Abstract:
Vibration or the like is prevented for long-term use by normalizing, with operation continuing, a tread of a crawler belt link through grinding in an early stage where uneven wear such as corrugated wear occurs. With a crawler belt of a crawler vehicle wound, an abrasive plate for grinding the tread of the crawler belt link is disposed to contact the tread. While the crawler vehicle does normal traveling work, the abrasive plate corrects the tread of the crawler belt link for the uneven wear. The vibration of a vehicle body can thus be prevented during travel with no uneven wear produced.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a crawler belt link grinding system and a crawler structure including the grinding system that find use in a crawler type work vehicle having its lower structure equipped with a crawler belt, such as construction equipment including a hydraulic excavator and a bulldozer or other industrial equipment.  
       BACKGROUND ART  
       [0002]     In a conventional crawler structure of a crawler type work vehicle, a traveling crawler belt is formed of crawler belt links wound endlessly between a sprocket and an idler that are disposed in respective rear and front positions of a main frame. This crawler belt is held by a plurality of track rollers on a ground-contact side, is held by carrier rollers on a non-ground-contact side to maintain uniform tension and is driven by being wound around a sprocket member of the sprocket.  
         [0003]     In such a crawler structure, when a tread of the crawler belt link is in rolling contact with the track roller, the carrier roller or the idler during travel, the tread wears down unevenly, thus showing corrugated wear. Such uneven wear is caused, for example, during travel on soft ground G as shown in  FIG. 13 ( a ). Since soft ground G easily causes sinking, earth and sand easily adhere to the crawler belt. The earth and sand adhere between tread  51  of crawler belt link  50  and idler  55 , thus causing the wear when tread  51  slides in surface D of contact with idler  55 . Moreover, as shown in  FIG. 13 ( b ), when ground G is soft enough to easily cause sinking as in the above case, the earth and sand adhere to respective ends of treads  51  of crawler belt links  50  at track roller  56 , thus causing the wear during slide. Briefly speaking, traveling on the soft ground quite often causes the part contacting idler  55  or track roller  56  to show severe partial wear because crawler belt  52  sinks easily, and consequently, tread  51  of crawler belt link  50  shows corrugated wear  53  as illustrated in  FIG. 13 ( c ). A high degree of corrugated wear results in vibration of a vehicle body during travel on a stable hard road, and when the corrugated wear becomes noticeable, noise is caused, thus adversely affecting an environment. Accordingly, the link must be replaced when tread  51  of crawler belt link  50  shows the severe corrugated wear, and such replacement reduces cost efficiency.  
         [0004]     For solving the problem of wear of the crawler belt link, no concrete means is proposed. A known measure against the wear of the crawler belt link is disclosed, for example, in Japanese Utility Model Unexamined Publication No. H01-125286. According to this publication, a flange of the track roller is ground according to wear of the tread of a track link (crawler belt link) at the track roller. The flange is thus prevented from contacting a connecting pin boss of the track link, whereby the use of the crawler belt link is extended.  
         [0005]     However, the measure disclosed in Japanese Utility Model Unexamined Publication No. H01-125286 is not a technique adapted to solve the problem that is addressed by the present invention because this measure is based on the assumption that the link shows overall wear. This measure solves problem that only the initial flange maintains its size as a result of the tread showing the wear at the roller where relative wear is caused, by grinding the flange according to the wear of the tread. As described earlier, no measure against the corrugated wear or uneven wear of the crawler belt link is found, so that there is no other choice but to replace the link. Accordingly, the reduction of running costs remains unattained under present circumstances.  
         [0006]     In view of such circumstances, the present invention aims to provide a crawler belt link grinding system and a crawler structure including the grinding system that allow a tread to withstand long-term use by normalizing, with operation continuing, the tread through grinding in an early stage where uneven wear such as corrugated wear occurs.  
