EP4688544A1

EP4688544A1 - Track shoe

Info

Publication number: EP4688544A1
Application number: EP24717470.9A
Authority: EP
Inventors: Andy M. C. FUNG; Seiji Iijima; Niladri MANNA
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2023-04-05
Filing date: 2024-03-08
Publication date: 2026-02-11
Also published as: CN120916937A; GB202305095D0; GB2628813B; WO2024211050A1; GB2628813A

Abstract

A track shoe for a work machine. The track shoe includes a base element and a telescopic element. The base element has a first thickness extending between a first ground-engaging surface and an opposing first link-facing surface. The telescopic element has a second thickness extending between a second ground-engaging surface and an opposing second link-facing surface. The telescopic element is coupled to the base element. The telescopic element is slidable with respect to the base element to adjust a span of the track shoe between a fully retracted state and a fully extended state.

Description

TRACK SHOE

Technical Field

This disclosure is directed towards a track shoe, and in particular to a track shoe for a work machine having a ground-engaging track system.

Background

Ground-engaging track systems are used on a variety of work machines, particularly for off-road environments. Typical applications for work machines incorporating track systems are mining, construction, agriculture, forestry, landfills, and various others. Work machines incorporating track systems are typically supported on an undercarriage assembly that has one or more continuous tracks that enable the machine to traverse the ground or terrain. Each continuous track may include a plurality of track links that are pivotally joined or linked together, for example by pins, the track links being arranged in a continuous loop or belt similar to a closed chain. Track shoes (also known as track pads) are attached to the track links to engage the ground. The continuous track is disposed around a plurality of wheels, idlers, and/or rollers arranged along a lower side of the machine. The track can be made to translate about the wheels or rollers with respect to the machine by a drive sprocket operatively coupled to a prime mover. The hinged connection between the individual track links enables the continuous track to articulate, for example flex or bend, as it moves in a loop about the plurality of rollers, thereby bringing successive track shoes into engagement with the ground. The continuous track can be advanced in a forward direction to move the work machine forward, or in a reverse direction to move the work machine backward. Two continuous tracks provided on opposing sides of a work machine can be rotated at differing speeds to turn the work machine.

An advantage of continuous tracks is that they can better support and distribute the weight of the machine, since a continuous track provides more surface contact with the ground, and thus better traction, relative to other forms of propulsion such as pneumatic tires or wheels. Accordingly, continuous tracks can better traverse soft or loose soil or other materials without becoming stuck or spinning. In addition, the improved traction can facilitate climbing capability or the ability to drive along steep grades in the work surface. Furthermore, because the individual track shoes and links are often made of steel, continuous tracks are typically more durable than pneumatic tires or the like.

The optimal span of a track shoe (wherein the ‘span’ of a track shoe is a dimension of the track shoe perpendicular to the track shoe’s direction of travel when the track shoe is mounted on a track system) will depend on ground conditions. Track shoes having a larger span are required for softer ground, such that the weight of the machine may be distributed over a larger surface area. However, track shoes having a larger span are typically more flexible than track shoes having a smaller span. Thus, track shoes with a smaller span, being more rigid, are preferred for harder ground. Operators may therefore require multiple sets of track shoes to meet various expected ground conditions, which is costly. Furthermore, the process of removing and replacing each track shoe on a track system is time consuming and therefore costly.

Summary

According to the present disclosure, there is provided a track shoe for a work machine. The track shoe includes a base element and a telescopic element. The base element has a first thickness extending between a first groundengaging surface and an opposing first link-facing surface. The telescopic element has a second thickness extending between a second ground-engaging surface and an opposing second link-facing surface. The telescopic element is coupled to the base element. The telescopic element is slidable with respect to the base element to adjust a span of the track shoe between a fully retracted state and a fully extended state.

Optionally, the first ground-engaging surface of the base element comprises a recessed region, the recessed region having a second thickness smaller than the first thickness, and the telescopic element comprises a sliding section, the sliding section having a fourth thickness smaller than the third thickness, wherein the thickness reduction is taken from the second link-facing surface. The sliding section is slidable within the recessed region.

