KARLSSON, Bjorn Marten (88 Sandpiper Loop, Yangebup, Western Australia 6164, AU)
DALLARD, Bradley John (13 Capill Corner, Leeming, Western Australia 6149, AU)
KARLSSON, Bjorn Marten (88 Sandpiper Loop, Yangebup, Western Australia 6164, AU)
| CLAIMS: 1 . An earth moving apparatus member having an outer surface which curves between a base portion and a side portion, the earth moving apparatus member having a wear member receiver located on the outer surface, the wear member receiver having an inwardly projecting portion having an upper surface, the upper surface forming an acute angle with respect to the base portion of the outer surface, and an outwardly projecting portion having an engagement surface, the engagement surface extending away from the side portion of the outer surface, whereby a wear member can locate about the wear member receiver and be restrained from moving in at least one direction. 2. An earth moving apparatus member as claimed in claim 1 , wherein the wear member receiver is prismatic. 3. An earth moving apparatus member as claimed in claim 1 , wherein the wear member receiver has at least one leg extending between the inwardly projecting portion and the outwardly projecting portion, the leg having tapered sides such that the leg narrows away from the outer surface. 4. An earth moving apparatus member as claimed in claim 3, wherein the wear member receiver has two such legs. 5. An earth moving apparatus member as claimed in any preceding claim, wherein the inwardly projecting portion is formed by single, continuous members. 6. An earth moving apparatus member as claimed in any one of claims 1 to 4, wherein the inwardly projecting portion is formed by a number of discontinuous members. 7. An earth moving apparatus member as claimed in any preceding claim, wherein the outwardly projecting portion is formed by single, continuous members. 8. An earth moving apparatus member as claimed in any one of claims 1 to 6, wherein the outwardly projecting portion is formed by a number of discontinuous members. 9. An earth moving apparatus member as claimed in claim 4, wherein the inwardly projecting portion is formed by two members, one associated with each leg, and the outwardly projecting portion being formed by a single member extending between the two legs. 10. An earth moving apparatus member as claimed in claim 9, wherein each leg has an outer side which is relatively steep and an inner side which is at a wide angle with respect to the first portion of the outer surface. 1 1 . A wear member for attachment to a wear member receiver located on a surface subject to wear, the wear member having a first body portion arranged to locate about the wear member receiver and a second body portion arranged to locate adjacent a side portion of the surface subject to wear, the first body portion having a catch portion located at an inner end thereof, the catch portion being sized and shaped so as to locate between a inwardly projecting portion of the wear member receiver and the surface subject to wear, the first body portion having at least one hollow arranged to locate about a leg of the wear member receiver, the hollow having at least one bearing surface arranged to engage with a bearing surface of the leg of the wear member receiver, and the second body portion having a lock receiving aperture and a bearing surface arranged to engage with a lock, such that the application of a force from the lock to the bearing surface of the second body portion acts to engage the bearing surface of the first portion hollow with its associated leg bearing surface. 12. A wear member as claimed in claim 1 1 , wherein the wear member is a heel shroud and the surface subject to wear is the corner or heel of an earth moving bucket. 13. A wear member as claimed in claim 1 1 or claim 12, wherein the wear member receiver has two legs and the first body portion has two corresponding hollows. 14. A wear member as claimed in claim 13, wherein the first body portion has a further, non load-bearing hollow which provides a means for indicating a maximum degree of desirable wear. 15. A wear member as claimed in any one of claims 1 to 14, wherein the locking aperture extends through an outward face of the second body portion, allowing for a body of a lock to be inserted through the outward face. 16. A wear member as claimed in claim 15, wherein the locking aperture opens out to a side wall of the second body portion, allowing for a lock activator to be inserted into the lock body. |
FIELD OF THE INVENTION
The present invention relates to the attachment of wear members such as heel shrouds to surfaces subject to abrasive wear, such as earth moving buckets.
