Wear member for earth working equipment

Abstract

A wear member for protecting a portion of an excavation bucket, the wear member including: a first leg portion extending in a longitudinal direction and having an outer surface and an inner surface and a lock hole passing through the outer and inner surfaces; a second leg portion spaced apart from the first leg portion and extending longitudinally, the second leg portion having an inner surface, wherein the first and second leg portions converge to a front end portion having an inner surface, the inner surfaces of the first and second leg portions and the inner surface of the front end portion forming a recess for receiving the portion of the excavation bucket; and a tunnel extending transversely through the front end portion of the wear member and forward of the inner surface of the front end portion.

Description

WEAR MEMBER FOR EARTH WORKING EQUIPMENTTECHNICAL FIELD

[0001] The present invention relates to wear members for earth working equipment, and in particular, a shroud, for an excavation bucket.BACKGROUND ART

[0002] During mining and / or construction operations, replaceable wear members are typically used to protect earth working equipment, such as excavation buckets. During use, the wear members gradually wear down due to the abrasive conditions and heavy loading. Once depleted, the wear members are removed from the equipment and replaced. Using wear members provides a cost-effective approach to digging and other earth working operations because it lessens the need of having to repair or replace the more expensive underlying equipment such as a lip of a bucket.

[0003] A wear member such as a shroud is commonly used to protect the digging, or lip portion and sides of an excavation bucket. Shrouds are commonly secured to bucket. In some examples, by mechanical means (for example, a lock pin, bolt, or other fastening mechanism). In other examples, shrouds are secured to the bucket by welding. During earth working operations, the shrouds may be subjected to a variety of directional forces, which can include axial, vertical, and lateral loads.

[0004] High hardness alloys are desirable for wear members as they provide durability, wear resistance, and improved performance in challenging conditions such as earth working equipment. However, higher hardness may lead to manufacturing difficulties such as cracking and / or breakages.SUMMARY OF THE INVENTION

[0005] This summary is provided to introduce a selection of concepts that are further described in the detailed description below.

[0006] One example of the present disclosure provides a wear member to protect a portion of an excavation bucket. The wear member may be a shroud mounted to the lip portion and secured in place using a mechanical lock. The wear member includes a first leg portion extending in a longitudinal direction and having a top, or outer surface and a bottom, or inner surface, and a lock hole passing through the outer and inner surfaces. The wear member also includes a second leg portion spaced apart from the first leg portion and extendinglongitudinally. The second leg portion has a top, or inner surface and a bottom, or outer surface. The leg portions converge at one end to form a front portion having an inner surface. The inner surfaces of the leg portions and the inner surface of the front end portion form a cavity, or recess for receiving the lip portion of the excavation bucket. The wear member includes a tunnel extending transversely through the front end portion and forward of the inner surface of the front end portion.

[0007] Preferably, the shroud includes two openings located on opposing sides of the front end portion, wherein the tunnel extends and connects the two openings.

[0008] Still preferably, each opening has a first diameter, and the tunnel has a second diameter, different from the first diameter.

[0009] In one example the tunnel has an ovate cross section having two different radii.

[0010] In another example the tunnel has a triangular cross section with rounded corners.

[0011] In one example, each opening may lie in a plane generally parallel to the leg portions.

[0012] In one example, the front portion includes opposing sides and each side includes a first surface generally perpendicular to the leg portions and a second surface inclined from the first planar surface toward the recess.

[0013] Preferably, each opening extends over both the first and second planar surfaces.

[0014] In one example each opening is ovate shaped formed by a combination of two different sized radii.

