US20060225313A1

US20060225313A1 - Wear assembly

Info

Publication number: US20060225313A1
Application number: US11/401,773
Authority: US
Inventors: Robert McClanahan; Adam Stitzel
Original assignee: Esco Corp
Current assignee: Esco Corp
Priority date: 2005-04-12
Filing date: 2006-04-11
Publication date: 2006-10-12
Also published as: AU2006201511A1

Abstract

A wear assembly for excavating equipment which has a wear member overlying a leading edge of the excavating equipment, a removable lock for releasably holding the wear member to the leading edge, and a stabilizer, wherein (i) the wear member has a pair of legs to straddle the leading edge with a first leg extending along a first side of the leading edge and a second leg extending along a second side of the leading edge opposite the first side, (ii) the first leg has an opening for receiving the lock and a second leg free of such locks, and (iii) the stabilizer is fixed to the second side of the leading edge and includes a holding surface to overlie a portion of the second leg to prevent the second leg from moving away from the second side of the leading edge.

Description

FIELD OF THE INVENTION

This invention relates to a wear assembly and, particularly, to a replaceable assembly for protecting a leading edge or edges of a bucket or other earth engaging equipment.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention finds utility in connection with excavating equipment, for example, along the leading edge of a dragline bucket, front end loader, face shovel, etc. In many instances the bucket may be equipped with transversely spaced excavating teeth to facilitate earth penetration. In the past, many operators have found it advantageous to protect both the bucket lip between the teeth and the bucket wings. One example of such a construction is disclosed in co-owned U.S. Pat. No. 3,621,594 marketed by ESCO Corporation of Portland, Oreg., U.S.A. under the trademark “ZIPPER LIP.” Another type of lip wear edge can be seen in co-owned U.S. Pat. No. 3,865,177. Other patents dealing with lip wear edges are U.S. Pat. Nos. 3,995,384 and 4,748,754. Other protective shrouds can be seen in co-owned U.S. Pat. Nos. 3,171,500; 4,129,934; 4,932,478; and 5,088,214.
In this industry, it is advantageous for wear members to possess the conflicting goals of being reliably locked in place during operation yet being easily replaced when worn. The arduous environments and especially the ever present shock loads hinder the realization of these contradictory goals. It is also beneficial to keep the weight of the wear members to a minimum in order to maximize the potential carrying weight of the buckets. Further, it is generally desirable to limit costs, difficulties of use, and risks of failure.
Many of the disadvantages of the prior art were largely overcome through the provision of a generally U-shaped wear member that fits over the digging edge or the like and includes a slot in one of the legs for receipt of a boss fixed to a face of the excavator such as disclosed in U.S. Pat. No. 5,088,214, hereby incorporated by reference. In this construction, the wear member is equipped with an opening adjacent the rear end for the receipt of a lock which resists forward or disengaging movement and which is not subject to deterioration due to heavy, cyclic loadings. The bottom leg freely extends along the bottom of the lip and helps with the upper leg to hold the lip and thereby resist the loads applied to the front of the wear member. This construction is reliable, easy to assemble and replace, and requires minimal parts. It has been found, however, that under heavy loading, particularly heavy loads applied upward against the bottom of the wear member, that high stresses can be found in the top leg of the wear member. Such loading can lead to a shortened useable life for the wear member and even breakage.
To improve on this assembly, a stabilizer is provided to restrain the lower leg of the wear member, which previously freely extended along the bottom of the bucket. In this way, the stress in the wear member can be reduced in a simple, cost-effective, and low-weight manner. While leg restraints have been used in past assemblies, they have been limited to use facilitating the interaction of the lock and the leg. See, for example, U.S. Pat. Nos. 5,553,409; 5,052,134; and 3,736,664.
Other advantages and objects of the invention may be seen in the details of the ensuing description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in conjunction with the attached illustrations described briefly below.
FIG. 1 is a fragmentary perspective view of an excavator bucket and showing a boss-equipped lip at the lower left.
FIG. 1A is a front view of an alternate wear member.
FIG. 2 is a cross sectional view along line 2-2 applied to FIG. 1.
FIG. 3 is a fragmentary top plan view of the wear member of FIG. 2.
FIG. 4 is an enlarged fragmentary sectional view of a lip equipped with a modified boss.
FIG. 5 is a bottom view of a wear member on a lip and provided with a stabilizer.
FIG. 5A is a perspective view of a rear portion of the bottom leg of the wear member.
FIG. 5B is an enlarged cross sectional view of the portion noted in circle 5B in FIG. 2.
FIG. 6 is an enlarged fragmentary transverse sectional view taken along the sight line 6-6 applied to FIGS. 2 and 3.
FIG. 7 is a view similar to FIG. 6, but with parts omitted and as would be seen along the sight line 7-7 applied to FIG. 1.
