Patent Publication Number: US-2022234660-A1

Title: Ultrasonic wear measurement for a track pad

Description:
TECHNICAL FIELD 
     The present disclosure relates to track pads that are used to support heavy equipment such as electric rope shovels, hydraulic mining shovels, and the like. Specifically, the present disclosure relates to such track pads that allow for accurate wear measurement of load bearing surfaces. 
     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 the undercarriage that may cause the track pads to wear. More specifically, load bearing surfaces of the track pad may become worn due to the repeated roller contact between the idler, track rollers, and sprocket of the undercarriage. This may be exacerbated by the contaminants that infiltrate at the rolling point of contact between a track pad and any of these undercarriage components. Eventually, the thickness of the load bearing structure may be become too thin, warranting replacement. It is desirable to monitor this wear and replace the track pad at planned service intervals to reduce the unplanned downtime of the machine. 
     Current techniques to measure this wear include comparing the distance from the top surface of a drive lug to the load bearing surface after use and compare that to the original distance when the track pad is new. However, the top surface of a drive lug is also subject to wear, which may lead to an underestimation of the wear and unforeseen track problems in between planned service intervals. 
     U.S. Pat. Appl. Publ. No. 20160023696 A1 discloses a crawler shoe for a mining vehicle that includes a first wear surface, a second wear surface positioned opposite the first wear surface, a recess formed within the first wear surface and including a measurement datum formed at a bottom portion of the recess. The measurement datum is positioned below the first wear surface such that the measurement datum is subjected to less service wear than the first wear surface. An approximately linear transmission path may be provided that is configured to receive an ultrasonic signal, and that extends from the measurement datum to the second wear surface. 
     However, since the recess is on the bottom of the track pad, the track chain assembly typically needs to be removed and disassembled to allow access to the recess for insertion of an ultrasonic probe to measure the wear. An easier method of wear measurement that does not necessarily need the track chain to be disassembled is thus warranted, 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. The track pad includes a load bearing surface, while the ground engaging surface may lack apertures, and the track pad may define an interior cored-out portion including a planar surface that is disposed both laterally and along the track chain traveling direction adjacent to the load bearing surface, and vertically underneath the load bearing surface. 
     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 top surface may extend laterally from the first lateral end to the second lateral end, while the ground engaging surface may extend uninterruptedly from the first lateral end to the second lateral end. The top surface may include a planar load bearing surface that is perpendicular to the vertical direction. Also, the shoe member may define an interior hollow portion that may be partially defined by an interior planar surface that is disposed below the first planar load bearing surface. 
     An onboard track machine wear measurement system according to an embodiment of the present disclosure may comprise an ultra-sonic probe that is attached to an undercarriage of the machine that is disposed adjacent a track chain assembly, and a controller that is in communication with the ultra-sonic probe. The controller may be configured to determine the thickness of a load bearing wall of a track component of the track chain assembly. 
    
    
     
       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 an electric 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 perspective view of a track pad of  FIG. 2  shown in isolation. 
         FIG. 4  is cross-sectional view of the track pad of  FIG. 3 , revealing the cored-out interior structure of the track pad with a flat surface that may be used to measure the thickness of the load bearing wall, and the wear of the load bearing surface via ultra-sonic wear measurement. 
         FIG. 5  is a schematic diagram representing an on-board track machine wear measurement system according to an embodiment of the present disclosure that may be used to measure the thickness of the load bearing wall of the track pad of  FIG. 4 . 
         FIG. 6  is a flow chart containing a method that may be executed by the controller of the wear measurement system of  FIG. 5 . 
     
    
    