       SUMMARY OF THE INVENTION  
       [0007]     To achieve the object described above, a crawler belt link grinding system of the present invention includes: 
        an abrasive plate for grinding a tread of a crawler belt link, the abrasive plate being disposed to contact the tread with a crawler belt of a crawler structure wound.        
 
         [0009]     According to the present invention, while a crawler vehicle does normal traveling work, the abrasive plate corrects the tread of the crawler belt link for uneven wear. Vibration of a vehicle body can thus be prevented during travel with no uneven wear produced, and durability of the crawler belt can be maintained.  
         [0010]     In the present invention, the abrasive plate is disposed above a track frame. Thus, the abrasive plate can secure its position for mounting with ease, and detachment and adjustment to the position are facilitated.  
         [0011]     In the invention, the abrasive plate may be disposed below a rear portion of the track frame and supported by a support member added to a bogie supporting a track roller, or may be supported by the support member, which is added to the rear portion of a bottom side of the track frame. Consequently, grinding can be performed even on a ground-contact side of the crawler belt, the detachment of the abrasive plate and the adjustment to the position of the abrasive plate are possible, and the crawler belt links can be prevented from rising during travel.  
         [0012]     In the invention, it is preferable that the abrasive plate mounted can be detached or withdrawn from a grinding position. When replacement or grinding is not required of the abrasive plate, the abrasive plate can be removed or moved away from a position of contact with the crawler belt link, so that needless wear and an increase in resistance can be prevented.  
         [0013]     Moreover, the abrasive plate disposed has an adjustable setting position. Adjusting the abrasive plate to an optimum position for grinding before use can shorten a period of time during which the abrasive plate is used, thus achieving a desired object, and can prevent the needless wear and the increase in resistance that is associated with the grinding.  
         [0014]     Preferably, the abrasive plate of the present invention includes an abrasive surface including an abrasive disposed thereon, and the abrasive surface is provided to contact at least one of the crawler belt links in parallel with the crawler belt link. Adopting such a structure allows smooth grinding for normalizing the tread of the crawler belt link and prevents irregular wear of the abrasive surface of the abrasive plate, thus extending the life of the abrasive plate.  
         [0015]     A crawler structure of the present invention includes: 
        an endless crawler belt wound between a sprocket and an idler of a crawler vehicle; and     a crawler belt link grinding system for grinding a tread of a crawler belt link of the crawler belt.        
 
         [0018]     According to this invention, the tread of the crawler belt link is automatically ground by the crawler belt link grinding system during travel of the vehicle that is effected by driving the crawler structure. Since the crawler belt link is driven so as not to have the uneven wear, the vibration is suppressed, whereby smooth travel is secured.  
         [0019]     In this invention, it is preferable that the crawler belt link grinding system is supported at a track frame and grinds the tread of the crawler belt link on at least one of a non-ground-contact side and a ground-contact side of the crawler belt. The incorporation of the crawler belt link grinding system is thus rationalized, so that the crawler belt wound can have the tread of its link ground in the process of being driven, while the vehicle is in operation. Consequently, the uneven wear can be corrected for in a short time, and the crawler belt can be driven normally. In this way, trouble resulting from the uneven wear is prevented with ease.  
         [0020]     In this invention, the crawler belt link grinding system preferably includes an abrasive plate formed to have a flat abrasive surface. With this structure, the tread of the crawler belt link that comes into contact with the abrasive plate is always corrected to have a flat surface, thereby being prevented from having the uneven wear. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a side view of a work machine equipped with a crawler structure in accordance with a first exemplary embodiment of the present invention.  
         [0022]      FIG. 2  is a front elevation of an essential part of the crawler structure in accordance with the first embodiment.  
         [0023]      FIG. 3  is a top plan view of the essential part in  FIG. 2  with an upper portion of a crawler belt removed.  
         [0024]      FIG. 4  is an enlarged sectional view of an essential part of an abrasive plate in accordance with the first embodiment.  
