AU2004287905A1 - Replaceable excavator bucket components - Google Patents

Description

WO 2005/045142 PCT/CA2004/001913 TITLE OF THE INVENTION REPLACEABLE EXCAVATOR BUCKET COMPONENTS FIELD OF THE INVENTION The invention relates to excavating equipment, and in particular 5 excavation buckets having replaceable lip protectors and wing segments to permit rapid in situ bucket renovation after extensive wear. BACKGROUND OF THE INVENTION Excavator buckets such as those used in hard rock mining operations generally experience a high level of wear on the exposed lower lip, requiring 10 regular replacement of the lip protector portion of the bucket. The same can also be true of the corner wing segments which both protect the exposed lower corners of the bucket and effectively extend the bucket depth. Typically, bucket renovation is accomplished by providing a removable lip protector which is rigidly fastened to the bucket by welding 15 same onto the lower bucket plate. Replacement of the lip protector component requires cutting of the welded attachment, followed by welding a new lip element in place. Optionally other components may be replaced such as bucket corner wing segments. In an underground mining environment such work requires costly containment or gas dispersal 20 systems in order to carry out the work safely or alternatively the bucket be carried to the surface in order that the work may be carried out in a facility located on the surface (often away from the mining site). The large buckets used in modern LHD mining operations may be too large to be carried whole to the surface, requiring such buckets to be cut in half before they are 25 brought to the surface for maintenance work. The refurbished bucket is then restored after it has been brought back into the subsurface mine environment. Regardless of how it is carried out with conventional equipment, maintenance work of this nature is time consuming, costly and removes costly mining equipment from operation for a protracted period. 30 Modern underground mining operations often make use of an excavator bucket system and method referred to as a "Load, Haul, Dump" WO 2005/045142 PCT/CA2004/001913 -2 ("LHD") machine, in which an excavator machine provided with a relatively large bucket is used to haul broken-up ore or rock from a face to a relatively distant chute or other removal location which is within the mine but at some distance from the rock face. This system eliminates the use of a temporary 5 subsurface rail line and car system to carry the ore over this distance. However, such a method places great reliance on large excavator buckets and imposes a heavy wear load on the bucket, in particular the bucket lip. This may be addressed by providing replaceable wear protectors that cover the exposed lip. 10 A bucket for L.H.D. use may include a lead, or prow-shaped extension fastened to the lower bucket lip to protect the bucket shell from wear and enhance its scooping abilities. Typically, an operator is provided with a choice of several different lead configurations for different mining environments. Hence, multiple lip wear protectors must be provided in a 15 typical mining operation to accommodate different lead configurations, including both the front-to-back displacement of the lead (i.e. depth of the lead) and the overall side-to-side width of the bucket. Conventional bucket lip systems include the "Esco Delta V"T prefabricated lip assemblies. These consist of a prow-shaped lead in which 20 the exposed leading edge is protected by weld-on replaceable lip wear elements. .Cast corner pieces are also provided, comprising vertical plates for welding onto opposed sides of the assembly. The assembly is intended to be welded onto the lower plate of an excavator bucket, with the lip wear elements being periodically replaced by a cutting and welding operation as 25 described above. A similar system is sold by Hensley, which includes forwardly-protruding teeth. Replaceable lip protectors are also disclosed in U.S. Patent 3,995,384 to Wood, which describes replaceable bucket lip protectors or teeth. The lip protectors and the lower bucket lip are provided with mating or interlocking components for releasably fastening the lip 30 protectors to the bucket and retaining same in position by means of a removable pin. A replaceable lip system is also disclosed in the present inventor's Canadian Application No. 2,358,339. In order to avoid the considerable time and expense involved in replacing conventional welded-on lip wear protectors, it is desirable to WO 2005/045142 PCT/CA2004/001913 -3 provide lip protectors which mechanically fasten to the excavator bucket, for example with bolts or pins, in order to permit easy and simple replacement of these elements in the subsurface environment. It is also desirable to provide corner elements which are readily 5 replaceable in a similar fashion and which integrate with the replaceable lip segments to provide a monolithic bucket structure. Finally, it is desirable to provide replaceable lip segments which include self-sharpening front points to enhance mucking abilities of the bucket. SUMMARY OF THE INVENTION 10 In general terms, the present invention relates to replaceable wear elements which are mounted to an excavator bucket front shell, consisting of a prow-shaped base plate and an array of mechanically attached lip wear protectors for protecting the exposed front lip of the base plate. The base plate has a forwardly extending lead terminating in a central tip, thus giving 15 its leading edge a chevron shape. The rear edge of the base plate includes a suitable welding surface such as a weld preparation ledge for welding the plate onto the lip of the bucket shell. The segments each have a parallelogram shape for attaching to the base plate in side-by-side abutting array, and include a horizontal rearward-facing groove (i.e. opening to the 20 rear of the segment) to snugly receive the base plate. Mechanical fasteners such as bolts are provided to attach the lip wear segments to the base plate. Preferably the lip wear segments are generally tapered from front to rear with an arcuate upper surface and a flat lower surface which angles downwardly and rearwardly such that the segment includes a heel that 25 protrudes below the base plate and the corresponding bucket shell for additional wear resistance. Preferably, the horizontal groove within the segment tapers inwardly to snugly receive a base plate having a corresponding bevelled front edge region for an improved fit between these elements. 