are incurred, e.g., part costs, delivery costs, fitting time and machine down time. In addition, improving a durability of a rear of the wing may protect features of the wear part disposed behind the wing during use. For example, a fastener configured to couple the wear part to a machine may be disposed behind the wing. Such a fastener, if unprotected, may be worn down during use such that the wear part is no longer securely coupled to the machine, leading to loss of the wear part. Further, if unprotected, engagement features of such a fastener may be worn away or deformed during use such that the fastener may not provide purchase for tools configured to facilitate removal of the fastener such that the wear part may be difficult to remove, e.g., for machine maintenance. Accordingly, improving a durability of a rear of the wing according to the present invention avoids or at least delays damage to features disposed behind the wing caused by wear through use. In some embodiments, the first portion comprises a tile having a first durability. In some embodiments, the second portion comprises a tile having a second durability. In some embodiments, the first durability is substantially identical to the second durability. Alternatively, the first and second durability may be substantially different. In either case, both the first and second durability are substantially greater than the third durability. Tiles may provide a modular and economical way to provide durability to portions of a wing. In particular, tiles may be used to apply durable portions to a wide variety of wings, e.g., wings having different size and shapes, without requiring manufacture of many different dedicated parts, further reducing costs. Tiles may also allow precise placement of durable portions on the wing. Moreover, tiles may be easy to procure and apply to a wing. The tiles may be affixed to the wing using brazing. Different types of brazing may be used. For example, the tiles may be affixed to the wing by induction brazing. During induction brazing, an underside of a tile and a surface of the wing configured to receive the tile may be coated in a flux. A metallic strip, e.g., a silver or copper strip, may then be sandwiched between the fluxed surfaces of the tile and the wing. Finally, induction heating is used to heat the assembly to a temperature which allows the braze to fuse the tile and the wing together. Alternatively, the tile may be integrally cast with the wing. For example, a tool used for casting a wing may comprise a hole configured to receive one end of a pin, while the tile comprises a hole configured to receive another end of the pin. The pin holds the tile in place in the mould while the wing is cast. The resulting cast wing has tiles integral to the component. Alternatively, the tiles may be attached to the wing by rivets. It will be appreciated that any suitable fixing, fastening, moulding or manufacturing method may be used to provide tiles on a wing. The third durability may be substantially identical to a durability of a base of the wear part. For example, the third portion may be formed of a same material as the base of the wear part. In this case, both the first and second durability are substantially greater than a durability of the base. Alternatively, the third durability may be substantially greater than a durability of a base of the wear part. In some embodiments, the third portion also comprises a tile. In some embodiments, the first portion and / or the second portion comprise tungsten. The first and second portions may be formed of a different material to the third portion. For example, the first and second portions may be formed of a material having a greater durability than a material of the third portion. In some embodiments, the first portion and / or the second portion may comprise tungsten carbide. In some embodiments, the first portion and / or the second portion may comprise high chromium plate. In some embodiments, the first portion may comprise tungsten carbide and the second portion may comprise high chromium plate. High chromium plate may comprise a chromium plating, a chromium carbide plating or a chromium-molybdenum alloy steel plate. It will be appreciated that other durable or hardened materials may be used. Additionally or alternatively, the first durability and the second durability may be greater than the third durability by virtue of a coating, e.g., a ceramic coating, or a treatment, e.g., hard anodising or heat treatment. In this case, the first, second and third portions may be formed of a same material. Similarly, the first portion may be formed of a different material to the second portion such that the first durability and the second durability are substantially different. Alternatively, the first portion and the second portion may be formed of a substantially identical material such that the first durability and the second durability are substantially identical. Further, where the first and second portions are formed of a substantially identical material, the first durability and the second durability may yet be substantially different, for example, the first portion may be heat treated to increase durability. It will be appreciated that any suitable combination of materials and treatments may be used to provide a wing comprising a first portion, second portion and third portion, each having a respective durability, according to the first aspect of the invention. In