         [0025]      FIG. 5  is a sectional view of a mounting part for an abrasive plate in accordance with a second exemplary embodiment of the present invention.  
         [0026]      FIG. 6  is a side view of a crawler belt link grinding system in accordance with a third exemplary embodiment of the present invention.  
         [0027]      FIG. 7  is a top plan view of the system in  FIG. 6 .  
         [0028]      FIG. 8  is a side view of a crawler belt link grinding system in accordance with a fourth exemplary embodiment of the present invention.  
         [0029]     FIGS.  9 ( a ) and  9 ( b ) are respective top plan and side views of a crawler belt link grinding system in accordance with a fifth exemplary embodiment of the present invention.  
         [0030]      FIG. 10  is a side view of a crawler belt link grinding system in accordance with a sixth exemplary embodiment of the present invention.  
         [0031]      FIG. 11  is a view taken along line A-A of  FIG. 10 .  
         [0032]      FIG. 12  is a view taken along line B-B of  FIG. 10 .  
         [0033]     FIGS.  13 ( a ),  13 ( b ) and  13 ( c ) illustrate a phenomenon leading to corrugated wear of a conventional crawler belt link, and FIGS.  13 ( a ) and  13 ( b ) illustrate respective parts contacting an idler and a track roller, respectively, while  FIG. 13 ( c ) illustrates the link showing the corrugated wear. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]     Referring to the accompanying drawings, a description will be provided hereinafter of concrete exemplary embodiments of a crawler belt link grinding system and a crawler structure according to the present invention.  
       First Embodiment  
       [0035]      FIG. 1  is a side view of a work machine equipped with a crawler structure in accordance with a first exemplary embodiment of the present invention.  FIG. 2  is a front elevation of an essential part of the crawler structure in accordance with the present embodiment, and  FIG. 3  is a top plan view of the essential part in  FIG. 2  with an upper portion of a crawler belt removed.  FIG. 4  is an enlarged sectional view of an essential part of an abrasive plate.  
         [0036]     Crawler structure  10  of the present embodiment is used as a lower structure of work machine  1 , such as a bulldozer, which travels on rough terrain for work. This crawler structure  10  is equipped with, at each side of track frame  11 , endless crawler belt  14  wound between sprocket  12  and idler  13  that are disposed at respective ends of track frame  11 , a plurality of track rollers  15  for maintaining contact between crawler belt  14  and the ground during travel, and carrier rollers  16  for retaining tension of crawler belt  14 . Crawler structure  10  is also equipped with crawler belt link grinding system  20 , supported above track frame  11 , for correcting respective treads  14   b  of a plurality of crawler belt links  14   a,  which form crawler belt  14 , for uneven wear.  
         [0037]     Crawler belt link grinding system  20  is formed mainly of abrasive plate  21 . This abrasive plate  21  includes base frame  22  having base end bosses  23 ,  23  supported by mounting brackets  25 ,  25  standing on respective two mounting seats  17 ,  17 , and abrasive layers  28  formed on a top surface of base frame  22 . Mounting seats  17 ,  17  have a required spacing and are formed along a traveling direction on a top surface of track frame  11  between carrier rollers  16 ,  16 , which are provided along the traveling direction on the top surface of track frame  11  to have a required spacing.  
         [0038]     Base frame  22  of abrasive plate  21  is formed to have top surface  24  having width B larger than an outside width of crawler belt links  14   a  and length L longer than one pitch P (which is about 1.5 in the present embodiment and is shown in  FIG. 2 ) of crawler belt link  14   a.  This base frame  22  is detachably mounted by inserting mounting bracket  25 , which is fixed on mounting seat  17 , between base end bosses  23 ,  23  that are formed at each base end of frame  22  below top surface  24  and separated along the direction of the width, and inserting mounting shaft  26  through respective transverse support holes of mounting bracket  25  and base end bosses  23 ,  23 . Top surface  24  of base frame  22  is formed integrally with abrasive layers  28 . These abrasive layers  28  grind treads  14   b  of crawler belt links  14   a  in succession during travel.  