30 In one aspect, the invention relates to replaceable corner shrouds or "wing segments". These mount to opposing sides of the bucket at the lower front corners thereof, where the bucket sidewalls meet the floor to WO 2005/045142 PCT/CA2004/001913 -4 effectively extend the scooping region of the bucket and protect exposed portions of the bucket. These segments are L-shaped (when seen from a front elevation) composed of a vertical plate which merges with the side plate of the bucket and a horizontal plate which protrudes inwardly from the 5 vertical plate to fit within a corresponding cut-out in the base plate. The base plate and horizontal plate of the wing segment form a continuous monolithic plate when fastened together. The wing segments may include replaceable inside wear plates which line the inside surface of the vertical plates. The horizontal plates of the wing segments include a bevelled front 10 edge which is flush with the front edge of the base plate and has the same cross-sectional configuration (thereby forming an extension of the forward edge) to snugly receive a lip wear protector. The lip wear protector may overhang the corner segment laterally in an outboard direction thus permitting a degree of flexibility in selecting the size of the lip wear 15 protectors when assembling these elements onto a given bucket which has a base plate and corner members pre-mounted. The invention further includes excavation buckets which include the components described herein, provided either installed to the bucket or as a kit. 20 In a further aspect, the invention relates to mechanically attached lip wear protectors having a substantially parallelogram shape for attachment to a prow-shaped base plate or lead, the wear protectors having substantially parallel lateral edges, with thickened ribs extending in a longitudinal direction (from front to back) adjacent to each lateral edge. 25 The space between the ribs is defined by a recessed upper surface and optionally a recessed lower surface relative to upper and lower surfaces of the ribs. The ribs inhibit the outward flow of muck towards the bucket corners, providing quicker filling, a higher payload and reduced wear. As well, the ribs wear during use at a substantially slower rate than the thinner 30 web-like regions of the segments between the ribs, resulting in the ribs forming forwardly protruding points to improve penetration into a muck pile. Preferably the segments are shaped such that - the web between the thickened ribs has a relatively thin forward edge which wears reasonably WO 2005/045142 PCT/CA2004/001913 -5 quickly so as to permit the ribs to protrude outwardly from the inter-rib web regions. The present invention is further defined by reference to the claims of this patent specification. 5 Having thus generally described this invention, the invention will now be described with more particularity by way of a detailed description of embodiments thereof. DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of an excavator bucket, lead, corner 10 shroud unit and lip wear protector array, in an exploded view. FIGURE 2 is a side elevational view of the circled portion of the lead shown in Figure 1. FIGURE 3 is a plan view from above of an excavator bucket, lead and lip protector array, illustrating an alternative corner shroud assembly. 15 FIGURE 4 is a side elevational view from the direction indicated as 4-4 in Figure 3. FIGURE 5 is a sectional view along line 5-5 of Figure 3. FIGURE 6 is a sectional view along line 6-6 of Figure 3. FIGURE 7 is a perspective view of another embodiment of the lip wear 20 protector. FIGURE 8 is a top plan view of a third embodiment. FIGURE 9 is a side elevational view of the third embodiment, as viewed from the direction illustrated by line 9-9 of Figure 8. FIGURE 10 is a cross-sectional view of the third embodiment, viewed 25 along line 10-10 of Figure 8. DETAILED DESCRIPTION Referring to Figure 1, an excavator bucket 10 includes a curved back plate 12 joining with generally flat upper and base portions 14 and 16, and sidewalls 18. Typically the bucket 10 is made of heavy gauge mild steel. 30 The base16 includes a forward lip or edge 17, which as discussed below is WO 2005/045142 PCT/CA2004/001913 -6 capped with protective elements. The sidewalls 18 include generally central apertures 20 (or alternatively bosses) for pivotal attachment to a pair of hydraulic rams of the mechanical components of the loader, which are not shown. A third, central hydraulic ram 22 is also pivotally mounted to the 5 rear face of the bucket. The excavating machine (not shown) typically has sufficient power to force the bucket into the rubble pile by utilizing the forward momentum and driving force developed by the machine engine. The machine will typically include a levelling system to maintain the bucket at dead level. 10 A prow-shaped (or delta-shaped) base plate 30 is welded to the front edge 17 of the bucket 10, the plate 30 being characterized by a lead or forward protrusion of the central tip with the opposing left and right front edges sweeping outwardly and rearwardly. The base plate 30 may be made of mild steel or a high carbon steel for improved wear characteristics. As 15 well, the base plate 30 may have a greater thickness than the bucket plate, for improved wear. The base plate 30 has a flat upper surface which when the lead plate is fastened to the bucket in the intended fashion, is flush with the adjacent inner surface of the bucket. 'The leading edge 32 of the base plate 30 is prow or chevron-shaped in plan, with opposed left and right front 20 edges,. 34 converging towards a central tip 36. The lead is thus characterized by a forward displacement of the tip 36 relative to the outermost parts of the leading edge. As seen in Figure 2, a region of the base plate 30 which is immediately aft of the leading edge 32 tapers towards said leading edge, with the taper being defined by an upwardly 25 angled portion 38 of the lower surface of the plate. The tapered portion 38 has a taper of up to 300 from the horizontal, with a preferred taper being about 100. The tapered portion terminates with a squared-off leading edge 32. The rear edge 40 of the base plate 30 is welded to the lower portion 30 16 of the bucket 10. A flush weld line is formed by providing the rear edge 40 of the base plate with an upper tapered region, such when the respective surfaces 32 and 40 abut, an upwardly opening channel opening is formed therebetween to receive a weld line.