Optionally, the first thickness is substantially equal to the third thickness, and the sum of the second thickness and the fourth thickness is substantially equal to the first thickness and the third thickness.

Optionally, the track shoe comprises a first set of apertures for mounting the track shoe on a track link box at a first predetermined span.

Optionally, the track shoe comprises a second set of apertures for mounting the track shoe on a track link box at a second predetermined span.

Optionally, the track shoe comprises one or more further sets of apertures for mounting the track shoe on a track link box at one or more further predetermined spans.

Optionally, the apertures comprise first apertures in the recessed region of the base element and second apertures in the sliding section of the telescopic element.

Optionally, the track shoe further comprises retaining means for retaining the base element and the telescopic element in a single plane as the track shoe is extended and retracted.

Optionally, the retaining means comprises a longitudinal tongue projecting from at least one side wall of the recessed region or from at least one side wall of the sliding section, and a complementary longitudinal groove in the corresponding side wall of the sliding section or the recessed region, respectively.

Optionally, at least a part of abutting portions of the base element and the telescopic element comprise corresponding chamfered edges, wherein the corresponding chamfered edges together form a V-shaped notch.

Optionally, each of the corresponding chamfered edges has a draft angle in a range of 2 degrees to 11 degrees.

Optionally, each of the corresponding chamfered edges has a draft angle in a range of 5 degrees to 8 degrees. Optionally, the track shoe further comprises at least one grouser extending from each of the first and second ground-engaging surfaces.

Optionally, a first longitudinal edge of the track shoe comprises an upturned lip, and a second opposing longitudinal edge of the track shoe comprises a downturned lip.

According to the present disclosure, there is further provided a ground-engaging track for a work machine. The track comprises two parallel track chains. Each track chain comprises a plurality of track links coupled together in an end-to-end arrangement, with corresponding track links of the two parallel track chains being coupled together to form a plurality of track link boxes. A track shoe according to the present disclosure is mounted on at least one of the track link boxes.

According to the present disclosure, there is further provided a work machine comprising the ground-engaging track of the present disclosure.

Brief Description of the Drawings

Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic side elevation of a work machine comprising a track shoe in accordance with the present disclosure;

Figure 2 shows a top perspective view of a track shoe in accordance with the present disclosure, with the track shoe in a retracted state;

Figure 3 shows a top perspective view of the track shoe of Figure 2, with the track shoe in an extended state;

Figure 4 shows a bottom perspective view of the track shoe of Figures 2 and 3, with the track shoe in a retracted state;

Figure 5 shows a bottom perspective view of the track shoe of Figures 2 to 4, with the track shoe in an extended state;

Figure 6 shows a top perspective view of a telescopic element of the track shoe of Figures 2 to 5; Figure 7 shows a schematic representation of a longitudinal crosssection of the track shoe of Figures 2 to 6, with the track shoe in an extended state; and

Figure 8 shows a perspective view of the attachment of two track shoes of Figures 2 to 6 and Figure 7 to track link boxes, with the track shoes in a retracted state.

Detailed Description

Figure 1 illustrates a work machine 10 comprising a track shoe such as the track shoe 30 of the present disclosure. The work machine 10 illustrated in Figure l is a high drive track-type tractor. However, it will be appreciated that the work machine 10 may be any other machine having a continuous track. For example, the work machine 10 may be a half-track machine, an excavator, a tank, or another type of tracked work machine.

The work machine 10 may include a machine frame 12 having one or more ground-engaging track systems 14 coupled to the machine frame 12. Typically, a pair of identical track systems 14 are disposed on opposite sides of the machine frame 12. Each track system 14 may comprise an endless track 15 extending about a plurality of rotatable elements, which may include a drive sprocket 16, a back idler 18 and a front idler 20, as well as a plurality of track rollers 22. The back idler 18, front idler 20, and track rollers 22 may be supported by a track roller frame 23. In the track system 14 illustrated in Figure 1, the drive sprocket 16 is positioned in a so-called ‘high drive’ configuration. In other instances, the track system 14 may have an oval track configuration with one drive sprocket and one idler.