         [0039]     Abrasive layer  28  formed on the top surface of base frame  22  has a rough surface formed by overlaying, for example, super hard material including material having cemented carbide particles dispersed therein. Abrasive layers  28  each have the form of a block having a required size. As shown in  FIG. 3 , these abrasive layers  28  are arranged in a right position that treads  14   b  of crawler belt links  14   a  pass. Instead of being overlaid to form an overlay, which is flat from corner to corner, the super hard material for abrasive layer  28  is preferably overlaid to form stripes crossing the traveling direction of crawler belt links  14   a.  Since a plurality of stripes (hills  28   a ) and grooves  28   b  alternately form abrasive layer  28  (see  FIG. 4 ), the tread of crawler belt link  14   a  is ground by those hills  28   a  formed by overlaying, and chips are effectively discharged sideward by grooves  28   b.  Consequently, clogging hardly takes place.  
         [0040]     Crawler belt link grinding system  20  thus formed is mounted at such a height for use that abrasive layers  28  formed on the top surface of abrasive plate  21  contact tread  14   b  of crawler belt link  14   a  of crawler belt  14  that moves between front and rear carrier rollers  16 ,  16 . Abrasive layers  28  of abrasive plate  21  are disposed to be virtually parallel with a portion of crawler belt  14  that extends between front and rear carrier rollers  16 ,  16 .  
         [0041]     When work machine  1  travels, crawler belt  14  is driven by being wound around sprocket  12  and idler  13  and moves upwardly of track frame  11 . When this crawler belt  14  passes abrasive plate  21  disposed as described earlier, tread  14   b  of crawler belt link  14   a  is ground by grazing abrasive layers  28  of crawler belt link grinding system  20  thus included in crawler structure  10  between carrier rollers  16 ,  16 . Since tread  14   b  of crawler belt link  14   a  grazes against abrasive layer  28  while moving, tread  14   b  is not ground hard. This graze is repeated, whereby the uneven wear is prevented. In the place where abrasive plate  21  is disposed, crawler belt links  14   a  are substantially held under tension by carrier rollers  16 ,  16  and come into contact with abrasive layers  28  extending along a distance more than one pitch of crawler belt link  14   a,  so that treads  14   b  are always kept flat for grinding when passing the abrasive parts. In this way, treads  14   b  become flattened. Accordingly, crawler belt link  14   a  can be prevented from developing partial wear conventionally caused by contact with idler  13  or track roller  15  during travel on the soft ground. Consequently, corrugated wear (uneven wear), which results in vibration of a vehicle body or noise, can be eliminated.  
         [0042]     Crawler belt link grinding system  20  of the present embodiment can basically be detached from track frame  11 . In cases where no grinding is required, abrasive plate  21  may be removed for storage by pulling out mounting shaft  26 , which is inserted through mounting bracket  25  and base end bosses  23  for support. This prevents needless wear of tread  14   b  of crawler belt link  14   a  and an increase in resistance that is associated with grinding, and allows grinding only when necessary.  
       Second Embodiment  
       [0043]      FIG. 5  is a sectional view of a mounting part for an abrasive plate in accordance with a second exemplary embodiment of the present invention.  
