Abstract:
A wear part for surfaces exposed to abrasive material. The wear part is particularly well suited for use on earth working equipment used in environments where dead bedding material is possible. The wear part in the form of a wear runner has stops to cause material to dead bed and at least one ramp to minimize the wear caused by the dead bed material.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority benefits to U.S. Provisional Patent Application No. 61/924,575 filed Jan. 7, 2014 which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a replaceable wear element for protecting an underlying surface of earth working equipment from abrasive earthen material. 
       BACKGROUND OF THE INVENTION 
       [0003]    In mining and construction, wear parts, often called wear runners, are commonly provided along the faces of excavating equipment that engage abrasive material. The wear part protects the underlying equipment from undue wear and extends the life of the excavating equipment. 
         [0004]    Typically the wear parts have a leading edge that initially contacts the abrasive material and a top surface over which the abrasive material travels as the excavating equipment engages the abrasive material. The movement of the abrasive material on the top surface wears the wear part such that the wear part needs replacement. The wear parts are often replaced a number of times due to the highly abrasive environment in which they are used. The wear parts may be welded to the excavating equipment, or the wear part may have multiple pieces such as a base that is secured to the excavating equipment and a wear member that is mechanically attached to the base. 
         [0005]    In some cases, earthen material can be used to protect the wear parts and extend the life of the wear parts. As the wear parts travel through the material to be excavated, the material is encouraged to pile up and stick to portions of the wear part. As the earthen material builds up it covers portions of the wear part to act as an additional wear surface. This technique is known as dead bedding. Dead bedding can extend the useful life of a wear part with less cost than increasing the thickness of the wear part, and is generally lighter than the metal used for the wear part. Dead bedding is also desirable because, should the material be worn or washed away, new material will be built up to replace the displaced material. In many cases, to get material to dead bed, a tumble bar in the front of the excavating equipment and an abutment surface in the rear of the excavating equipment is used. 
         [0006]    As one example, wear runners or wear parts  13   a  may be used inside a dipper bucket  3  ( FIGS. 3 and 4 ). The dipper bucket  3  may be equipped with one or more tumble bar(s)  18  at the front end of the bucket to encourage the material to tumble over the wear parts  13   a  ( FIG. 3 ). Encouraging the material to tumble causes the material to generally create impact forces on the wear parts and minimizes the frictional wear on the top surfaces of the wear parts. In another example, a bucket  3  may not be provided with a tumble bar at the front of the bucket and the wear parts  13   a  may be arranged in a straight line across the front of the bucket so that the leading edge  25   a  of the wear parts  13   a  acts as a tumble bar ( FIG. 4 ). The rear of the bucket may be equipped with another tumble bar or rear abutment surface  20  to stop the material from tumbling ( FIG. 3 ). As the material contacts the rear abutment surface  20  the material builds up in a forward direction (i.e., toward the direction of the flow of the material into the bucket as indicated by arrow  22 ). The material builds up and covers some of the wear parts between the rear abutment surface  20  and the front tumble bar  18 . Material properties (e.g., material angle of repose) determines how far forward the material will build up over the wear parts. The top surface on the wear parts not protected with earthen material experience wear as the excavating equipment continues to dig. To reduce the weight of each wear part  13   a  and minimize the top surface that experiences wear on the wear part, each wear part may have recess  31   a  and/or a cavity  33   a  ( FIG. 4   a ) for earthen material to collect within the wear part and between wear parts arranged in a pattern  28 ,  28   a  as shown in  FIGS. 3 and 4 . Eventually, as the excavating equipment continues to dig the front tumble bar  18  or the leading edge  25   a  of the wear parts  13   a  and the rear abutment surface  20  wear causing the earthen material over the wear parts to be worn away and lost. As the earthen material over the wear parts is lost all of the wear parts begin to be exposed and wear. The generally flat top surface of the wear part causes the entire top surface of the wear part to experience frictional wear. The frictional wear on the top surface causes the wear parts to be worn and need replacement prematurely. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention pertains to a wear part for surfaces exposed to abrasive material. The wear part is particularly well suited for use on earth working equipment used in environments where dead bedding material is possible. 
