Replaceable wear element

An assembly of wear elements for installation on the wearable part of a structure engageable with abrasive material including a relatively elongated base element adapted to be secured to the wearable part and a relatively elongated wear element releasably, reversibly mounted on the base element, each of the elements having first and second pair of longitudinally spaced apart dovetail surfaces with one of the elements having third and fourth pairs of longitudinally spaced apart dovetail surfaces.

BACKGROUND AND SUMMARY OF INVENTION 
This invention relates to a replaceable wear element and, more 
particularly, an element for installation on the wearable part of a 
structure engageable with abrasive material. 
This invention is an improvement on co-owned U.S. Pat. No. 4,716,666. In 
that patent, a pair of spaced apart dovetails were employed to provide a 
readily replaceable wear element--as for the underside of an excavating 
bucket. The assembly of base and wearable element was intended for 
installation in only one direction. This has not served the needs of 
operators in excavating, mining, etc. where reversibility is required. 
According to the instant invention, we achieve reversibility through a 
novel duplication of dovetail surfaces which makes possible the 
utilization, for example, of a single element where previously two 
different replacement elements had to be stored. For example, in the case 
of a bucket, it is advantageous to provide a wear element that wraps 
around a corner and thus, utilizing the patent teachings, it would be 
necessary to have both right and left hand styles. Now, through the 
practice of the invention, only a single, versatile replacement element is 
needed. This is a matter of some consequence to operators because buckets 
are usually employed in primitive conditions and storage facilities 
limited. Thus, anything that reduces the number of parts to be stored is 
highly desirable. 
According to the invention, each of the base and wear elements has first 
and second pairs of longitudinally spaced apart dovetail surfaces with one 
of the elements having third and fourth pairs of longitudinally spaced 
apart dovetail surfaces and with the dovetail surfaces of the third and 
fourth pairs being interlaced with the dovetail surfaces of the first and 
second pairs. This permits reversible mounting of the four pair-equipped 
element on the two pair-equipped element. Additional details of 
construction and the advantages stemming therefrom can be seen in the 
ensuing specification.

DETAILED DESCRIPTION 
In the illustration given and with reference first to FIG. 1 which is 
entitled PRIOR ART, the symbol A designates the base element as seen in 
U.S. Pat. No. 4,716,666 and the symbol B designates the wearable 
element--in this case a runner for the underside of a dragline bucket. The 
arrow designated C shows the path through which the element B is moved in 
being installed on the base element A, i.e., it is first moved upwardly 
into general co-planar relation and thereafter slid rearwardly so as to 
engage the two pairs of mating dovetails, D and E on element A and D' and 
E' on element B. The two pairs of dovetail elements are separated by a 
notch F. 
Now referring to FIG. 2 which illustrates the assembly of the instant 
invention, the numeral 10 designates generally a base element while the 
numeral 11 designates generally the wearable element. In the illustration 
given, the base element 10 includes a generally plate-like body 12 which 
is relatively elongated to provide end walls 13, 14 and sidewalls 15, 16. 
One body surface 17 is the surface which normally would be secured to the 
wearable part of a structure (not shown). Such a part, however, could be 
the corner portion 18 of a bucket--see FIG. 4. 
The surface opposite to the attached surface 17 can be seen only in FIG. 4 
and is designated 19 and constitutes the surface in confronting relation 
to the wearable element 11. 
Still referring to the base element 10 of FIG. 2, it will be noted that the 
body is equipped with integral transversely extending flanges as at 20, 
21, 22 and 23 separated by relatively longitudinally elongated notches 24 
and 25. The extremities of the flanges 20-23 are shaped to provide 
divergent/convergent dovetail surfaces. In other words, the surfaces are 
doubly sloped--both in the top to bottom direction of the normal dovetail 
and also sloped fore/aft to provide the divergence/convergence. The 
dovetail surfaces employed herein are like those in the previously 
mentioned co-owned U.S. Pat. No. 4,716,666 and express reference is hereby 
made to that patent for additional details of structure and operation. 