         [0044]     In the present embodiment, when no grinding using abrasive plate  21  is required, the removal of abrasive plate  21  that is described earlier is replaced by the use of mounting shaft  26 A with an eccentric structure as a mounting shaft passing through a base end boss of base frame  22  and shaft support bosses of a mounting bracket. In other words, the following structure is adopted. Mounting bracket  25 A is formed to fork into two shaft support bosses  25   a,  and base end boss  23 A of base frame  22  is inserted between these shaft support bosses  25   a,    25   a  of mounting bracket  25 A. Mounting shaft  26 A has an intermediate section having the eccentric structure, and this eccentric section  26   a  of mounting shaft  26 A is inserted into a shaft hole of base end boss  23 A for support. By displacing eccentric section  26   a  through rotation of mounting shaft  26 A, the amount of eccentricity a is increased, whereby abrasive plate  21  can be moved vertically by an amount which is twice the amount of eccentricity a. Under normal conditions, abrasive plate  21  is used by setting eccentric section  26   a,  for example, between a neutral height position and a highest position. Abrasive plate  21  can be put out of use by displacing eccentric section  26   a  to a lowest position through rotation for bringing abrasive layer  28  out of contact with tread  14   b  of crawler belt link  14   a.    
         [0045]     With the use of mounting shaft  26 A provided with such an eccentric section  26   a,  the height can be adjusted easily by rotating mounting shaft  26 A even when an adjustment is made to the contact between abrasive layer  28  of abrasive plate  21  and tread  14   b  of crawler belt link  14   a.  To facilitate the rotation, the following structure is adopted as an example. Mounting shaft  26 A is formed to have hexagonal shaft end part  26   b,  which is somewhat long. Torque is transmitted with a wrench. Shaft end part  26   b  is partly provided with threaded part  26   c,  and lock nut  26   d  is screwed onto threaded part  26   c.  This nut  26   d  can be locked by being brought into contact with an outer end face of shaft support boss  25   a  of mounting bracket  25 A. With this structure, a rotation angle of mounting shaft  26 A can be decided arbitrarily. Such operation can be done outside track frame  11 , so that the work is facilitated.  
       Third Embodiment  
       [0046]      FIG. 6  is a side view of a crawler belt link grinding system in accordance with a third exemplary embodiment of the present invention, and  FIG. 7  is a top plan view of the system in  FIG. 6 .  
         [0047]     In addition to abrasive plate  21  mentioned earlier, crawler belt link grinding system  20 A of the present embodiment includes another abrasive plate  21 A near idler  13 . This abrasive plate  21 A is basically similar in structure to above-described abrasive plate  21  except that this plate  21 A has a somewhat different support structure. Accordingly, the following description refers to only those different in structure from those of the foregoing embodiments. Elements similar to those in the foregoing embodiments have the same reference marks, and the detailed descriptions of those elements are omitted.  
         [0048]     In abrasive plate  21 A, base frame  22 A having a required size has one end along a traveling direction, and base end bosses  23  are attached to this end. Base frame  22 A is supported above track frame  11  by passing mounting shaft  26  through mounting bracket  25  in the same manner as described earlier. Abrasive layers  28  formed on a top surface of base frame  22 A are so disposed that tread  14   b  of crawler belt link  14   a  of crawler belt  14  that slopes away from idler  13  to be passed to one of carrier rollers  16  comes into contact with these abrasive layers  28  for grinding.  
         [0049]     In crawler belt link grinding system  20 A thus constructed, the plurality of abrasive plates  21 ,  21 A are disposed at an upper central position and an upper slanting position, respectively, thus performing further correction through grinding. Abrasive plate  21 A provided at the slanting position also serves as a guide for retaining tension by preventing the slack of crawler belt  14  between idler  13  and carrier roller  16 . When abrasive plate  21 A at the slanting position is put out of use, abrasive plate  21 A can be brought out of contact with crawler belt link  14   a  by rotating mounting shaft  26  at a shaft supporting part. Using an eccentric shaft as mounting shaft  26  as described earlier allows withdrawal of abrasive plate  21 A from a grinding position through the same operation and also allows adjustment to the grinding position.  
       Fourth Embodiment  
       [0050]      FIG. 8  is a side view of a crawler belt link grinding system in accordance with a fourth exemplary embodiment of the present invention.  
