HEEL SHROUD WITH STRESS CONCENTRATION REDUCTION SHAPE AND ENHANCED DURABILITY FOR USE IN CONSTRUCTION MACHINERY - Patent application

Abstract

The heel shroud (200, 300) includes a lower leg (202, 302) and a side leg (204, 304) extending perpendicularly from the lower leg (202, 302) and forming an inner corner (206, 306) with the lower leg (202, 302). The heel shroud (200, 300) defines a first side (208, 308) and a second side (210, 310), and the lower leg (202, 302) includes a curved inner surface (212, 312) that extends from the first side (208, 308) to the second side (210, 310) and at least partially forms the inner corner (206, 306). The first side (208, 308) defines a first wear indicator (214) or stress reducing feature (216) located at the inside corner (206, 306).

Description

[Technical field]

[0001] The present disclosure relates to heel shrouds used to protect work implements such as buckets of heavy machinery such as hydraulic mining shovels. In particular, the present disclosure relates to such heel shrouds that may have stress concentration reducing geometries and / or durability enhancing features. [Background technology]

[0002] In various mining applications, the curved shells of buckets or other work implements used by heavy machinery such as hydraulic mining shovels are subjected to heavy loads and / or abrasive environments. Thus, heel shrouds may be provided that are intended to extend the life of the bucket. However, the amount of material required to create such heel shrouds can increase costs and require sections that act as stress risers or the like. This can result in more costly and undesirable maintenance being required earlier in the useful life of the heel shroud or its work implement than expected.

[0003] US Patent Publication No. 2009 / 0133633 discloses a track slider for use in heavy machinery such as an electric roper excavator. The slider includes an elongated base portion coupled to a frame and a sliding portion extending from the elongated base portion. The sliding portion includes an outer surface configured to slidably engage a track link of a track assembly. The sliding portion includes a set of wear indicators defined on the outer surface. The set of wear indicators includes a first wear indicator and a second wear indicator. The first and second wear indicators are located at a first predetermined thickness and a second predetermined thickness, respectively, measured along a central axis of the sliding portion. Furthermore, the first wear indicator indicates partial wear of the sliding portion, and the second wear indicator indicates substantial wear of the sliding portion. However, US Patent Publication No. 2009 / 0133633 is silent about the possibility of a stress reducing shape of the heel shroud.

[0004] On the other hand, Patent Document 2 discloses an earth excavation tool with a plurality of wear-resistant inserts. According to Patent Document 2, the wear-resistant inserts are fixed between the ribs to minimize the peeling of the inserts during use. However, Patent Document 2 does not disclose any method for adding durability to a heel shroud having a right-angled shape for protecting a curved shell such as a bucket. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 10,562,257(B2) [Patent Document 2] U.S. Patent No. 4,052,802(A) Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, there remains a need for a heel shroud that can provide extended service life. [Means for solving the problem]

[0007] A heel shroud according to one embodiment of the disclosure may include a lower leg and a side leg extending orthogonally from the lower leg and forming an inner corner with the lower leg. The heel shroud may define a first side, a second side, and the lower leg may include a curved inner surface extending from the first side to the second side and at least partially forming the inner corner. The first side may define a first wear indicator or stress reducing feature disposed at the inner corner.

[0008] A heel shroud according to another embodiment of the present disclosure may include a lower leg and a side leg extending orthogonally from the lower leg and forming an inner corner with the lower leg. The heel shroud may define a first side, a second side, the lower leg may include a curved inner surface extending from the first side to the second side and at least partially forming the inner corner, the first side defining a first wear indicator disposed at the inner corner.

[0009] A heel shroud according to yet another embodiment of the present disclosure may include a lower leg and a side leg extending orthogonally from the lower leg and forming an inner corner with the lower leg. The heel shroud may define a first side, a second side, and the lower leg may include a curved inner surface extending from the first side to the second side and at least partially forming the inner corner. The first side may define a stress concentration reducing shape at the inner corner including a concave arc surface.