         [0008]    In one aspect of the invention, the leading surface is inclined forward such that the wear part has an included angle of less than 90 degrees between the leading edge and the attachment surface to encourage dead bedding as well as cause material tumble. Alternatively, the leading surface and the trailing surface may both be inclined so as to have an included angle of less than 90 degrees between the leading edge and the attachment surface and between the trailing edge and the attachment surface to encourage dead bedding as well as cause material tumble regardless of whether the leading edge faces the flow of material or the trailing edge faces the flow of material (or whether the material flows alternatively in either direction). In one preferred construction, the included angle is greater than about 50 degrees to lessen the hydraulic lift effect the material may impose on the wear part (i.e., to lift it from the attachment surface) and less than about 85 degrees to better capture the material between adjacent wear parts, although other inclinations outside the preferred range can be used. 
         [0009]    In another aspect of the invention, the wear part generally tapers (i.e., narrows) from the leading end to the trailing end. Generally tapering the wear part from the leading end to the trailing end discourages the dead bed material from washing away or scouring the wear part, provides a ramp to create a skip effect (i.e., protecting areas rearward of the leading end of the wear part when the trailing end faces the flow of material), allows the wear part to wear more slowly (i.e., only the leading edge of the top surface of the wear part is exposed once the wear part begins to experience wear), and reduces the amount of throw away material once the wear part needs replacement. 
         [0010]    In another aspect of the invention, the wear part has a raised trailing end. The raised trailing end gives the wear part a rear abutment surface and allows the wear part to dead bed itself (i.e., without other bars or parts capturing the earthen material to overlie the wear parts). 
         [0011]    In another aspect of the invention, the trailing end of the wear part is provided with a ramp. In one preferred construction, the ramp is inclined away (i.e., rearward) from the trailing end. The ramp creates a skip effect protecting areas rearward of the upper end of the ramp when the lower end of the ramp faces the flow of material. This inclination can, then, also work more effectively as a leading end if the material flow is reversed. 
         [0012]    In another aspect of the invention, the wear part is provided with a lifting eye spaced from the attachment surface without extending above the top surface of the wear part. Locating the lifting eye away from the attachment surface allows rigging to remain attached to the wear part until the wear part is fully installed. Also, locating the lifting eye so that it does not extend above the top surface of the wear part allows material to flow over the wear part without disrupting the flow of material over the wear part. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a side view of a cable shovel. 
           [0014]      FIG. 2  is a perspective view of cable shovel bucket. 
           [0015]      FIG. 3  is a perspective view of a cable shovel bucket with prior art wear parts and tumble bars secured to a wall of a bucket. The door, rear wall, teeth, and other details of the bucket are omitted to simplify the drawing. 
           [0016]      FIG. 4  is a perspective view of the bucket shown in  FIG. 3  with prior art wear parts secured to a wall of a bucket in a pattern that varies from the pattern shown in  FIG. 4 . 
           [0017]      FIG. 4   a  is a perspective view of the wear part shown in  FIGS. 3 and 4 . 
           [0018]      FIG. 5  is a top view of a wear part in accordance with the present invention. 
           [0019]      FIG. 6  is a cross section of the wear part in  FIG. 5  taken along lines  6 - 6  in  FIG. 5 . 
           [0020]      FIG. 7  is a bottom view of the wear part in  FIG. 5 . 
           [0021]      FIG. 8  is a side view of the wear part in  FIG. 5 . 
           [0022]      FIG. 9  is a bottom perspective view of the wear part in  FIG. 5  secured to a base. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The present invention pertains to a wear part for protecting a surface that experiences wear and handles material that is suitable for dead bedding. The present invention is particularly well suited for use on various kinds of earth working equipment including, for example, excavating equipment and ground conveying equipment. Excavating equipment is intended as a general term to refer to any of a variety of excavating machines used in mining, construction and other activities, and which, for example, include dozers, loaders, dragline machines, cable shovels, face shovels, and hydraulic excavators. Excavating equipment also refers to the ground-engaging components of these machines such as the bucket. Ground conveying equipment is also intended as a general term to refer to a variety of equipment that is used to convey earthen material and which, for example, includes chutes and mining truck beds. For convenience of discussion, the wear part is discussed in terms of a wear member for protecting a surface on a cable shovel bucket; however, the wear member may be used to protect surfaces of other earth working equipment. 