FIG. 8 is a view similar to FIG. 7 but with the inventive lock installed and in the process of removal.
FIG. 9 is a view similar to FIG. 8 but with the lock in a subsequent position incident to removal.
FIG. 10 is a perspective view of a wear member of the prior art as described in U.S. Pat. No. 5,088,214.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, numeral 20 designates generally a bucket having sidewalls or wings as at 21 equipped with a forwardly-facing protector 22, and a rear wall 23 merging into a bottom wall 24. The bottom wall 24 terminates in a forwardly positioned lip 25. The sidewalls and lip form a leading edge to the bucket. This is, of course, simply one example of an excavator which can be provided with a wear assembly in accordance with the present invention. The present invention could be used with other kinds of buckets or other digging equipment (e.g., dredge cutterheads).
The lip 25 is equipped with transversely spaced-apart excavating teeth generally designated 26 (see the lower right), each of which preferably includes an adapter 27 fixed to the lip 25 and a point or tip 28 releasably mounted on each adapter 27. The portions of the lip 25 between the teeth are protected by wear members 30 mounted to the lip through cooperation with upstanding bosses 29 (see the lower left).
As can be seen in FIG. 2, the wear member 30 is generally U-shaped having a longer upper or inner leg 31 in confronting relation with the upper or inner face 25 a of the lip 25 and a lower or outer shorter leg 32 in confronting relation with the lower or outer face 25 b of the lip 25. Of course, the upper leg could be shorter or have the same length as the lower leg. In the illustrated example, the legs 31, 32 are connected by a forwardly projecting connecting portion 33 which is generally aligned with the lip 25 and preferably includes a cutting or penetrating edge as at 34 (see also FIG. 1). In FIG. 1, the upper leg 31 of shroud 30 is split so as to include two branches each adapted to receive a boss 29. In a preferred alternative (FIG. 1A), the wear member 30A is provided with a single upper leg 31A adapted to receive a single boss (not shown). In either construction, the lower leg is preferably formed as a single unified leg. While the invention is particularly well suited for use as a shroud, other wear members could be secured via concepts of the present invention.
The boss 29 (again referring to FIG. 1) is, in a preferred construction generally T-shaped and advantageously welded to the lip 25. Alternatively, it may be integrally cast or bolted to the upper face 25 a (compare FIGS. 6 and 4, respectively). In addition, the boss may have other configurations besides a T-shape, such as dovetailed or having other arrangements of rails. The boss may also have a parallelepiped shape with no rails. The boss may have any of a variety of shapes so long as it provides a rearwardly facing surface against which the lock abuts to hold the wear member to the excavator. While the boss is preferably mounted on inner face 25 a, it could alternatively be fixed to outer face 25 b.
In the illustrated embodiment (see FIG. 6), the inner surface 36 of each upper leg 31 (i.e., the surface that faces the lip 25) is equipped with the slot 35 to develop an advantageous longitudinal rearward mounting movement of the wear member 30 on the boss 29. For this purpose, the slot in each upper leg 31 opens in the rear wall of the leg to define opening 37 at the rear end thereof (see FIG. 3) to ensleevingly receive the boss 29. In the illustrations, the slot has a T-shaped configuration to match the boss. If the boss is provided with dovetails, no rails or other shapes, the slot is preferably shaped to have the corresponding configuration. Also, although the slot is provided in the upper leg 31, it could alternatively be provided instead in the lower leg 32 if the boss is fixed to the outer surface 25 b.
To accommodate the locking of the wear member 30 in place on the lip 25, a lock generally designated 38 is provided. In the illustrated embodiments, the lock 38 is mounted in a transversely enlarged opening 39 (compare FIGS. 2 and 3 with FIG. 7) in the outer or top surface 40 of the leg 31. The opening 39 communicates with the slot 35 and is positioned a spaced distance rearwardly of the cutting edge 34 and forwardly of the opening 37 so as to be aligned with the rear end 41 of the boss 29 (see FIG. 2). Nevertheless, many other locking arrangements could be used than is disclosed. For example, the opening may have different shapes, be in different locations, open to receive the lock laterally, or be an opening that is not enclosed on all sides. Irrespective of the actual boss and lock construction, the wear assembly includes a generally U-shaped wear member that includes a pair of legs that straddle an edge (e.g., a digging edge) of an excavator. One of the legs (regardless of whether it is split or unified) cooperates with a boss and includes an opening to receive a lock that holds the wear member in place. The opposite leg extends freely over the other side of the lip or other edge without a lock or boss. In the preferred construction, the opposite leg without the lock is on the underside or outside of the bucket to avoid the wear and tear on the lock that occurs on the outside of the bucket.