BACKGROUND TO THE INVENTION
Buckets for earth moving equipment, such as excavators, are subject to a high degree of abrasive wear. This wear is particularly pronounced at a leading edge of the bucket, where ground engaging tools such as adaptors and teeth are used to penetrate matter being dug. It is also found at bucket corners and heels, although wear in these areas is not as pronounced as at the leading edge.
In order to prolong the working life of a bucket, and to retain structural strength in the face of this wear, it is common practice to fix replaceable wear members to those parts of the bucket most subject to wear. Traditionally wear members such as teeth, adaptors, wear strips and heel shrouds have been welded into place on a bucket.
Although the welding of wear members to buckets provides a secure means of attachment, it has significant practical difficulties. Replacement of worn members requires the cutting out of the worn member, and the fitting and re- welding of a new member in its place. Such metal-working operations require specialised equipment and trained boilermakers.
Where the bucket is being employed remotely, the removal of the bucket, transportation to a suitable workshop, replacement of the worn member and transportation back to the remote location can result in a significant time delay, and thus a loss of production. As excavators are often highly expensive, the underutilisation caused by the need for bucket repairs has a significant economic consequence.
In response to this problem, methods of mechanically attaching ground engaging tools to the leading edge of the bucket have been developed. An example of such a method is disclosed in the international patent application published as number WO02/12642, in the name of a predecessor of the present applicant. Ground engaging tools in accordance with this application are shown attached to the leading edge of the excavator bucket 170 of Figure 13 of the present application.
Generally, known methods of mechanically attaching ground engaging tools to a bucket leading edge involve providing the ground engaging tool with a channel which locates about the bucket leading edge, and then clamping or bolting the ground engaging tool in a particular position along the bucket edge.
The geometry of this arrangement greatly assists in the attachment of ground engaging tools. The principle forces to which the tools are subjected are shear forces and compressive forces, and generally speaking these forces are transmitted directly to the bucket leading edge, rather than through the clamp or bolt being used. The mechanical attachment is thus only really required to prevent lateral movement of the tool along the bucket edge, or the pulling away of the tool from the bucket edge.
There have been relatively few attempts to provide a mechanical attachment of heel shrouds to excavator buckets. There would appear to be two reasons for this. Firstly, the rate of wear of heel shrouds is less than that of ground engaging tools, and thus the economic advantage of mechanical attachment, whilst significant, is not as great as for ground engaging tools at the bucket leading edge. Secondly, and perhaps more significantly, the geometry of heel shroud attachment is much less promising than at the bucket leading edge.
Heel shrouds must be mounted around corners or heels of the bucket. As such, there is no lip for them to clamp around. In other words, the angle included by a heel shroud is in the order of 90°, as opposed to an included angle of about 20° typical for ground engaging tools. Any force acting on the heel shroud, except for a direct compressive force, will act directly on the attachment system on at least one face. This places significant stress upon the attachment system. To date, therefore, welding has proved the only suitable method of attachment.
Research by the applicant has revealed an attempt to overcome this problem by bolting of heel shrouds to bucket corners and heels. This technique has several drawbacks. Firstly, the drilling of bolt holes within the bucket can reduce the bucket strength. Secondly, there is a tendency for bolts to deform under load. When this occurs, it can be impossible to remove a bolt using normal mechanical tools, and it may be necessary to cut the bolt from the bucket. This, of course, eliminates any advantage gained by the use of such bolts.
The present invention seeks to provide a means of mechanically attaching a heel shroud to an excavator bucket which does not require bolting through the bucket walls.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention there is provided an earth moving apparatus member having an outer surface which curves between a base portion and a side portion, the earth moving apparatus member having a wear member receiver located on the outer surface, the wear member receiver having an inwardly projecting portion having an upper surface, the upper surface forming an acute angle with respect to the base portion of the outer surface, and an outwardly projecting portion having an engagement surface, the engagement surface extending away from the side portion of the outer surface, whereby a wear member can locate about the wear member receiver and be restrained from moving in at least one direction.
The invention has been envisaged with the earth moving apparatus member being a bucket, such as an excavator bucket, the outer surface being a bucket corner or bucket heel and the wear member being a heel shroud. The base portion may be the floor of the bucket, or may be the curved, rear portion of the bucket.