         [0024]    Relative terms such as front, rear, top, bottom and the like are used for convenience of discussion. The terms front or forward are generally used to indicate the usual direction of travel during use (e.g., while digging), and upper or top are generally used as a reference to the surface over which the material passes when, for example, it is gathered into the bucket. Nevertheless, it is recognized that in the operation of various earth working machines the wear member may be oriented in various ways and move in all kinds of directions during use. Further, the earthen material may flow in more than one direction. For example, in the example of some excavating machines the earthen material will flow into the bucket during digging and in the opposite direction when dumped from the bucket. 
         [0025]    A cable shovel  1  is equipped with a bucket  3  for gathering earthen material  2  while digging ( FIG. 1 ). The bucket  3  includes a frame or shell  4  defining a cavity  16  for gathering material during the digging operation ( FIG. 2 ). Shell  4  may include a rear wall  6  having attachment supports  8  to attach the bucket  3  to earth working equipment, a front wall  10  opposite the rear wall  6 , and a pair of opposing sidewalls  14  each located between the rear wall  6  and the front wall  10 . A door  12  is hinged to rear wall  6  so as to be closed during digging and define the bottom wall of the bucket, and opened during dumping. Multiple configurations of buckets are known and variations in bucket geometry exist. The drawings illustrate one example for explanation of the various inventive features of the present invention. Moreover, other kinds of excavating machines will have different kinds of buckets. For example, in a dragline bucket the front and top are typically open, or in a hydraulic excavator there is no door. The specific geometry of the bucket is not intended to be limiting as the present invention can be used with various types of buckets and in non-bucket applications (e.g., truck trays). In the drawings, the bucket  3  has a lip  5  that extends forward of the front wall  10  and is the digging edge of the bucket  3  ( FIG. 2 ). The digging edge is that portion of the equipment that leads the contact with the ground. Multiple tooth assemblies  7  and shrouds (not shown) are often secured to the digging edge to protect the edge and break up the ground ahead of the lip  5 . 
         [0026]    In accordance with the invention, wear member  13  has a leading surface  15 , a trailing surface  17 , a top surface  19  to engage earthen material and protect the underlying equipment, an attachment surface  21  to secure the wear member  13  to excavating equipment, and a pair of side surfaces  23  extending between the top surface  19  and the attachment surface  21  ( FIGS. 5-9 ). Both the leading surface  15  and the trailing surface  17  have an included angle θ, and θ′ that is preferably less than 90 degrees between the leading surface  15  or the trailing surface  17  and the mounting surface (i.e., the surface to be protected) of the earth working equipment. In the preferred construction, the attachment surface  21  follows the mounting surface though other arrangements are possible. The leading and trailing surfaces  15 ,  17  can act as a tumble bar to cause earthen material to tumble across the wear member  13  regardless of whether the leading surface  15  faces the flow of material or the trailing surfaces  17  faces the flow of the material. In this way the wear member forms a tumble bar feature regardless of whether the wear part is attached with the leading surface or the trailing surface facing in opposition to the flow of the material, or if the earthen material flows in two directions such as the inner bottom wall of a dragline bucket. The included angle θ′ of the trailing surface  17  may or may not equal the included angle θ of the leading surface  15 . In one preferred embodiment, the included angle θ and θ′ is each greater than about 50 degrees. The included angle is preferably greater than about 50 degrees to lessen the hydraulic lift effect on the wear part as the material being excavated encounters the leading or trailing surface but could in certain circumstances be less than 50 degrees. While it is preferred that both θ and θ′ to be less than 90 degrees, it is possible for either or both θ and θ′ to be equal to or greater than 90 degrees. Leading surface  15  and trailing surface  17  are preferably generally planer. However, the leading surface  15  and trailing surface  17  may have other shapes, (for example, curved inward or outward, segmented, irregular) such that only part of the leading (or trailing) surface is at an angle between the leading edge  25  (or trailing edge  27 ) of the wear member  13  and the leading edge  26  (or trailing edge  29 ) of the attachment surface  21  that is less than 90 degrees. 
