Patent Publication Number: US-10322760-B2

Title: Undercarriage clamping master track link

Description:
TECHNICAL FIELD 
     The present disclosure relates to a method and apparatus for machining a master track link used for completing a track chain assembly of an endless undercarriage drive employed by earth moving, construction and mining equipment and the like. Specifically, the present disclosure relates to a clamping master track link has one or more struts each divided by a gap. 
     BACKGROUND 
     Earth moving, construction and mining equipment and the like work are often used in rough, off-road terrain. These machines often employ an endless drive with track shoes that is better able to propel the machines in such environments over obstacles and uneven terrain, etc. The track chains, which include shoes, are held together by a series of interconnected track links, pins and bushings that are supported on the drive sprocket, idler and support rollers of the machine. As can be imagined, a device is typically provided that allows the track chain to be routed about the drive sprocket, idler and support rollers before the free ends of the chain are joined together. This device is called a “master link”. 
     Also, depending on the weight of the machine, the size of the chain, the environment in which the machine operates, and other factors, the chains and/or track shoes may wear or be damaged and may require periodic inspection, servicing, repair, and/or replacement. Hence, a master link may also be provided in the chain to allow disassembly of the chain (i.e., separation of two ends of the chain). 
     As can be imagined, it is desirable for master track links to have at least three traits. First, it is desirable that the master track links be reliable or durable. That is to say, the master track link should not be prone to unintentional disassembly when a track chain is in use. If this happens, the track chain assembly may fall off the undercarriage of the machine, leading to unwanted downtime and maintenance of the machine to get the machine up and running again. Second, it is desirable that the master track link be able to be easily serviceable. That is to say, it should not be time consuming to detach the master track link so that maintenance as described above can be performed. Third, it is desirable to be able to cost effectively manufacture the master track link. 
     Some master track link designs in current use a pin that is press fit into the master track link while others use a pin that is slip fit and held into place using a cotter pin. The press fit provides a low cost, robust design in terms of reliability or durability but is not easily serviced. On the other hand, the slip fit pin is higher cost but provides a robust design in terms of serviceability, however, it is less desirable in terms of durability or reliability. If the cotter pin falls out, the master track link will often fall off the pin. 
     Accordingly, a need exists for a method and apparatus related to a master track link that can provide a better combination of serviceability, durability or reliability and cost. 
     One prior master track link using a clamping method to hold onto pins is disclosed in U.S. Pat. No. 7,877,977 to Johannsen et al. The &#39;977 patent suggests providing a clamping master track link that is configured to clamp on bushing/pin combinations on both ends of the master track link (see FIGS. 4 and 5 of the &#39;977 patent). Furthermore, it discloses a straight link where the holes configured to clamp on the bushing/pin combinations are in the same plane. However, this is incompatible with many track chain assembly designs already in the field. Also, this master track link design uses three small gaps between the struts, which require expensive machines such as grinding or wire EDM to manufacture the track link. Therefore, a master track link that is less costly, more durable or reliable, and more serviceable and that can be retrofitted with track chain assemblies already in the field is still warranted. 
     SUMMARY 
     A clamping master track link is provided according to an embodiment of the present disclosure and comprises a body that defines a first bore and a second bore, a first aperture disposed between the first bore and the second bore, a second aperture disposed between the first aperture and the second bore, a first strut with a first gap disposed between the first aperture and the second aperture, a second strut with a second gap disposed between the first aperture and the first bore, and a bridge disposed between the second aperture and the second bore. 
     A clamping master track link is provided according to an embodiment of the present disclosure and comprises a body defining a top surface, a bottom surface, a first side surface and a second side surface defining a thickness therebetween, a proximate end and a distal end. The body also defines a first bore adjacent the distal end and a second bore adjacent to the proximate end, a first aperture disposed between the first bore and the second bore, the first aperture being disposed nearer the first bore than the second bore, a second aperture disposed between the first aperture and the second bore, a first strut disposed between the first aperture and the second aperture, the body defining a first gap dividing the first strut into a first upper portion and a first lower portion, and a second strut disposed between the first aperture and the first bore, the body defining a second gap dividing the second strut into a second upper portion and a second lower portion. The first gap defines a first minimum distance and the second gap defines a second minimum distance and the ratio of the second minimum distance to the first minimum distance ranges from 3 to 10. 