     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 an electric rope 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 a hydraulic mining shovel, 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, an electric 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. This same control system may be part of or incorporate, or be in communication with the onboard track machine wear measurement system  300  that will be discussed in further detail later herein. 
     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 . 
     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 herein. The track guiding rollers  124  guide the track pads  200  as the track chain assembly  126  is driven by the drive sprocket wheel  122 . The track chain assembly  126  may have any track chain member, track pin retention device, and/or track chain assembly. 
       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 a load bearing surface 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 . 
     A track pad  200  according to an embodiment of the present disclosure may ease wear measurement will now be described with reference to  FIGS. 2 and 3 . 
     The track pad may comprise a shoe member  208  including a ground engaging surface  204 , and defining a track chain traveling direction  210  (typically perpendicular to the axis A 206  of bore  206  that provides a pivoting axis for the joint between two track pads), 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 . 
     Moreover, the shoe member  208  may further define a first lateral end  216 , a second lateral end  218 , as well as 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 , as well as a width  226  from the front end  220  to the rear end  222  along the track chain traveling direction  210  that is less than the lateral distance  224 . 
     A first link member  228  may extend upwardly from the shoe member  208  that includes 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  that both extending from the first link member  228  in a second direction opposite of the first direction, forming a first fork portion  244 . 
     As just mentioned herein, the track pad  200  also includes a load bearing surface  202  on top of the track pad for receiving the weight of the machine through the track roller. The ground engaging surface  204  may lack apertures. Instead, the track pad  200  may defines an interior cored-out portion  236  including a planar surface  238  that is disposed both laterally and along the track chain traveling adjacent to the load bearing surface  202 , and vertically underneath the load bearing surface  202 . 
     A second link member  228   a  may extend upwardly from the shoe member  208  including a fourth lug member  230   a  that extends from the second link member  228   a  along the first direction parallel to the track chain traveling direction  210 , a fifth lug member  232   a , and a sixth lug member  234   a  both extending from the second link member  228   a  in the second direction opposite of the first direction, forming a second fork portion  254 . 
     The first lug member  230  may be disposed laterally between the second lug member  232 , and the third lug member  234 . Likewise, the fourth lug member  230   a  may be disposed laterally between the fifth lug member  232   a , and the sixth lug member  234   a . This allows the first lug member of a track pad to mate with the second and third lug member of an adjacent track pad such to form a pivoting connection of a track chain assembly as shown in  FIG. 2 . 
     With continued reference to  FIGS. 3 and 4 , the first lug member  230  may define a first bore (e.g., see  206 ) defining an axis of rotation (e.g., see A 206 ) that is perpendicular to the track chain traveling direction  210  as alluded to earlier herein. The load bearing surface  202  may include a flat face  240  for reducing friction between this face and the track roller and/or for easing wear measurement. 
     The track pad  200  may further comprises a central support portion  242  with the load bearing surface  202  disposed on top of this central support portion  242 . A first drive lug  246 , and a second drive lug  246   a  are also provided that are intended to be engaged by the drive sprocket to move the track chain assembly, and as a result the machine. The first drive lug  246  may be disposed laterally adjacent to the load bearing surface  202  toward the first lateral end  216 , whereas the second drive lug  246   a  may be disposed laterally adjacent the load bearing surface  202  toward the second lateral end  218 . 
     A first lateral intermediate surface  248  may be disposed laterally between the first drive lug  246  and the first link member  228 , and a second lateral intermediate surface  248   a  may be disposed laterally between the second drive lug  246   a  and the second link member  228   a.    
     Various features may also be provided to aid in manufacturing the track pad  200  via a casting process. For example, a first aperture  250  may extend vertically through the first lateral intermediate surface  248  to the interior cored-out portion  236 , and a second aperture  250   a  that extend vertically through the second lateral intermediate surface  248   a  to the interior cored-out portion  236 . Similarly, the central support portion  242  defines a horizontal aperture  252  extending through the central support portion  242 . 
     A first top beveled surface  256  may extend laterally from the first link member  228  to the first lateral end  216 , as well as a second top beveled surface  256   a  that may extend laterally from the second link member  228   a  to the second lateral end  218 . A first side aperture  258  may extend through the first top beveled surface  256  to the interior cored-out portion  236 , and a second side aperture  258   a  extending through the second top beveled surface  256   a  to the interior cored-out portion  236 . Bottom chamfered surfaces on the ground engaging surface may be disposed vertically below the top beveled surfaces as shown in  FIGS. 3 and 4 . This may not be the case for other embodiments of the present disclosure. 
