Geometric Profiles for Improved Manufacturability of Ground Engaging Tools

Abstract

The wear member (200) includes a first leg (202), a second leg (204), and a throat portion (206) connecting the first leg (202) to the second leg (204). The first leg (202) defines a first leg thickness (T202), and the throat portion (206) defines a throat thickness (T206) disposed adjacent the first leg thickness (T202). A ratio of the throat thickness (T206) to the first leg thickness (T202) is between 1.1 and 1.2.

Description

[Technical field]

[0001] The present disclosure relates generally to manufacturing processes for producing ground engaging tools and, more particularly, to improved geometric profiles for improving manufacturability of ground engaging tools. [Background technology]

[0002] Ground engaging tools, edge protectors, shrouds, etc. (sometimes collectively referred to as wear parts) are routinely used in machines in the civil engineering, mining, agricultural, and construction industries. These parts are typically manufactured from iron using a casting process, as shown in FIG. 1. More specifically, the shroud 50 shown in FIG. 1 is manufactured using side risers (also called feeders, because they feed material into the cavity to compensate for shrinkage). The use of side risers limits the number of cavities in the mold, reducing the productivity of the manufacturing process.

[0003] Figure 2 shows what would happen if the side risers were eliminated to improve the productivity of the manufacturing process. In particular, the risk of porosity would increase to undesirable levels, leading to problems such as shroud cracking during use. Also, the current manufacturing process, due in part to the use of side risers, only has a yield of about 50%, a rework rate of 28%, and scrap of 22%.

[0004] U.S. Patent No. 10,294,638 B2 discloses a shroud configured to be attached to a work tool. The shroud may include a body defining a closed end, an open end, a first side, and a second side. The first side and the second side extend from the closed end to the open end. A working section is disposed near the closed end, a first leg extends rearwardly from the working section to the open end, and a second leg extends rearwardly from the working section to the open end. The side surfaces also form sides of the legs. A throat connects the legs and the working section. The first and second legs define a slot, the slot defines an assembly direction to the work tool, and the body defines a Cartesian coordinate system with an X-axis parallel to the assembly direction. The working portion may define a ground engaging surface at the closed end, the ground engaging surface including a convex arc portion intersecting the X-axis, a first concave arc portion extending from the convex arc portion toward the first side, and a second concave arc portion extending from the convex arc portion toward the second side when the ground engaging surface is projected onto the XY plane along the Z-axis.

[0005] However, the '638 patent does not mention the manufacturing process of the shroud. Therefore, a manufacturing process that improves productivity and yield rate is needed.

[0006] A wear member configured to be attached to a work implement according to an embodiment of the present disclosure may include a first leg, a second leg, and a throat portion connecting the first leg to the second leg. The first leg may define a first leg thickness and the throat portion may define a throat thickness disposed adjacent the first leg thickness. A ratio of the throat thickness to the first leg thickness may be in the range of 1.1 to 1.2.

[0007] A shroud configured for attachment to an edge of a work implement in accordance with an embodiment of the present disclosure may include a top leg including an aft surface having an aft gate defect, a bottom leg including a bottom surface having a bottom gate defect, and a throat portion including a first bevel portion extending from the top leg and a second bevel portion extending from the first bevel portion to the bottom leg. The top leg may define a first top leg thickness, and the first bevel portion may define a first bevel portion thickness that is greater than the top leg thickness.

[0008] A mold for casting a shroud according to an embodiment of the present disclosure may include a plurality of cavities, a sprue, and a feeder system connecting the sprue to the plurality of cavities. The feeder system includes a plurality of aft gates in fluid communication with the plurality of cavities and the sprue. [Brief description of the drawings]