some embodiments, the first portion extends across substantially an entire span of the wing in a direction substantially parallel with the leading edge. In this way, an entire span of the leading edge of the wing is provided with increased durability, increasing a service life of the leading edge. In some embodiments, the second portion projects between the leading edge and the trailing edge by a distance that is less than a third of a chord of the wing. In other words, a dimension of the second portion measured between the leading edge and the trailing edge of the wing may be less than a third of a dimension of the entire wing measured between the leading edge and the trailing edge of the wing. In this way, the use of high value materials or processes to produce a high durability second portion is economical. In some embodiments, a distance from a centre of the second portion to the trailing edge is less than a distance from the centre of the second portion to the leading edge. In other words, the second portion is disposed closer to the trailing edge than to the leading edge. In this way, the second portion is appropriately located to provide durability to a rear of the wing such that a profile of the wing may be preserved even while the wear part wears, retaining the original performance of the wing, and features disposed behind the wing may be protected by the durable rear of the wing. In some embodiments, the distance from a centre of the second portion to the trailing edge is substantially half the distance from the centre of the second portion to the leading edge. In other words, the second portion protects a rear third of the wing. In some embodiments, a width of the first portion and a width of the second portion are different. In some embodiments, a width of the first portion is greater than a width of the second portion. In other words, a dimension of the first portion measured perpendicular to the leading edge of the wing is greater than a dimension of the second portion measured perpendicular to the leading edge of the wing. Accordingly, the first portion being wider than the second portion, the first portion may protect a wider extent of the wing and be configured to resist impact of compacted topsoil. In some embodiments, the trailing edge of the wing is reinforced using hardfacing. In this way, a durability of the rear of the wing is further increased to preserve an original profile, and thereby performance, of the wing for a long service life. Hardfacing may include applying hard, wearresistant material to a surface of the trailing edge, e.g., by welding or thermal spraying. In some embodiments, the wing comprises a ridged profile. The ridges of the wing may assist in deflecting soil incident on the wing to reduce wear of the wing. A number of ridges may coincide with a number of portions of the wing such that each portion forms one ridge. Alternatively, one portion may comprise a plurality of ridges. In particular, the third portion may comprise a plurality of ridges. In some embodiments, the soil-engaging wear part further comprises a base. In some embodiments, the first portion, second portion and third portion are disposed upon the base. For example, where the first and second portions comprise tiles, the tiles may be disposed upon a base material to form the wing. The base may provide a mounting surface for the portions, improving an ease of manufacturability. In some embodiments, the soil-engaging wear part further comprises a fourth portion having a fourth durability and disposed substantially at the trailing edge. The fourth portion may comprise a plurality of ridges. In some embodiments, the fourth durability is substantially less than the first durability and the second durability, and substantially greater than the third durability. In this way, the fourth portion provides further durability to a rear of a wing. By being less durable than the first and second portions, the fourth portion may be inexpensive and cost-effective. In some embodiments, the soil-engaging wear part further comprises a mounting interface configured to couple the wear part to a machine and disposed proximate the trailing edge. The mounting interface may comprise an aperture configured to receive a fastener, e.g., a bolt or a pin. The mounting interface may be disposed behind the wing of the wear part, in a ‘shadow’ of the wing such that, in use, the mounting interface is protected from impacts and wear by the rear of the wing. In this way, a fastener may be protected from wear by the rear of the wing so that the fastener is not worn and deformed but easy to remove when necessary. In some embodiments, the soil-engaging wear part further comprises a nose configured to initiate disturbance of topsoil and disposed proximate the leading edge. The nose may be disposed on a central portion of the wear part disposed between wings of the wear part. The nose may be a tip, or leading point or leading edge of the wear part as a whole, such that the leading edge of each wing is disposed behind the nose in use. The nose may comprise a nose portion having a nose durability. The nose durability may be greater than the third durability. The nose durability may be greater than the fourth durability. The nose durability may be greater than the second durability. The nose durability may even be greater than the first durability. The nose portion may comprise a tile formed from a high durability material, e.g., a