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  
       [0001]     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  
       [0002]     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.  
         [0003]     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.  
         [0004]     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.  
         [0005]     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.  
         [0006]     Other advantages and objects of the invention may be seen in the details of the ensuing description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The invention is described in conjunction with the attached illustrations described briefly below.  
         [0008]      FIG. 1  is a fragmentary perspective view of an excavator bucket and showing a boss-equipped lip at the lower left.  
         [0009]      FIG. 1A  is a front view of an alternate wear member.  
         [0010]      FIG. 2  is a cross sectional view along line  2 - 2  applied to  FIG. 1 .  
         [0011]      FIG. 3  is a fragmentary top plan view of the wear member of  FIG. 2 .  
         [0012]      FIG. 4  is an enlarged fragmentary sectional view of a lip equipped with a modified boss.  
         [0013]      FIG. 5  is a bottom view of a wear member on a lip and provided with a stabilizer.  
         [0014]      FIG. 5A  is a perspective view of a rear portion of the bottom leg of the wear member.  
         [0015]      FIG. 5B  is an enlarged cross sectional view of the portion noted in circle  5 B in  FIG. 2 .  
         [0016]      FIG. 6  is an enlarged fragmentary transverse sectional view taken along the sight line  6 - 6  applied to  FIGS. 2 and 3 .  
         [0017]      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 .  
         [0018]      FIG. 8  is a view similar to  FIG. 7  but with the inventive lock installed and in the process of removal.  
         [0019]      FIG. 9  is a view similar to  FIG. 8  but with the lock in a subsequent position incident to removal.  
         [0020]      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  
       [0021]     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).  
         [0022]     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).  
         [0023]     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  30 A is provided with a single upper leg  31 A 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.  
         [0024]     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.    
         [0025]     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.    
         [0026]     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.  
         [0027]     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.  
         [0028]     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 .  
         [0029]     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 .  
         [0030]     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 .  
         [0031]     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 .  
         [0032]     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.  
         [0033]     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.  
         [0034]     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.  
         [0035]     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.  
         [0036]     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 .  
         [0037]     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 ,  5 A, and  5 B). 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.  
         [0038]     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.  
         [0039]     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.  
         [0040]     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 .  
         [0041]     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 .  
         [0042]     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.  
         [0043]     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 .  
         [0044]     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 .  
         [0045]     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.  
         [0046]     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.