The track 15 may comprise two parallel track chains 24, each track chain 24 comprising a plurality of track links 25 coupled together in an end-to-end arrangement, to form an ‘endless’ chain. Adjacent track links 25 in each track chain 24 may be coupled together via track link pins 26. The track link pins 26 may additionally couple together corresponding track links 25 in the two parallel chains box 27 comprising two parallel track links 25 joined together by track link pins 26. A plurality of track shoes 30 may be attached to the track 15. A track shoe 30 is typically bolted to each track link box 27.

As shown in Figures 2 to 5, the track shoe 30 generally comprises a base element 40 (which may also be referred to as a ‘first section’ or a ‘shoe plate’) and a telescopic element 60 (which may also be referred to as a ‘second section’, an ‘extending section’, or a ‘shoe extension’), with the telescopic element 60 being operable to adjust a dimension of the track shoe 30 between a fully retracted state and a fully extended state. In particular, the telescopic element 60 may be slidable with respect to the base element 40 to adjust the dimension of the track shoe 30. The adjustable dimension of the track shoe may, in particular, be a dimension of the track shoe 30 perpendicular to the track shoe’s direction of travel when the track shoe 30 is mounted on the track 15. This may typically be a length of the track shoe 30, where the length of an element is generally understood to be greater than its width. The length of the track shoe 30 may equate to a width of the assembled track 15. This dimension may also be referred to as the ‘span’ of the track shoe 30 and the resulting track 15.

The base element 40 may be a generally planar element extending across a first thickness 90 between a first ground-engaging surface 41, which may be configured for engaging the ground, and an opposing first link-facing surface 42, which may face the track links 25. The dimensions across the first groundengaging and/or first link-facing surfaces 41,42 may be substantially greater than the first thickness 90. The first ground-engaging and/or first link-facing surfaces 41,42 may be substantially rectangular. The base element 40 may have a first longitudinal edge 43, a second longitudinal edge 44 opposing the first longitudinal edge 43, a first lateral edge 45, and a second lateral edge 46 opposing the first lateral edge 45.

The first ground-engaging surface 41 may be provided with one or more longitudinal protrusions 47 (or ridges) generally extending along the first ground-engaging surface 41 from the first lateral edge 45 to the second lateral edge 46. Such longitudinal protrusions 47, commonly known as ‘grousers’, may function to increase the traction of the track shoe 30 in loose or soft ground by increasing contact between the first ground-engaging surface 41 and the ground. The one or more longitudinal protrusions 47 may project from the first groundengaging surface 41 in a generally perpendicular direction. Where more than one longitudinal protrusion 47 is provided, the longitudinal protrusions 47 may be generally evenly spaced across the first ground-engaging surface 41 in a lateral direction.

The first ground-engaging surface 41 may further be provided with a recessed region 48 (visible in Figure 3) for receiving the telescopic element 60. The recessed region 48 may comprise a recess 49 extending from the first groundengaging surface 41 into the thickness of the base element 40, such that the recessed region 48 may have a second thickness 91 that may be smaller than the first thickness 90. The recess 49 may extend from the first lateral edge 45 towards (but not reaching) the second lateral edge 46, such that the recess 49 has an end wall 110. The recess 49 may be positioned between the first longitudinal edge 43 and the second longitudinal edge 44, such that the recess has opposing first and second side walls 111. The recess 49 may be positioned generally centrally between the first longitudinal edge 43 and the second longitudinal edge 44. The longitudinal protrusion(s) 47 may not be present in the recessed region 48.

The first longitudinal edge 43 of the base element 40 may be provided with an upturned lip 51. The second longitudinal edge 44 may be provided with a downturned lip 52. The upturned and downturned lips 51,52 may enable adjacent track shoes 30 to partially overlap each other when the track shoes 30 are mounted on a track system 14.