WO 2005/045142 PCT/CA2004/001913 -7 The lead, or forward protrusion of the tip 33 relative to the side edges of the base plate 30, provides an improved scooping operation of the assembled excavator bucket when in use. The lead distance is designated in Figure 1 as a, which represents the forward displacement of the tip 33 5 relative to the forward side corners of the base plate 30. The dimension a will be selected in part by the conditions expected to be encountered by the bucket in the particular mining operation. Hence, the present invention contemplates a range of lead distances. Without intending to be restricted to any particular range of lead distances, a convenient range for distance a 10 is between 6 and 12 inches. However, it will be seen that the actual lead amount will vary depending on the bucket width and the expected use of the bucket. Opposed wing segments 44 at each lower side corner of the assembly are welded onto the bucket assembly to provide improved scooping ability. 15 The wing segments 44, seen in Figures 1 and 4, each are generally L-shaped in front elevation, comprising a triangle-shaped vertical side plate 46 and a horizontal floor plate 48. The vertical plate 46 forms a gusset-like extension of the vertical sidewall18 of the bucket 10 to effectively increase the bucket carrying capacity. The floor plate 48 has a cross sectional front to rear 20 configuration (in side view) identical or substantially identical to the base plate including a tapered forward edge 45 to snugly receive a lip wear segment 60, described below. The forward edge 45 protrudes forwardly of the side plate, in order to permit the lip wear segment 60 to protrude or overhang laterally beyond the edge of the wing segment 44. This permits 25 use of a variety of sizes of wear segments 60 without being required to precisely fit between the opposed wing segments 44. A rearward-facing edge 50 of the wing 44 is bevelled for welding to the corresponding lower corner of the bucket 10. The floor plate 48 extends inwardly from the side plate and fits within a cut-out region of the base plate 30 such that when 30 welded to the base plate, the floor and base plates form a substantially monolithic plate. In plan view, the floor plate is generally rectangular, but with its inside rear corner 51 being angled to abut with an outwardly flared region 53 of the base plate 30. The inside edge 54 of the plate 48 abuts the outer -side edge 55 of the base plate 30 and is welded thereto for a rigid WO 2005/045142 PCT/CA2004/001913 -8 attachment. When these two plates are joined, they effectively form a monolithic member with flush upper and lower surfaces and a continuous bevelled front edge. Hence, the bucket 10, base plate 30 and wing segments 44 when welded together effectively form a rigid monolithic unit. 5 The corners are protected from wear by replaceable corner wear shrouds 57 which are bolted over the side plates 46 of the wing segments 44. The exposed upper edge 54 of the segments 44 may be bevelled. The wing segments 44 include reinforced exterior flanges 59 which protrude downwardly and laterally outwardly from the base plate thereby 10 providing further wear protection. The base plate 30 includes an array of unthreaded holes 56 for receiving fastening bolts 58 for the lip wear elements 60, as will be described below with reference to Figures 1, 3 and 6. The leading edge of the base plate 30 is protected against wear by an 15 array of lip wear segments 60 that are removably fastened to the base plate. The lip segments 60 have a parallelogram shape (with non-right corner angles) when seen in plan. Each segment 60 is generally planar, comprising upper and lower surfaces 61(a) and (b), opposed lateral edges 63 and leading and trailing edges 65(a) and (b). The parallelogram shape 20 corresponds with the angle of the leading edge 32 of the corresponding base plate 30 such that when mounted the lateral edges 63 are aligned with the main axis of the excavator and the leading and trailing edges 65 (a) and (b) are parallel to the leading edge of the base plate 30. Thus, it is contemplated that the corner angles of the lip segments 60 will range from 25 900 (i.e. for use with a base plate with no lead) to about 200 (i.e. for use with a base plate having a width of about 54 inches and a lead of about 10 inches. However, it will be readily seen that this range is merely an example and the segments 60 may exceed this range. The segments 60 are preferably mounted in a side-by side array such 30 that neighbouring segments nearly abut each other leaving a narrow gap to present a nearly continuous exposed surface with narrow uniform gaps between the segments. Alternatively, the segments 60 may be mounted in an abutting gapless array.

