Patent Publication Number: US-2022227436-A1

Title: Debris path for mining track utilizing a sealed joint

Description:
TECHNICAL FIELD 
     The present disclosure relates to track pads that are used to support heavy equipment such as hydraulic mining shovels, and the like. Specifically, the present disclosure relates to such track pads that allow debris or other contaminants to migrate away from seals used in a pinned joint that joins a pair of such track pads. 
     BACKGROUND 
     In various mining applications, the track pad is subject to heavy loads, requiring that the track pad be robust. Also, dirt, rocks, debris, and other contaminants may infiltrate various components of a track chain using such track pads. More specifically, the track chain using such track pads may have a pinned joint with seals for preventing the unwanted loss of lubrication. Contaminants may infiltrate these seals, which can eventually damage the seal or otherwise interfere with the seal&#39;s function, allowing lubrication to leak out of the joint. Eventually, the lack of lubrication may cause galling, seizing, or other mechanical problems with the track chain, necessitating maintenance of the track chain and downtime for the machine. This is unwanted since it adversely affects the profitability of an economic endeavor using the machine. 
     Chinese patent no. CN2702902Y discloses a track driven machine including a track chain with two chain links that form a pinned joint. More particularly, a pin and a bushing with a seal are provided. The bushing has chamfers on its outer circumferential surface at the axial ends of the bushing. Similar chamfers are provided on the interior circumferential surface at the axial ends of the bushing. The inner chamfers extend further axially than the outer chamfers. The purpose of these chamfers is to ease assembly of the pinned joint, provide for a long service life, and reduce the amount of noise created by the pinned joint as the track chain moves. 
     However, this prior art fails to disclose a track pad or a track chain that helps reduce the likelihood of contaminants infiltrating a seal assembly of the pinned joints of the track chain, etc. 
     SUMMARY 
     A track pad according to an embodiment of the present disclosure may comprise a shoe member including a ground engaging surface, and defining a track chain traveling direction, a lateral direction perpendicular to the track chain traveling direction, and a vertical direction perpendicular to both the lateral direction, and the track chain traveling direction. The shoe member may further define a first lateral end, a second lateral end, a front end along the track chain traveling direction, and a rear end along the track chain traveling direction, a lateral distance from the first lateral end to the second lateral end, and a width from the front end to the rear end along the track chain traveling direction that is less than the lateral distance. A first link member may extend upwardly from the shoe member including a first lug member extending from the first link member in a first direction parallel to the track chain traveling direction, as well as a second lug member and a third lug member both extending from the first link member in a second direction opposite of the first direction, forming a first fork portion including a first lateral outside surface, a second lateral outside surface, a first lateral outside surface, a second lateral outside surface, a first lateral inside surface, and a second lateral inside surface. The second lug member defines a first aperture that extends laterally through the first lateral outside surface and the first lateral inside surface, forming a first intersection with the first lateral inside surface that includes a first blend extending from the first lateral inside surface to the first aperture. 
     A track pad according to another embodiment of the present disclosure may comprise a shoe member including a ground engaging surface, and defining a track chain traveling direction, a lateral direction perpendicular to the track chain traveling direction, and a vertical direction perpendicular to both the lateral direction, and the track chain traveling direction. The shoe member may further define a first lateral end, a second lateral end, a front end along the track chain traveling direction, and a rear end along the track chain traveling direction, a lateral distance from the first lateral end to the second lateral end, and a length from the front end to the rear end along the track chain traveling direction that is less than the lateral distance. A first link member may extend upwardly from the shoe member including a first top rail surface (e.g., may be planar), a first lug member extending from the first link member in a first direction parallel to the track chain traveling direction, and a second lug member and a third lug member both extending from the first link member in a second direction opposite of the first direction. The second and the third lug members may define a first pair of chamfered surfaces that are laterally opposite of each other and facing each other. 