     These various apertures allow for removal of the sand core that forms the cored-out portion. This features may be omitted in other embodiments of the present disclosure. 
     The track pad  200  according to another embodiment may be described as follows with reference to  FIGS. 3 and 4 . The track pad  200  may have a top surface  260  that extends laterally from the first lateral end  216  to the second lateral end  218 . The ground engaging surface  204  may extend uninterruptedly from the first lateral end  216  to the second lateral end  218 . The top surface  260  defines a plurality of apertures extending (e.g., see  250 ,  250   a ,  258 ,  258   a ) through the top surface  260  to an interior hollow portion (e.g., see  236 ), and the top surface  260  includes a planar load bearing surface (e.g., see  240 ) that is perpendicular to the vertical direction  214 , and the interior hollow portion (e.g., see  236 ) is partially defined by an interior planar surface (e.g., see  238 ) that is disposed below the first planar load bearing surface (e.g., see  240 ). 
     In addition, the interior hollow portion is at least partially defined by a bottom interior surface  262  that is disposed vertically below the interior planar surface (e.g., see  238 ). This may not be the case for other embodiments of the present disclosure. 
     As best seen in  FIG. 4 , the track pad  200  may define a minimum vertical height  264  from load bearing surface  202  to the interior planar surface (e.g., see  238 ), and the bottom interior surface  262  is spaced a minimum vertical distance  268  from the interior planar surface (e.g., see  238 ). A ratio of the minimum vertical height to the minimum vertical distance may range from 1.02 to 1.73 (e.g., with a nominal value of 1.33) in some embodiments of the present disclosure. 
     In such an embodiment, the minimum vertical distance  266  may range from 66.5 mm to 112.5 mm (e.g., with a nominal value of 86.5 mm), the minimum vertical height may range from 88.5 mm to 150.0 mm (e.g., with a nominal value of 115.0 mm), and a similar vertical height dimension (not shown) may be measured from the bottom interior surface to the ground engaging surface  204  that may range from 98.5 mm to 166.4 mm (e.g., with a nominal value of 128.0 mm). Also, the interior hollow portion has a hour glass configuration extending from the first lateral end  216  to the second lateral end  218  with a necked down region defined by the minimum vertical distance  266 . It should be noted that these dimensions and ratios are material dependent so that the composition and hardness of the material affects them. The above parameters may be applicable when alloy steel is employed. But, if a softer material such as a steel employing manganese is employed, then thicker dimensions might be warranted. For this embodiment, one skilled in the art might expect up to 30.0 mm of wear on the top surface, and 15.0 mm of wear on the bottom surface depending on the application before maintenance is required. 
     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. 
     Again, 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 ease the measuring of the wear of a track pad or other track component such as a track link, a track shoe, etc. 
     In practice, an onboard track machine wear measurement system  300  may be provided that allows the measurement of wear of track component of a track chain assembly while the track chain is being used by the machine. 
     Such a system  300  may comprise an ultra-sonic probe  302  that is attached to an undercarriage of the machine that is disposed adjacent a track chain assembly (as shown in  FIG. 1 ). A controller  304  may be provided that is in communication with the ultra-sonic probe  302  (see  FIG. 5 ). The controller  304  may be configured to execute a method  400  as depicted in  FIG. 6  including the step of determining the thickness of a load bearing wall of a track component of the track chain assembly (see step  402  in  FIG. 6 ). The controller may take the form of any suitable process device including a microcontroller, a microprocessor, hardwired logic, software, computer, etc. 
     The track component may take the form a track pad  200  including a load bearing surface  202 , and a ground engaging surface  204 , and the ultra-sonic probe  302  may be facing the load bearing surface  202  (see  FIG. 5 ). More specifically, the track pad may include a hollow interior (e.g., see  236 ) with a flat surface (e.g., see  240 ) that is disposed underneath the load bearing surface  202 . 
     The controller  304  may be configured to compare the thickness of the load bearing wall to a threshold value and signal if the thickness falls below the threshold value. (see step  404  in  FIG. 6 ) 
     As seen in  FIG. 5 , an output device  306  may be provided that conveys a signal that the track pad needs maintenance, to be replaced, etc. The output device  306  may take any suitable form including a monitor, an alarm, an auditory signal via a speaker, a light, etc. 
     An input device  308  may be in communication with the controller  304  and may take the form of a keyboard, a mouse, a GUI (graphical user interface), HMI (human machine interface), a touchscreen, a voice command, etc. 
     The controller  304  may be in communication with a network  310  and the server  312  to allow others access to the wear measurement information including a base station, the Cloud, etc. 
     Looking once more at  FIG. 1 , the controller may be configured to measure the load bearing wall thickness of a plurality of track pads that pass the ultra-sonic probe as the track chain moves in operation (see  404  in  FIG. 6 ). 
     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.