The telescopic element 60 may again be a generally planar element extending across a third thickness 95 between a second ground-engaging surface 61, which may be configured for engaging the ground, and a second link-facing surface 62, which may face the track links 25. The dimensions across the second coupling and/or second ground-engaging surfaces 61,62 may be substantially greater than the third thickness 95. The third thickness 95 of the telescopic element 60 may be substantially equal to the first thickness 90 of the base element 40. The second link-facing and/or second ground-engaging surfaces 61,62 may be substantially rectangular. The telescopic element 60 may have a third longitudinal edge 63, a fourth longitudinal edge 64 opposing the third longitudinal edge 63, a third lateral edge 65, and a fourth lateral edge 66 opposing the third lateral edge 65. A width of the telescopic element 60 may be substantially equal to a width of the shoe plate 4; that is to say, the third lateral edge 65 may be substantially equally sized with the first lateral edge 45.

Like the first ground-engaging surface 41 of the base element 40, the second ground-engaging surface 61 of the telescopic element 60 may be provided with one or more longitudinal protrusions 47 (or ridges), generally extending along the second ground-engaging surface 61 from the third lateral edge 65 to the fourth lateral edge 66. The one or more longitudinal protrusions 47 may project from the second ground-engaging surface 61 in a generally perpendicular direction. The number of longitudinal protrusions 47 provided on the second ground-engaging surface 61 of the telescopic element 60 may correspond to the number of longitudinal protrusions 47 provided on the first ground-engaging surface 41 of the base element 40. The lateral spacing of the longitudinal protrusions 47 on the second ground-engaging surface 61 may correspond to the lateral spacing of the longitudinal protrusions 47 on the first ground-engaging surface 41 of the base element 40.

The telescopic element 60 may comprise a sliding section 68, which may be configured to slide within the recessed region 48 of the base element 40. The sliding section 68 may extend from the fourth lateral edge 66 in a direction towards (but not reaching) the third lateral edge 65. The sliding section 68 may have a reduced width relative to the rest of the telescopic element 60; that is to say, the fourth lateral edge 66 may be shorter than the third lateral edge 65. Thus’ the sliding section 68 may have opposing third and fourth side walls 112. Shoulders 70 may be formed at a transition point between the fourth lateral edge 66 and the third lateral edge 65, where the sliding section 68 terminates.

The reduced width of the sliding section 68 may be sized smaller than the width of the recessed region 48 of the base element 40, to provide a clearance fit between the sliding section 68 and the recessed region 48. The term ‘clearance fit’ is used herein to mean that the dimensions of a male and female part are such that a clearance or gap exists between the male and female parts when they are assembled. Thus, the sliding section 68 may be located within (and be slidable within) the recessed region 48. The lateral positioning of the reduced width of the sliding section 68 between the third lateral edge 65 and the fourth lateral edge 66 may correspond to the lateral positioning of the recessed region 48 between the first longitudinal edge 43 and the second longitudinal edge 44.

The sliding section 68 may have a fourth thickness 96, which may be less than the third thickness 95. The thickness reduction may be taken from the second link-facing surface 62 such that the second link-facing surface 62 has a stepped profile from the third lateral edge 65 to the fourth lateral edge 66. In contrast, the second ground-engaging surface 61 may be substantially continuous from the third lateral edge 65 to the fourth lateral edge 66. The sum of the fourth thickness 96 of the sliding section 68 of the telescopic element 60 and the second thickness 91 of the recessed region 48 of the base element 40 may be substantially equal to the first and third thicknesses 90,95 of the base element 40 and the telescopic element 60.

As for the first and second longitudinal edges 45,46 of the base element 40, the third longitudinal edge 63 may be provided with an upturned lip 51 and the fourth longitudinal edge 64 may be provided with a downturned lip 52.

