Anti-toenailing track shoe

Abstract

The machine track (20) comprises a track shoe (30) having a first outboard edge (36) and a second outboard edge (38), and a first set of pin lugs (42) and a second set of pin lugs (44). A roller pad (46) is positioned between the sets of pin lugs (42, 44) and includes a roller contact surface (48) extending between the first roller pad end (50) and the second roller pad end (52). The first roller pad end (50) comprises a relatively soft material (82), and the second roller pad end (52) comprises a relatively hard material (84) forming a trimming edge (86) for trimming the interfering material of the adjacent track shoe (30) in the machine track (20), which is plastically deformed by roller contact with the adjacent track shoe (30) during use.

Description

Technology Field

[0001] The present invention generally relates to a machine track, and more specifically to a track shoe having a track pad structured to trim plastically deformed material from an adjacent track shoe during use. Background Technology

[0002] Ground-meshing tracks are used in a wide variety of machines operating in off-road environments. A typical machine track includes a number of jointly coupled track links attached to track shoes to form an infinite loop extending around one or more rotatable track meshing elements, such as idlers and drive sprockets. Track rollers supported by a roller frame support the weight of the machine on the track as the machine moves around the workspace.

[0003] Enormous engineering endeavors are concentrated on the design of various track system components to provide robust support for the machinery, as well as static friction in extremely harsh environments. Track-type machinery is typically quite heavy, and since off-road work sites may feature substrates formed of hard rock material, the equipment requires demanding wear conditions, high mechanical loads, and corrosion conditions. Various wear-resistant and corrosion-resistant materials, lubrication strategies, and the geometry and proportions of the track components themselves have been proposed over the decades. For certain mining machines, the use of the tracks may require significant downtime, during which the machine naturally does not operate. If the use of the tracks cannot be anticipated—for example, in the event of a breakdown on-site—it can lead to significant economic consequences. For certain mining machines, on-site track use may even require additional heavy equipment to prepare for the inspection and replacement of track components. U.S. Patent No. 9,688,325 by Hakes relates to one known undercarriage assembly for a moving machine comprising a track link having a body portion having a protruding pin lug, a sprocket lug, and a roller lug.

[0004] In one embodiment, the track shoe comprises a track shoe body having a first outboard edge, a second outboard edge, and a ground contact surface. The track shoe body further comprises a first set of pin lugs adjacent to the first outboard edge, a second set of pin lugs adjacent to the second outboard edge, and a roller pad positioned between the first set of pin lugs and the second set of pin lugs. The roller pad comprises a roller contact surface positioned opposite the ground contact surface and extending in the front-rear direction between the first roller pad end and the second roller pad end. The first roller pad end comprises a relatively soft material, and the second roller pad end comprises a relatively hard material forming a trimming edge for trimming interference material of an adjacent track shoe on a machine track.

[0005] In another embodiment, the machine track comprises a plurality of track shoes and a plurality of track pins coupling the plurality of track shoes together. The plurality of track shoes each comprise a first set of pin lugs, a second set of pin lugs, and a roller pad. The roller pads each comprise a first roller pad end formed of a relatively soft material and a second roller pad end formed of a relatively hard material forming a trimming edge. The roller pads are positioned in series alignment, so that the trimming edge of the second roller pad end of each roller pad is positioned adjacent to the first roller pad end of an adjacent roller pad among the roller pads.

[0006] In another additional aspect, the track shoe comprises a single-piece track shoe body having a first set of pin lugs, a second set of pin lugs, and a roller pad positioned between the first set of pin lugs and the second set of pin lugs. The roller pad comprises a roller contact surface extending in the forward and backward direction between a first roller pad end and a second roller pad end. The first roller pad end comprises a relatively soft material, and the second roller pad end comprises a relatively hard material forming a trimming edge for trimming an interfering material of an adjacent track shoe on a machine track. Brief explanation of the drawing

[0007] FIG. 1 is a schematic diagram of a track-type machine according to one embodiment; FIG. 2 is a schematic perspective view of a track joint assembly in a machine track according to one embodiment; FIG. 3 is a cross-sectional view through a track shoe according to one embodiment; FIG. 4 is a cross-sectional view through a track joint assembly of a machine track in one configuration; FIG. 5 is a cross-sectional view through the track joint assembly of a machine track in another configuration. Specific details for implementing the invention

[0008] Referring to FIG. 1, a machine (10) according to one embodiment is illustrated. The machine (10) comprises a track-type machine having a machine frame (12) on which a cab (14) is mounted. A mechanism system (16) is also coupled to the frame (12). The frame (12) may be supported on and rotatable with respect to a ground engagement track system (18) having a track (20) extending around a plurality of rotatable track engagement elements. The rotatable track engagement elements may include one or more idlers (22), drive sprockets (24), and a plurality of track rollers (28), all of which are mounted on a track roller frame (26). The machine (10) is illustrated in the context of a mining machine (10) comprising a hydraulically operated mechanism system in which the mechanism system (16) is structured to operate at least primarily at a mining site, namely a hydraulic mining shovel. The machine (10) can alternatively be a rope shovel such as an electric rope shovel, or various other types of equipment such as a tractor or an excavator.