     A track chain assembly is provided according to an embodiment of the present disclosure and comprises a plurality of track pins and track bushings disposed about the track pins, and a plurality of track links that are connected to each other by either a track pin or a track bushing, wherein at least one track link defines a plurality of apertures for receiving a track pin or bushing. The chain assembly may also include a plurality of track fasteners, a plurality of track shoes attached to the track links via the track fasteners; and at least one clamping master track link including a body defining a top surface, a bottom surface, a first side surface and a second side surface defining a thickness therebetween, a proximate end and a distal end. The body may define a first bore adjacent the distal end and a second bore adjacent to the proximate end, a first aperture disposed between the first bore and the second bore, the first aperture being disposed nearer the first bore than the second bore, a second aperture disposed between the first aperture and the second bore, a first strut disposed between the first aperture and the second aperture, the body defining a first gap dividing the first strut into a first upper portion and a first lower portion, a second strut disposed between the first aperture and the first bore, the body defining a second gap dividing the second strut into a second upper portion and a second lower portion. The first bore may define a first longitudinal axis and the second bore may define a second longitudinal axis and the body jogs, forming an offset master track link such that the first bore and second bore are offset from each other along either the first or second longitudinal axis. The first bore may define a first diameter, the second bore may define a second diameter, the first diameter may be less than the second diameter, and the first bore is a blind bore and the second bore is a thru bore, and the body includes a bridge disposed between the second aperture and the second bore. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure. In the drawings: 
         FIG. 1  is a side-view of a machine that may use various track chain assemblies with a clamping master track link according to various embodiments of the present disclosure. 
         FIG. 2  is a side-view of a track chain assembly of the machine of  FIG. 1  removed from the machine. 
         FIG. 3  is a top-view illustration of the track chain assembly of  FIG. 2 . 
         FIG. 4  is a front oriented perspective view of an exemplary clamping master track link subassembly of the track chain assembly of  FIG. 2 . 
         FIG. 5  is a rear oriented perspective view of the exemplary clamping master track link subassembly of  FIG. 4 . 
         FIG. 6  is a front oriented perspective view of an exemplary clamping master track link subassembly using fasteners having different dimensions from each other used to attach a shoe to the clamping master track link and to provide the necessary clamping action to attach the clamping master track link to a track chain assembly. 
         FIG. 7  is a front oriented perspective view of an exemplary clamping master track link that uses pockets with nuts therein for receiving the fastener used to attach a shoe to the clamping master track link and to provide the necessary clamping action to attach the clamping master track link to a track chain assembly. 
         FIG. 8  is a top oriented perspective view of a track chain assembly according to various embodiments of the present disclosure showing the free ends of the chain as they approach the free ends of the opposing clamping master track link while completing the assembly of the track chain assembly. 
         FIG. 9  is a top oriented perspective view of a track chain assembly of  FIG. 8  showing the mating of the free ends of the opposing clamping master track links before the final pin is inserted into the bores of the links and the bore of the bushing and before the shoe is attached to the clamping master track links, completing assembly of the track chain assembly by causing the impingement of the clamping master track links onto the final pin. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In some cases, a reference number will be indicated in this specification and the drawings will show the reference number followed by a letter for example,  100   a ,  100   b  or by a prime for example,  100 ′,  100 ″ etc. It is to be understood that the use of letters or primes immediately after a reference number indicates that these features are similarly shaped and have similar function as is often the case when geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters and primes will often not be included herein but may be shown in the drawings to indicate duplications of features, having similar or identical function or geometry, discussed within this written specification. 
     Various embodiments of an apparatus and a method for creating a track chain assembly using a clamping master track link will now be described. In some embodiments, the clamping master track link is an offset link that may be used with track chain assemblies already in the field. 
       FIG. 1  illustrates an exemplary machine  100  having multiple systems and components that cooperate to accomplish a task. Machine  100  may embody a mobile machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art. For example, machine  100  may be an earth moving machine such as an excavator, a dozer, a loader, a backhoe, a motor grader, or any other earth moving machine. Machine  100  may include a power source  102  and an undercarriage assembly  104 , which may be driven by power source  102  and supported by one or more spaced-apart idler wheels  106 . 