[0009] [Figure 1] 1 shows a casting process for producing a shroud (a type of ground engaging tool) using top and side risers according to a prior art example. The side risers and side gates limit the number of cavities in which the shroud is produced. [Diagram 2] A plot created using FEA (Finite Element Analysis) showing that the elimination of the side risers used in Figure 1 increases the risk of porosity in the shroud. [Diagram 3] FIG. 1 is a perspective view of a machine, such as an excavator, that uses a shrouded bucket constructed in accordance with an embodiment of the present disclosure. [Figure 4] FIG. 4 is a front perspective view of the bucket and shroud of FIG. 3 separated from the machine. [Diagram 5] FIG. 5 is a side perspective view of the bucket and shroud of FIG. 4. [Figure 6] FIG. 5 is a perspective view showing a shroud similar to that shown in FIG. 4 in an exploded state. [Figure 7] 7 is a cross-sectional view of the shroud of FIG 6 taken along its midplane (indicated by line 7-7). The thickness of the transition or throat between the top and bottom legs of the shroud is increased to reduce flow resistance. [Figure 8] FIG. 8 illustrates a casting process that uses only a top riser and a single rear gate to manufacture the shroud of FIG. 7 and allows for an increased number of cavities in the mold. [Figure 9] Plot created using FEA showing that removing the side risers / side gates does not increase the risk of porosity in the shroud of Figure 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Reference will now be made in detail to the embodiments of the present disclosure that 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, reference numbers are set forth in this specification and appear in the drawings followed by a letter (e.g., 100a, 100b) or a prime (e.g., 100', 100''). The use of a letter or prime immediately following a reference number should be understood to indicate 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 explanation herein, letters and primes are often not included herein, but may be shown in the drawings to indicate overlap of features described herein.

[0011] Various embodiments of the wear member or shroud are disclosed that may improve the manufacturing process and increase yield rates without adversely affecting the strength of the wear member or shroud. More specifically, the profile shape of the wear member or shroud may enable such improvements in the manufacturing process.

[0012] 3 shows a machine 100 in the form of an excavator that uses a bucket 102 to move dirt, rocks, etc., and is propelled by a track system 104 and driven by an engine. A cab 106 is also provided to accommodate an operator (not shown) who controls the movement of the bucket via a stick and boom system 108. The bucket and machine may take different forms in various embodiments of the disclosure, as described in the following paragraphs.

[0013] 4 and 5 illustrate that a shroud 200, tip 110, and adapter 112 may be attached to the front lip 114 of a bucket. The shroud, tip, adapter, and the like may be more generally characterized herein as "wear members." It is also understood that other work implements besides buckets, such as shears, grapples, rippers, and the like, may employ wear members configured in accordance with various embodiments of the present disclosure.

[0014] 5 and 6, such a wear member (e.g., shroud 200) may include a first leg 202, a second leg 204, and a throat 206 connecting the first leg 202 to the second leg 204. The first leg 202 may define a first leg thickness T202, while the throat 206 may define a throat thickness T206 disposed adjacent the first leg thickness T202 (e.g., closer to the first leg than to the second leg). In some embodiments of the present disclosure, the ratio of the throat thickness T206 to the first leg thickness T202 is in the range of 1.1 to 1.2. The slight increase in throat thickness mitigates flow stagnation during the casting process, and a rear gate 302 may be used for the mold 300 (see also FIG. 8) without increasing the risk of porosity formation in the throat.

[0015] As a result, as shown in Figures 6 and 7, the first leg 202 may define a rear surface 208 that includes a rear gate defect 210. The first leg 202 may take the form of a top leg that is longer than the second leg 204, and the second leg 204 may take the form of a bottom leg that is shorter than the top leg. This may not be the case in other embodiments of the present disclosure. The second leg 204 may have a bottom surface 212 with a bottom gate defect 214 resulting from the top riser 304 shown in Figure 8.

[0016] Again, the wear member may be, but is not required to be, a shroud 200. As best shown in FIG. 6, the first leg 202, the second leg 204, and the throat 206 may define a first side 216 and a second side 218. The throat 206 may include a rib 220 spaced apart from the first side 216 and the second side 218 and forming a first notch 222 and a second notch 224. As best shown in FIG. 7, the rib 220 at least partially defines the throat thickness T 206. In other embodiments, the ribs or additional material extend completely to both sides such that no notches or the like are present.

