Heel shroud for construction machinery with stress concentration reduction shape and enhanced durability
The heel shroud design addresses the issue of stress concentration and premature wear by incorporating a stress-reducing shape and wear indicators, resulting in extended service life and reduced maintenance costs.
Patent Information
- Application Number
- JP2024551901
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-03-09
- Filing Date
- 2023-02-27
- Publication Date
- 2025-03-21
AI Technical Summary
Existing heel shrouds for heavy machinery buckets face challenges in reducing stress concentration and extending service life, leading to premature wear and increased maintenance costs.
The heel shroud design incorporates a stress-reducing shape at internal corners, featuring a curved inner surface and a flat bottom surface with wear member receiving pockets, along with wear indicators to monitor wear and reduce stress concentration.
This design effectively reduces stress concentration and extends the service life of heel shrouds, leading to reduced maintenance costs and improved durability.
Smart Images
Figure 2025507821000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention 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 heel shrouds characterized by shapes that reduce stress concentrations and / or enhanced durability. [Background technology]
[0002] In various mining applications, the curved shells of buckets and other work implements used in heavy machinery such as hydraulic mining shovels are subjected to heavy loads and 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 increases costs and may require sections that act as stress concentrators, etc. This may result in unnecessary maintenance being required earlier in the useful life of the heel shroud or its work implement at a higher cost than expected.
[0003] U.S. Patent No. 10,562,257B2 (Patent No. 257) discloses a track slider for use in heavy equipment such as an electric roper shovel. The slider includes an elongated base portion coupled to a frame and a slide portion extending from the elongated base portion. The slide portion includes an outer surface configured to slidably engage a track link of a track assembly. The slide 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 disposed at a first predetermined thickness and a second predetermined thickness, respectively, measured along a central axis of the slide portion. Furthermore, the first wear indicator indicates partial wear of the slide portion, and the second wear indicator indicates substantial wear of the slide portion. However, Patent No. 257 is silent about the possibility of a stress reducing shape of the heel shroud.
[0004] Meanwhile, U.S. Patent No. 4,052,802A (Patent No. 802) discloses an earth excavation tool with a plurality of wear-resistant inserts. According to Patent No. 802, the wear-resistant inserts are fixed between the ribs to minimize the spalling of the inserts during use. However, Patent No. 802 does not say anything about how to add durability to a heel shroud in a right-angle configuration to protect curved shells such as buckets.
[0005] Therefore, a need remains for a heel shroud with service life extending features. Summary of the Invention
[0006] A heel shroud according to one embodiment of the disclosure may include a bottom foot and a side foot extending perpendicularly from the bottom foot to form an interior corner with the bottom foot. The heel shroud may define a first side and a second side, and the bottom foot may include a curved interior surface extending from the first side to the second side to at least partially form the interior corner. The first side may define a stress reducing shape disposed at the interior corner, or may include a wear member attached to the side foot and another wear member attached to the bottom foot.
[0007] A heel shroud according to another embodiment of the present disclosure may include a bottom foot and a side foot extending orthogonally from the bottom foot to form an interior corner with the bottom foot. The heel shroud may define a first side and a second side, the bottom foot may include a curved inner surface extending from the first side to the second side to at least partially form the interior corner, and a flat bottom surface defining a lower wear member receiving pocket.