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief description of the drawings]

[0011] [Figure 1] 1 illustrates a machine in the form of a hydraulic mining shovel having a work implement in the form of a bucket with a heel shroud constructed in accordance with various embodiments disclosed herein. [Diagram 2] FIG. 2 is a perspective view of the bucket and heel shroud of FIG. 1 removed from the machine for clarity. [Diagram 3] FIG. 3 is a perspective view of a heel shroud removed from the bucket of FIG. 2 constructed in accordance with an embodiment of the present disclosure including stress reducing shapes at the inside corners. [Figure 4] FIG. 4 is a front view of the heel shroud of FIG. 3. [Diagram 5] FIG. 5 is a side view of the heel shroud of FIG. [Figure 6]FIG. 4 is a perspective view of another embodiment of a heel shroud similar or identical to the heel shroud of FIG. 3, except with added durability enhancements such as a chockey bar. [Figure 7] FIG. 7 is a front view of the heel shroud of FIG. [Figure 8] FIG. 7 is an enlarged detail view of the heel shroud of FIG. 6 more clearly showing the stress reducing features. [Figure 9] FIG. 7 is a rear perspective view of the heel shroud of FIG. [Figure 10] FIG. 1 illustrates a rear perspective view of a heel shroud configured with wear indicators positioned near the inside of an inner corner of the heel shroud. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Reference will now be made in detail to the embodiments of the present disclosure as illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. In some cases, a reference number may be shown herein and in the drawings followed by a letter, e.g., 100a, 100b, etc. It should be understood that the use of an English letter immediately following a reference number indicates that these features have a similar shape and similar function, as is often the case when geometric shapes surround a symmetrical planar mirror image. For ease of description herein, letters are often not included herein, but may be shown in the drawings to indicate duplication of features described herein.

[0013] Although the configurations are shown in relation to a hydraulic mining shovel, the configurations disclosed herein are universally applicable to various other types of machines that typically employ a track system rather than wheels. The term "machine" may refer to any machine that performs any type of operation associated with an industry, such as mining, civil engineering, or construction, or other industry known in the art. For example, the machine may include an excavator, a wheel loader, a cable shovel, or a dragline. Additionally, one or more implements may be connected to the machine. Such implements may be utilized for various operations, such as, for example, lifting and loading. Hydraulic mining shovels may be used to load overburden and ore into haul trucks during the mining process in various open pits, among other uses.

[0014] With reference to FIG. 1 , there can be seen a machine 100, such as a hydraulic mining shovel, that can use a work implement 110, such as a bucket, that uses heel shrouds 200, 300 constructed in accordance with various embodiments of the present disclosure. The machine 100 can include a body 104 having a cab 106 that houses a machine operator. The machine can also include a boom system 108 that is pivotally connected to the body 104 at one end and supports the implement 110 at an opposite, distal end. In an embodiment, the implement 110 can be any suitable implement, such as a bucket, clamshell, blade, or any other type of suitable device. A control system can be housed within the cab 106 that can be adapted to enable the machine operator to operate and articulate the implement 110 for digging, excavation, or any other suitable application.

[0015] Body 104 may be supported on a main frame 112 that is supported on an undercarriage structure 114. Undercarriage structure 114 includes a support structure 118 that supports a track system 102 utilized for operation of machine 100. Track system 102 may include first and second track roller frame assemblies 116 spaced apart from and adjacent respective first and second sides of undercarriage structure 114. It should be understood that only one of track roller frame assemblies 116 is shown in FIG.

[0016] Each of the track roller frame assemblies 116 carries an idler wheel 120, a drive sprocket wheel 122, and a number of track guide rollers 124. The drive sprocket wheels 122 are driven in forward and reverse directions by the machine 100 (via a motor, such as an internal combustion engine). An endless track chain assembly 126 surrounds each drive sprocket wheel 122, idler wheel 120, and track guide rollers 124. The track chain assembly 126 includes a number of interconnected track pads 128. The track guide rollers 124 guide the track pads 128 as the track chain assembly 126 is driven by the drive sprocket wheel 122.

[0017] 2, bucket 110a has a curved shell 130 to which one or more heel shrouds 200, 300 configured according to various embodiments of the present disclosure may be attached by welding, fastening, etc. Additionally, multiple tips 132, adapters 134, and shrouds 136 may be attached to a forward lip 138 of the bucket.