     A track chain assembly according to an embodiment of the present disclosure may comprise a first track pad including a first pair of lugs defining a gap therebetween, and a second track pad including an intermediate lug disposed in the gap. The first pair of lugs and the intermediate lug each may define a concentric bore, defining an axis of rotation for a pinned joint of the track chain assembly, and the concentric bore of one of the first pair of lugs is in communication with the gap with a first blend disposed axially between the gap and the concentric bore of one of the first pair of lugs. 
    
    
     
       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  illustrates a machine in the form of a hydraulic mining shovel that has an undercarriage that may use track chain assemblies having track pads constructed according to the various embodiments disclosed herein. 
         FIG. 2  is a perspective view of a portion of the undercarriage, track chain assembly, and track pads of  FIG. 1 . 
         FIG. 3  is a sectional view of the track chain assembly including the two track pads of  FIG. 2  taken along lines  3 - 3  thereof, depicting a pinned joint that allows the track chain assembly to be flexible since the track pads are free to rotate relative to each other along with a debris path allowing contaminants to egress away from the seal assembly of the pinned joint. 
         FIG. 4  is an enlarged detail view of a single instance of the debris path of  FIG. 3 , showing the debris path more clearly. 
         FIG. 5  is a side sectional view of a single instance of the track pad of  FIG. 2 , taken along lines  5 - 5  thereof. 
         FIG. 6  is an enlarged detail view of the track pad of  FIG. 2 , showing the chamfer(s) that may provide one boundary of the debris path of  FIG. 4 . 
     
    
    
     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  etc. It is to be understood that the use of letters 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 will often not be included herein but may be shown in the drawings to indicate duplications of features discussed within this written specification. 
     While the arrangement is illustrated in connection with a hydraulic mining shovel, the arrangement disclosed herein has universal applicability in various other types of machines commonly employ track systems, as opposed to wheels. The term “machine” may refer to any machine that performs some type of operation associated with an industry such as mining, earthmoving, or construction, or any other industry known in the art. For example, the machine may be an excavator, wheel loader, cable shovel, or dragline or the like. Moreover, one or more implements may be connected to the machine. Such implements may be utilized for a variety of tasks, including, for example, lifting and loading. Among other uses, a hydraulic mining shovel can be used to load overburden and ore into haul trucks during the mining process in various surface mine applications. 
     Looking at  FIG. 1 , a machine  100  that may use track pads constructed according to various embodiments of the present disclosure can be seen. The machine  100  may include a body  104  with a cab  106  to house a machine operator. The machine may also include a boom system  108  pivotally connected at one end to the body  104  and supporting an implement  110  at an opposing, distal end. In embodiments, the implement  110  can be any suitable implement, such as a bucket, a clamshell, a blade, or any other type of suitable device. A control system can be housed in the cab  106  that can be adapted to allow a machine operator to manipulate and articulate the implement  110  for digging, excavating, or any other suitable application. 
     The body  104  may be supported on a main frame  112  supported on an undercarriage structure  114 . The undercarriage structure  114  includes a supporting structure  118  that supports a track system  102  utilized for movement of the machine  100 . The track system  102  may include first and second track roller frame assemblies  116 , which are spaced from and adjacent respective first and second sides of the undercarriage structure  114 . It will be appreciated that only one of the track roller frame assemblies  116  is visible in  FIG. 1 . 
     Each of the track roller frame assemblies  116  carries an idler wheel  120 , a drive sprocket wheel  122 , and a plurality of track guiding rollers  124 . The drive sprocket wheel  122  is powered in forward and reverse directions by the machine  100  (via a motor such as an internal combustion engine). An endless track chain assembly  126  encircles each drive sprocket wheel  122 , the idler wheel  120 , and the track guiding rollers  124 . The track chain assembly  126  includes a plurality of interconnected track pads  200 , also referred to as track chain members. The track guiding rollers  124  guide the track pads  200  as the track chain assembly  126  is driven by the drive sprocket wheel  122 . 
