Abstract:
A chain made up of bush link plates, bushes fitted into bush fitting holes, and rollers fitted rotatably on an outer circumference of each of the bush. In order to make it possible to replace the roller without removing the bush from the bush link plates, in the chain made up of the bush link plates provided with bush fitting holes, the bushes fitted into the bush fitting holes, and the rollers fitted rotatably on the outer circumference of each of the bushes, the roller is formed from split rollers made by splitting the roller into two or more parts.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a chain provided with rollers on an outer circumference of each of bushes. 
       BACKGROUND OF THE INVENTION 
       [0002]      FIG. 8  shows one type of a chain structure. 
         [0003]    A chain  160  is provided with platy pin link plates (outer link plates)  162  opposed to each other, and a pin insertion hole is made in each of both ends of the pin link plate (the outer link plate)  162 . 
         [0004]    Further, the chain  160  is provided with platy bush link plates (inner link plates)  164  opposed to each other, and a bush fitting hole is made in each of both ends of the bush link plate (the inner link plate)  164 . 
         [0005]    Each of fitting portions on both ends of a cylindrical bush  166  is fitted into the bush fitting hole, and a cylindrical roller  168  is fitted rotatably on an outer circumference of the bush  166 . 
         [0006]    Both the ends of the bush  166  are each provided with the fitting portion fitted into each of the bush fitting holes of the bush link plates (the inner link plates)  164 , and a central portion of the bush  166  is provided with a pin through hole penetrated by a pin  170 . 
         [0007]    Further, the chain  160  is provided with rod-like pins  170 . A cylindrical main body of the pin  170  is allowed to penetrate the pin through hole of the bush  166 , and each end of the pin  170  is locked to the pin link plate (the outer link plate)  162 . 
         [0008]    The chain  160  is thus assembled and thereby is structured by flexibly linking these parts. 
       PRIOR ART DOCUMENTS 
     Patent Documents 
       [0009]    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2007-176615 
       SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
       [0010]    When driving a chain provided with rollers over the long term, the rollers are abraded and then it becomes necessary to replace only the rollers in some cases. On this occasion, conventionally the roller fitted rotatably on an outer circumference of a bush is a one-body cylindrical part, and hence in order to replace the roller, it is necessary to remove the bush from bush link plates and then remove the original roller abraded and finally fit a new roller on the chain. 
         [0011]    It is an object of the present invention to make it possible to replace the roller without removing the bush from the bush link plates. 
       Means for Solving Problems 
       [0012]    The present invention is intended to solve the above problem. Therefore, there is provided a chain made up of bush link plates provided with bush fitting holes, a bush fitted into the bush fitting holes, and a roller fitted rotatably on an outer circumference of the bush. In this chain, the roller is formed from split rollers made by splitting the roller into two or more parts. 
         [0013]    Further, in the present invention, at least one of end faces of the above split roller is provided with a groove, and by engaging a stop ring with the above groove, the split rollers are joined together. 
         [0014]    Furthermore, a protrusion and a depression, which are allowed to engage with each other when combining the above split rollers with each other, are provided on each of combining surfaces of the above split rollers. 
       Effects of the Invention 
       [0015]    According to the present invention like this, in the chain made up of each of the bush link plates provided with the bush fitting holes, each of the bushes fitted into the bush fitting holes, and each of the rollers fitted rotatably on the outer circumference of each of the bushes; the roller is formed from the split rollers made by splitting the roller into two or more parts, and thereby it becomes possible to replace the roller without removing the bush from the bush link plates. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1( a )  is a plain view of a chain according to a first embodiment of the present invention. 
           [0017]      FIG. 1( b )  is a side view of a chain according to a first embodiment of the present invention. 
           [0018]      FIG. 2( a )  is a front view showing a split roller making up a roller of the chain according to the first embodiment of the present invention, 
           [0019]      FIG. 2( b )  is a side view showing a split roller making up a roller of the chain according to the first embodiment of the present invention. 
           [0020]      FIG. 3( a )  is a front view showing a stop ring making up the roller of the chain according to the first embodiment of the present invention. 
           [0021]      FIG. 3( b )  is a side view showing a stop ring making up the roller of the chain according to the first embodiment of the present invention. 
           [0022]      FIG. 4( a )  is a front view showing a split roller making up a roller of a chain according to a second embodiment of the present invention, 
           [0023]      FIG. 4( b )  is a side view showing a split roller making up a roller of a chain according to a second embodiment of the present invention. 