[0018] 3-5 and 8, various embodiments of heel shrouds 200, 300 that exhibit wear and may have additional features to reduce stress or wear will now be described.

[0019] 3-5, such a heel shroud 200 may include a lower leg 202 and a side leg 204 extending perpendicularly from the lower leg 202. It may resemble an L-shaped body with an inner corner 206 formed by the intersection of the side leg 204 and the lower leg 202. The heel shroud 200 may also define a first side 208, a second side 210, and the lower leg may include a curved inner surface 212 intended to mate with a curved shell, such as a bucket. This curved inner surface 212 (see also FIG. 9) may extend from the first side 208 to the second side 210 to at least partially form the inner corner 206.

[0020] As best shown in Figures 5 and 8, the first side 208 can define a first wear indicator 214 and / or a stress reducing feature 216 disposed at the inside corner 206. In some embodiments, the same feature can serve both functions, as shown in Figures 5 and 8, but this is not necessarily the case. In some embodiments, only a wear indicator or a stress reducing feature may be provided.

[0021] 3-5, the wear indicator 214 will now be described in more detail. It should be noted that for any of the embodiments described herein, a lateral mid-plane, such as that shown in FIG. 4, may represent a plane of symmetry 218, with all or nearly all of the features of the heel shroud 200 being symmetrical about this plane. Thus, it will be understood that the second side 210 (as also shown in FIG. 9) also defines a second wear indicator 214a that is symmetrical to the first wear indicator 214. This may not be the case in other embodiments of the present disclosure.

[0022] 5 , the side leg 204 can define a planar inner surface 220 that at least partially forms or leads to an inner corner 206. The inner corner can be configured to provide a corner relief that is spaced a predetermined distance 223 from a theoretical sharp corner 222 defined by the intersection of the planar inner surface 220 of the side leg 204 and the curved inner surface 212 of the bottom leg 202.

[0023] The first wear indicator 214 defines an upper sloped wall 224 (so called because it does not extend in a purely horizontal or vertical orientation), a lower sloped wall 226 parallel to the upper sloped wall 226, and a gap distance 228 measured perpendicular to the upper sloped wall 224 and the lower sloped wall 226.

[0024] 5 and 9 together, the first wear indicator 214 may define a lateral depth 230, and in some embodiments of the present disclosure, the ratio of the gap distance 228 to the lateral depth 230 may range from 0.8 to 1.2.

[0025] 5, the bottom leg 202 may define a bottom outer surface 232 and a first minimum distance 234 measured from the first wear indicator 214 to the bottom outer surface 232, and the side leg 204 defines a side outer surface 236 and a second minimum distance 238 measured from the first wear indicator 214 to the side outer surface 236. It should be understood that these dimensions are measured in (or projected onto) the first side plane 208 as shown in FIG. 5. In some embodiments of the present disclosure, the ratio of the first minimum distance 234 to the second minimum distance 238 ranges from 0.75 to 1.0, or vice versa.

[0026] Specifically, as shown in FIG. 5, the first wear indicator 214 may include a vertical surface 240 that at least partially defines the second minimum distance 238 and a horizontal surface 242 (which may also be referred to as a “horizontal surface”) that at least partially defines the first minimum distance 234.

[0027] 8, there is shown a stress concentration reducing feature 216 at the inside corner 306 that includes a concave arc surface 244. More specifically, the stress reducing feature 216 includes a first pocket 246 extending from the concave arc surface 244, the first pocket 246 having a pocket floor 248 connected to the concave arc surface 244 by a plurality of convex arc surfaces 250 (see also FIG. 5).

[0028] 5, the concave arc surface 244 may define a radius of curvature ROC 244 that may range from 5.0 mm to 12.0 mm (e.g., in some embodiments, about 8.0, 8.5, or 9.0 mm). As previously described herein with reference to FIG. 9, a second pocket 246a may be provided that is symmetrical to the first pocket 246 (and thus another stress reducing shape).