[0009] Those skilled in the art will understand that certain mining machines, such as the illustrated hydraulic mining shovel, may be operated for a long time in a fixed location within a workplace, such as a mining site, to capture, lift, and pour material, such as a mining truck. These machines typically transport (tram) (i.e. move) ore across the workplace for a short period, with a progress rate of typically only about 10%. Since such machines can weigh 3 million pounds and potentially even more, the tracks may undergo, for example, extreme wear, load, and material deformation, even if the frequency of transporting ore is relatively infrequent. It is generally desirable for the tracks used with these machines to have a service life of tens of thousands of hours. As will become further apparent from the description below, in particular, the machine (10) and the track system (18) are structured to extend the service life compared to other strategies, reducing the need for on-site use or the risk of premature failure.

[0010] Referring now to FIG. 2, a section of a machine track (20) including a track joint assembly (32) is illustrated. The track joint assembly (32) includes a plurality of track shoes (30) and a plurality of track pins (80) coupling the track shoes (30) together. In the illustrated embodiment, each of the plurality of track shoes (30) is substantially identical, and thus it should be understood that the following description regarding a single track shoe (30) is referenced in a manner similar to any of the track shoes in the track (20). Likewise, specific features of each track shoe (30) that are similar or identical to one another are discussed herein and are illustrated in the drawings by similar reference numerals.

[0011] The track shoe (30) comprises a track shoe body (34) which may be a single piece and has a first outboard edge (36), a second outboard edge (38), and a ground contact surface (40). The track shoe (30) may additionally comprise a shoe plate (54) comprising each of the first outboard edge (36) and the second outboard edge (38) as well as the ground contact surface (40). The shoe plate (54) is part of the track shoe body (34) and also includes a front edge (56) and a rear edge (58) extending between the first outboard edge (36) and the second outboard edge (38), respectively. In the illustrated embodiment, the shoe plate (54) and the track shoe (30) / shoe body (34) have a main diameter (60) extending between the first outboard edge (36) and the second outboard edge (38), and a secondary diameter (62) extending between the front edge (56) and the rear edge (58). The ground contact surface (40) may include a footprint that is substantially flat and generally rectangular. The track shoe (30) / shoe body (34) further includes a first set of pin lugs (42) adjacent to the first outboard edge (36) and a second set of pin lugs (44) adjacent to the second outboard edge (38). The first set of pin lugs (42) and the second set of pin lugs (44) may be integral with the shoe plate (54). Additionally, the track shoe body (34) may be a single piece having a first set of pin lugs (42), a second set of pin lugs (44), and other features not yet described formed by single-piece casting or forging of steel, iron, or other materials. Any reference to the track shoe (30) or the shoe body (34) herein may be understood to generally refer to either one similarly.

[0012] The shoe body (34) further comprises a roller pad (46) positioned between a first set of pin lugs (42) and a second set of pin lugs (44). The roller pad (46) comprises a roller contact surface (48) positioned opposite the ground contact surface (40) and extending in the front-rear direction between a first roller pad end (50) and a second roller pad end (52). The first roller pad end (50) may be positioned substantially in the same location as the front edge (56) and may form part thereof, while the second roller pad end (52) may be positioned substantially in the same location as the rear edge (58) and may form part thereof. As used herein, the terms "front" and "rear" should be understood in a relative sense to each other and are not restrictive regarding the orientation of the track shoe (30) on the track (20). In some cases, the machine (10) can carry ore in the "forward" direction for approximately the same amount of time it operates in the "rear" direction.