       FIG. 2  illustrates a portion of the track chain assembly  126  including two pads  200  that are pivotally connected to each other. A track roller  124  is also shown that rides on the rail surfaces  202 ,  202   a  of the track pads  200 . Hence, the weight of the machine  100  is transmitted through the undercarriage structure  114  (see  FIG. 1 ) through the track rollers  124  to the track pad  200 , which transmits that load to the ground through its ground engaging surface  204 . A thru-slot  136  extends along the track chain traveling direction  210  that allows the guide ridge  134  of the track roller to pass from one track pad to the next unhindered while providing lateral guidance of the track chain assembly  126 . 
       FIG. 3  depicts the pinned pivotal connection of a track pad  200  to an adjacent track pad  200 , which may be similarly or identically configured as each other in order to form the track chain assembly  126 . A pin  152  (e.g., may be part of a cartridge pin assembly  128 ) is shown that is disposed in the bores  206  of the lug members of the link members of the track pads  200  (which will be discussed in more detail momentarily), allowing one track pad  200  to pivot relative to the other. A pin retention bolt assembly  130  that helps to prevent “walking” of the cartridge pin assembly  128  laterally out of the bores is also shown. 
     The track chain assembly  126  according to an embodiment of the present disclosure may be further characterized as follows with reference to  FIGS. 3 and 4 . The track chain assembly  126  may comprise a first track pad  200  including a first pair of lugs (later referred to herein as a second lug  232  and a third lug member  234 ) defining a gap  236  laterally between the second lug and the third lug. A second track pad  200   a  may also be provided that includes an intermediate lug (later referred to herein as a first lug  230 ) that is disposed in the gap  236 . The first pair of lugs and the intermediate lug each defines a concentric bore (e.g., see  206 ,  206   a,    206   b ), defining an axis of rotation  132  for a pinned joint  138  of the track chain assembly  126 , and the concentric bore (e.g.,  206 ) of one of the first pair of lugs is in communication with the gap  236  with a first blend  238  disposed axially between the gap  236  and the concentric bore  206  of one of the first pair of lugs. 
     As used herein, a “blend” means any transitional surface that connects two adjacent surfaces and may include an arcuate surface (e.g., a radius, an ellipse, a polynomial spline, etc.), or a chamfer (e.g., a conical face), etc. 
     Similarly, the concentric bore  206   a  of the other of the first pair of lugs may also be in communication with the gap  236  with a second blend  238   a  disposed axially between the gap  236 , and the concentric bore  206   a  of the other of the first pair of lugs. 
     More specifically, the first blend  238  may take the form of a first interior chamfer  240  (so called since it faces laterally toward the gap  236 ), and the second blend  238   a  may take the form of a second interior chamfer  240   a.  This may not be the case for other embodiments of the present disclosure. 
     Each of the concentric bore  206 ,  206   a,    206   b  may define the same diameter D 206  (i.e., within 0.005 of an inch of each other), but not necessarily so. When true, and the track chain assembly  126  may further comprise a cartridge pin assembly  128  that is disposed in each concentric bore  206 ,  206   a,    206   b  to help provide the pivoting function of the pinned joint  138 . 
     To that end, the cartridge pin assembly  128  may include a bushing  140  defining a first bushing chamfer  142  at one of its lateral ends, and a second bushing chamfer  142   a  at the other of its lateral ends that are in communication with the gap  236 . The first bushing chamfer  142  may be parallel to the first interior chamfer  240 , and the second bushing chamfer  142   a  may be parallel to the second interior chamfer  240 . In such a case, these chamfers by be symmetrical to each other about a midplane disposed laterally between them. This may not be the case for other embodiments of the present disclosure. 
     In other embodiments as shown in  FIG. 4 , a funnel angle  266  may be formed between the first bushing chamfer  142 , and the first interior chamfer  240  that diverges toward the gap  236  to help force contaminants away from the seal assembly  150 . A similar arrangement could be present for the second bushing chamfer  142   a  and the second interior chamfer  142   a.  This funnel angle  266  may equal to or greater than 10 degrees. As shown, this angle may range from 15.0 degrees to 25.0 degrees (e.g., 20.0 degrees). 