[0008] A heel shroud according to yet another embodiment of the present disclosure may include a bottom foot and a side foot extending orthogonally from the bottom foot to form an interior corner with the bottom foot. The heel shroud may also define a first side and a second side, and the bottom foot may include a curved inner surface extending from the first side to the second side to at least partially form the interior corner. The flat bottom surface may define a lower wear member receiving pocket and the side leg may define a side wear member receiving pocket in communication with the lower wear member receiving pocket. [Brief description of the drawings]
[0009] 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. [Figure 1] 1 illustrates a machine in the form of a hydraulic mining shovel with a work implement in the form of a bucket with a constructed heel shroud according to various embodiments disclosed herein. [Diagram 2] FIG. 2 is a perspective view of the bucket of FIG. 1, also showing the heel shroud removed from the machine for greater clarity. [Diagram 3] FIG. 3 is a perspective view of a heel shroud removed from the bucket of FIG. 2 and constructed in accordance with an embodiment of the present disclosure including stress reducing shapes at the interior 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 its stress reducing geometry. [Figure 9] FIG. 7 is a rear perspective view of the heel shroud of FIG. [Figure 10] FIG. 13 is a rear perspective view of the heel shroud with wear indicators located near the inside of the inner corners of the heel shroud. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are 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 will be shown in this specification and in the drawings followed by a letter (e.g., 100a, 100b, etc.). It should be understood that the use of a letter immediately following a reference number indicates that those features are similarly shaped and have similar functions, as is often the case when geometry is mirrored about a plane of symmetry. For ease of explanation herein, letters are often not set forth herein, but may be shown in the drawings to indicate duplication of features described herein.
[0011] Although the arrangement is illustrated in relation to a hydraulic mining shovel, the arrangement disclosed herein is universally applicable to various other types of machines that typically employ a track system rather than wheels. The term "machine" refers to any machine that performs some task related to an industry, such as mining, civil engineering, construction, or other industry known in the art. For example, the machine may be an excavator, wheel loader, cable shovel, dragline, etc. Additionally, one or more implements may be connected to the machine. Such implements may be utilized for various tasks, such as lifting and loading. Hydraulic mining shovels may be used to load overburden or ore onto haul trucks during the mining process in various open pit mines, among other uses.
[0012] Turning to FIG. 1 , a machine 100, such as a hydraulic mining shovel, is shown that may use a work implement 110, such as a bucket, employing heel shrouds 200, 300 constructed in accordance with various embodiments of the present disclosure. The machine 100 may include a body 104 with a cab 106 for housing a machine operator. The machine may also include a boom system 108 pivotally connected at one end to the body 104 and supporting the implement 110 at an opposite distal end. In an embodiment, the implement 110 may be any suitable implement, such as a bucket, clamshell, blade, or other type of suitable device. A control system may be housed within the cab 106, and the control system may be adapted to enable a machine operator to operate and control the implement 110 for digging, excavation, or other suitable applications.
[0013] 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 used to move machine 100. Track system 102 may include first and second track roller frame assemblies 116 that are disposed adjacent to and spaced from first and second sides of undercarriage structure 114. It has been noted that only one of track roller frame assemblies 116 is visible in FIG. 1 .
[0014] 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 wheels 122.
[0015] 2, bucket 110a has a curved shell 130 to which one or more heel shrouds 200, 300 configured in accordance with 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 front lip 138 of the bucket.
[0016] 3-5 and 8, various embodiments of heel shrouds 200, 300 that may include additional features to indicate wear and reduce stress or wear will now be described.
[0017] As shown in Figures 3-5, such a heel shroud 200 may include a bottom leg 202 and a side leg 204 extending perpendicularly from the bottom leg 202. It may resemble an L-shaped body with an interior corner 206 formed by the intersection of the side leg 204 and the bottom leg 202. The heel shroud 200 may also define a first side 208 and a second side 210, and the bottom leg may include a curved interior surface 212 intended to mate with a curved shell, such as a bucket. This curved interior surface 212 (see also Figure 9) may extend from the first side 208 to the second side 210 to at least partially form the interior corner 206.
[0018] As best shown in Figures 5 and 8, the first side 208 may define a first wear indicator 214 and / or a stress reducing feature 216 located at the interior 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.
[0019] 3-5, the wear indicator 214 will now be described in detail. It should be noted that in any embodiment described herein, the lateral mid-plane shown in FIG. 4 represents a plane of symmetry 218 about which all or nearly all features of the heel shroud 200 may be symmetrical. It will thus be understood that the second side 210 also defines a second wear indicator 214a (also shown in FIG. 9) that is symmetrical to the first wear indicator 214. This may not be true for other embodiments of the present disclosure.