In the illustrated embodiments, the lock 38 is formed of a steel casting or block 42. Each is intended to fit within an opening 39 in the fashion illustrated in FIG. 8. The lock block 42 is relatively elongated transversely of each leg 31 and is equipped with a slot 43 at one end and an arcuate surface 44 at the other end. Received within the slot 43 is a latch assembly generally designated 45 (see FIG. 8) which includes a rubber or elastomeric body 46 bonded to a steel latch element 47. The slot 43 is centrally longitudinally recessed top and bottom as at 48 to receive upstanding and depending ribs 49 on the latch assembly 45. Additionally, the slot 43 has an inner end of partially arcuate nature as at 50 so as to receive a similarly contoured portion 51 on the latch assembly 45. Alternatively, the lock and latch arrangement can be manufactured as one unit using a substantially non-compressible but flexible material such as rubber to be confined in the opening 39. Moreover, as noted above, other locks and other lock arrangements could be used to cooperate with one of the legs to hold the wear member to the excavator.
For the illustrated embodiment, the basic steps of lock removal are shown in FIGS. 8 and 9. In FIG. 8, it is seen that the latch element 47 is positioned under a keeper means or tab 52 provided in the confronting sidewall 53 of the opening 39 (see FIG. 7). The sidewall 53 in addition to providing the keeper means 52 is slotted as at 54 (see FIG. 3) to permit the insertion of a screwdriver tip (or other tool) illustrated at 55 in FIG. 8. The other sidewall 56 of the opening 39 is equipped with an arcuate protrusion as at 57 which is normally confronted by the arcuate recess 44 of the lock block 42 so as to provide a pivot for the block 42.
Upon pivoting upward movement of the screwdriver tip to the position 55′ illustrated in FIG. 9, the rubber body 46 is resiliently deformed so as to retract or upset (in effect) the latch assembly 45 and this action enables the latch element 47 to pass by the keeper means 52.
It will be appreciated that installation of the wear member is accomplished by following the reverse of the steps illustrated—the latch assembly 45 is retracted upon engaging the ramp or sloping wall 57 (see FIG. 7) of the keeper means 52 and thereafter snaps in place as it goes “over center” past the keeper means 52 to assume the configuration depicted in FIG. 8.
In operation, the lock 38 including the block 42 and latch assembly 45 is not adversely stressed by impact loads or forces as in the prior art. The lock 38 remains confined between the rear wall 41 of the boss 29 and the rear wall 58 of the opening 39. This places the steel block 42 in compression but does not affect the latch assembly 45. Any stress on the latch assembly 45 merely shifts the latch element 47 under the keeper means 52.
The block 42 in the illustrated embodiment is equipped with longitudinally extending flanges as at 59 (see FIG. 10) which are received within similarly contoured recesses 60 in the top wall 40 of the wear member 30 (see also FIG. 7). These elements 59-60 enable the proper positioning of the lock 38 within the opening 39. These elements 59-60 are, however, unnecessary and are preferably excluded.
Under loading, the wear element 30 can be subjected to various force components and in resisting these, the invention provides advantages not found in the prior art. For example, there may be a sizable positive thrust component T-see the left hand portion of FIG. 2. With the inventive construction there is no deformation of the boss 29. This stems from the fact that this component extends longitudinally, i.e., the surfaces 29 a, 29 b on the boss 29 and confronting surfaces 35 a, 35 b in the wear member slot 35 extend longitudinally so as not to affect the bearing therebetween.
The provision of the slot 35 in combination with the similarly contoured boss 29 makes possible advantageous installation and operation. By the straightforward rearward sliding movement of the wear member 30 on the boss 29, there is no need for any pivoting movement and this, in itself, makes possible for longer lower legs 32, according to intended design and usage. Also, by providing a relatively elongated bearing area between the boss 29 and the wear member 30, shock loads and other impacts can be readily transmitted from the portion 33 to the lip 25. This also provides an advantageous lateral stabilization but without the need for extensive locks or secondary surfaces.
On the other hand, there may be a substantial negative thrust, viz., a vector extending in the opposite direction to that depicted at T in FIG. 2. This is not an unusual occurrence—resulting, for example, from back drag. In such a situation, the lock 38, is subjected to compression which, in the case of the resilient locks of the prior art, results in cyclic deformation and possible premature failure.
In contrast, the invention provides for heavy loading and high compressive stresses on the lock generally designated 38 as a result of reaction forces resulting from normal operative loads at the leading edge of the wear member 30.