The wear member receiver may be prismatic. It is preferred, however, that the wear member receiver has at least one leg extending between the inwardly projecting portion and the outwardly projecting portion, the leg having tapered sides such that the leg narrows away from the outer surface. In a preferred embodiment, the wear member receiver has two such legs. At least one of the tapered sides provides a bearing surface, and allows for a wedging action to secure the wear member to the wear member receiver.
The inwardly projecting portion and outwardly projecting portion may each be formed by single, continuous members or by a number of discontinuous members. In the preferred embodiment, the inwardly projecting portion is formed by two members, one associated with each leg, with the outwardly projecting portion being formed by a single member extending between the two legs. This allows for the engagement surface of the outwardly projecting portion to receive a load distributed along it, and allows for the inwardly projecting portions to engage with a catch portion of the wear member.
The tapered sides of the leg or legs may be symmetrical about a central plane of each leg. In the preferred embodiment each leg has an outer side which is relatively steep and an inner side which is at a wide angle with respect to the first portion of the outer surface. This allows the inner sides to act as the bearing surfaces in preference to the outer sides.
In accordance with a second aspect of the present invention there is provided a wear member for attachment to a wear member receiver located on a surface subject to wear, the wear member having a first body portion arranged to locate about the wear member receiver and a second body portion arranged to locate adjacent a side portion of the surface subject to wear, the first body portion having a catch portion located at an inner end thereof, the catch portion being sized and shaped so as to locate between a inwardly projecting portion of the wear member receiver and the surface subject to wear, the first body portion having at least one hollow arranged to locate about a leg of the wear member receiver, the hollow having at least one bearing surface arranged to engage with a bearing surface of the leg of the wear member receiver, and the second body portion having a lock receiving aperture and a bearing surface arranged to engage with a lock, such that the application of a force from the lock to the bearing surface of the second body portion acts to engage the bearing surface of the first portion hollow with its associated leg bearing surface.
Preferably the wear member is a heel shroud, with the surface subject to wear being the corner or heel of an earth moving bucket such as an excavator bucket.
Where the wear member receiver has two legs, the first body portion may have two corresponding hollows. In a preferred embodiment, the first body portion has a further, non load-bearing hollow which serves both to reduce the weight of the wear member and also to provide a means for indicating a maximum degree of desirable wear. The first body portion of the wear member preferably includes side walls arranged, in use, to surround the wear member receiver and to protect it.
Preferably, the locking aperture extends through an outward face of the second body portion, allowing for a body of a lock to be inserted through the outward face. Preferably also, the locking aperture opens out to a side wall of the second body portion, allowing for a lock activator to be inserted into the lock body.
BRIEF DESCRIPTION OF THE DRAWINGS
It will be convenient to further describe the invention with reference to a heel shroud, being a preferred embodiment of the present invention. Other embodiments are possible, and consequently, the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:
Figure 1 (a) is a first perspective of a portion of a bucket heel to which a heel shroud is to be attached in accordance with the present invention;
Figure 1 (b) is a second perspective of the bucket heel portion of Figure
1 (a);
Figure 1 (c) is a side view of the bucket heel portion of Figure 1 (a);
Figure 2(a) is a first perspective of a heel shroud to be attached to the bucket heel portion of Figure 1 (a);
Figure 2(b) is a second perspective of the heel shroud of Figure 2(a);
Figure 2(c) is a side view of the heel shroud of Figure 2(a);
Figure 2(d) is a lower perspective of the heel shroud of Figure 2(a);
Figure 3(a) is a first perspective of a lock for use in securing the heel shroud of Figure 2(a) to the bucket heel of Figure 1 (a);
Figure 3(b) is a second perspective of the lock of Figure 3(a);
Figure 3(c) is a lower perspective of the lock of Figure 3(a);
Figure 4 is a perspective of a lock activator for use in conjunction with the lock of Figure 3(a);
Figures 5(a) to 1 1 (a) are sequential perspectives of the bucket heel shroud of Figure 2(a) being attached to the bucket heel portion of Figure 1 (a); Figures 5(b) to 1 1 (b) are side view corresponding to the perspectives of Figures 5(a) to 1 1 (a) respectively;
Figure 12 is a cross section through a portion of the bucket heel with attached shroud of Figure 1 1 ; and
Figure 13 is a perspective of an excavator bucket to which are attached a plurality of heels shrouds in accordance with the present invention.