     Power source  102  may drive undercarriage assembly  104  of machine  100  at a range of output speeds and torques. Power source  102  may be an engine such as, for example, a diesel engine, a gasoline engine, a gaseous fuel-powered engine, or any other suitable engine. Power source  102  may also be a non-combustion source of power such as, for example, a fuel cell, a power storage device, or any other source of power known in the art. 
     Undercarriage assembly  104  may include two separate continuous tracks  108 , one on either side of machine  100  (only one of which is shown in  FIG. 1 ). Each track  108  may be driven by power source  102  via one or more drive sprockets  110 . In addition, each track  108  may include a chain  112  and a plurality of track shoes  114 , each configured to selectively engage a surface, e.g., the ground. Each chain  112  may include a plurality of link subassemblies  116  and a master link subassembly  200 . Support rollers  152  are also provided at the bottom of the track to support the chain. 
       FIGS. 2 and 3  respectively illustrate side-view and top-view perspectives of an exemplary chain assembly  112  and, specifically, a plurality of exemplary link subassemblies  116  and a master link subassembly  200 . Each one of link subassemblies  116  may include a respective pair of offset link members  118  or a respective pair of inner and outer links when straight links are used (not shown). Each offset link member  118  may include fastener holes  120 , e.g., a threaded hole, configured to receive a fastener  150 , e.g., a bolt, or cap screw, to attach a track shoe  114  to a given one of link subassemblies  116 . Master track link assembly  200  may include a clamping master track link  202 . The master track link subassembly may be used to complete the chains assembly  112  in a manner that will be further described below with reference to  FIGS. 8 and 9  later herein. 
     Adjacent ones of link subassemblies  116  may be interconnected by way of rod assemblies  122  in the form of pins or bushings. More specifically, each rod assembly  122  may include a substantially cylindrical bushing  124  disposed about a substantially cylindrical pin  126 . A pair of bearings (not shown) that are freely rotatable relative to pin  126 , and a pair of seals (not shown) may also be provided in the rod assembly or in one of the link members proximate the rod assembly to prevent the loss of lubrication and provide freedom of movement. In some embodiments, the bearings and seals may be combined functionally in the same assembly. The bushing  124  may be pressed into an aperture  128  of one end  130  of the offset link member  118  and the pin  126  may extend through this end  130  of the offset link member  118  and be received in the aperture  132  of other end  134  of the adjacent offset link member  118 ′. The pin  126  may be retained in the other end  134  of the adjacent offset link member  118 ′ by being pressed into that link member  118 ′ or be retained therein using a cotter pin or another similar device when a slip fit is being used. Other configurations and methods of assembling the link subassemblies  116  may be provided to create a track chain assembly  112 . Of course, a plurality of offset link members  118  are connected in a manner similar to what has just been described to form the track chain assembly  112 . 
     More particularly, the first and second rod assemblies  122  may interface with apertures  128 ,  132  of adjacent offset link members  118 ,  118 ′ such that consecutively connected link subassemblies  116  may be pivotally interconnected to one another to form the track chain assembly  112 . For example, the outer end  134  of one offset link member  118 ′ may mate in fixed manner with the pin  126  (such as when a press fit is employed) and house the seals and/or bearings assemblies while the inner end  130  of the adjacent offset link member  118  may mate with the bushing  124  in a fixed manner (such as when a press fit if employed). At the same time, the pin  126  may be free to rotate within the bushing  124  such as when some clearance is provided between the pin and the bore of the bushing. Consequently, a pair of adjacent offset link members  118  may be configured to pivot with respect to one another to form an articulating track chain assembly  112 . Similarly, master track link subassembly  200  may be interconnected between two standard link subassemblies  116  by way of rod assemblies  122 . 
     A track shoe  114  may be connected to each offset link member  118 . Each track shoe  114  may include a base portion  136 , a ground-engaging surface  138 , a leading edge  140 , and a trailing edge  142 . Each track shoe  114  may also include opposing side edges  144  (only one of which shown in  FIG. 2 ) disposed between leading edge  140  and trailing edge  142 . One or more grousers or ribs  146  may be provided to engage the ground, improving traction. Additionally, each track shoe  114  may also include two pairs of threaded shoe holes  148 , each pair disposed along a respective one of the side edges  144  and configured to align with a pair of fastener holes  120  associated with an offset link member  118 . In some embodiments, holes  148  may be clearance holes and not be threaded. 