The track shoe 30 may be assembled by coupling the telescopic element 60 to the base element 40 by receiving the sliding section 68 of the telescopic element 60 into the recessed region 48 of the base element 40. In the present disclosure the term “coupled” means two parts contacting each other, such as one part resting on another part, and does not connote or imply any form of attachment. The track shoe 30 may be arranged in a fully retracted state (as illustrated in Figure 2) by sliding the sliding section 68 of the telescopic element 60 into the recessed region 48 of the base element 40 in a longitudinal direction 120 as far as possible, such that the shoulders 70 of the telescopic element 60 abut the first lateral edge 45 of the base element 40. The span of the track shoe 30 may be increased from the fully retracted state up to a fully extended state extended state (shown in Figure 3), by sliding the sliding section 68 of the telescopic element 60 out of the recessed region of the recessed region 48 of the base element 40 in the longitudinal direction 120.

The track shoe 30 may be provided with a plurality of apertures 50,69 for receiving fasteners 80 (for example, bolts) for coupling the track shoe 30 to the two corresponding track links 25 of a track link box 27. The apertures 50,69 may be through-holes, such that a fastener 80 may pass through each aperture 50,69 in the track shoe 30 to be secured in a track link 25 below it. In particular, at least one aperture 50,69 may be provided for coupling the track shoe 30 to each of the corresponding track links 25 of a track link box 27. Optionally, two or more apertures 50,69 may be provided for coupling the track shoe 30 to each of the corresponding track links 25 of a track link box 27. The apertures 50,69 may be located in the recessed region 48 of the base element 40 and in the sliding section 68 of the telescopic element 60, with the base element 40 having first apertures 50 and the telescopic element 60 having second apertures 69. The respective first and second apertures 50,69 may co-axial such that a fastener 80 may pass first through the telescopic element 60, then through the base element 40, and into the track link 25.

The apertures 50,69 may be positioned to enable the track shoe 30 to be mounted on a track link box 27 at a first predetermined span (or extension) of the track shoe 30. Optionally, additional apertures 50,69 may be provided to enable the track shoe 30 to be mounted on a track link box 27 at a second further predetermined span (or extension) of the track shoe 30. Optionally, additional further apertures 50,69 may be provided to enable the track shoe 30 to be mounted on a track link box 27 at one or more further predetermined spans (or extensions) of the track shoe 30. The apertures 50,69 for the first predetermined span of the track shoe 30 may be referred to as a first ‘set’ of apertures 50,69. The apertures 50,69 for the second predetermined span of the track shoe 30 may be referred to as a second set of apertures 50,69. The apertures 50,69 for the further predetermined span of the track shoe 30 may be referred to as further sets of apertures 50,69. The track shoe 30 may be appropriately sized such that the span of the track shoe 30 may be varied as required. For example, the track shoe 30 may be sized such that the span of the track shoe 30 may be adjustable from a first predetermined span of 600mm to a second predetermined span of 790mm. In this case, a first set of apertures 50,69 may be positioned for mounting the track shoe 30 with a span of 600mm, and a second set of apertures may be positioned for mounting the track shoe 30 with a span of 790mm. Optionally, further sets of apertures may be positioned for mounting the track shoe 30 with a span of between 600mm and 790mm. Of course, there are many possibilities of track shoe 30 span variations, which may be determined by the intended use and ground conditions.