[0013] In an actual embodiment, the first set of pin lugs (42) and the second set of pin lugs (44) may each be arranged in a Y-pattern, and the pin lugs (42 and 44) ​​of each set extend forward and backward on both sides of the ground contact surface (40). It may be noted that the first set of pin lugs (42) and the second set of pin lugs (44) each extend forward and backward, respectively, beyond the front edge (56) and beyond the rear edge (58), the significance of which will become more apparent from the following description. The first set of pin lugs (42) and the second set of pin lugs (44) may each additionally include two front lugs (64 and 66) that extend between the space (68), and one rear lug (70) in an inboard-outboard position that corresponds to the inboard-outboard position of the corresponding space (68). The inboard-outboard position can be understood by reference to the inboard-outboard direction, which means a direction toward or away from the first outboard edge (36) and a direction toward or away from the second outboard edge (38), respectively. It will be understood that the outboard direction is a direction toward either the first outboard edge (36) or the second outboard edge (38) and away from the longitudinal front-back centerline defined by the roller pad (46). The inboard direction is opposite to the outboard direction. Accordingly, the rear lug (70) is positioned to correspond to the space formed between the two front lugs on the adjacent track shoe (30). The first set of pin lugs (42) and the second set of pin lugs (44) each additionally include a front pin bore (72) extending through the corresponding two front lugs (64, 66) and a rear pin bore (74) extending through the corresponding one rear lug (70).The track shoe (30) further comprises a first drive lug (76) positioned on the inboard of the first set of pin lugs (42) and on the outboard of the roller pad (46), and a second drive lug (78) positioned on the inboard of the second set of pin lugs (44) and on the outboard of the roller pad (46). The drive lugs (76, 78) are structured to engage with the drive sprocket (24). It may be further noted from FIG. 2 that in each of the first set of pin lugs (42) and the second set of pin lugs (44), the rear lug (70) is positioned behind the second roller pad end (50) on the track shoe (30). In each of the first set of pin lugs (42) and the second set of pin lugs (44), the front pin bore (72) is in a front-rear position corresponding to the front-rear position of the first roller pad end (50). This configuration, above all, enables the roller pads (46) to be positioned adjacent to each other on adjacent track shoes (30) to support the track rollers (28). The track shoes (30) are aligned in series and are therefore each in the same orientation within the track (20).

[0014] Now, referring to FIG. 3, it can be seen that the second roller pad end (52) comprises a substantially vertical end wall (88), and the first roller pad end (50) comprises another substantially vertical end wall (90). In one embodiment, the end walls (88 and 90) may be angled only slightly inward toward the ground contact surface (40). The first roller pad end (50) comprises a relatively soft material (82) and may be formed of the relatively soft material (82), whereas the second roller pad end (52) comprises a relatively hard material (84) and may be formed of the relatively hard material (84). The relatively soft material (82) and the relatively hard material (84) may be iron materials such as iron or steel that are differentially hardened to different material hardness. The relatively soft material (82) may have a material hardness of about 45 HRC (Rockwell hardness C) or less, and the relatively hard material (84) may have a material hardness greater than 45 HRC. As used herein, “about” may be understood in the context of conventional rounding for a certain number of significant digits. Thus, “about 45” means 44.5 to 45.4, etc. High-frequency hardening of part or all of the second roller pad end (52) may enable different material hardnesses. In a further embodiment, the relatively hard material (84) may have a material hardness of about 50 HRC or more. The relatively soft material (82) may have a material hardness of at least about 40 HRC, but the present disclosure is not limited thereto. Other techniques for selective hardening, such as selective heat treatment of specific parts of the roller pad (46), are considered within the scope of the present disclosure. Also, Figure 3 shows specific dimensions and proportional properties of the track shoe (30) and the track shoe body (34).The roller contact surface (48) has a first travel length (102) between and including the first roller pad end (50) and the second roller pad end (52). The roller pad (46) further has a first thickness (106) from the roller contact surface (48) and between the roller contact surface (48) and the ground contact surface (40). A relatively hard material (84) within the second roller pad end (52) forms a trimming edge (86) for trimming the interfering material of an adjacent track shoe (30) on the machine track (20), as further discussed herein. In a practical implementation strategy, the trimming edge (86) has a second travel length (104) that is less than 50% of the first travel length (102). The second travel length (104) may be less than 25% of the first travel length (102), and in other additional cases, may be about 10% or less of the first travel length (102). The trimming edge (86) further has a second thickness (108) smaller than the first thickness (106) from the roller contact surface (48) and between the roller contact surface (48) and the ground contact surface (40). The second thickness (108) may be less than 75% of the first thickness (106), and in some cases less than 60% of the first thickness (106), or potentially less than 50%. Industrial applicability

[0015] Generally, with reference to the drawings, but especially to FIGS. 4 and FIGS. 5 from now on, a track (20) and a track joint assembly (32) are each shown in a first configuration having two track shoes (30) that can be seen as two track shoes (30) in contact with a track roller (28) on the base layer, and a second configuration in which two track shoes (30) can be seen as moving around a drive sprocket (24) or an idler (22). In FIG. 4, the track roller (28) is shown so that the track roller (28) can be seen rolling against the roller contact surface (48) in contact with the roller contact surface (48). Additionally, a track shoe (30) that may be seen passing through before the pass of the roller (28) is shown, and the roller (28) rolls along the roller contact surface (48) and transmits the weight load of the machine (10) to the roller surface (48) to a sufficient degree and for a sufficient number of times, thereby plastically deforming the relatively soft material (82) to form a tornado (110) of the material (82). The tornado (110) is deformed across the gap between adjacent track shoes (30), and accordingly, the tornado (110) almost touches the trimming edge (86) of the track shoe (30) shown on the right.