material comprising tungsten. The nose may be disposed at a first end of a leading face of the wear part. The leading face may comprise tiles formed from a high durability material, e.g., a material comprising tungsten. The leading face may comprise a relatively narrow front face of a spine of the wear part, the spine being a central portion of the wear part disposed between wings of the wear part, and may extend substantially from a top of the wear part to the nose at the bottom of the wear part, proximate the wings. The leading face may be flanked by side portions reinforced using hardfacing. According to a second aspect of the invention, there is provided a wing configured for use in the soil-engaging wear part of the first aspect of the invention, the wing comprising: a leading edge and a trailing edge; a first portion having a first durability; a second portion having a second durability; and a third portion having a third durability; wherein the first portion is disposed substantially at the leading edge; the second portion is disposed substantially between the leading edge and the trailing edge; and the third portion is disposed substantially between the first portion and the second portion; and wherein the first durability and the second durability are substantially greater than the third durability. Accordingly, the wing of the second aspect of the invention is configured for use in the soilengaging wear part of the first aspect of the invention. It will be appreciated that the wing of the second aspect of the invention may comprise any features of the wing described in relation to the first aspect of the invention. In some embodiments, the wing is replaceable on the wear part. Accordingly, when a wing wears out, it may be replaced on the wear part by a new wing. In this way, a spine, leading face and nose of the wear part need not be replaced at the same time as the wing. Further, each wing in a pair of wings may be replaced at different times, according to wear on each wing. In this way, each part of the wear part may be used for a maximum service life, the life of the part as a whole is not dictated by one, relatively wear vulnerable part. As a result, an economy and efficiency of the wear part is improved. The wing may be coupled to the wear part by a fastener, or any other suitable mechanism. For example, a spine of the wear part may be provided in two halves configured to hold a portion of the wing in place when assembled together. In this case, the wing may be removed and replaced on the wear part by disassembly of the spine of the wear part to release the worn wing and reassembling the spine of the wear part around the new wing. According to a third aspect of the invention, there is provided a kit of parts comprising parts operable to be assembled into the soil-engaging wear part of the first aspect of the invention. The kit of parts may comprise a pair of wings and a spine operable to be assembled into the soilengaging wear part of the first aspect of the invention. It will be appreciated that the kit of parts of the third aspect of the invention may comprise any features described in relation to the first and second aspects of the invention. Brief Description of the Drawings Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawing, in which: Figure 1 depicts a soil-engaging wear part according to an embodiment of a first aspect of the invention. Detailed Description With reference to Figure 1, there is illustrated a soil-engaging wear part 100 configured to disturb topsoil, the soil-engaging wear part 100 including a wing 102 comprising a leading edge 104 and a trailing edge 106, wherein the wing 102 comprises: a first portion 108 having a first durability; a second portion 110 having a second durability; and a third portion 112 having a third durability; wherein the first portion 108 is disposed substantially at the leading edge 104; the second portion 110 is disposed substantially between the leading edge 104 and the trailing edge 106; and the third portion 112 is disposed substantially between the first portion 108 and the second portion 110; and wherein the first durability and the second durability are substantially greater than the third durability. The wing 102 further comprises a base 114. The first portion 108 and the second portion 110 are mounted on the base 114. The third portion 112 and a fourth portion 116, disposed at the trailing edge 106 of the wing 102 and reinforced using hardfacing, are integrally formed as one part with the base. In an alternative embodiment, the third portion 112, the base 114 and the fourth portion 116 may be formed of one material, having one durability. In an alternative embodiment, the third portion 112 and / or the fourth portion 116 may be mounted on the base 114. The wear part 100 further comprises a spine 118 disposed between wings 102 of the wear part 100. The spine 118 comprises a leading face 120 which extends from a top of the wear part 100 to a bottom of the wear part 100, proximate the wings 102. At a bottom of the leading face 120, the spine 118 comprises nose 122. The nose 122 is configured to initiate disturbance of topsoil and disposed proximate the leading edge 104 of the wing 102. A front of the nose 122 is protected by high durability tiles 124. The tiles 124 are arranged along the leading face 120 so that tiles extend from a top of the wear part 100 to a bottom of the wear part 100. In other embodiments, tiles