Still further, the loading on the wear element 30 may produce a vertical component, viz., one at right angles to the vector T, such as vector F (FIG. 2). In accordance with the present invention, the lower side of the bucket or other excavator (i.e., the side opposite the boss and lock irrespective of whether it is the lower side) is provided with a stabilizer 70 to restrain movement of the free leg 32 (i.e., the unlocked leg) away from the bucket during such vertical loading (FIGS. 2, 5, 5A, and 5B). In one preferred embodiment, the stabilizer is welded W, but could be cast, bolted, or otherwise fixed to the surface of the bucket. The stabilizer includes a ledge or holding surface 72 that overlies the face 25 b of lip 25. A grip portion 74 formed on the rear end 76 of leg 32 is adapted to be slipped under ledge 72. The grip portion 74 is preferably defined as a reduced thickness portion at the rear end of leg 32 to minimize the extension of the stabilizer from the bucket, but it could have other configurations. As seen in FIG. 5B, leg 32 tends to shield stabilizer 70 during use. To facilitate sliding together of the wear member and the stabilizer, the grip portion 74 and ledge 72 are preferably formed to have inclined complementary contact surfaces 78, 80. Nevertheless, other arrangements could be used such as, for example, contact surfaces that are not inclined, or a grip portion that is simply the rear end of the leg 32 without any special configuration, or a leg that includes a tab that fits into a cavity in a solid block stabilizer.
When a vertical load is applied to the underside of the wear member, such as F, the load in wear member of the prior art (i.e., as described in U.S. Pat. No. 5,088,214) is primarily resisted by the U-shaped configuration of the wear member straddled about the digging edge of the bucket. Under heavy loading, high levels of stress can develop in the upper leg, i.e., the leg with the lock. To reduce this stress, the stabilizer prevents the bottom leg from swinging outward away from the bottom of the bucket and thereby provides additional support to resist such loading. Moreover, this additional support is provided without a substantial increase in the weight, complexity or cost of the wear assembly.
The invention provides positive but releasable retention of a protective wear member to the leading edge of a bucket lip or bucket wings or sidewalls—these latter also having wearable edges like the bucket lip.
The invention also finds advantageous application to the sides or wings 21 as well as other earth-engaging edges of an excavator. As previously pointed out relative to FIG. 1, the wing 21 is covered by the protector 22.
The wear member 22 is again seen to be generally U-shaped but in this embodiment has legs which are substantially of the same length in proceeding rearwardly from the forward connecting portion 33.
Exemplary of the invention is a wear member utilized to protect the leading edge of a large front end loader bucket lip. Protection of earth-engaging bucket lips is a constant maintenance problem and many forms of protection have been utilized over the years. Normally, wear edge protectors are welded, bolted, or mechanically attached. The most desirable designs are those that are mechanically attached and easy to install and remove. Although the structure is illustrated for a front end loader lip and wings, variations of this design could be utilized on face shovels, cable shovels, draglines and other earth moving equipment.
The invention includes an easily changeable wear member 30 with one or more rearwardly projecting portions or legs 31. As illustrated, the leg 31 includes a T-shaped longitudinally extending slot 35 which engages a mating or similarly contoured boss 29. The required number of bosses may either be bolted or welded to the lip or integrally cast therewith. The rearward sliding of the wear member on the lip also places grip portion 74 under ledge 72 of the stabilizer 70.
The wear member 30 is releasably held in position by means of a lock 38 installed in an opening 39 (see FIG. 3) in each leg 31. The opening 39 is located rearwardly of the rear end of the boss 29. Thus, when a lock 38 is installed into each opening 39, the wear member 30 is prevented from moving off of the lip 25. Conversely, removal of each lock 38 allows easy disassembly of the wear member 30 from the lip 25.
In the illustrated embodiment, the lock opening 39 has an arcuate protrusion 57 (see FIG. 7) at the upper edge normal to the leading edge or forward wall of the opening 39. The arcuate protrusion 57 serves as a pivot point for installation of the lock as illustrated in FIG. 9. The sidewall 53 opposite to that equipped with the arcuate protrusion 57 is equipped with a tab or keeper means 52 which retains the latch assembly 45 in place-until the rubber body 46 is deformed under the influence of a screw driver tip 55 so as to permit passage of the latch element 47 past the keeper means 52. By providing the keeper means to the side, i.e., laterally offset from the slot 35, the latch assembly 45 is not substantially subjected to adverse stresses yet is advantageously located for easy replacement.
While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A wear assembly for excavating equipment comprising a wear member overlying a leading edge of the excavating equipment, a removable lock for releasably holding the wear member to the leading edge, and a stabilizer, wherein (i) the wear member has a pair of legs to straddle the leading edge with a first leg extending along a first side of the leading edge and a second leg extending along a second side of the leading edge opposite the first side, (ii) the first leg has an opening for receiving the lock and a second leg free of such locks, and (iii) the stabilizer is fixed to the second side of the leading edge and includes a holding surface to overlie a portion of the second leg to prevent the second leg from moving away from the second side of the leading edge.