DESCRIPTION OF PREFERRED EMBODIMENT
Figures 1 (a) to 1 (c) show a portion of an excavator bucket corner 10 having an inner surface 12 and an outer surface 14. The outer surface 14 has a base portion or floor 16 which extends inwardly of the bucket leading edge (not shown), and a side portion 18 which is oriented at about 1 10° to the base portion 16. The base portion 16 and side portion 18 are joined by a curved portion 17.
The bucket corner portion 10 has a wear member receiver 20 affixed to the most outward part of the base portion 16 of the outer surface 14. In the preferred embodiment of the invention, the wear member receiver is cast integrally with the bucket corner portion 10.
The wear member receiver 20 is formed from two parallel legs 22, each extending towards an opposing side of the base portion 16. Each leg 22 has a inner end 24 closest to a centre line of the base portion 16, and a outer end 26 furthest from the centre line of the base portion 16.
Each leg 22 has a inwardly projecting portion 28 at the inner end 24. The inwardly projecting portion 28 has a sloped upper surface 30 which extends outwardly from the base portion 16 of the outer surface 14. The slope is such that the upper surface 30 is disposed at an acute angle relative to the base portion 16, thereby creating a generally triangular hollow 32 between the upper surface 30 and the base portion 16. In the embodiment shown, the acute angle is about 60°.
Each leg 22 has tapered sides, an inner tapered side 34 and an outer tapered side 36. The outer tapered sides 36 are oriented at about 80° to the base portion 16. The inner tapered sides 34 are oriented at about 60° to the base portion 16. The outer tapered sides 36 are thus relatively steep, with the inner tapered sides 34 being at a relatively wide angle. Each leg 22 has a outwardly projecting portion 40 at the outer end 26. The outwardly projecting portion 40 includes a sloped upper surface 42 which extends outwardly from the curved portion 17 of the outer surface 14, between the base and side portions 16, 18. The orientation of the upper surface 42 is such that it is oriented at about 90° to the side portion 18 of the outer surface 14.
The wear member receiver 20 includes a connecting member 44 which extends between the respective outwardly projecting portions 40 of the two legs 22. The connecting member 44 and the two outwardly projecting portions 40 together define an outwardly projecting portion of the wear member receiver 20.
The connecting member 44 has an upper surface which joins, and is a continuation of, the upper surfaces 42. This upper surface and the upper surfaces 42 combine to form an engaging surface 46 which extends across the outer part of the wear member receiver 20.
Figures 2(a) to 2(d) show a wear member, being a heel shroud 60, which mounts to the wear member receiver 20.
The heel shroud 60 is comprises a first body portion 62 and a second body portion 64.
The first body portion 62 has a generally rectangular prismatic outer shape, with inner end wall 66, and a outer end wall 68, and two generally parallel side walls 70. The first body portion 62 has a slightly convex, rectangular lower surface 72. The first body portion 62 also has an upper surface 74 which is arranged, in use, to abut the base portion 16 of the outer surface 14 of the bucket heel 10.
The first body portion 62 has two hollows 76 internally of the upper surface 74. The hollows 76 are each sized to engage with a corresponding leg 22 of the wear member receiver 20. The hollows 76 each have an inner, tapered side wall 78 and an outer tapered side wall 80. The respective slope of the side walls 78, 80 corresponds to the slope of the sides 34, 36 of the legs 22 of the wear member receiver 20.
The hollows 76 each have a catch portion 82 located at an inner end thereof. The catch portion 82 is formed by a tapered end wall, oriented so as to lengthen the hollow 76 away from the upper edge 74. The catch portion 82 is complementary in shape to the triangular hollow 32 of the wear member receiver 20.