Retaining means (which may also be referred to as ‘guiding means’) may be provided for retaining the base element 40 and the telescopic element 60 in the same plane as the track shoe 30 is extended, by guiding the extension of the telescopic element 60. The retaining means may comprise a longitudinal tongue 100 extending generally perpendicularly from at least one of the opposing first and second side walls 111 of the recessed region 48 of the base element 40, or from at least one of the opposing third and fourth side walls 112 of the sliding section the sliding section 68 of the telescopic element 60, with a complementary longitudinal groove 101 in the respective corresponding side wall of the telescopic element 60 or the base element 40. When the track shoe 30 is assembled by sliding the sliding region 68 of the telescopic element 60 into the recessed region 48 of the base element 40, the longitudinal tongue 100 slides within the longitudinal groove 101. The longitudinal tongue 100 may be sized smaller than the longitudinal groove 101, to provide a clearance fit between the longitudinal tongue 100 and the longitudinal groove 101. As is depicted in the embodiment of Figures 2 to 5, the first side wall 111 of the base element 40 may be provided with the longitudinal tongue 100 and the corresponding third side wall 112 of the telescopic element may be provided with the longitudinal groove 101. In an alternative embodiment, both of the first and the second side walls 111 of the base element and both of the third and fourth side walls 112 of the telescopic element 60 may be provided with retaining means. The base element 40 and the telescopic element 60 may each be provided with a corresponding chamfered edge 113 where the fourth lateral edge 66 of the telescopic element 60 abuts the end wall 110 of the recess 49 of the base element 40. The corresponding chamfered edges 113 of the base element 40 and the telescopic element 60 may together form a V-shaped notch. The chamfered edges 113 may be formed at any angle. Optionally, the chamfered edges 113 may have a draft angle (that is, angle to a plane perpendicular to the first/second ground engaging surface 41,61) in a range of 2 degrees to 11 degrees. Optionally, the chamfered edges 113 may have a draft angle in a range of 5 degrees to 8 degrees. In the embodiment of Figures 2 to 5, the corresponding chamfered edges 113 of the base element 40 and the telescopic element 60 are provided on one of the longitudinal protrusions 47. In an alternative embodiment, corresponding chamfered edges 113 of the base element 40 and the telescopic element 60 may be provided on more than one of the longitudinal protrusions 47. In a further alternative embodiment, corresponding chamfered edges 113 of the base element 40 and the telescopic element 60 may be provided along at least a part of the fourth lateral edge 66 of the telescopic element 60 and the end wall 110 of the recess 49 of the base element 40.

Although a specific embodiment has been described, the skilled person will consider various adjustments and/or modifications, in addition to modifications described above. For example, the recess 49 may extend across the full width of the base element 40, from the first longitudinal edge 43 to the second longitudinal edge 44, such that the recess 49 has no side walls 111. In such an embodiment, the sliding section may have an equal width relative to the rest of the telescopic element 60; that is to say, the fourth lateral edge 66 may be of substantially equal length to the third lateral edge 65.

Industrial Applicability

The track shoe has industrial applicability in the field of work machines, and particularly in the field of work machines having ground-engaging track systems. In use, the assembled track shoe 30 may be adjusted to a desired predetermined span (for example, based on the ground conditions) by sliding the telescopic element 60 within the base element 40. At the predetermined spans, first apertures 50 in the base element 40 and second apertures 69 in the telescopic element 60 align for any apertures 50,69 of the relevant set of apertures where the sliding section 68 of the telescopic element 60 overlies the recessed region 48 of the base element 40. The track shoe 30 may then be mounted on a track link box 27 by inserting fasteners 80 through the relevant apertures 50,68 for the required span, and into the track links 25 below (as shown in Figure 8). If the relevant set of apertures 50,69 comprises any second apertures 69 in the sliding section 68 of the telescopic element 60 not overlying the recessed region 48 of the base element 40, a spacer 130 having a thickness substantially equal to the second thickness 91 of the recessed region 48 may be inserted between the sliding section 68 of the telescopic element 60 and the track link 25. The spacer 130 may, for example, comprise a washer. Where the fasteners 80 comprise bolts, a nut (not shown) may be used to secure each bolt.

If there is a desire to increase or decrease the span of the track shoe 30 post-assembly (such as if the work machine will be used for different ground conditions), this may be achieved by removing the fasteners 80 from the set of apertures 50,69 for the currently selected predetermined span of the track shoe 30, sliding the telescopic element 60 within the base element 40 to the now desired predetermined span of the track shoe 30, and then securing the fasteners 80 in the relevant set of apertures 50,69 for that span.