     More particularly, the first bushing chamfer  142  may be spaced away from the first interior chamfer  140  a minimum distance  144  (see  FIG. 4 ), forming a first debris path  146 . A second debris path  146   a  may be formed by the second interior chamfer  140   a  and the second bushing chamfer  142   a  (see  FIG. 3 ). These paths may allow dirt, debris, or other contaminants to egress away from the seals of the pinned joint. 
     Focusing on  FIG. 4 , the cartridge pin assembly  128  may define a seal receiving void  148  that is in communication with one of the concentric bores (e.g., see  206 ), and the first debris path  146 . A seal assembly  150  may be disposed therein. 
     Looking at  FIGS. 3 and 4 , a ratio of the same diameter D 206  of each concentric bore to the minimum distance  144  may range from 15.0 to 30.0 in some embodiments of the present disclosure (e.g., 18.0 to 22.0). In such a case, the minimum distance  144  may range from 3.0 mm to 7.0 mm (e.g., 5.0 mm). Other ratios and dimensions are possible in other embodiments of the present disclosure. 
     As best seen in  FIG. 3 , one of the first pair of lugs (e.g., see  234 ) may include a shoulder stop surface  242 , and the cartridge pin assembly  128  may be disposed axially adjacent to the shoulder stop surface  242  (e.g., may abut this surface). 
     Other components of the cartridge pin assembly  128  include a pin  152  or shaft, a first end collar  154  attached to the pin, a second end collar  156  attached to the pin, a first bearing  158  disposed radially and axially between the bushing  140 , the pin  152  and the first end collar  154 , and a second bearing  158   a  disposed radially and axially between the bushing  140 , the pin  152 , and the second end collar  156 . 
     The bearings may help prevent the seal assembly  150  from being crushed by axial loads (so they may also be referred to as thrust bearings) while the bushing provides lubrication voids  160  to ease the rotation of the bushing, and therefore one track pad  200  relative to the pin and the end collars, and the other track pad  200   a.    
     Details of various embodiments of the track pad that may be used to construct and/or repair, etc. the track chain assembly will now be discussed in detail with reference to  FIGS. 2  thru  6 . 
     Such a track pad  200  may comprise a shoe member  208  including a ground engaging surface  204 , and defining a track chain traveling direction  210 , a lateral direction  212  that is perpendicular to the track chain traveling direction  210 , and a vertical direction  214  that is perpendicular to both the lateral direction  212 , and the track chain traveling direction  210 . The shoe member  208  further defines a first lateral end  216 , a second lateral end  218 , a front end  220  along the track chain traveling direction  210 , and a rear end  222  along the track chain traveling direction  210 . A lateral distance  224  may be measured from the first lateral end  216  to the second lateral end  218  (see  FIG. 5 ), as well as a width  226  from the front end  220  to the rear end  222  (see  FIG. 2 ) along the track chain traveling direction  210  that is less than the lateral distance  224 . 
     Looking at  FIG. 2 , a first link member  228  may extend upwardly from the shoe member  208  including a first lug member  230  extending from the first link member  228  in a first direction parallel to the track chain traveling direction  210 , a second lug member  232 , and a third lug member  234  both extending from the first link member  228  in a second direction opposite of the first direction, forming a first fork portion  244 . 
     Referring now to  FIGS. 3  thru  6 , this fork portion may include a first lateral outside surface  246 , a second lateral outside surface  248 , a first lateral inside surface  250 , and a second lateral inside surface  252 . The second lug member  232  defines a first aperture (e.g., see  206 ) that extends laterally through the first lateral outside surface  246 , and the first lateral inside surface  250 , forming a first intersection with the first lateral inside surface  250  that includes a first blend  238  extending from the first lateral inside surface  250  to the first aperture. 