[0016] It will be understood that when the machine (10) transports ore to different work positions in the workshop, the track (20) can move forward and backward relative to the track roller (28). When the track roller (28) rolls relative to the track (20) in the left direction of FIG. 4, the relatively hard material (84) will be resistant to plastic deformation. When the track roller (28) rolls relative to the track (20) in the right direction of FIG. 4, the machine weight will tend to cause the relatively soft material (82) to be compressed and plastically deformed, creating a tornado (110). In earlier track systems, it was observed that so-called tornadoing could eventually create plastically deformed material in one track shoe interfering with adjacent track shoes, to the extent that contact between adjacent roller pads and destruction of the tornado occurred.

[0017] As can be seen from FIG. 5, when the track shoes (30) rotate relative to each other, the trimming edge (86) of the track shoe (30) shown on the right can engage with and trim the material forming the tornado (110). In the previously mentioned earlier strategy, the tornado is usually destroyed into a relatively large piece, which can cause a location where crack propagation deep enough into the track link can occur, and thus failure must be anticipated. According to the present disclosure, the relatively hard material (84) forming the trimming edge (86) can be expected to cut, grind, or otherwise trim a relatively small piece of the relatively soft material of the adjacent track shoe, instead of being destroyed into a piece where crack propagation or other problems may occur. Therefore, when the track (20) is used in the field, it will be understood that the trimming edge (86) can gradually trim small pieces, even very small granules, of the relatively soft material (82) and reduce the risk of failure during field use. Other earlier specific strategies required attempting to harden the entire roller contact surface of the track shoe or manually cutting the tornail using a cutting torch. While these approaches may prevent track failure or reduce the overall wear rate, they do not contribute to the track shoe having a biased wear pattern that addresses the root cause of the tornailing phenomenon described herein more directly and elegantly.

[0018] The present invention is for illustrative purposes only and should not be construed as narrowing the scope of the disclosure in any way. Accordingly, those skilled in the art will understand that various modifications may be made to the embodiments disclosed herein without departing from the whole and reasonable scope and spirit of the disclosure. Other aspects, features, and advantages will become apparent upon reviewing the accompanying drawings and claims. In this specification, the singular forms (“a” and “an”) are intended to include one or more items and may be used interchangeably with “one or more.” If only one item is intended, “one” or a similar term is used. Additionally, terms used herein such as “has,” “have,” “having,” etc. are intended to be open-ended terms. Also, the phrase “based on” is intended to mean “based, at least in part, on” unless otherwise explicitly stated.