The first body portion 62 has a further hollow 84 located between the two hollows 76. The further hollow 84 has side walls which are nearly parallel, and nearly perpendicular to the upper surface 74. The further hollow 84 has a depth from the upper surface 74 which is slightly greater than the depth of the hollows 76.
The first body portion 62 has a further generally cut away area 86 internally of the upper surface 74, located towards the outer end wall 68. This further cut away area 86 is complementary in shape to the rearwadly projecting portion 40 of the wear member receiver 20.
The second body portion 64 is generally perpendicular to the first body portion 62, extending above the upper surface 74 towards the outer end wall 68. It has an inner face 92 arranged, in use, to abut the side portion 18 of the outer surface 14 of the bucket corner portion 10. The second body portion 64 has an outer face 94 which at its upper end extends away from the inner face 92 at about a 45° angle, so as to define a generally triangular cross sectional shape. At its lower end the outer face 94 joins the outer end wall 68 of the first body portion 62. The second body portion has a first side wall 96, and a generally triangular second side wall 98.
A lock receiving aperture 100 extends between the inner face 92 and the outer face 94. The lock receiving aperture 100 has a substantially flat floor 102, generally parallel to the lower surface 74 of the first body portion 62. The lock receiving aperture has parallel side walls 104, each having guiding channels 106 adjacent the floor 102, creating an L-shaped path.
The lock receiving aperture 100 also opens out onto the first side wall 96, at the inner face 92. This opening creates a gap 108 between the second body portion 64 and the side portion 18 of the bucket corner portion 10 through which the lock receiving aperture 100 can be accessed.
The lock receiving aperture 100 has a ceiling 1 10 having an introduction region 1 12 substantially parallel to the floor 102; a bearing region 1 14 forward of the introduction region 1 12, the bearing region being angled relative to the introduction region 1 12 such that, when in position, the bearing region 1 14 is substantially parallel to the engaging surface 46 of the wear member receiver 20; and a tapered side portion 1 16 arranged to receive a lock activator as will be described below.
Figures 3(a) to 3(c) show a lock 130 which is used to secure the heel shroud 62 to the bucket corner portion 10. The lock 130 has a body portion 132 and an activating portion 134.
The body portion 132 is generally sized and shaped to be complementary in shape to the lock receiving aperture 100. It has two transverse projections 136 which are arranged to locate within the guiding channels 106 of the lock receiving aperture 100.
The activating portion 134 is positioned forward of the body portion 132. It includes an upper bearing face 140 which extends forwardly of the body portion 132 at an incline, corresponding to the incline of the bearing region 1 14 of the lock receiving aperture.
The activating portion 134 has a first lower bearing face 141 which is inclined about a transverse axis relative to the lock's movement, so as to be parallel to the upper bearing face 140. The activating portion 134 also has a second lower bearing face 142 located at the forward end of the first lower bearing face 141 . The second lower bearing face 142 is inclined upwardly towards the first side wall 96 of the second body portion 64 of the heel shroud 60, thus opening towards the gap 108. When considered in relation to the body portion 132, the second lower bearing face is thus inclined firstly about the transverse axis and secondly about an axis aligned with the lock's movement. These can be considered as an inclination in pitch and in roll. In pitch, the second lower bearing face 142 is inclined in the same direction as the first lower bearing face 140, to correspond to the engaging surface 46 of the wear member receiver 20. In roll, the second lower bearing face 142 is inclined upwardly towards the gap 108. The inclination in roll corresponds to the inclination of the tapered side portion 1 16 of the ceiling 1 10.
The activating portion 134 has an internally threaded bolt hole 144 which is parallel to, and directly above, the second lower bearing face 142.
Figure 4 shows a lock activator 150. The lock activator 150 has a wedging portion 152, which is substantially right triangular prismatic in shape. The wedging portion 152 has an upper bearing surface 154, which in cross section represents the hypotenuse of the right-angled triangle, a lower bearing surface 156 and a side surface 158. The angle between the upper and lower bearing surfaces 154, 156 is equal to the inclination in roll of the second lower bearing face 142 of the lock 130.