may protect only the nose 122, or tiles may extend partially along the leading face from a nose towards a top of the wear part. The tiles 124 comprise tungsten carbide. The leading face 120 is flanked by side portions 126 reinforced using hardfacing. In other embodiments, no side portions 126 may be provided. The wear part 100 further comprises a mounting interface 128 configured to couple the wear part 100 to a machine and disposed proximate the trailing edge 106 of the wing 102. The mounting interface 128 comprises an aperture configured to receive a fastener, such as a bolt, for coupling the wear part 100 to a machine. The mounting interface 128 is disposed in the ‘shadow’ of the wing 102 such that, in use, the mounting interface 128 is shielded from impact and protected from damage and wear by the rear of the wing 102. The first portion 108 is made up of two tiles arranged end to end. The second portion 110 is also made up of two tiles arranged end to end. In other embodiments, the first and second portions 108, 110 may each comprise any suitable number of tiles, for example, 1, 2, 3 or 4 tiles. The third portion 112 is not made up of tiles but instead comprises ridges formed in the casting process used to form the wing 102. The third portion 112 is formed as part of a base of the wing 102, from a cast metal alloy. The first portion 108, the second portion 110 and the third portion 112 extend across substantially an entire span of the wing 102 in a direction substantially parallel with the leading edge 104. The first portion 108 is wider than the second portion 110 in a dimension measured from the leading edge 104 to the trailing edge 106, and the third portion 112 is wider than the first portion 108. In other embodiments, any suitable alternative relative dimensions may be used. The wing 102 is shaped as though clipped such that the tip of the wing 102 has a straight edge arranged substantially parallel with a root of the wing 102. As a result, the overall shape of the wing 102 is a trapezium. The leading edge 104 is arranged at an acute angle to the root of the wing 102, approximately a 45-degree angle. In other embodiments, the leading edge 104 may be arranged at an angle between 70-degrees and 30-degrees to the root of the wing 102, in particular, at an angle between 50-degrees and 60-degrees. The trailing edge 106 is arranged substantially perpendicular to a root of the wing 102. As the first, second and third portions 108, 110, 112 are substantially parallel with the leading edge 104, they form an acute angle with the trailing edge 106. In particular, the second portion 110 extends from a point approximately central to the root of the wing 102 to a tip end of the trailing edge 106 of the wing 102. In other embodiments, for example where the angle of the leading edge 104, the shape of the wing 102, or the arrangement of the portions is different, the second portion may be arranged differently. At the inner rear corner of the wing 102, the fourth portion 116 is provided in a triangle shape. The fourth portion comprises three rows reinforced with hardfacing arranged substantially parallel with the leading edge 104 that taper to a point at the inner rear corner of the wing 102. The second portion 110 is arranged approximately two thirds of the way along the wing 102 from the leading edge 104 to the trailing edge 106. In other words, a distance from a centre of the second portion 110 to the trailing edge 106 is substantially half the distance from the centre of the second portion 110 to the leading edge 104. The wing comprises a ridged profile. The ridges are formed by the tiles and hardfacing of the first, second, third and fourth portions 108, 110, 112, 116 and the shape of the base 114 of the wing 102. The ridges may assist in deflecting soil incident on the wing 102 to reduce wear of the wing 102. Further embodiments within the scope of the present invention may be envisaged that have not been described above. For example, the soil-engaging wear part may be used in any suitable machine, such as a subsoiler machine, a seed drill, a plough, a cultivator, a harrow, a rotavator, any other type of tilling or drilling machine, or for any other suitable purpose. The soil-engaging wear part may achieve its superior durability in any suitable manner. The soil-engaging wear part may comprise any number of parts. For example, each wear part may comprise two wings extending from one spine. Alternatively, each spine may comprise four wings. Each wear part 5 may comprise a symmetrical design such that the wear part is reversible, further extending service life. The wear part may constitute a foot, tine, frog, leg or wing suitable for use with a machine. Alternatively, the wear part may be suitable for mounting on a foot, tine, frog, leg or wing of a machine. The components of the soil-engaging wear part may be coupled together in any suitable manner. For example, the wings may be connected to the spin using fasteners such as bolts, or 10 by welding. To provide a durable and cost-effective soil-engaging wear part, an innovative design is required. The present invention utilises a unique arrangement of durable portions on a wing of a wear part to provide a cost-effective wear part capable of a long service life. The invention is not limited to 15 the specific examples or structures illustrated, a greater number of components than are illustrated in the figures could be used, for example.