[0017] 6 and 7, an embodiment of the shroud may be more specifically described as including a top leg (see, e.g., first leg 202) including an aft surface 208 having an aft gate defect 210, and a bottom leg (see, e.g., second leg 204) including a bottom surface 212 having a bottom gate defect 210. The throat portion 206 may include a first bevel portion 226 extending from the top leg and a second bevel portion 228 extending from the first bevel portion 226 to the bottom leg at an oblique angle 230 (see, e.g., FIG. 7). The top leg defines a first top leg thickness (see, e.g., T202), and the first bevel portion defines a first bevel portion thickness (see throat thickness T206) that is greater than the top leg thickness. Additionally, the second bevel portion defines a second bevel portion thickness T228 that is greater than the first bevel portion thickness. As shown, the top leg thickness and the first bevel thickness are substantially constant, while the second bevel thickness varies, which may not be the case in other embodiments of the present disclosure.

[0018] As previously described with reference to FIG. 6, the throat may define a first side and a second side that may be free of gate defects since the side gate is eliminated. A protrusion (see, e.g., rib 220) is laterally spaced from the first and second sides to form a first side recess (see, e.g., first notch 222) and a second side recess (see, e.g., second notch 224). As best seen with reference to FIG. 7, the protrusion at least partially defines a first bevel thickness (see, e.g., T206) and a second bevel thickness (see, e.g., T228). This may not be the case in other embodiments of the present disclosure.

[0019] 6, the top leg defines at least a first retention mechanism receiving opening 232. Also, a lifting eye 234 extends from the first beveled portion to the top leg. Other locations or lifting eyes are possible, and these features may be omitted, such as in other embodiments of the present disclosure.

[0020] The shroud shown is a center shroud, as evidenced by the symmetry about the lateral midplane (or cross section of FIG. 7), however, the inventors have also simulated that the shroud could be a left or right shroud that is asymmetric about the lateral midplane (similar to that shown in U.S. Pat. No. 10,724,212 B2, FIGS. 19 and 21, or in FIGS. 1, 4, and 5 of the present application).

[0021] 6, the protrusion defines a protrusion lateral width W220 and the throat defines a throat lateral width W206. In some embodiments of the present disclosure, the ratio of the protrusion lateral width to the throat lateral width may be in the range of 0.5 to 0.9. Similarly, the rear gate defect defines a rear gate defect lateral width W210 and the ratio of the rear gate defect lateral width to the throat lateral width W206 may be greater than 0.25. In some embodiments, this ratio may be greater than 0.35 (e.g., in some embodiments, it may be about 0.4).

[0022] The configurations, proportions, and dimensional ranges of any of the features of the embodiments described herein may vary depending on the application, other than as expressly described or shown. [Industrial Applicability]

[0023] Indeed, wear members or shrouds according to any of the embodiments described herein may be provided, sold, manufactured, purchased, etc., as needed or desired in an aftermarket or OEM (original equipment manufacturer) context. For example, the wear members or shrouds may be used to retrofit work implements already in the field, or may be sold with the equipment (e.g., excavators, wheel loaders, etc. machines) that use the work implement at the time of the original sale of the equipment.

[0024] The wear member or shroud may be manufactured from iron, cast iron, steel, grey cast iron, or other suitable material that is durable and can be used in a casting process. The shape of the wear member or shroud is formed during casting and then rough and / or finish machined as required. Suitable machining processes include milling, turning, EDM, and the like. The wear member may be separated from the top riser and aft gate to form a gate defect that is a protrusion, a recess, or a combination of a protrusion and a recess relative to the outer surface of the wear member or shroud. The gate defect may be removed by machining, or the like.

[0025] Figures 8 and 9 show that by modifying the throat thickness, it is possible to eliminate the side gate and employ a single rear gate, allowing more cavities to be used, thus improving yield without increasing the risk of porosity.

[0026] More specifically, Figure 8 shows a mold 300 for casting a shroud (or other wear member). The mold 300 may include multiple cavities 306, a sprue 308, and a feeder system 310 (also called a spider system or runner system) that connects the sprue to the multiple cavities. Also shown are multiple rear gates 302 in fluid communication with the multiple cavities, and a sprue and top riser 304.

[0027] In some embodiments, each of the plurality of cavities is connected to the feeder system by an aft gate of the plurality of aft gates, and each of the plurality of cavities is in fluid communication with the top riser, which may not be the case in other embodiments of the present disclosure.

[0028] It should be understood that the mold is actually a negative image (also called a "shot") of the cast part shown in FIG.