         [0027]    Similar to wear members  13   a , leading surface  15 , trailing surfaces  17 , and side surfaces  23  may have recesses  31 . When multiple wear members  13  are attached to a bucket or truck tray, recesses  31  create pockets that allow material to build up between the wear members located to the sides of each wear member, in front of each wear member, and rearward of each wear member. Wear members  13  may be arranged in a pattern similar to the patterns  28  and  28   a  shown in  FIGS. 3 and 4  or may be arranged in a completely different pattern depending on the earth working application that the wear member  13  is being used in. 
         [0028]    Similar to wear members  13   a , top surface  19  may have one or more cavity or pocket  33  to collect earthen material. The presence of a cavity or cavities lessens the material usage and weight of the wear member, and better collects and maintains earthen material. Nevertheless, cavity  33  could be omitted. The cavity  33  may be rectangular, elliptical or any other shape. A hole  35  may extend between the cavity  33  and the attachment surface  21 . Hole  35  generally matches the shape of a lock  37  used to secure the wear member  13  to a base  39  fixed to excavating equipment (as shown in  FIGS. 6 ,  7 , and  9 ). Other bases, locks and holes could be used (as discussed below). In alternative embodiments (not shown), wear member may be welded to a base or welded directly to the excavating equipment without the use of a lock. The weld-on wear members can be identical to what is shown (e.g., with hole  35 ) so only one form of part need be made and/or stored, or it can be made without the hole and/or other changes (such as weld recesses) to better accommodate welding to the attachment surface. 
         [0029]    The use of an inclined leading (or trailing) surface with the pockets and other features of the wear member tend to cause the material to stay within the pockets formed within and between the wear members for effective dead bedding. In one preferred embodiment the included angle θ and θ′ is less than about 85 degrees to maximize the amount of material that is captured and maintained within the pockets. 
         [0030]    Wear member  13  is generally tapered (i.e., gradually narrows) from the leading edge  25  to the trailing edge  27 . As seen in  FIG. 6 , top surface  19  is inclined to slope downward toward trailing surface  17 . This narrowing could be continuous or discontinuous, and could be uniform or changing. The taper and the cavity  33  discourages the dead bed material from washing away or scouring the wear member. The taper also provides a ramp if the material is flowing in the opposite direction (i.e., where the trailing surface  17  faces opposite to the flow of the earthen material), to create a skip effect or shadow where material flows up and off the ramp and avoids a section of the underling excavating equipment. The inclination of top surface  19  (i.e., the narrowing of the wear member) also enables the use of a raised portion  41  with an abutment surface  43  (as discussed below) that is generally at about the same height as the leading surface  15  to improve the flow of the material over the wear member. Nevertheless, the raised portion could be higher or lower than the leading surface or could be omitted completely. The taper along with abutment surface  43  encourages the build up of earthen material and increases the thickness of the earthen material over portions of the wear member instead of using metal to increase the thickness of the wear member. This reduces the weight of the wear member, reduces the cost of the wear member, and reduces the throw away material once the wear member has been completely worn. 
         [0031]    The wear member usually begins to wear initially along the leading edge  25  (i.e., along the intersection of leading surface  15  and top surface  19 ). Because the leading edge of the wear member  13  is initially exposed to wear, a portion of the leading surface  15  adjacent the leading edge  25  and a portion of the top surface  19  adjacent the leading edge  25  may be overlaid with a hardfacing material or made from a material having different properties than adjacent sections of the wear member (not shown) to extend the life of the wear member. Hardfacing and/or varying types of material may, of course, be provided at other locations of the wear member. The hardfacing may be, for example, tungsten carbide or spherical carbide. 