     Typically, each one of shoe holes  148  may correspond to an associated fastener receiving hole  120  situated on the bottom surface of each of the offset link members  118 . As such, each track shoe  114  may respectively connect to a pair of opposing pair of offset link members  118  from one side of the track chain assembly to the other side of the track chain assembly shown in  FIG. 3 . Threaded fasteners  150 , such as, for example, bolts or cap screws, may be respectively disposed in each one of shoe holes  148  and fastener receiving holes  120  to fasten a track shoe  114  to a respective pair of opposing offset link members  118 . It is contemplated that the spacing of the fastener receiving holes  120  for each offset link member  118  may be substantially similar such that each track shoe  114  may be configured to be connectable to each of offset link members, assuming that each track shoe is also similarly or identically configured. 
     Turning now to  FIGS. 4  thru  7 , master track link subassemblies  200  according to various embodiments of the present disclosure are depicted. A master track link subassembly  200  may comprise a clamping master track link  202  that includes a body  204  defining a top surface  206 , a bottom surface  208 , a first side surface  210  and a second side surface  212  defining a thickness therebetween, a proximate end  214  and a distal end  216 . The body  204  may also define a first bore  218  adjacent the distal end  216  and a second bore  220  adjacent to the proximate end  214 . These bores  218 ,  220  may extend from or be at least partially defined by either or both side surfaces  210 ,  212 . As shown, the bores are cylindrical but may have another suitable configuration. 
     Furthermore, the body  204  may further define a first aperture  222  disposed between the first bore  218  and the second bore  220 , the first aperture  222  being disposed nearer the first bore  218  than the second bore  220 . Similarly, the body  204  may further define a second aperture  224  disposed between the first aperture  222  and the second bore  220 . These apertures extend from the first side surface  210  completely through the body  204  to the second side surface. 
     As a result of the placement of these bores  218 ,  220  and apertures  222 ,  224 , the body  204  includes a first strut  226  disposed between the first aperture  222  and the second aperture  224 . Also, the body  204  defines a first gap  228  dividing the first strut  226  into a first upper portion  230  and a first lower portion  232 . Likewise, the body  204  includes a second strut  234  disposed between the first aperture  222  and the first bore  218 , the body  204  defining a second gap  236  dividing the second strut  234  into a second upper portion  238  and a second lower portion  240 . Both gaps  228 ,  236  extend completely through the body  204  from the first side surface  210  to the second side surface  212 , providing the necessary flexibility for the clamping master track link  202  as will be described later herein. The body  204  includes a bridge  246  disposed between the second aperture  224  and the second bore  220 . This bridge  246 , which may also be referred to as a unitary or undivided strut, provides the requisite rigidity near the second bore of the clamping master track link  202  as will also be explained later herein. 
     For the embodiments shown in  FIGS. 4  thru  7 , the clamping master track link  202  is an offset link, similar to the standard offset links described above with reference to  FIGS. 2 and 3 . That is to say, the proximate end  214  is offset from the distal end  216  in a direction that is parallel to the longitudinal axis L 126  of the pins  126  and bushings  124  of the track chain assembly  112  as best seen in  FIG. 3 . Returning to  FIGS. 4 and 5 , the clamping master track link  202  may be described as follows. The first bore  218  defines a first longitudinal axis L 218  and the second bore  220  defines a second longitudinal axis L 220  and the body  204  jogs, forming an offset master track link such that the first bore  218  and second bore  220  are offset or spaced away from each other along either the first or second longitudinal axis L 218 , L 220 . Other configurations are possible for the clamping master track link including a straight link configuration, etc. 
     For the embodiments shown in  FIGS. 4 and 5 , the first bore  218  defines a first diameter D 218  and the second bore  220  defines a second diameter D 220 . The first diameter D 218 , being configured to mate with a pin  126 , is less than the second diameter D 220 , which configured to mate with a bushing  124 . The second bore  220  is a thru bore, extending completely through the body  204  of the link while and the first bore  218  is a blind bore forming a bottom annular surface  242  as best seen in  FIG. 5 . A third bore  244  extends from the bottom annular surface  242  completely through the body  204  of the clamping master track link member. During assembly of the track chain assembly  112 , which usually occurs at the manufacturer, the stand offset link members  118  are assembled as previously described above with respect to  FIGS. 2 and 3 . 