[0029] 5 and 8 simultaneously, the first pocket 246 can include a first planar sidewall (e.g., upper angled wall 224) that extends from the pocket floor 248 to the first side 208, and a second planar sidewall (e.g., lower angled wall 226) that extends from the pocket floor 248 to the first side 208. These walls may be, but are not necessarily, parallel.

[0030] In FIG. 5, the bottom leg 202 and the side leg 204 also intersect at an outer corner 252, and in some embodiments of the present disclosure, the first pocket 246 extends toward the outer corner 252. Additionally, a concave curved surface 254 (as used herein, "curved surface" may be interpreted as "arcuate" having a non-planar shape) may extend from the first planar sidewall (e.g., see upper angled wall 224) to the second planar sidewall (e.g., see lower angled wall 226). A plurality of concave arcuate blends 256 may extend from the pocket floor t248 toward the first planar sidewall, the second planar sidewall, and the concave curved surface 254. Similarly, a plurality of convex arcuate blends 258 may extend from the first planar sidewall, the second planar sidewall, and the concave curved surface 254 to the first side 208.

[0031] These various curved or arced surfaces can help reduce stress concentrations and help extend the useful life of the heel shroud. As described later in this specification, the inventors have performed finite element analysis (FEA) and shown that this shape reduces stress concentrations in the heel shroud during use.

[0032] 6 and 7, a heel shroud 300 that may have some stress reducing features 216, and / or wear members 400, 500, 600 attached to the side legs 304, and / or wear members 400, 500, 600 attached to the bottom legs 302 will be described. The wear members may have "hardened" features to make them wear slower or more durable than cast heel shrouds, which are typically made from iron, gray cast iron, and the like. For example, any of the "wear members" described herein may be made from chrome white iron, heat treated to ASTM Class 2 category, Type B, with a minimum hardness of Rockwell scale C for high wear resistance.

[0033] Geometrically speaking, the lower leg 302 extends from a first side 308 to a second side 310 and includes a curved inner surface 312 that at least partially forms an inner corner 306, and a flat lower surface 314 that defines a lower wear member receiving pocket 316. Similarly, the side leg 304 may define an outer planar surface 318 that defines a side wear member receiving pocket 320. As shown, the lower wear member receiving pocket 316 and the side wear member receiving pocket 320 are contiguous, forming an L-shaped cavity 322. In other embodiments of the present disclosure, they may be separated by a rib or other structure.

[0034] 7, the heel shroud 300 can define a lateral width W300 measured from the first side 308 to the second side 310, and the L-shaped cavity 322 can define a lateral cavity width W322. In some embodiments of the present disclosure, the ratio of the heel shroud lateral width to the lateral cavity width can range from 1.09 to 1.32. As a result, the L-shaped cavity 322 can be bounded by a first lateral rib 360 and a second lateral rib 362 that is symmetrical (with respect to a lateral midplane such as those previously described herein) to the first lateral rib 360. These ribs can provide protection for wear members and their mounting structures.

[0035] Side leg 304 may also include a tapered portion 364 (i.e., the portion that tapers toward the inner surface of the side leg) that includes an outer upper cavity 366 disposed vertically above and separated from side wear member receiving pocket 320 by a laterally extending rib 368. Another of these features may be omitted in other embodiments of the present disclosure.

[0036] Located within the side wear member receiving pocket 320 may be a laterally extending wear member 400. As shown, the wear member 400 may take the form of a chockey bar 400a having four sections 402 separated by V-shaped notches 404 that are added upon removal of the sections to adjust the length of the chockey bar.

[0037] As best seen in FIG. 6, a mounting plate 370 is interposed between the side legs 304 and the chockey bar 400a. Fillet welds 372 (see figure) are used to attach the mounting plate and chockey bar to the side legs. Other forms of attachment, such as fasteners, may be employed in other embodiments of the present disclosure. Any of the "mounting plates" described herein may be manufactured from a mild steel backplate that can absorb shock and provide durability.