[0015] In another example each opening may have a triangular cross section with rounded corners.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0017] Figure l is a perspective partial view of a lip on an excavating bucket;

[0018] Figure 2 is a perspective view of a shroud in accordance with the present invention;

[0019] Figure 3; is a side view of the shroud in Figure 2;

[0020] Figure 4A is a front cross section of the shroud as shown in Figure 3;

[0021] Figure 4B is the front cross section of the shroud as shown in Figure 4A with a draft angle on the tunnel;

[0022] Figure 5 is a top view of the shroud in Figure 2; and

[0023] Figure 6 is a side cross section of the shroud shown in Figure 5.DESCRIPTION OF EMBODIMENTS

[0024] Referring to Figure 1, the digging edge, or lip portion 10 is the outer rim of a bucket (now shown) that suffers wear due to engaging earthen material. The lip portion 10 has a direction of advance during operation of the earth working equipment (e.g., a digging operation) that is generally in the longitudinal direction L though the lip portion 10 can be moved in many directions. The movement of the lip portion 10 during a digging operation can, e.g., be a generally linear motion, e.g., with a swinging movement (such as, e.g., with a hydraulic excavator), but other motions are also possible.

[0025] To reduce wear to the lip, a plurality of wear members, or wear assemblies, are added to the lip portion 10. The wear members may include teeth 12 and / or shrouds 14 and are typically secured to the lip portion 10 in a known manner using a lock or fastening member 16. As shown in Figure 1, the shrouds 14 are secured between adjacent teeth 12, but other configurations are possible. For example, shrouds may be situated on the wings of the bucket or may make up the entire wear protection of the lip without teeth.

[0026] The shroud 14 may be cast in an alloy with a high hardness such as between 500 and 550 Brinell at the surface. The shroud 14 includes a first leg portion 18 having an outer, or top surface 30 and an inner, or bottom surface 19, and a second leg portion 20 having an inner, or top surface 21. The first and second leg portions 18, 20 are spaced apart, converging at a front end portion 22 and extending rearwardly longitudinally. The front end portion 22 has an inner surface 23. The inner surfaces 19, 21 of the leg portions 18, 20 and the inner surface 23 of the front end portion 22, together, define a transverse cavity, channel, or recess 24 for receiving the lip portion 10 (Figure 1).

[0027] Referring to Figures 2-6, the shroud 14 includes a lock opening 26 at a rear portion 28 of the first leg portion 18. The lock opening 26 extends from the outer, or top surface 30 of the first leg portion 18 generally perpendicularly through to the cavity 24. The lock opening 26 is for receiving a fastener, or lock to releasably mechanically secure the shroud 14 to the lip portion 10 in a known manner, but other configurations are possible.

[0028] Referring to Figures 3 and 4 the shroud 14 includes a through hole, or tunnel 32 extending transversely through the front end portion 22. The tunnel 32 may be curved or angled to aid in inspection. The front end portion 22 includes opposing sides 38A and 38B. Each side 38A, 38B includes a first surface 34 generally perpendicular to the leg portions 18, 20 and a second surface 36 inclined from the first surface 34 toward the recess 24. Each side 38A, 38B includes an opening 33A, 33B, and the tunnel 32 extends between the openings 33A, 33B. Each opening 33A, 33B may extend over the two surfaces 34, 36, and may be ovate shaped having two different radii 35A, 35B (one opening 33A is shown in Figure 3). The openings 33A, 33B may be other shapes such as oval, triangular, or circular. The surfaces 34, 36 may be planar, curved, angled, or any combination of thereof.