When the track shoe 30 is mounted and used in a fully retracted state, packed material and debris may become lodged between the sliding section 68 of the telescopic element 60 and the recessed region 48 of the base element 40. The packed material may create disengagement-resisting forces, including frictional forces, that oppose movement of the telescopic element 60 relative to the base element 40 in the longitudinal direction 120 to extend the span of the track shoe 30. In such a case, a pry tool (not shown) may be engaged with the V-shaped notch formed by the corresponding chamfered edges 113 of the base element 40 and the telescopic element 60, to aid in prying the telescopic element 60 away from the base element 40.

By virtue of being able to adjust the span of the track shoe 30, the width of an assembled track 14 of a work machine 10 can be modified to cater to differing ground conditions, without requiring multiple sets of track shoes. Thus a single set of track shoes 30 may cater to a variety of required track 14 widths, obviating the need for multiple sets of track shoes 30 and thereby reducing costs. Furthermore, the adjustment process may be carried out without removing the track shoes 30 from the respective track link boxes 27; this may reduce the time required to change the width of a track 14 (relative to replacing each track shoe with a different track shoe of the required span), thereby saving time and reducing costs.

Claims

1. A track shoe for a work machine, the track shoe comprising: a base element having a first thickness extending between a first ground-engaging surface and an opposing first link-facing surface; and a telescopic element having a third thickness extending between a second ground-engaging surface and an opposing second link-facing surface, wherein: the telescopic element is coupled to the base element; and the telescopic element is slidable with respect to the base element to adjust a span of the track shoe between a fully retracted state and a fully extended state; wherein the first ground-engaging surface of the base element comprises a recessed region, the recessed region having a second thickness smaller than the first thickness; and the telescopic element comprises a sliding section, the sliding section having a fourth thickness smaller than the third thickness, wherein the thickness reduction is taken from the second link-facing surface; and the sliding section is slidable within the recessed region.

2. A track shoe according to claim 1, wherein the first thickness is substantially equal to the third thickness, and wherein the sum of the second thickness and the fourth thickness is substantially equal to the first thickness and the third thickness.

3. A track shoe according to claim 2, wherein the track shoe comprises a first set of apertures for mounting the track shoe on a track link box at a first predetermined span.

4. A track shoe according to claim 3, wherein the track shoe comprises a second set of apertures for mounting the track shoe on a track link box at a second predetermined span.

5. A track shoe according to claim 4, wherein the track shoe comprises one or more further sets of apertures for mounting the track shoe on a track link box at one or more further predetermined spans.

6. A track shoe according to any one of claims 3 to 5, wherein the apertures comprise first apertures in the recessed region of the base element and second apertures in the sliding section of the telescopic element.

7. A track shoe according to any one of the preceding claims, further comprising retaining means for retaining the base element and the telescopic element in a single plane as the track shoe is extended and retracted.

8. A track shoe according to claim 7, wherein the retaining means comprises a longitudinal tongue projecting from at least one side wall of the recessed region or from at least one side wall of the sliding section, and a complementary longitudinal groove in the corresponding side wall of the sliding section or the recessed region, respectively.

9. A track shoe according to any one of the preceding claims, wherein at least a part of abutting portions of the base element and the telescopic element comprise corresponding chamfered edges, wherein the corresponding chamfered edges together form a V-shaped notch.

10. A track shoe according to claim 9, wherein each of the corresponding chamfered edges has a draft angle in a range of 2 degrees to 11 degrees.

11. A track shoe according to any one of the preceding claims, further comprising at least one grouser extending from each of the first and second ground-engaging surfaces.

12. A track shoe according to any one of the preceding claims, wherein a first longitudinal edge of the track shoe comprises an upturned lip, and a second opposing longitudinal edge of the track shoe comprises a downturned lip.

13. A ground-engaging track for a work machine, the track comprising: two parallel track chains, each track chain comprising a plurality of track links coupled together in an end-to-end arrangement, wherein corresponding track links of the two parallel track chains are coupled together to form a plurality of track link boxes; and a track shoe according to any one of the preceding claims mounted on at least one of the track link boxes.

14. A work machine comprising the ground-engaging track of claim 13.