The lock activator 150 has an externally threaded bolt 160 located in a bearing above the upper bearing surface 154. The bolt 160 has a central axis parallel to the upper bearing surface 154. The bolt 160 is sized so as to engage with the bolt hole 144 of the lock 130. When the bolt 160 is engaged with the bolt hole 144, the upper bearing surface 154 is arranged to bear against the second lower bearing face 142 of the lock 130. Turning of the bolt results in movement of the lock activator 150 in a direction parallel to the second lower bearing face 142.
Attachment of the heel shroud 60 to the bucket corner portion 10 will now be described with reference to Figures 5 to 1 1 .
The heel shroud 60 is first hooked about the inner end 24 of the wear member receiver 20. This is done by engaging the catch portion 82 of the hollows 76 of the heel shroud 60 in the triangular hollow 32 at the inner end 24 of the wear member receiver 20. This is shown in Figure 5.
The heel shroud 60 can then be rotated about the inwardly projecting portion 28 of the wear member receiver 20 through the position shown in Figure 6 to the position of Figure 7. In the position of Figure 7 the upper surface 74 of the first body portion 62 of the heel shroud 60 is close to the base portion 16 of the outer surface 14 of the bucket corner portion 10. The inner face 92 of the second body portion 64 of the heel shroud 60 is abutting the side portion 18 of the outer surface 14 of the bucket corner portion 10. The legs 24 of the wear member receiver 20 are located within the hollows 76 of the heel shroud 60. The outwardly projecting portion 40 of the wear member receiver 20 is located within the cut away portion 86 of the heel shroud 60.
The lock 130 can then be introduced into the lock receiving aperture 100 from the outside, as shown in Figure 8. The transverse projections 136 locate within the guiding channels 106, allowing the lock 130 to move inwards and then up in an V shaped path, to its final position shown in Figure 9. In this position the lock 130 has moved inward to a position where the lock activating portion 134 is accessible through the gap 108. The upper bearing face 140 of the lock 130 locates against, or close to, the bearing region 1 14 of the ceiling 1 10. The first lower bearing face 141 of the lock 130 locates against, or close to, the engaging face 46 of the lock receiving member 20. The lock thus acts to prevent the heel shroud 60 from rotating backwards.
The lock activator 150 can then be introduced into the gap 108 as shown in Figures 10 and 1 1 , with the bolt 160 being engaged within the bolt hole 144. The upper bearing face 154 of the lock activator 150 abuts the second lower bearing face 142 of the lock 130. The lower bearing face 156 of the lock activator 150 abuts the engaging face 46 of the lock receiving member 20.
Advancement of the bolt 160 within the bolt hole 144 causes a wedging action. The lock 130 and lock activator 150 are placed into compression, with forces acting in one direction on the engaging face 46 and forces acting in the other direction on the bearing region 1 14. This has the effect of urging the heel shroud 60 upwards, and the first body portion 62 of the heel shroud 60 towards the base portion 16 of the outer surface 14.
This action in turns creates a wedging effect between the inner tapered sides 34 of the legs 22 and the inner side walls 78 of the hollows 76. This can be seen in Figure 12. The net effect of this action is to maintain the heel shroud 60 tightly in place.
During use, the heel shroud 60 is subject to wear, and also to vibration. Should vibration cause the shroud to become loose, further advancement of the bolt 160 within the bolt hole 144 will allow the shroud to be tightened.
The further hollow 84 of the heel shroud 60, in addition to reducing the volume of material required, acts as an indicator of useful life. When the heel shroud 60 becomes worn through, the first indication of this will be the lower surface 72 wearing through to the further hollow 84. This will allow for replacement of the heel shroud 60 before the surface wears through to the other hollow 76, which may cause damage to the wear member receiver 20.
It will be understood that, in practice, a plurality of heel corner portions 10 including cast wear member receivers 20 can be welded around the corners of an excavator bucket 170. A corresponding plurality of heel shrouds 60 can then be affixed about the corner of the excavator bucket 170. Such a bucket is shown in Figure 13.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.