         [0051]     In addition to earlier-described abrasive plate  21  disposed above a central portion of track frame  11 , crawler belt link grinding system  20 B of the present embodiment includes abrasive plate  21 A disposed between front carrier roller  16  and idler  13  and abrasive plate  21 B disposed between rear carrier roller  16  and sprocket  12 . These abrasive plates  21 A,  21 B are provided at respective portions where wound crawler belt  14  slopes. As in the case of the third embodiment, abrasive plates  21 A,  21 B each have base end bosses  23  at one base end, and these base end bosses  23  and mounting bracket  25  are supported by mounting shaft  26 . Accordingly, the following description refers to only those different from those of the foregoing embodiments. Elements similar to those in the foregoing embodiments have the same reference marks, and the descriptions of those elements are omitted.  
         [0052]     In crawler belt link grinding system  20 B of this embodiment, abrasive plate  21 B having a required size is disposed at the portion, where the crawler belt is stretched from sprocket  12  in a sloping condition, so as to correspond to the slope. In other words, base frame  22 B having the required size has the end along a traveling direction that is attached to base end bosses  23 , is supported above track frame  11  by passing mounting shaft  26  through mounting bracket  25  in the same manner as described earlier, and has the other end supported from below by being connected to track frame  11  by auxiliary support piece  29 . Except for the above, abrasive plate  21 B is similar in structure to abrasive plate  21 A.  
         [0053]     In crawler belt link grinding system  20 B thus constructed, the plurality of abrasive plates  21 ,  21 A,  21 B are disposed substantially above the entire section of a non-ground-contact side of crawler belt  14  between idler  13  and sprocket  12 , so that treads  14   b  of crawler belt links  14   a  are ground by sliding friction against abrasive layers  28  of abrasive plates  21 ,  21 A,  21 B while being held under tension associated with the movement of crawler belt  14 . Consequently, uneven wear can be prevented promptly from taking place. If grinding speed increases, for example, all the abrasive plates may be removed, or one or two of the abrasive plates may selectively be left for operation. Abrasive plates  21 A,  21 B located at the respective slanting positions also serve as guides-for retaining the tension by preventing the slack of crawler belt  14  when used.  
       Fifth Embodiment  
       [0054]     FIGS.  9 ( a ) and  9 ( b ) are respective top plan and side views of a crawler belt link grinding system in accordance with a fifth exemplary embodiment of the present invention.  
         [0055]     Crawler belt link grinding system  20 C of the present embodiment is basically similar to that of the first embodiment except that its abrasive plate  21 C has a different support structure. Originally, two carrier rollers  16  are provided above track frame  11 . However, mounting bracket  25 C is provided in place of one of these rollers  16  for abrasive plate  21 C. This mounting bracket  25 C supports an end of support shaft  32  passing through boss  31  provided to the center of a bottom surface of base frame  22 C having a required size, and abrasive plate  21 C is disposed to contact respective treads  14   b  of crawler belt links  14   a  of wound crawler belt  14 .  
         [0056]     For grinding by contact with treads  14   b  of side-by-side crawler belt links  14   a,  a top surface of base frame  22 C is formed to have rough surfaces by overlaying the same super hard material as that of earlier-described abrasive plate  21  that includes the material having the cemented carbide particles dispersed therein. In this embodiment, abrasive layers  28 ′ are not provided in blocks, but are provided to extend substantially throughout the entire length of base frame  22 C. Abrasive layer  28 ′ extends to a curved portion located at each end of frame  22 C, so that tread  14   b  of crawler belt link  14   a  undergoes grinding reasonably from a position where this tread  14   b  comes into contact with that abrasive layer  28 ′ for the first time. However, the abrasive layers are not limited to this arrangement and can be arranged in blocks as described earlier.  
         [0057]     Similarly to the crawler belt link grinding system of each of the foregoing embodiments, crawler belt link grinding system  20 C of the present embodiment is such that traveling crawler belt link  14   a  is ground by grazing abrasive layer  28 ′. When this system  20 C is put out of use, this system  20 C can be removed or can be brought out of contact by, for example, forming support shaft  32  into an eccentric shaft described earlier and displacing system  20 C downward from a grinding position (position of the treads of the moving crawler belt links) by the amount of eccentricity.  