         [0032]    Wear member  13  preferably includes a raised portion  41  adjacent the inclined top surface  19 . The raised portion  41  projects above the top surface  19  and provides an abutment surface  43  to stop the tumbling of the earthen material and cause the material to dead bed the cavity  33 , recesses  31 , and the top surface  19  of the wear member  13 . The wear member  13  is preferably also provided with an abutment surface  43 ′ at the front end of cavity  33  so that the wear member  13  can cause material to build up regardless of whether the trailing surface  17  or the leading surface  15  faces into the flow of material. 
         [0033]    A ramp  45  may be provided adjacent the trailing surface  17  of the wear member. The ramp  45  is preferably inclined upward and away from the trailing edge  27 , as shown in  FIGS. 5-9 , but may be inclined in the opposite direction (not shown). Like the taper of the wear member, the ramp  45  creates a skip effect protecting areas rearward of the upper edge  47  of the ramp  45  when the lower edge  49  of the ramp  45  faces the flow of material. Like leading edge  25 , the surfaces adjacent the upper edge  47  of ramp  45  may be overlaid with hardfacing or made from a material having different properties than adjacent sections of the ramp to extend the life of ramp  45 . 
         [0034]    Wear member  13  may be provided with a lifting eye  51  to ease handling during installation. Lifting eye  51  is preferably spaced from the attachment surface  21  to ease coupling and decoupling of the hook or other connection means, and preferably does not protrude above a plane extending along the top surface  19  of the wear part  13  to improve the flow of material over the wear members. The lifting eye  51  may be located within the recess  31  in leading surface  15  and be located adjacent the leading edge  25 . Locating the lifting eye  51  away from the attachment surface  21  allows rigging (not shown) to remain attached to the wear member  13  until the wear part is fully installed. The location of the lifting eye allows material to flow over the wear member without disrupting the flow. 
         [0035]    Attachment surface  21  may have a cavity  53  for accepting a base  39  that is secured to the excavating equipment. Cavity  53  generally matches the shape of base  39  (See  FIG. 9 ). The cavity may have dovetails and recesses that mate with dovetails on the base, such as disclosed in U.S. Pat. RE. No. 33,454, which is incorporated herein by reference. The cavity  53  may have reversible dovetails  55  and recesses  57  so that wear member  13  can be mounted on base  39  in either direction, such as disclosed in U.S. Pat. No. 5,063,695 which is incorporated herein by reference. Cavity  53  may be provided with projections  59  for engaging the base  39  and/or lock  37  as disclosed in U.S. Pat. No. 5,241,765, which is incorporated herein by reference. 
         [0036]    Base  39  may be generally rectangular and have dovetails  61  that correspond to dovetails  55  on the wear member  13 . A hole  63  that aligns with the hole  35  in the wear member  13 , when the wear member is installed on the base, may extend through the base to accept a lock  37  to secure the wear member to the base. The base  39  may have recesses (not shown) that correspond to projections  59  on wear member  13 . The base may be welded or otherwise secured to the excavating equipment. For example, the base may be welded to front wall  10  of bucket  3  and wear member  13  may be installed on base  39 . Alternatively, the wear member may be welded to the earth working equipment with or without the use of a base. 
         [0037]    Lock  37  generally corresponds to the shape of hole  35  in wear member  13  and hole  63  in base  39 . The lock, for example, may have a body and a resilient member as disclosed in U.S. Pat. No. 5,241,765 or U.S. Pat. No. 7,144,183 which are each incorporated herein by reference. 
         [0038]    Although the above discussion has discussed the invention in connection with a wear member for use on a cable shovel bucket, the wear member can be used on various types of buckets, for example, dragline buckets, hydraulic face shovel buckets, excavator buckets, and loader buckets. Moreover, a wear member of the present invention can also be used to dead bed material and protect the underlying surface on other kinds of earth working equipment such as chutes or truck trays or non-earth working equipment such as grain elevators. Although the wear member are disclosed in this application primarily in the context of wear runners, the inventive concepts could be incorporated into other kinds of wear parts. 
         [0039]    The above disclosure describes specific examples of a wear member for use with earth working equipment. The wear member includes different aspects or features of the invention. The features in one embodiment can be used with features of another embodiment. The examples given and the combination of features disclosed are not intended to be limiting in the sense that they must be used together.