     When the desired length of the chain assembly has been achieved, the distal end  216  of a pair of opposing master track link members are attached to pair of opposing free ends of the chain where the bushing  124  is pressed into second bore  220 . The bridge  246  provides the needed rigidity so that the pressing operation generates a suitable amount of retention force, helping to ensure that the master track link  202  does not fall off the chain assembly  112 . Then, once the chain assembly  112  has been routed about the drive sprockets  110 , idler wheels  106 , rollers, etc. of the undercarriage  104 , the chain is completed by inserting a pin  126  into the first bore  218  and creating a clamping action holding the proximate end  214  of the master track link  202  onto the pin  214  and a bushing  124  firmly using a fastener as will be described in more detail momentarily. 
     To that end, the size of the gaps are instrumental in allowing this clamping action to take place in a suitable manner. Consequently, the first gap  228  defines a first minimum distance d 228  and the second gap  236  defines a second minimum distance d 236  and the ratio of the second minimum distance d 236  to the first minimum distance d 228  may range from 3 to 10. In some instances, this ratio may range from 6 to 7. Exemplary values of the first minimum distance d 228  versus the second minimum distance d 236  are 0.75 mm to 5 mm respectively. The value of this ratio or the distances may be varied as needed or desired in other embodiments. 
     The necessary flexibility may also be expressed in terms of a ratio of the height H of the body  204 , which is the minimum distance from the top surface  206  to the bottom surface  208 , to the first minimum distance d 228 . This ratio may range from 100 to 150. In particular embodiments, this ratio may range from 130 to 140. Exemplary values of the height H may range from 90-130 mm. 
     For the embodiments in  FIGS. 4  thru  7 , the body  204  may further define a first cross-hole  248  extending in a direction perpendicular to the first longitudinal axis L 218  of the first bore  218  from the top surface  206  to the first aperture  222  and a second cross-hole  250  extending in a direction perpendicular to the second longitudinal axis L 220  of the second bore  220  from the top surface  206  to the second aperture  224 . The first cross-hole  248  may define a first diameter D 248  and the second cross-hole  250  may define a second diameter D 250 . In some embodiments, the first diameter D 248  is greater than the second diameter D 250 , allowing a larger fastener to be used near the first bore  218  than the fastener used near the second bore  220 . This may allow the force generated near the first bore  218  to be greater where clamping force is most needed to impinge upon the pin  126 . 
     In a more general sense, as best understood by referring to  FIGS. 6 and 7 , various embodiments of the present disclosure include a first master track link fastener  252  disposed in the first cross-hole  248 , which is a clearance hole, and a second master track link fastener  254  disposed in the second-cross-hole  250 , which is also a clearance hole. In some cases, the first master track link fastener  252  and the second master track link fastener  254  may define different dimensions from each other. In other words, the first and second master track link fasteners may be differently configured one from another. 
     For example, the first master track link fastener  252  may define a first length L 252  and the second master track link fastener  254  may defines a second length L 254  that is less than the first length L 252 . The first master track link fastener  252 , which is nearest the first bore  218  may be longer than the second master track link fastener  254  in order to provide most or all the necessary clamping force on the pin  126 . Alternatively, as just alluded to above, the first master track link fastener  252  may define a first diameter D 252  and the second master track link fastener  254  may define a second diameter D 254  that is smaller than the first diameter D 252 . This too may allow the first master track link fastener to provide more clamping force than the second master track link fastener. Other dimensional variances or combinations of dimensional variances are possible. 
     As best seen in  FIG. 7 , the first cross-hole  248  extends from the top surface  206  to the bottom surface  208  and the bottoms surface  208  defines a notch or a pocket  256  in communication with the first cross-hole  248  and proximate the first master track link fastener  252 . A nut  258  may be disposed in the pocket  256  so that the fastener simply needs to be rotated to be tightened. Similar structure may be provided for the second master track link fastener if needed or desired. In many instances, it is desirable for the nut to be flush to recessed compared to the bottom surface so that the nut does not hinder the function of the bottom surface as a support surface. 