WO 2005/045142 PCT/CA2004/001913 As seen in Figure 3, the segment array comprises left and right hand segments 60(a) and 60(b) for mounting on opposed sides of the base plate 30. The upper surface 61(a) of each segment includes a leading portion 64 which is arcuate and concave in side sectional view. The lower surface 5 61(b) includes a forward region 66 opposed to the arcuate portion 64, which is substantially flat and upwardly forwardly sloping, thereby forming a tapered forward region to the segment 60 in which the upper surface 64 is arcuate and the lower surface 66 is generally flat. The leading edge 65(a) of the segment 60 is squared off. The rearward portion of the segment 60 is 10 substantially thicker than the forward portion and includes spaced apart horizontal upper and lower walls 72, 74 of a horizontal channel 76 opening rearwardly. The lower wall 74 protrudes further rearwardly than the upper wall 72 and is substantially thicker in cross section than the upper wall to provide a "heel" to the assembly which provides additional wear protection 15 at the exposed lower surface of the segments 60 which typically experience a high degree of wear from bucket contact on rough surfaces. The bucket itself (which is very costly relative to the replaceable elements described above) is thus more protected from wear. The internal horizontal channel 76 has a tapered innermost region 80 terminating in a squared floor 90, 20 corresponding with the tapered leading edge 38 of, the base plate 30. The respective male and female components are machined for a tight fit to prevent unwanted movement of the lip elements. It will be seen that the assembly shown in Figure 3 does not illustrate the corner shrouds described above. 25 The lip segments 60 are releasable fastened to the lead plate 30 by mechanical fastening elements, which in the illustrated example comprise bolts 58 extending through aligned apertures 56 within the wear elements 60 and base plate 30. A recessed region 80 within the lower flange of the lip element permits the bold head to be fully recessed. Preferably, the bolts 30 58 are tightened against a nut such as a Stover T M locknut 88 to resist back off in adverse conditions which may be experienced by the device. A reasonably precise fit between the lip wear elements 60 and the base plate 30, together with a suitable fastener such as a bolt and nut, provides for an essentially rigid connection between components which reduces metal WO 2005/045142 PCT/CA2004/001913 -10 fatigue and reduces bolt shear stresses. The resulting connection is of similar strength to a welded connection, but with the advantage of easy replacement of the lip wear segments 60 by unbolting the worn segments and bolting on new or refurbished segments in their place. 5 Each segment 60 includes at least one wear-indicating hole 90 to indicate the extent of wear and signal the operator to replace the lip wear segments at a suitable time to avoid damaging or wearing into the base plate. The wear-indicating hole 90 comprises a relatively small aperture extending through or partially through the lip segment 60 at a suitable 10 position forwardly of the horizontal channel 76. For example, the hole 90 may be positioned near the rearward edge of the arcuate upper surface of the wear element. The hole 90 includes a visual indicator 92 which becomes visible when the wear element has worn to a predetermined level. For example, the visual indicator 92 may comprise a texture or color transition 15 within the interior of the hole which becomes visible when the surrounding metal has worn to a predetermined extent or a different hole diameter which becomes visible at this time. The cross sectional configuration of the lip wear segments 60 makes them at least partially-self-sharpening. The arcuate upper surface 64 tends 20 to wear at a generally even rate, resulting in the segment maintaining a substantially constant profile for much of its useful life. The lower flanges of the lip wear segments 60 preferably include shoe elements 94 to provide additional resistance to wear. These shoes 94 comprise