[0020] 5 , the side leg 204 may define a planar inner surface 220 that at least partially forms or leads to an interior corner 206. The interior corner may be configured to provide corner relief a predetermined distance 223 away from a theoretical sharp corner 222 defined by the intersection of the interior planar surface 220 of the side leg 204 with the curved inner surface 212 of the bottom leg 202.
[0021] The first wear indicator 214 defines a top sloped wall 224 (so called because it does not extend purely horizontally or vertically), a bottom sloped wall 226 that is parallel to the top sloped wall 226, and a gap distance 228 measured perpendicular to the top sloped wall 224 and the bottom sloped wall 226.
[0022] 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 be in the range of 0.8 to 1.2.
[0023] In FIG. 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 is understood that these dimensions are measured in (or projected onto) the first lateral 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.
[0024] 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 (also referred to as the “horizontal surface”) that at least partially defines the first minimum distance 234.
[0025] 8, a stress concentration reducing feature 216 is shown at an interior corner 306 that includes a concave arcuate surface 244. More specifically, the stress reducing feature 216 includes a first pocket 246 extending from the concave arcuate surface 244, the first pocket 246 having a pocket bottom surface 248 connected to the concave arcuate surface 244 by a plurality of convex arcuate surfaces 250 (see also FIG. 5).
[0026] 5, the concave arcuate surface 244 may define a radius of curvature ROC 244 in the range of 5.0 mm to 12.0 mm (e.g., about 8.0, 8.5, or 9.0 mm in some embodiments). As discussed above with reference to FIG. 9, a second pocket 246a symmetrical to the first pocket 246 (and thus another stress reducing shape) may be provided.
[0027] 5 and 8 together, the first pocket 246 may include a first planar sidewall (e.g., top angled wall 224) that extends from the pocket floor 248 to the first side 208, and a second planar sidewall (e.g., bottom angled wall 226) that extends from the pocket floor 248 to the first side 208. These walls may be, but are not necessarily, parallel.
[0028] In FIG. 5, the bottom leg 202 and the side leg 204 also intersect at an exterior corner 252, and in some embodiments of the present disclosure, the first pocket 246 extends toward the exterior corner 252. Additionally, a concave curved surface 254 (where "curve" as used herein may be interpreted as an "arc" having a non-planar shape) may extend from the first planar sidewall (e.g., see top angled wall 224) to the second planar sidewall (e.g., see bottom angled wall 226). A plurality of concave arc-shaped blends 256 may extend from the pocket floor t 248 toward the first planar sidewall, the second planar sidewall, and the concave curved surface 254. Similarly, a plurality of convex arc-shaped blends 258 may extend from the first planar sidewall, the second planar sidewall, and the concave curved surface 254 toward the first side 208.
[0029] These various curved or arcuate surfaces may reduce stress concentrations and contribute to extending the useful life of the heel shroud. As described later, the inventors performed FEA (finite element analysis) and showed that this shape reduces stress concentrations in the heel shroud during use.
[0030] 6 and 7, a heel shroud 300 that may have 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 now be described. The wear members may be characterized as "hardened" in that they wear slower and are more durable than cast heel shrouds, which are typically made of iron, gray cast iron, and the like. For example, any of the "wear members" described herein may be made of chrome white iron, heat treated to ASTM Class 2 Category, Type B, with a minimum hardness of Rockwell scale C, for high wear resistance.
[0031] Geometrically speaking, the bottom leg 302 includes a curved inner surface 312 that extends from a first side 308 to a second side 310 forming at least partially an interior corner 306, and a flat bottom 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.
[0032] Focusing on FIG. 7, the heel shroud 300 may define a lateral width W300 measured from the first side 308 to the second side 310, and the L-shaped cavity 322 may 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 may be in the range of 1.09 to 1.32. As a result, the L-shaped cavity 322 may be bounded by a first lateral rib 360 and a second lateral rib 362 symmetrical to the first lateral rib 360 (centered about the lateral midplane discussed above). These ribs may protect the wear members and their mounting structures.