[0029] It should be understood that the foregoing description provides examples of the disclosed assemblies and techniques. However, it is anticipated that other embodiments of the present disclosure may differ in detail from the foregoing examples. All references to the present disclosure or examples thereof are intended to refer to the specific examples described therein, and are not intended to imply any more general limitation of the scope of the present disclosure. All language of distinction and disparagement regarding certain features is intended to indicate a lack of preference for those features, but is not intended to be entirely excluded from the scope of the present disclosure unless otherwise stated.

[0030] Recitation of ranges of values ​​herein is intended to be merely a shorthand method of referring individually to each separate value falling within the range, unless otherwise stated herein, and each separate value is incorporated into the specification as if it were individually set forth herein.

[0031] As used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." Where only one item is intended, the term "a" or similar terms are used. Also, as used herein, the terms "has," "have," "having," "with," and the like are intended to be open-ended terms. Additionally, the phrase "based on" is intended to mean "based at least in part on," unless expressly specified otherwise.

[0032] 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 described herein without departing from the scope or spirit of the present invention. Other embodiments of the present disclosure will be obvious to those skilled in the art in 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, some steps of any method may be omitted, may be performed in a different order than specifically mentioned, and may even be performed simultaneously or stepwise. Furthermore, changes or modifications to specific aspects or features of the various embodiments may be made to create further embodiments and features, 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.

[0033] Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, this disclosure includes any combination of the above-described elements in all possible variations thereof unless otherwise indicated herein or clearly contradicted by context.

Claims

1. A wear member (200) configured to be attached to a work implement (102), said wear member (200) comprising: a first leg (202); A second leg (204), and a throat portion (206) connecting the first leg (202) to the second leg (204); said first leg (202) defining a first leg thickness (T202) and said throat (206) defining a throat thickness (T206) disposed adjacent the first leg thickness (T202), a ratio of said throat thickness (T206) to said first leg thickness (T202) being in the range of 1.1 to 1.2, said wear member (200).

2. 2. The wear member (200) of claim 1, wherein the first leg (202) defines a rear surface (208) having a rear gate defect (210) and the second leg (204) defines a bottom surface (212) having a bottom gate defect (214).

3. The wear member (200) of claim 2, wherein the first leg (202) is a top leg and is longer than the second leg (204).

4. The wear member (200) of claim 2, wherein the second leg (204) is a bottom leg and is shorter than the first leg (202).

5. 2. The wear member of claim 1, wherein the wear member is a shroud, the first leg, the second leg, and the throat define the first and second sides, the throat including a rib spaced from the first and second sides forming a first notch and a second notch, the rib at least partially defining a throat thickness.

6. A shroud (200) configured to be attached to an edge (114) of a work implement (102), said shroud (200) comprising: a top leg (202) including a rear surface (208) having a rear gate defect (210); a bottom leg (204) including a bottom surface (212) having a bottom gate defect (214); the throat portion (206) includes a first beveled portion (226) extending from the top leg (202) and a second beveled portion (228) extending from the first beveled portion (226) to the bottom leg (204); The shroud (200), wherein the top leg (202) defines a first top leg thickness (T202) and the first bevel portion (226) defines a first bevel portion thickness (T206) that is greater than the top leg thickness (T202).

7. The shroud (200) of claim 6, wherein the second bevel portion (228) defines a second bevel portion thickness (T228) that is greater than the first bevel portion thickness (T206).

8. 8. The shroud of claim 7, wherein the throat portion (206) includes a protrusion (220) defining a first side (216) and a second side (218) and spaced laterally from the first side (216) and the second side (218) to form a first side recess (222) and a second side recess (224), the protrusion (220) at least partially defining a first bevel thickness (T206) and a second bevel thickness (T228).

9. The shroud (200) of claim 6, wherein the shroud (200) is a center shroud.

10. 9. The shroud of claim 8, wherein the first side (216) and the second side are free of gate defects (218), the protrusion (220) defines a protrusion lateral width (W220), the throat (206) defines a throat lateral width (W206), a ratio of the protrusion lateral width (W220) to the throat lateral width (W206) is in the range of 0.5 to 0.9, and the aft gate defect (210) defines an aft gate defect lateral width (W210), and a ratio of the aft gate defect lateral width (W210) to the throat lateral width (W206) is greater than 0.25.

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