thickened portions of the lower flange, which may be conveniently 25 provided at the bolt hole positions 56. As seen in Figures 4 and 6, the shoes 94 protrude downwardly from the bucket to elevate the lip segments 60 above the ground to minimize wear of the base plate 30 and other system components including the bucket. The lip wear segments 60 are provided in varying widths to 30 accommodate buckets of different sizes. As well, the segments maybe provided in different parallelogram shapes, including rectangular, to accommodate different lead lengths of the base plate associated with the segments. The segments may protrude laterally outwardly from the wing segments 44, thus permitting the use of standard size segments 60 to WO 2005/045142 PCT/CA2004/001913 - 11 accommodate a wide range of bucket sizes, as the segments 60 do not have to precisely fit the bucket width. It is contemplated that base plates 30 with wing segments 44 welded in place, along with multiple lip wear segments 60, may be provided to mine 5 operators for attachment by welding and bolting as required to their existing buckets. The assembly of these elements may be carried out at the mine site. Figure 7 illustrates another version of the lip wear segment 60. In this version, the upper surface of the segment includes broad scallop-shaped 10 recesses 100 which extend longitudinally from the front edge of the segment 60. The scalloped recesses 100 are rectangular in plan view, and have a curved bottom 102. The recesses 100 provide an enhanced scooping action which is useful in some applications. As well, the recessed portions will tend to wear more rapidly than the non-recessed regions, resulting in the 15 formation of an irregular leading edge similar to the embodiment next described. Figure 8 illustrates yet another embodiment of the invention, in which the lip wear segments 60(a) and 60(b) have generally the same parallelogram configuration in plan view, but wherein each segment 60 20 comprises thickened ribs 120 extending along the lateral side edge regions thereof. As before, segments 60(a) and (b) define right- and left-hand fistings for the bucket assembly. The portion of the segment lying between these side ribs forms a relatively thinner web 122. As will be seen from the cross sectional view of Figure 10, the side ribs 120 have substantially flat 25 upper and lower surfaces tapering inwardly and forwardly towards a squared front edge 124, while the inter-rib web 122 has an arcuate, upwardly concave upper surface 126. The lower surface 128 of the web region is substantially flat. Preferably, both upper and lower surfaces of the web are recessed relative to the ribs, although it is also contemplated that only the 30 upper surface is thus recessed. In operation, the relatively thin forward region of the inter-rib web 122 will wear relatively quickly in comparison with the side ribs 120 and will thus effectively recess through use in the region between the ribs. The ribs 120 will thus protrude outwardly relative to the web regions 122 between the ribs, effectively forming forwardly- WO 2005/045142 PCT/CA2004/001913 -12 protruding teeth to aid in penetration of a muck pile and to provide increased wear resistance. As well, the ribs assist in the muck-scooping process by directing muck directly rearwardly and limiting travel of the muck laterally towards the wing segments thereby minimizing wear. As seen in 5 Figures 9 and 11, the wing segments 44 of the third embodiment may be substantially the same as those of the first and second embodiments. The present invention has been described only in part by way of a detailed description of embodiments thereof, which is not intended to limit in any respect the scope of the invention. However, it will be seen by those 10 skilled in the art to which this invention relates that numerous and varied departures from the embodiments described herein may be made, without departing from the scope and spirit of the present invention, including without limitation any mechanical and functional equivalent of any component, element or part described herein.