           [0024]      FIG. 5( a )  is a front view showing a split roller making up a roller of a chain according to a third embodiment of the present invention. 
           [0025]      FIG. 5( b )  is a side view showing a split roller making up a roller of a chain according to a third embodiment of the present invention. 
           [0026]      FIG. 6( a )  is a front view showing a split roller making up a roller of a chain according to a fourth embodiment of the present invention. 
           [0027]      FIG. 6( b )  is a side view showing a split roller making up a roller of a chain according to a fourth embodiment of the present invention. 
           [0028]      FIG. 7( a )  is a plain view of a chain according to a fifth embodiment of the present invention. 
           [0029]      FIG. 7( b )  is a side view of a chain according to a fifth embodiment of the present invention. 
           [0030]      FIG. 8  is an overall view of a conventional chain. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    Hereunder is a specific description on embodiments of the present invention based on drawings. The descriptions on parts the same as in a conventional example are omitted. 
         [0032]      FIG. 1( a )  is a plain view and  FIG. 1( b )  is a side view of a chain  2  according to a first embodiment of the present invention.  FIG. 2( a )  and  FIG. 2( b )  are views showing a split roller  20  ( 12 ) making up a roller  10  of a chain  2  according to the first embodiment of the present invention:  FIG. 2( a )  is a front view and  FIG. 2( b )  is a side view.  FIG. 3( a )  is a front view and  FIG. 3( b )  is a side view showing a stop ring  38 . 
         [0033]    The roller  10  of the chain  2  according to the first embodiment of the present invention is formed by joining a couple of the split rollers  20  ( 12 ) shown in  FIG. 2( a )  and  FIG. 2( b )  by means of the stop ring  38  shown in  FIG. 3( a )  and  FIG. 3( b ) . Drawings of stop rings for both axis and hole in second to fifth embodiments are omitted. 
         [0034]    As shown in  FIG. 2( a )  and  FIG. 2( b ) , the split roller  20  is approximately semicylindrical and is formed, in each of both end faces  22 ,  24 , with a groove  32  for engaging with the stop ring  38  for axis. In order to engage with the stop ring  38  for axis, the groove  32  is formed so that a deeper portion than the end faces  22 ,  24  thrusts into a portion in the radial direction (so as to thrust into a portion in the inner circumferential surface  30  direction) of the roller. 
         [0035]    The stop ring  38  for axis elastically deforms in such a direction as to expand its own diameter, and therefore with combining surfaces  26  combined with each other in the couple of the split rollers  20 , the stop ring  38  for axis is allowed to elastically deform in such a direction as to expand its own diameter to work into a deeper portion of the groove  32  and engage with the groove  32 , thereby enabling the couple of the split rollers  20  to be joined together and then integrated. 
         [0036]    The combining surface  26  of each split roller  20  is provided with a protrusion  34  and a depression  36 . When combining a couple of the combining surfaces  26  with each other in joining the couple of the split rollers  20 , since the protrusion  34  and the depression  36  are allowed to engage with each other, the couple of the split rollers  20  are joined together without being displaced from each other, thereby permitting the cylindrical roller  10  to be formed. 
         [0037]    In this manner, in the chain  2  according to the first embodiment of the present invention, by engaging the stop ring  38  for axis with the groove  32  formed in each split roller  20  with the couple of the split rollers combined with each other, the couple of the split rollers  20  are joined together to permit the roller  10  to be formed. 
         [0038]    By making up the roller of the chain as just described, when the roller has been abraded due to the repeated use over the years, and hence it has become necessary to replace the roller of the chain, it becomes possible to remove the roller readily from the chain and then fit a new roller thereon. 
         [0039]      FIG. 4( a )  and  FIG. 4( b )  are views showing a split roller  40  making up a roller of a chain according to the second embodiment of the present invention:  FIG. 4( a )  is a front view and  FIG. 4( b )  is a side view. 
         [0040]    As shown in  FIG. 4( a )  and  FIG. 4( b ) , the split roller  40  is approximately semicylindrical and is formed, in each of both end faces  42 ,  44 , with a groove  52  for engaging with a stop ring for axis. Besides, each lateral face in the split roller  40  is provided with a protrusion  54  and a depression  56 . 
         [0041]    Also in the split roller  40  making up the roller of the chain according to the second embodiment, by engaging the stop ring for axis with the groove  52  formed in the split roller  40  and joining the couple of the split rollers  40  together to form the roller, when the roller of the chain has been abraded due to the repeated use over the years and hence has become necessary to be replaced, it becomes possible to remove the roller readily from the chain and then fit a new roller thereon. 