Claims

1. A soil-engaging wear part configured to disturb topsoil, the soil-engaging wear part including a wing comprising a leading edge and a trailing edge, wherein the wing comprises:a first portion having a first durability; a second portion having a second durability; and a third portion having a third durability;wherein the first portion is disposed substantially at the leading edge; the second portion is disposed substantially between the leading edge and the trailing edge; and the third portion is disposed substantially between the first portion and the second portion; andwherein the first durability and the second durability are substantially greater than the third durability.

2. The soil-engaging wear part according to claim 1, wherein the first portion comprises a tile having a first durability.

3. The soil-engaging wear part according to claim 1 or claim 2, wherein the second portion comprises a tile having a second durability.

4. The soil-engaging wear part according to any preceding claim, wherein the first durability is substantially identical to the second durability.

5. The soil-engaging wear part according to any preceding claim, wherein the first portion and / or the second portion comprise tungsten.

6. The soil-engaging wear part according to any preceding claim, wherein the first portion extends across substantially an entire span of the wing in a direction substantially parallel with the leading edge.

7. The soil-engaging wear part according to any preceding claim, wherein the second portion projects between the leading edge and the trailing edge by a distance that is less than a third of a chord of the wing.

8. The soil-engaging wear part according to any preceding claim, wherein a distance from a centre of the second portion to the trailing edge is less than a distance from the centre of the second portion to the leading edge.

9. The soil-engaging wear part according to claim 8, wherein the distance from a centre of the second portion to the trailing edge is substantially half the distance from the centre of the second portion to the leading edge.

10. The soil-engaging wear part according to any preceding claim, wherein a width of the first portion and a width of the second portion are different.

11. The soil-engaging wear part according to claim 10, wherein a width of the first portion is greater than a width of the second portion.

12. The soil-engaging wear part according to any preceding claim, wherein the trailing edge of the wing is reinforced using hardfacing.

13. The soil-engaging wear part according to any preceding claim, wherein the soil-engaging wear part further comprises a base.

14. The soil-engaging wear part according to claim 13, wherein the first portion, second portion and third portion are disposed upon the base.

15. The soil-engaging wear part according to any preceding claim, wherein the soil-engaging wear part further comprises a fourth portion having a fourth durability and disposed substantially at the trailing edge.

16. The soil-engaging wear part according to claim 15, wherein the fourth durability is substantially less than the first durability and the second durability, and substantially greater than the third durability.

17. The soil-engaging wear part according to any preceding claim, further comprising a mounting interface configured to couple the wear part to a machine and disposed proximate the trailing edge.

18. The soil-engaging wear part according to any preceding claim, further comprising a nose configured to initiate disturbance of topsoil and disposed proximate the leading edge.

19. A wing configured for use in the soil-engaging wear part according to any preceding claim, the wing comprising:a leading edge and a trailing edge;a first portion having a first durability; a second portion having a second durability; and a third portion having a third durability;wherein the first portion is disposed substantially at the leading edge; the second portion is disposed substantially between the leading edge and the trailing edge; and the third portion is disposed substantially between the first portion and the second portion; andwherein the first durability and the second durability are substantially greater than the third durability.

20. The wing according to claim 19, wherein the wing is replaceable on the wear part.

21. A kit of parts comprising parts operable to be assembled into the soil-engaging wear part according to any one of claims 1 to 18.15

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