[0038] Additionally, a pair of transversely extending wear members 500 may be disposed within the lower wear member receiving pocket 316. A similar mounting technique is used, including providing a pair of mounting plates 374 interposed between the lower leg 302 and the pair of transversely extending wear members 500. In this case, the pair of transversely extending wear members 500 is also a chockey bar 500a having seven sections 502 or the like. A lifting hook 376 may be disposed laterally between the pair of transversely extending wear members 500. In other embodiments of the present disclosure, the hook may be located in other locations, such as on the upper surface of the side legs. Another wear member 600 in the form of a wear button 600a is also used, disposed laterally between the pair of transversely extending wear members 500. This may not be the case in other embodiments of the present disclosure.

[0039] Another embodiment of heel shroud 300 may be described as follows with reference to Figures 6 and 7. Flat lower surface 314 defines a lower wear member receiving pocket 316, while side legs 304 define lateral wear member receiving pockets 320 that communicate with lower wear member receiving pocket 316. A first wear member (see, e.g., 500 or 600) may be disposed in lower wear member receiving pocket 316, while a second wear member (see, e.g., 400) may be disposed in lateral wear member receiving pocket 320.

[0040] For example, the first wear member can be either a chock bar 500a or a wear button 600a, and the second wear member can be either a chock bar 400a or a wear button. As shown in Figures 6-8, the first wear member is a chock bar 500a and the second wear member is a wear button 600a. In this example, a pair of chock bars are laterally disposed on either side of the wear button. This may not be the case in other embodiments of the present disclosure. Also, the lifting hook 376 extends transversely from adjacent the wear button 600a toward the side leg 304.

[0041] The heel shroud may be one piece as shown in the figure, or may be an assembly of various components such as wear members, mounting plates, etc. Often the heel shroud is made essentially of a metallic material such as cast iron, steel, gray cast iron, etc.

[0042] Any of the foregoing features and associated dimensions may be varied in other embodiments of the present disclosure differently than those shown or described herein. [Industrial Applicability]

[0043] In fact, the work implement, bucket, and heel or portions thereof can be sold, manufactured, purchased, etc. in an aftermarket or original equipment situation and installed on a machine according to any of the embodiments described herein. That is, a machine may be sold with a work implement, or bucket, and / or heel shroud and / or portions thereof according to the embodiments described herein, or the machine may be modified, repaired, refurbished to use any of the embodiments described herein. The various components, including but not limited to the heel shroud, may be made from any suitable material, such as cast iron, gray iron, steel, etc.

[0044] The inventors have iterated designs to place the wear indicator / stress reducing features in various locations on the heel shroud. For example, the wear indicator / stress reducing features (see, for example, cavity 702 of heel shroud 700 in FIG. 10 for a non-limiting example) were placed toward the inside of the inner corner of the heel shroud. The size, shape, and placement of the cavity were changed 11 times, and then placed on the outer side as shown in FIG. 9. FEA showed that placing the cavity on the side of the heel shroud reduced stress by 10% and only increased internal stress by 3%, still well below the allowable values. Thus, one skilled in the art would expect an improvement in the durability of the heel shroud.

[0045] In various embodiments, the heel shroud is designed with external wear indicators on both the left and right sides of the shroud. By placing the indicator features on the left and right sides of the outer shroud shape (as shown in hypothetical heat treatment analysis), stress concentrations originally created by the internal indicator features are eliminated. This solution provides guidance on when to replace the shroud by placing visible wear indicators on both sides of the shroud, and by having the indicators visible throughout the life of the shroud, allows for an estimation of remaining life.

[0046] In other embodiments, the wear of Laminated Wear Product (LWP) welds on the heel shroud is protected. Typically, the heel shroud is designed with a designated location for attaching the LWP and a protective feature in the form of a rib that surrounds the weld used to attach the LWP. This feature was designed to protrude above the height of the weld used in this application, protecting the weld from abrasives and extending the life of the LWP. This feature also serves as an indication of a critical location for adding an LWP, maximizing the life of the heel shroud. This feature also allows the heel shroud to be used without an LWP, if desired. It can also provide protection for various types of overlays, including Abrasion Resistant Material (ARM) and Plasma Transferred Arc (PTA) welds.