[0029] The tunnel 32 may have a uniform cross section as illustrated in Figure 4A or may include sloped side walls 32A, 32B, or a draft angle, shown here to be about 3 degrees to aid in manufacturing as shown in Figure 4B. It should be appreciated that the draft angle more or less (such as 0 - 10 degrees) depending on manufacturing requirements. The tunnel 32 may have an ovate cross section similar to the openings 33A, 33B. In other examples, the tunnel 32 may be generally circular. The tunnel 32 may extend from the opening 35A in one side 38A to the opening 35B in the other side 38B. Other configurations are possible. For example, the tunnel 32 may converge at the center from both sides or may have any other cross sectional shapes than circular or ovate as illustrated. The two openings 33A, 33B are illustrated to be similar in size with the tunnel 32, but other configurations are possible. For example, the openings 33A, 33B may have a larger radius or dimension than the tunnel 32. As shown in Figure 6, the tunnel 32 should be large enough to reduce an inscribed sphere 40 of the casting. The inscribed sphere 40 is defined as the largest internal sphere captured within the surfaces of the front end portion 22 of the shroud 14. The tunnel 32 is positioned to reduce cracking during quenching of the front end portion 22 of the shroud 14, but other configurations are also possible. For example, the tunnel may be T-shaped, wherein a third opening extending from the tunnel 32 to the interior surface 23B of the front end portion 22 of the shroud 14. The third opening being parallel with the leg portions 20, 22 through to the cavity 24, but other exits are also foreseen. For alloys with a higher hardness, there is more martensitic transformation, and this causes higher transient stresses during quench and residual stresses in the casting which leads to breaks and cracking. The tunnel 32 reduces thethickness in the heavy area of the front end 22, resulting in less residual stresses in the casting and minimal breaks and cracking.

[0030] When the shroud 14 is installed (See Figure 1), the leg portions 18, 20 straddle the lip portion 10 and extend rearwardly along the lip portion 10, and the tunnel, or opening 32 is positioned in front of the lip portion 10. During use, the front end portion 22 contacts earthen material during the excavation process. The lock opening 26 is positioned behind a front end of the lip portion 10, and the tunnel 32 is in an area away from high contact stress areas.

[0031] Advantageously, as the shroud 14 reaches end of life, the tunnel, or opening 32 may become more visible thus acting as a wear indicator.

[0032] It will be appreciated that the foregoing describes only some embodiments of the inventions, and those skilled in the art will recognize that variations can be made to the details of the above-described examples without departing from the underlying principles of the disclosure.LIST OF REFERENCE NUMERALSLip portion 10Teeth 12Shroud 14Fastening member 16First leg portion 18Inner, bottom surface of first leg portion 19Second leg portion 20Front end portion 22Inner surface of front end portion 23Cavity or Recess 24Lock opening 26Rear portion of the first leg 28Outer or top surface of the first leg 30Through hole, tunnel, opening 32Sloped, angled side wall 32A, 32BOpenings 33A, 33BFirst surface 34Diameter of opening 35A, 35BSecond surface 36Opposing Sides 38A, 38BInscribed Sphere 40

Claims

CLAIMS1. A wear member for protecting a portion of an excavation bucket, the wear member including: a first leg portion extending in a longitudinal direction and having an outer surface and an inner surface and a lock hole passing through the outer and inner surfaces; a second leg portion spaced apart from the first leg portion and extending longitudinally, the second leg portion having an inner surface, wherein the first and second leg portions converge to a front end portion having an inner surface, the inner surfaces of the first and second leg portions and the inner surface of the front end portion forming a recess for receiving the portion of the excavation bucket; and a tunnel extending transversely through the front end portion of the wear member and forward of the inner surface of the front end portion.

2. The wear member of claim 1, wherein the shroud includes two openings located on opposing sides of the front end portion, and the tunnel extends between and connects the two openings.

3. The wear member of claim 2, wherein each opening has a first diameter and the tunnel has a second diameter, different from the first diameter.

4. The wear member of claim 1, wherein the tunnel has a generally ovate cross section.

5. The wear member of claim 1, wherein the front end includes opposing sides and each side includes a first surface generally perpendicular to the leg portions and a second surface inclined from the first planar surface toward the recess.

6. The wear member of claim 5, wherein each opening extends over both the first and second surfaces.

7. The wear member of claim 1, wherein each opening is an ovate shape formed by a combination of two different sized radii.

8. The wear member of claim 7, wherein the tunnel has an ovate cross section similar to each opening.

9. The wear member of claim 1, wherein the wear member is cast with an alloy providing a surface hardness of between 500 and 550 Brinell.

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