       Sixth Embodiment  
       [0058]     In each of the foregoing embodiments, the crawler belt link grinding system having the abrasive plate disposed above track frame  11  has been described. In a sixth exemplary embodiment of the present invention, an abrasive plate is disposed below track frame  11 .  FIG. 10  is a side view of a crawler belt link grinding system in accordance with the present embodiment.  FIGS. 11 and 12  are views taken along respective lines A-A and B-B of  FIG. 10 .  
         [0059]     Crawler belt link grinding system  20 D of this embodiment is constructed to include two separate abrasive plates  21 D facing each other across traveling centerline X of crawler belt links  14   a.  These abrasive plates  21 D are disposed at a front position (left position in the drawing) of sprocket  12  of a crawler structure to correspond to respective crawler belt link treads  14   b  of crawler belt  14 .  
         [0060]     Each abrasive plate  21 D includes a rectangular base member secured to an inner periphery of leading end part  35   a  of support arm (support member)  35 , and is disposed to contact tread  14   b  of crawler belt link  14   a  of crawler belt  14  moving on a ground-contact side to be wound around sprocket member  12 ′ of sprocket  12 . Support arm  35  has a base end attached to an outer end of pivot shaft  19  of bogie  18  supporting track roller  15 . The pair of left and right support arms  35  supporting abrasive plates  21 D are each shaped to bend inwardly toward traveling centerline X of crawler belt  14  at its intermediate section and to extend from the base end to the part secured to abrasive plate  21 D, are disposed to be symmetrical with respect to traveling centerline X and are coupled together by stay bolt  36  at the parts secured to the respective abrasive plates so as to face each other across a specified spacing.  
         [0061]     Abrasive plates  21 D of crawler belt link grinding system  20 D thus constructed are formed into two left and right separate pieces so as not to contact sprocket member  12 ′ of sprocket  12 , and are each equipped with abrasive layer  28   a  at a surface facing tread  14   b  of crawler belt link  14   a.  Abrasive layer  28   a  is formed by overlaying super hard material including material having cemented carbide particles dispersed therein in the same manner as in the foregoing embodiments. Abrasive plates  21 D are provided in a space formed between a position before a position where crawler belt  14  winds around sprocket member  12 ′ of sprocket  12  and track roller  15  so as to perform grinding during travel in the same manner as the abrasive plate located above track frame  11 .  
         [0062]     Abrasive plates  21 D disposed in the above-mentioned position not only prevents uneven wear by grinding but also suppress rising of crawler belt  14  moving in a feeding direction on the ground-contact side between sprocket member  12 ′ of sprocket  12  and track roller  15 , thereby preventing irregular load from acting on crawler belt links  14 . Vvhen crawler belt link  14  requires no grinding for correction, abrasive plate  21 D can be removed by detaching the base end of support arm  35  from pivot shaft  19  and disconnecting stay bolt  36 . Thus, resistance caused by grinding is eliminated.  
         [0063]     Abrasive plates  21 D of crawler belt link grinding system  20 D may arbitrarily be disposed near idler  13  on an as needed basis. Although support arm  35  is supported at bogie  18 , this arm  35  may be supported at track frame  11 . In that case, support arm  35  may be supported, for example, via a mounting seat and a mounting bracket as described in the foregoing embodiments or may be supported directly by track frame  11 .  
         [0064]     The above description has referred to the embodiments individually. However, the abrasive layers of the abrasive plate may arbitrarily be arranged, for example, in blocks or continuously on an as needed basis. The cantilever structure can be replaced by a structure having both ends supported. Instead of being formed by overlaying the hard material, the abrasive layer of the abrasive plate can be, for example, a fixed structure that has filing meshes made of hard material.