Illustrative of the dovetail surfaces is the outer wall or surface 26 of 
the flange portion 22 in the base element 10 (see the central right hand 
portion of FIG. 2). When the wear element 11 is moved into engagement with 
the base element 10--as illustrated by the curved arrows 27 in FIG. 2--the 
flange 22 is received within the notch 28. Then, when the wear element 11 
is moved in the direction of the arrow 29, the dovetail surface 26 engages 
a mating surface 30 in the wear element 11. Normally, the elements 10, 11 
are positioned as seen in FIG. 2 when the normal flow of abrasive material 
is in the direction of the arrow 29--which tends to seat more firmly the 
dovetail surfaces 26, 30 against each other. More properly, such movement 
includes the seating engagement of the dovetail surface 31 (the mirror 
image of the dovetail surface 30) against the dovetail surface provided at 
the extremity of the flange 20; and in similar fashion, the dovetail 
surface 32 on the wear element 11 is seated on the dovetail surface 33 on 
the flange 23 of the base element 10 and, in like fashion, the dovetail 
surface 34 is seated against the dovetail at the extremity of the flange 
21 on the base element 10. We have found it advantageous to incline the 
surfaces 30, 31, 32 and 34 at an angle of about 15.degree. relative to the 
longitudinal center line 35 of the wear element 11. It is to be understood 
that the mating dovetail surfaces as at 26, 33, etc. on the base element 
are similarly inclined to the longitudinal center line (not shown) of the 
base element 10. In some instances, we have found it to be further 
advantageous to reduce the inclination somewhat (to the range of about 
10.degree. to about 15.degree. C.) to insure better fits. 
Also assisting in developing better fits are the provision of rails 11A 
(see FIG. 4) on the surface of the wear element confronting the base 
element 10. These also can be seen in perspective in FIG. 1 adjacent the 
outstanding walls G and H and are designated by the symbol I. 
The operation described thus far is very much like that achieved through 
the practice of the invention in U.S. Pat. No. 4,716,666. To obtain the 
advantageous reversibility of the instant invention, we provide additional 
dovetail surfaces as at 36, 37 at the right hand end of the wearable 
element 11 in FIG. 2 and as at 38 and 39 just to the left of the 
transverse center line 40--again referring to FIG. 2. It will also be 
noted that the dovetail surfaces are symmetrical about the transverse 
center line 40 as they also are about the longitudinal center line 35. 
Therefore, as the wearable element 11 is rotated 180.degree. , it would 
have the same appearance as that shown in FIG. 2 but with the dovetail 
surface 39 now being in the place of the dovetail surface 30, the dovetail 
surface 37 occupying the position of the dovetail surface 32, etc. 
The dovetail surfaces in the wear element 11 are provided by outstanding 
wall portions as at 41 and 42 in a fashion similar to that provided at G 
and H in FIG. 1 relative to the prior art. More particularly, the surface 
remote from that being abraded is equipped with transversely-spaced, 
integral outstanding portions which provide confronting walls carrying the 
various dovetails. These confronting walls are mirror images and spaced 
equally away from the longitudinal center line 35. These confronting walls 
are equipped with two pairs of longitudinally spaced, substantially 
identical, transversely aligned notches intermediate the ends of the wear 
element 11. For example, one pair of notches is designated 28, 28' and the 
other pair 43, 43'. 
It will be seen that each notch is flanked at both longitudinal ends 
thereof by a segment of the opposed or confronting wall providing the 
same--with each of the flanking segments being convergently related to its 
longitudinal center line in proceeding away from its associated notch. 
This is illustrated by considering the dovetail surfaces as the segments 
referred to in connection with the notch 2 and the center line 35. The 
same applies to the segments 32, 38 relative to the notch 43, the segments 
34, 39 relative to the notch 43' and the segments 31, 37 relative to the 
notch 28'. 
The reversibility of the wear element 11 relative to the base element 10 
not only is advantageous in the case of left and right mountings as in 
FIG. 4 where the body 44 is extended transversely of the length of the 
dovetail along one sidewall to go around a corner as at 45, but also in 
the case of wear elements in general. Where the wear elements are flat but 
subjected to abrasive forces in only one longitudinal direction, wear 
normally occurs more at the lead portion than the trailing portion. 
Therefore, switching the wear element end for end effectively extends the 
life thereof. In the case of the right and left hand elements of the 
character seen in FIGS. 3 and 4, the reversible feature is especially 
advantageous because these normally are quite extensive and ponderous, 
sometimes necessitating an integral eye as at 46 to lift the same into 
position on the associated bucket 18. 