[0033] 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 top 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.
[0034] A transversely extending wear member 400 may be disposed within the side wear member receiving pocket 320. As shown, this wear member 400 may take the form of a chockey bar 400a with four sections 402 separated by V-notches 404 for adding removal of sections to adjust the length of the chockey bar.
[0035] As best seen in FIG. 6, a mounting plate 370 is disposed between the side legs 304 and the chockey bar 400a. Fillet welds 372 (see diagram) are used to attach the mounting plate and chockey bar to the side legs. Other forms of attachment, such as fasteners, may be used in other embodiments of the present disclosure. Any of the "mounting plates" described herein may be manufactured with a mild steel backplate that can absorb shock and provide added durability.
[0036] 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 bottom 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 with seven sections 502 or the like. A lifting hook 376 may be disposed transversely between the pair of transversely extending wear members 500. The hook may be disposed in other locations, such as at the top of the side legs, in other embodiments of the disclosure. Another wear member 600 in the form of a wear button 600a is also used and disposed laterally between the pair of transversely extending wear members 500. This may not be the case in other embodiments of the disclosure.
[0037] Another embodiment of the heel shroud 300 may be described as follows with reference to Figures 6 and 7. The flat bottom surface 314 defines a lower wear member receiving pocket 316, while the side legs 304 define side wear member receiving pockets 320 that communicate with the lower wear member receiving pocket 316. A first wear member (see, e.g., 500 or 600) may be disposed in the lower wear member receiving pocket 316, while a second wear member (see, e.g., 400) may be disposed in the side wear member receiving pocket 320.
[0038] For example, the first wear member may be one of the chock bar 500a or the wear button 600a, and the second wear member may be the other of the chock bar 400a or the wear button. As shown in Figures 6-8, the first wear member is the chock bar 500a and the second wear member is the wear button 600a. In this case, a pair of chock bars are disposed laterally 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.
[0039] The heel shroud may be one piece, as shown, or it may be an assembly of various parts including wear members, mounting plates, etc. In most cases, heel shrouds are typically constructed of metallic materials such as cast iron, steel, or gray cast iron.
[0040] Any of the foregoing features and associated dimensions may be varied in other embodiments of the present disclosure differently than as shown or described herein. [Industrial Applicability]
[0041] In practice, the work implement, bucket, and heel or portions thereof may be sold, manufactured, purchased, etc., and installed on the machine in an aftermarket or original equipment scenario in accordance with any of the embodiments described herein. That is, the machine may be sold with the work implement, bucket, and / or heel shroud and / or portions thereof in accordance with the embodiments described herein, or the machine may be modified, repaired, or refurbished to use any of the embodiments described herein. The various components, including but not limited to the heel shroud, may be manufactured from any suitable material, such as cast iron, gray iron, steel, etc.
[0042] The inventors performed design iterations placing 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, which shows 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, until it was placed on the outer side as shown in FIG. 9. FEA showed that placing the cavity on the side of the heel shroud reduced stresses by 10%, while the internal stresses only increased 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.
[0043] In various embodiments, the heel shroud is designed with an external wear indicator present on both the left and right side of the shroud. By placing the indicator features on the left and right side of the external shroud geometry (as shown in hypothetical heat treatment analysis), the stress concentrations originally created by the internal indicator features were eliminated. This solution provides guidance as to when to replace the shroud by placing a visible wear indicator on both sides of the shroud, and by having the indicator visible throughout the life of the shroud, allows for an estimation of remaining life.
[0044] In another embodiment, wear protection of laminated wear product (LWP) welds on the heel shroud is provided. 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 is 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 a designator 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 also allows protection for various types of overlays, such as wear resistant materials (ARM) and plasma transferred arc (PTA) welds.