     The third lug member  234  may define a third aperture (e.g., see  206   b ) that extends from the second lateral inside surface  252  toward the second lateral outside surface  248 , forming a second intersection with the second lateral inside surface  252  including a second blend (e.g., see  238   a ) extending from the second lateral inside surface  252  to the third aperture. 
     As alluded to earlier herein, the first blend, and the second blend may take the form of a plurality of chamfers (e.g., see  240 ,  240   a ). At least one of the plurality of chamfers may define an acute angle  256  with the lateral direction  212  that ranges from 30.0 degrees to 60.0 degrees (e.g., may be 45.0 degrees, see  FIG. 4 ) in some embodiments of the present disclosure. This angular range may be different in other embodiments of the present disclosure. 
     Also, the first aperture defines a first diameter (e.g., see D 206  in  FIG. 6 ), and the first blend may define a first lateral chamfer distance  258 . A ratio of the first diameter to the first lateral chamfer distance may range from 15.0 to 30.0 in some embodiments of the present disclosure. In such a case, the first lateral chamfer distance  258  may range from 3.0 mm to 7.0 mm (e.g., 5.0 mm). This may not be the case in other embodiments of the present disclosure. 
     Looking at  FIG. 3 , the third lug member  234  may define a first inside shoulder surface (e.g., see  242 ), and the third aperture (e.g., see  206   a ) may extend laterally to the first inside shoulder surface, while a first reduced diameter aperture  262  may extend laterally from the second lateral outside surface  248  to the third aperture. The reduced diameter aperture may be used to press out the cartridge pin assemblies when repair is desired. 
     A track pad  200  according to another embodiment of the present disclosure may also be described as follows looking at  FIGS. 2  thru  6 . A first link member  228  may extend upwardly from the shoe member  208  including a first top rail surface  202 . 
     The second and the third lug members  232 ,  234  may define a first pair of chamfered surfaces (e.g., see  240 ,  240   a ) that are laterally opposite of each other and facing each other. 
     In addition, each of the first pair and the second pair of chamfered surfaces may form an acute angle  256  with the lateral direction  212  as mentioned earlier herein that ranges from 30.0 degrees to 60.0 degrees. 
     In such a case, at least one of the plurality of bores defines a first diameter (e.g., D 206 ), and at least one of the first pair of chamfered surfaces defines a first radial chamfer distance  264 . A ratio of the first diameter to the first radial chamfer distance may range from 15.0 to 30.0 (e.g., 18.0 to 22.0) in some embodiments of the present disclosure. When present, the first radial chamfer distance  264  may range from 3.0 mm to 7.0 mm (e.g., 5.0 mm). 
     The track pad may be a unitary body as shown or be an assembly of different parts. Often, the shoe member and the first rail member, and the second rail member consist essentially of metallic material such as cast iron, steel, grey cast iron, etc. 
     Any of the aforementioned features and their associated dimensions and/or ratios may be altered to be different than what has been shown or mentioned herein in other embodiments of the present disclosure. 
     Industrial Applicability 
     In practice, a track chain assembly, a track pad or a portion thereof may be sold, manufactured, bought etc. and attached to the machine in the aftermarket or original equipment scenarios according to any of the embodiments discussed herein. That is to say, the machine may be sold with the track chain assembly, track pad and/or portion thereof according to embodiments described herein or the machine may be retrofitted, repaired, refurbished to use any of the embodiments discussed herein. The various components including, but not limited to the track pads, may be used from any suitable material such as cast iron, grey cast iron, steel, etc. 
     As can be seen, various embodiments of the track pad disclosed herein may provide reduce the likelihood of fouling of a seal assembly and/or a cartridge pin assembly by contaminants by providing a debris path for the egress of such contaminants away from the seal assembly. This may prolong the useful life of a track chain assembly using such track pads before maintenance is necessary, increasing the profit of an economic endeavor using the track pad(s). 
     As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has”, “have”, “having”, “with” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. 
     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.