An alternative form of the invention can be seen in FIG. 5 which is 
advantageously employed where the length of the wear element is a 
restriction. This is achieved in the wear element 111 of FIG. 5 by the 
elimination of one pair of notches, utilizing only the notches 128 and 
128'. As before in the case of the illustration of FIG. 2, the 
illustration of FIG. 5 makes use of opposed or confronting walls 147 and 
148 which are symmetrically related to the longitudinal center line (not 
shown). These are provided by upstanding integral portions as at 141 and 
142. Further, and again as in the instance of the showing in FIG. 2, the 
confronting walls 147, 148 are symmetrical about the transverse center 
line here designated 140. Also, again there are four pairs of dovetail 
surfaces but here the arrangement is somewhat different. The arrangement 
of the dovetail surfaces is the same in the respect that flanking the 
notch 128 are the surfaces 136 and 130 much the same as the surfaces 36 
and 30 flank the notch 28 in FIG. 2. Also in proceeding to the left, a 
further dovetail surface or wall segment 138 extends to the left of the 
segment 130 just as the surface 38 extends to the left of the surface 30 
in FIG. 2. However, the segment 32 of FIG. 2 has been relocated from the 
left hand end to the right hand end as at 132 in FIG. 5. More 
particularly, the opposed sidewalls 147 are arranged in two longitudinally 
spaced pairs separated by a notch in each wall. Each wall of each pair 
includes two angularly related wall segments with the wall segment 
immediately adjacent the notch being convergently related to its 
transversely aligned wall segment (136 versus 137) with the wall segment 
spaced from the notch being divergently related to its transversely 
aligned wall segment (132 versus 137). 
Common to both constructions is the fact that each notch is flanked at both 
longitudinal ends by a segment of the confronting wall with each of the 
flanking segment being convergently related to the longitudinal center 
line in proceeding away from the associated notch. Further, each 
confronting wall remote from the notch has two additional segments for 
cooperation with the flanking segments in reversibly mounting the body on 
the base element 10, 110. We construct the notches and segments as having 
approximately the same length with the first of the additional segments 
being spaced approximately two lengths from a first of the flanking 
segments and the second of the additional segments being spaced 
approximately two lengths from the second of the flanking segments with 
the first flanking and additional segments being parallel and the second 
and additional segments being parallel. 
The foregoing can be appreciated from a consideration of FIG. 5A which is a 
schematic top plan view of the showings in FIGS. 2 and 5 arranged to show 
corresponding elements, viz., the notches 28 and 128 being aligned as are 
the segments 30, 130, the segments 38, 138 and the segments 36, 136. The 
additional segments previously referred to include the segments 132 and 
138 in the case of the schematic view of FIG. 5. The segment 132 
cooperates with, i.e., is parallel to, the segment 130 and is spaced two 
lengths 1 therefrom. In the same fashion, the additional 138 is related to 
the flanking segment 136. Thus it will be seen relative to the showing in 
FIG. 5 that the additional segments are on opposite sides of the notch 
128. 
Still referring to FIG. 5A and in the case of the schematic representation 
of FIG. 2, the flanking segments are 36 and 30 with the additional 
segments being 38 and 32. It will be noted that the segment 38 is spaced 
two lengths from the segment 36 and is parallel thereto while the segment 
32 is spaced two lengths from the segment 30 and again is parallel 
thereto. 
It may be easier to understand the bi-directional dovetail constructions 
and features by noting that the variations are based on a repetitive 
pattern as seen in FIG. 8. For instance, one get the base/runner 
combination of FIG. 2 if the FIG. 8 showing is cut along the section lines 
2'--2' and 2"--2". One gets the base/runner combination of FIG. 5 if one 
cuts at 5'--5' and 5"--5". One gets the base/runner combination of FIG. 6 
if one cuts at 6'--6'--6"--6". In all cases one gets a base/runner 
combination that is reversible. One can choose to cut where necessary to 
obtain specific objectives such as an assembly with dovetails shifted 
towards the front, towards the rear, or an assembly that is more compact 
when individual mounting is permissible (as opposed to serial mounting). 
In the case of the embodiment of FIG. 2, it is possible to arrange the wear 
elements 11 in a continuous series--as in a wear runner for a dragline 
bucket, a lining for an ore chute, etc. with the end of one wear element 
abutting the other--and still provide the necessary sliding movement for 
removal when the same are removed serially. 
This is because the base 10 in FIG. 9 allows the wear element 11 to move 
the necessary distance M forward to disengage without blocking its 
movement with any necessary placement of base dovetails. However, to 
serially employ the embodiment of FIG. 5, end projections are added as at 
249 and 250 on the wear element 211 of FIGS. 6 and 7. FIG. 9A shows this 
version with end projections and the movement M' need to disengage 
dovetails and remove the wear element. 
While in the foregoing specification a detailed description of the 
invention has been set down for the purpose of illustration, many 
variations in the details hereingiven may be made by those skilled in the 
art without departing from the spirit and scope of the invention.