[0047] It will be apparent to those skilled in the art that various modifications and changes can be made to the embodiments of the apparatus and assembly methods as described herein without departing from the scope or spirit of the present invention. Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some apparatuses may have configurations and functions different from those described herein, and some steps of any method may be omitted or performed in a different order than specifically mentioned, and in some cases may be performed simultaneously or stepwise. Furthermore, some aspects or features of the various embodiments may be changed or modified to create further embodiments, and features and aspects of the various embodiments may be added to or substituted for other features or aspects of other embodiments to provide further embodiments.

[0048] Therefore, it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention(s) being indicated by the following claims and equivalents thereof.

Claims

1. A heel shroud (200, 300), A lower leg (202, 302); a side leg (204, 304) extending perpendicularly from said lower leg (202, 302) and forming an inner corner (206, 306) with said lower leg (202, 302); The heel shroud (200, 300) defines a first side (208, 308), a second side (210, 310), the lower leg (202, 302) includes a curved inner surface (212, 312) extending from the first side (208, 308) to the second side (210, 310) and at least partially forming the inner corner (206, 306), and the first side (208, 308) defines a first wear indicator (214) disposed at the inner corner (206, 306).

2. The heel shroud (200, 300) of claim 1, wherein the second side (210, 310) defines a second wear indicator (214a) that is symmetrical to the first wear indicator (214).

3. 3. The heel shroud (200, 300) of claim 2, wherein the side legs (204, 304) define planar inner surfaces (220) that at least partially form the inner corners (206, 306), the inner corners (206, 306) being configured to provide a corner relief that is spaced from a theoretical sharp corner (222) defined by an intersection of the planar inner surfaces (222) of the side legs (204, 304) with the curved inner surfaces (212, 312) of the lower legs (202, 302).

4. 2. The heel shroud of claim 1, wherein the first wear indicator defines an upper angled wall, a lower angled wall parallel to the upper angled wall, and a gap distance measured perpendicularly from the upper angled wall to the lower angled wall, the first wear indicator defining a lateral depth, a ratio of the gap distance to the lateral depth ranging from 0.8 to 1.

2.

5. 2. The heel shroud of claim 1, wherein the lower leg defines a lower outer surface and a first minimum distance measured from the first wear indicator to the lower outer surface, and the side leg defines a lateral outer surface and a second minimum distance measured from the first wear indicator to the lateral outer surface.

6. 6. The heel shroud of claim 5, wherein a ratio of the first minimum distance (234) to the second minimum distance (238) is in the range of 0.75 to 1.0, and the first wear indicator (214) includes a vertical surface (240) that at least partially defines the second minimum distance (238) and a horizontal surface (242) that at least partially defines the first minimum distance (234).

7. A heel shroud (200, 300), A lower leg (202, 302); a side leg (204, 304) extending perpendicularly from said lower leg (202, 302) and forming an inner corner (206, 306) with said lower leg (202, 302); The heel shroud (200, 300) defines a first side (208, 308), a second side (210, 310), the lower leg (202, 302) includes a curved inner surface (212, 312) extending from the first side (208, 308) to the second side (210, 310) and at least partially forming the inner corner (206, 306), the first side (208, 308) defining a stress concentration reducing shape (216) at the inner corner (206, 306) including a concave arc surface (244).

8. said stress reducing shape (216) including a pocket (246) extending from said concave arc surface (244), said pocket (246) including a pocket floor (248) connected to said concave arc surface (244) by a plurality of convex arc surfaces (250), said concave arc surface (244) defining a radius of curvature (ROC244) in the range of 5.0 mm to 12.0 mm; The heel shroud (200, 300) of claim 7, further comprising a second pocket (246a) symmetrical to said first pocket (246).

9. 8. The heel shroud (200, 300) of claim 7, wherein the first pocket (246) includes a first planar sidewall (224) extending from the pocket floor (248) to the first side (208, 308) and a second planar sidewall (226) extending from the pocket floor (248) to the first side (208, 308).

10. 10. The heel shroud (200, 300) of claim 9, wherein the first planar sidewall (224) and the second planar sidewall (226) are parallel, the lower leg (202, 302) and the side leg (204, 304) intersect at an outer corner (252), and the first pocket (246) extends toward the outer corner (252) and further comprises a concave curved surface (254) extending from the first planar sidewall (224) to the second planar sidewall (226).

Images