[0045] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and assembly methods described herein without departing from the scope or spirit of the 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, parts of the apparatus may differ in configuration and function from those described herein. Also, certain steps of the methods may be omitted, performed in a different order than specifically described, or even performed simultaneously or in sub-steps. Furthermore, variations or modifications to specific aspects or features of the various embodiments may be made to produce further embodiments, and features and aspects of the various embodiments may be added to or substituted for other features or aspects of the other embodiments to provide further embodiments.
[0046] Therefore, it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims and their equivalents.
Claims
1. A heel shroud (200, 300), A bottom leg (202, 302), and a side leg (204, 304) extending perpendicularly from said bottom leg (202, 302) and forming an interior corner (206, 306) with said bottom leg (202, 302); The heel shroud (200, 300) defines a first side (208, 308) and a second side (208, 308), and the bottom leg (202, 302) includes a curved inner surface (212, 312) extending from the first side (208, 308) to the second side (208, 308) and at least partially forming an interior corner (206, 306), and a flat bottom surface (314) defining a lower wear member receiving pocket (316).
2. 2. The heel shroud (200, 300) of claim 1, wherein the side leg (204, 304) comprises: The heel shroud (200, 300) defines an exterior planar surface (318) that defines a side wear member receiving pocket (320), the lower wear member receiving pocket (316) and the side wear member receiving pocket (320) being contiguous and forming an L-shaped cavity (322).
3. A heel shroud (200, 300) according to claim 2, wherein the heel shroud (200, the heel shroud (200, 300) defines a lateral width (W300) measured from the first side (208, 308) to the second side (208, 308), the L-shaped cavity (322) defines a lateral cavity width (W322), a ratio of the lateral width (W300) of the heel shroud (200, 300) to the lateral cavity width (W322) is between 1.09 and 1.32, and the L-shaped cavity (322) is bounded by a first lateral rib (360) and a second lateral rib (362) symmetrical to the first lateral rib (360).
4. The heel shroud (200, 300) of claim 2, wherein the side leg (204, 304) comprises: The heel shroud (200, 300) includes a tapered portion (364) including an outer upper cavity (366) disposed vertically above the side wear member receiving pocket (320), separated by a rib (368) extending laterally from the side wear member receiving pocket (320), and further includes a transversely extending wear member (400) disposed within the side wear member receiving pocket (320).
5. The heel shroud (200, 300) of claim 4, wherein the laterally extending The heel shroud (200, 300) further includes a wear member (400) that is a chockey bar (400a) and a mounting plate (370) interposed between the side leg (204, 304) and the chockey bar (400a).
6. The heel shroud (200, 300) of claim 1, The heel shroud (200, 300) further includes a pair of transversely extending wear members (500) disposed within the lower wear member receiving pocket (316), and a pair of mounting plates (374) interposed between the bottom foot (202, 302) and the pair of transversely extending wear members (500).
7. The heel shroud (200, 300) of claim 6, The heel shroud (200, 300) further includes a hook (376) disposed laterally between said pair of transversely extending wear members (500).
8. The heel shroud (200, 300) of claim 7, The heel shroud (200, 300) further includes a wear button (600a) disposed laterally between the pair of transversely extending wear members (500).
9. A heel shroud (200, 300), A bottom leg (202, 302), and a side leg (204, 304) extending perpendicularly from the bottom leg (202, 302) and forming an interior corner (206, 306) with the bottom leg (202, 302); The heel shroud (200, 300) defines a first side (208, 308) and a second side (208, 308), the bottom leg (202, 302) includes a curved inner surface (212, 312) extending from the first side (208, 308) to the second side (208, 308) and at least partially forming an interior corner (206, 306) and a flat bottom surface (314) defining a lower wear member receiving pocket (316), and the side legs (204, 304) define side wear member receiving pockets (320) in communication with the lower wear member receiving pocket (316).
10. The heel shroud (200, 300) of claim 9, The heel shroud (200, 300) further includes a first wear member (500, 600) disposed within the lower wear member receiving pocket (316) and a second wear member (400) disposed within the side wear member receiving pocket (300).