2. A wear assembly in accordance with claim 1 further including a boss fixed to the first side of the leading edge, and a slot within the first leg to receive the boss.

3. A wear assembly in accordance with claim 2 wherein the stabilizer includes a ledge to define the holding surface, and the second leg of the wear member includes a reduced-width grip portion to receive and cooperate with the ledge of the stabilizer.

4. A wear assembly in accordance with claim 3 wherein the grip portion is formed in a rear end of the first leg.

5. A wear assembly in accordance with claim 2 wherein the wear member is a shroud for a lip of a bucket.

6. A wear assembly in accordance with claim 1 wherein the stabilizer includes a ledge to define the holding surface, and the second leg of the wear member includes a reduced-width grip portion to receive and cooperate with the ledge of the stabilizer.

7. A wear assembly in accordance with claim 6 wherein the grip portion is formed in a rear end of the first leg.

8. A wear assembly in accordance with claim 1 wherein the wear member is a shroud for a lip of a bucket.

9. A bucket having sidewalls, a rear wall, a bottom wall having a lip defining a leading edge, and a wear assembly in accordance with claim 1.

10. A wear member for overlying a leading edge of excavating equipment, the wear member comprising a pair of legs to straddle the leading edge with a first leg extending along a first side of the leading edge and a second leg extending along a second side of the leading edge opposite the first side, the first leg having an opening for receiving a lock to releasably hold the wear member to the leading edge, the second leg being free of such locks and including a reduced-width grip portion to receive and cooperate with a stabilizer fixed to the second side of the leading edge to overlie the grip portion to prevent the second leg from moving away from the second side of the leading edge.

11. A wear member in accordance with claim 10 further including a slot within the first leg to receive a boss fixed to the first side of the leading edge.

12. A wear member in accordance with claim 11 wherein the grip portion is formed in a rear end of the first leg.

13. A wear assembly in accordance with claim 12 wherein the wear member is a shroud for a lip of a bucket.

14. A wear member in accordance with claim 10 wherein the grip portion is formed in a rear end of the first leg.

15. A wear assembly in accordance with claim 10 wherein the wear member is a shroud for a lip of a bucket.