         [0042]      FIG. 5( a )  and  FIG. 5( b )  are views showing a split roller  60  making up a roller of a chain according to the third embodiment of the present invention:  FIG. 5 ( a )  is a front view and  FIG. 5 ( b )  is a side view. 
         [0043]    As shown in  FIG. 5( a )  and  FIG. 5( b ) , the split roller  60  is approximately semicylindrical and is formed, in each of both end faces  62 ,  64 , with a groove  72  for engaging with a stop ring for hole. In order to engage with the stop ring for hole, the groove  72  is formed in such a manner that a deeper portion than the end faces  62 ,  64  expands in the outer circumferential surface  68  direction. 
         [0044]    The stop ring for hole elastically deforms in such a direction as to reduce its own diameter, and therefore with a couple of the split rollers  60  combined with each other, the stop ring for hole is allowed to deform elastically in such a direction as to reduce its own diameter. Accordingly, the stop ring for hole is allowed to work into the deeper portion of the groove  72  and engage with the groove  72 , thereby making it possible to join and integrate the couple of the split rollers  60  together. 
         [0045]    Further, each combining surface of the split roller  60  is provided with a protrusion  74  and a depression  76 . When combining the combining surfaces  60  with each other in joining the split rollers  60  together, since the protrusion  74  and the depression  76  are allowed to engage with each other, the couple of the split rollers  60  are combined without being displaced from each other to permit the cylindrical roller to be formed. 
         [0046]      FIG. 6( a )  and  FIG. 6( b )  are views showing a split roller  80  making up a roller of a chain according to the fourth embodiment of the present invention:  FIG. 6( a )  is a front view and  FIG. 6( b )  is a side view. 
         [0047]    Also by combining a couple of such split rollers  80  with each other, it becomes possible to join and integrate the couple of the split rollers  80  together as is done in the third embodiment. 
         [0048]    As above, the embodiments of the present invention are described. A technical scope of the present invention, however, does not limit the embodiments described above. Those skilled in the art obviously make various altered embodiments and various modifications even within the technical scope described in claims. Therefore, these altered embodiments and modifications are considered to obviously fall within the technological scope of the present invention. 
         [0049]    In the embodiments, e.g., the chain provided with (made up of) the pin link plates (the outer link plates) and the bush link plates (the inner link plates) has been described. Not limiting to these chains, however, the present invention is applicable also to a type of a chain provided with rollers in an outer circumference of each of bushes. 
         [0050]    Specifically, e.g., the present invention is applicable also to a chain of an offset type as shown in  FIG. 7( a )  and  FIG. 7( b ) . 
         [0051]    Further, in the embodiments, the examples where the grooves are provided on both the end faces of the split roller to engage with the stop rings have been described. The groove, however, may be provided on one end face to engage with the stop ring. Furthermore, in the embodiments, the examples where the roller is formed from the couple of the split rollers have been shown. Three or more split rollers, however, may be combined to form the roller. 
       EXPLANATION OF NUMERALS 
       [0000]    
       
         
           
               2 . chain 
               4 . pin link plate (outer link plate) 
               6 . bush link plate (inner link plate) 
               8 . bush 
               10 . roller 
               12 . split roller 
               14 . stop ring 
               16 . cotter pin 
               18 . T pin 
               20 . split roller 
               22 ,  24  end face 
               26 . combining surface 
               28 . outer circumferential surface 
               30 . inner circumferential surface 
               32 . groove 
               34 . protrusion 
               36 . depression 
               38 . stop ring 
               40 . split roller 
               42 ,  44  end face 
               46 . combining surface 
               48 . outer circumferential surface 
               50 . inner circumferential surface 
               52 . groove 
               54 . protrusion 
               56 . depression 
               60 . split roller 
               62 ,  64  end face 
               66 . combining surface 
               68 . outer circumferential surface 
               70 . inner circumferential surface 
               72 . groove 
               74 . protrusion 
               76 . depression 
               80 . split roller 
               82 ,  84  end face 
               86 . combining surface 
               88 . outer circumferential surface 
               90 . inner circumferential surface 
               92 . groove 
               94 . protrusion 
               96 . depression 
               100 . chain 
               102 . offset link plate 
               108 . bush 
               110 . roller 
               112 . split roller 
               114 . stop ring 
               116 . cotter pin 
               118 . T pin 
               160 . chain 
               162 . pin link plate (outer link plate) 
               164 . bush link plate (inner link plate) 
               166 . bush 
               168 . roller 
               170 . pin