Claims (16)

1. In a bucket assembly comprising an excavator bucket having sidewalls, a bucket floor plate and a lead plate forming a forward extension of said floor plate, the improvement consisting of said lead plate having a cut away portion at each rear corner thereof, said assembly including opposed wing members attachable to said sidewalls and lead plate, said wing members each comprising a generally vertical wall having a rear edge attachable to said sidewall of said bucket for effectively extending a lower portion of said bucket sidewall forwardly, and a generally horizontal base plate corresponding in dimension to said cut away portion for fitting therein, wherein said base plate has an exposed edge for attaching to a corresponding edge of said lead plate at the cut away portion thereof to form when attached a substantially continuous and monolithic member with said lead plate.

2. An assembly as defined in claim 1, wherein said base plate of said wing member comprises a shelf-like member tapering inwardly and rearwardly, said cut away portion having a corresponding taper outwardly and rearwardly.

3. A bucket assembly as defined in claim 1, wherein said base plate and lead plate have abutting sidewalls arranged for welding together.

4. A bucket assembly as defined in claim 1, wherein said base plate comprises a shelf protruding forwardly of said vertical wall thereof.

5. A bucket assembly as defined in claim 4, wherein said base plate and lead plate are both adapted to receive mechanically attachable lip wear segments fitting onto the forward edge region thereof.

6. A bucket assembly as defined in claim 1, wherein said wing members each comprise a mechanically attachable wear shroud releasably fastened to the inside of said vertical wall. WO 2005/045142 PCT/CA2004/001913 -14

7. A wing member for attaching an excavator bucket having sidewalls and a bucket floor plate, and a lead plate protruding forwardly of said sidewalls and floor plate, said lead plate having a cut away portion at each rear corner thereof, said wing member comprising a generally vertical wall having a rear edge attachable to said sidewall of said bucket for effectively extending the lower portion of said bucket sidewall forwardly, and a generally horizontal base plate corresponding in dimension to said cut away portion for fitting therein, to form when attached a substantially continuous and monolithic member with said lead plate.

8. A wing member as defined in claim 7, wherein said base plate of said wing member comprises a shelf-like member tapering inwardly and rearwardly.

9. A wing member as defined in claim 8, wherein said base plate is adapted to receive mechanically attachable lip wear segments fitting onto the forward edge region thereof.

10. A lip wear protector for attaching to a forward lip of generally horizontal plate associated with an excavator bucket, said protector comprising a rear portion for attachment to said 'floor plate, and a front region comprising substantially parallel side edges, a central web therebetween and a front edge, the side edge regions of said protector being thicker than the central web, said central web having a generally arcuate upper surface such that said thicker side regions form a rib projecting upwardly relative to said central web, said central web being adapted to wear more quickly than side regions such that said side regions form forwardly projecting points upon use of said assembly.

11. A protector as defined in claim 10, for mechanical attachment with the forward edge region of said floor plate.

12. A protector as defined in claim 10, for mechanical attachment with a prow-shaped leading edge of said floor plate, said protector having a WO 2005/045142 PCT/CA2004/001913 - 15 substantially parallelogram shape wherein said side edges are substantially aligned with the front to rear axis of said bucket.

13. A protector as defined in claim 10, wherein the lower face of said central region angles downwardly and rearwardly.

14. A protector as defined in claim 10, wherein said thickened side regions have substantially flat upper and lower surfaces.

15. A protector as defined in claim 10, further comprising a prow-shaped lead plate for mechanical fastening to .a plurality of said lip protectors, the forward edge of said lead having a generally chevron shape, with said protectors being generally parallelogram in shape with abutting sidewalls and forward edges corresponding in orientation with the leading edge of said lead plate.

16. An excavator bucket assembly comprising a bucket and at least one protector as defined in any of claims 10 to 15.