     On the other hand, as best seen in  FIGS. 4 and 5 , the body  204  of the master track link  202  may define a first threaded hole  260  in communication with the first aperture  222  and aligned with the first cross-hole  248 . The first threaded hole  260  may also be disposed between the first aperture  222  and the bottom surface  208 , that is to say, it may be a blind hole. A second threaded hole  262  may also be provided so that the threads of the second master track link fastener  254  may engage them. Again, the provision of the threaded holes  260 ,  262  the needed clamping action to be provided by simply rotating the fasteners  252 ,  254  without needing to hold a nut stationary. This may ease assembly. It is contemplated that the threaded holes may be thru holes in other embodiments. Also, any of these threaded holes may be at least partially defined by hardened material that forms the rail portions of the links, providing suitable support for the weight of the machine and its payload. 
     INDUSTRIAL APPLICABILITY 
     In practice, a master track link, a pair of master track links, a chain using a master track link or a pair of track links, or a pair of master track link subassemblies according to any embodiment described herein may be sold, bought, manufactured or otherwise obtained in an OEM or after-market context. 
     A master track link  202  or master track link subassembly  200  may be attached to the free end of a chain assembly  112  at the factory and sold as a replacement part or already installed on a machine such as shown and described previously with respect to  FIG. 1 . Completing the chain assembly  112  simply requires the user to align the free end of the clamping master track link  202  to the free end of the adjacent standard track link  118  (see step  300  in  FIG. 8 ), which already as has a bushing  124  installed via a press fit or by using some other suitable method. Then, the pin  126  would be inserted through the bushing  124  and be aligned with the first bore  218  of the opposing master track links  202  (see step  302  in  FIG. 9 ). Tightening one or more master track link fasteners  252 ,  254  while attaching the shoe  114  would cause the link  202  to impinge on the pin  126 , holding onto it firmly, completing the chain assembly  112  (see steps  304  and  306  in  FIG. 4 ). 
     The chain assembly  112  as a whole may be described as follows in reference to  FIGS. 1-9 . The track chain assembly  112  may comprise a plurality of track pins  126  and track bushings  124  disposed about the track pins  126 , and a plurality of track links  118  that are connected to each other by either a track pin  126  or a track bushing  124 , wherein at least one track link  118  defines a plurality of apertures  128 ,  132  for receiving a track pin  126  or bushing  124 . The chain assembly  112  would typically also include a plurality of track fasteners  150  and a plurality of track shoes  114  attached to the track links  118  via the track fasteners  150 . Finally, at least one and typically two opposing clamping master track links  202  are attached at one free end of the track chain assembly  112 . 
     The master track link  202  may include a body  204  defining a top surface  206 , a bottom surface  208 , a first side surface  210  and a second side surface  212  defining a thickness therebetween, a proximate end  214  and a distal end  216 . The body  204  may also define a first bore  218  adjacent the distal end  216  and a second bore  220  adjacent to the proximate end  214 . A first aperture  222  may be disposed between the first bore  218  and the second bore  220 , the first aperture  222  being disposed nearer the first bore  218  than the second bore  220 . A second aperture  224  may be disposed between the first aperture  222  and the second bore  220 . 
     As a result of this structure, the body  204  includes a first strut  226  disposed between the first aperture  222  and the second aperture  224  and defines a first gap  228  dividing the first strut  226  into a first upper portion  230  and a first lower portion  232 . The body  204  also includes a second strut  234  disposed between the first aperture  222  and the first bore  218  and defines a second gap  236  dividing the second strut  234  into a second upper portion  238  and a second lower portion  240 . 
     The first bore  218  defines a first longitudinal axis L 218  and the second bore  220  defines a second longitudinal axis L 220  and the body  204  jogs, forming an offset master track link  202  such that the first bore  218  and second bore  220  are offset from each other along either the first or second longitudinal axis L 218 , L 220 . The first bore  218  defines a first diameter D 218 , the second bore  220  defines a second diameter D 220 , the first diameter D 218  is less than the second diameter D 220 , the first bore  218  is a thru bore and the second bore  220  is a blind bore. The body includes a bridge  246  disposed between the second aperture  224  and the second bore  220 . This structure allows the bushing  124  to be press fit into the second bore  220  while the pin  126  may slide into the first bore  218 . Then, fasteners  252 ,  254  may be used to attach a shoe  114  to the master track link  202 , causing the link  202  to impinge upon and hold the pin  126 . 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and methods of assembly as discussed herein without departing from the scope or spirit of the invention(s). Other embodiments of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the equipment may be constructed and function differently than what has been described herein and certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments. 
     Accordingly, it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention(s) being indicated by the following claims and their equivalents.