Claims

Claim 1 As a track shoe (30), the track shoe body (34) comprises a first outboard edge (36), a second outboard edge (38), and a ground contact surface (40); the track shoe body (34) further comprises a first set of pin lugs (42) adjacent to the first outboard edge (36), a second set of pin lugs (44) adjacent to the second outboard edge (38), and a roller pad (46) positioned between the first set of pin lugs (42) and the second set of pin lugs (44); the roller pad (46) comprises a roller contact surface (48) positioned opposite the ground contact surface (40) and extending in the front-rear direction between a first roller pad end (50) and a second roller pad end (52); the first roller pad end (50) comprises a relatively soft material (82), and the second roller pad end (52) on the machine track (20) It comprises a relatively hard material (84) forming a trimming edge (86) for trimming interference material of an adjacent track shoe (30), the roller contact surface (48) has a first travel length between a first roller pad end (50) and a second roller pad end (52), and the trimming edge (86) has a second travel length (104) less than 50% of the first travel length (102); the roller pad (46) has a first thickness between the roller contact surface (48) and the ground contact surface (40), and the trimming edge (86) has a second thickness smaller than the first thickness between the roller contact surface (48) and the ground contact surface (40); the track shoe body (34) further comprises a shoe plate (54) including each of a first outboard edge (36), a second outboard edge (38), and a ground contact surface (40), and a first set of pin lugs (42) and Each of the second set of pin lugs (44) is a track shoe (30) that is integral with the shoe plate (54). Claim 2 A track shoe (30) according to claim 1, wherein the relatively soft material (82) has a material hardness of about 45 HRC or less, and the relatively hard material (84) has a material hardness of more than 45 HRC. Claim 3 In claim 1 or 2, the shoe plate (54) further comprises a front edge (56) and a rear edge (58) extending respectively between the first outboard edge (36) and the second outboard edge (38), and the shoe plate (54) has a main diameter extending between the first outboard edge (36) and the second outboard edge (38), and a minor diameter extending between the front edge (56) and the rear edge (58); the first set of pin lugs (42) and the second set of pin lugs (44) have two front lugs (64, 66) extending between a space (68), and one rear lug (70) in an inboard-outboard position corresponding to an inboard-outboard position of the corresponding space (68); a front pin bore (72) extending through the corresponding two front lugs (64, 66), and through the corresponding one rear lug (70). A track shoe (30) each having an extended rear pin bore (74); the front-rear position of the front pin bore (72) in each of the first set of pin lugs (42) and the second set of pin lugs (44) corresponds to the front-rear position of the first roller pad end (50), and the rear pin bore (74) in each of the first set of pin lugs (42) and the second set of pin lugs (44) is located behind the second roller pad end (52) in the front-rear direction. Claim 4 A machine track (20) comprising a plurality of track shoes (30); a plurality of track pins (80) coupling the plurality of track shoes (30) together; each of the plurality of track shoes (30) comprising a first set of pin lugs (42), a second set of pin lugs (44), and a roller pad (46); each of the roller pads (46) comprising a first roller pad end (50) formed of a relatively soft material (82) and a second roller pad end (52) formed of a relatively hard material (84) forming a trimming edge (86); the roller pads (46) are positioned in series alignment, and accordingly, the trimming edge (86) of the second roller pad end (52) of each roller pad (46) is positioned adjacent to the first roller pad end (50) of an adjacent roller pad (46) among the roller pads (46). Claim 5 In paragraph 4, each of the first set of pin lugs (42) and the second set of pin lugs (44) of each of the plurality of track shoes (30) includes a front lug (64, 66) in which a front pin bore (72) is formed internally, and a rear lug (70) in which a rear pin bore (74) is formed internally; the front-rear position of the front pin bore (72) corresponds to the front-rear position of the first roller pad end (50) in the corresponding track shoe (30); the rear lug (70) of each of the first set of pin lugs (42) and the second set of pin lugs (44) is positioned behind the second roller pad end (52) in the corresponding track shoe (30); and each of the plurality of track shoes (30) includes a first drive lug (76) positioned on the inboard of the first set of pin lugs (42) and on the outboard of the roller pad (46), and the inboard of the second set of pin lugs (44) and the roller A machine track (20) further comprising a second drive lug (78) positioned outboard of a pad (46); a roller contact surface (48) having a first travel length between a first roller pad end (50) and a second roller pad end (52), and a trimming edge (86) having a second travel length smaller than most of the first travel length; a roller pad (46) having a first thickness, and a trimming edge (86) having a second thickness smaller than the first thickness; a relatively soft material (82) having a material hardness of about 45 HRC or less, and a relatively hard material (84) having a material hardness greater than 45 HRC. Claim 6 A track shoe (30) comprising a single-piece track shoe body (34) comprising a first set of pin lugs (42), a second set of pin lugs (44), and a roller pad (46) positioned between the first set of pin lugs (42) and the second set of pin lugs (44); the roller pad (46) comprises a roller contact surface (48) extending in the front-rear direction between a first roller pad end (50) and a second roller pad end (52); the first roller pad end (50) comprises a relatively soft material (82), and the second roller pad end (52) comprises a relatively hard material (84) forming a trimming edge (86) for trimming an interfering material of an adjacent track shoe (30) on a machine track (20). Claim 7 In claim 6, the trimming edge (86) has a travel length extending in the forward and backward direction and a thickness extending in a vertical direction from the roller contact surface (48) which is greater than the travel length; the second roller pad end (52) comprises a substantially vertical end wall (88) that is transitioned to the trimming edge (86) and is partially formed by a relatively hard material (84), the track shoe (30). Claim 8 In claim 6 or 7, a relatively soft material (82) is pervasive within a single-piece track shoe body (34) outside the trimming edge (86); the single-piece track shoe body (34) comprises a ground contact surface (40), and each of a first set of pin lugs (42) and a second set of pin lugs (44) is arranged in a Y-pattern and extends forward and backward on both sides of the ground contact surface (40), the track shoe (30). Claim 9 A track shoe (30) according to claim 6 or 7, wherein the relatively soft material (82) has a material hardness of about 45 HRC or less, and the relatively hard material (84) has a material hardness of more than 45 HRC.

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