Abstract:
A chain guide for guiding a chain traveling around a sprocket supported on a frame of a motorcycle is disclosed. Typically, the chain guide includes a plastic chain guide support having a substantially U-Shaped body with a channel formed along an inner surface of the body. The body typically includes an outer surface and a ridge structure protruding outward from the outer surface so as to reinforce the chain guide support. The body of the plastic chain guide support is generally configured with at least one mounting hole sized to receive a fastener for securing the chain guide to the frame of the motorcycle. Typically the plastic chain guide support further is configured to house a chain guide insert in at least a portion of the channel.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a guide structure for guiding a chain to a sprocket of a motorcycle.  
       BACKGROUND  
       [0002]     Some motorcycles utilize a chain to transmit power from the motor to a rear wheel. Under some conditions, such as when the distance between the front and rear sprocket is substantial, undesirable motion of the chain may occur. Such motion can interfere with the rider and/or motorcycle operations.  
         [0003]     One solution to inhibit undesirable motion of the chain is a chain guide, which directs the chain between the front and rear sprocket. Chain guides typically include a metal channel secured to the frame of the motorcycle and a circular internal rubber insert through which the chain passes.  
         [0004]     The inventors herein have found a disadvantage with such an approach. Specifically, conditions may exist wherein the metal chain guide is contacted or impacted during chain guide operation. During such impact, the metal chain guide may deform causing the channeled portion to collapse around the chain. If the deformation of the chain guide is permanent, the operation of the motorcycle may be impaired. Further, such deformation may also cause damage to the motorcycle or cause injury to the rider and bystanders. Under some conditions, it may be difficult to repair the deformed chain guide to the tolerances achieved during manufacture, thus causing potentially impaired performance.  
       SUMMARY  
       [0005]     A chain guide for guiding a chain traveling around a sprocket supported on a frame of a motorcycle is provided. Typically, the chain guide includes a plastic chain guide support having a substantially U-Shaped body with a channel formed along an inner surface of the body. The body typically includes an outer surface and a ridge structure protruding outward from the outer surface so as to reinforce the chain guide support. The body of the plastic chain guide support is generally configured with at least one mounting hole sized to receive a fastener for securing the chain guide to the frame of the motorcycle. Typically the plastic chain guide support further is configured to house a chain guide insert in at least a portion of the channel.  
         [0006]     One potential advantage of such a plastic chain guide is that the ridge structure may be designed to deform only temporarily upon impact while returning to its original state after the impact has occurred. In some embodiments, the ridge structure may include a plurality of ridge portions protruding from the surface of the chain guide support to further strengthen the chain guide and/or provide the desired elastic properties. Thus, after an impact has occurred, the chain guide may return to working order without further repair or replacement. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]      FIG. 1  is an isometric view of a chain guide according to a first example embodiment.  
         [0008]      FIG. 2  is a top view of the chain guide of  FIG. 1 .  
         [0009]      FIG. 3  is a left side view of the chain guide of  FIG. 1 .  
         [0010]      FIG. 4  is a right side view of the chain guide of  FIG. 1 .  
         [0011]      FIG. 5  is a bottom view of the chain guide of  FIG. 1 .  
         [0012]      FIG. 6  is a front view of the chain guide of  FIG. 1 .  
         [0013]      FIG. 7  is a rear view of the chain guide of  FIG. 1 .  
         [0014]      FIG. 8  is a left side view of a chain guide according to a second example embodiment.  
         [0015]      FIG. 9  is a left side view of a chain guide according to a third example embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Referring now to  FIG. 1 , a chain guide according to one embodiment of the present invention is shown generally at  10 . Chain guide  10  typically includes a plastic outer chain guide support  100  configured to mount to a motorcycle frame  180 , as well as a chain guide insert  184  (see  FIGS. 3, 6 , and  7 ), which is typically made of rubber. Typically, chain guide support  100  is manufactured formed of a single piece of plastic, and mounts to motorcycle frame  180  via a plurality of mounting holes  150 - 158  and fasteners  186 .  
         [0017]     Chain guide support  100  includes a substantially U-shaped body having an outer wall  110 , a bottom portion  120 , and an inner wall  130 . When the chain guide is mounted to motorcycle frame  180 , the outer wall faces outward from the motorcycle, while the inner wall faces toward the motorcycle. Intermediate these walls, the U-shaped body has an elongate channel  101  formed along a length thereof. The channel is configured to house chain guide insert  184 . The channel is further configured to surround and guide a chain  182 , which slides over insert  184  and between walls  110  and  130 .  
         [0018]     Outer wall  110  is provided with openings  140  and  142  and inner wall  130  with openings  144  (see  FIG. 4 ) and  146  for allowing expulsion of debris and/or foreign material during chain operation. Openings  140  and  144  are typically aligned with each other as viewed from the side, as are and openings  142  and  146 , however, it will be appreciated that other configurations are possible.  
         [0019]     Typically, the outer wall  110  is further provided with three mounting holes  150 ,  152  and  154 , and the inner wall  130  is provided with two mounting holes  156  and  158 . Mounting holes  150  and  156  are aligned with each other, as are mounting holes  152  and  158 , to accommodate passage of fasteners  186 . It will be appreciated that other suitable configurations of mounting holes may be provided to facilitate mounting of the chain guide support to motorcycle frames of various shapes and sizes.  
         [0020]     Continuing with  FIG. 1 , the U-shaped body includes a ridge structure  102  projecting outward from the outer surface of the U-shaped body. Ridge structure  102  typically serves as a reinforcement means, and includes one or more ridge portions extending outward from outer wall  110 , bottom portion  120 , and/or inner wall  130 . These ridge portions may be interconnected or formed adjacent each other, and are configured to strengthen the chain guide support against deformation and/or fracture during chain guide operation. Ridge portions of varying sizes, shapes, and/or number may be used to reinforce portions of the chain guide support that are susceptible to damage.  
         [0021]     Typically, at least a portion of the ridge structure  102  is disposed adjacent an outer perimeter of the body of the plastic chain guide support. For example, ridge structure  102  may include a first ridge portion  172  disposed substantially parallel to and adjacent a front leading edge of the plastic chain guide support, and a second ridge portion  174  disposed parallel to and spaced apart from the first ridge.  
         [0022]     In addition, at least a portion of the ridge structure is typically formed adjacent a mounting hole. For example, in the embodiment of  FIG. 1 , a plurality of circular mounting holes  150 ,  152  and  154  are provided in the outer wall  110  of the body of the plastic chain guide support, and the ridge structure includes a corresponding circular ridge portion  160 ,  162 ,  164  surrounding each of the mounting holes.  
         [0023]     Each of the first and second ridge portions  170 ,  174  intersect at least one of the circular ridge portions. In addition, the ridge structure further includes a spanning ridge portion  170  that spans between at least two of the circular ridge portions. In the embodiment of  FIG. 1 , three mounting holes  150 ,  152  and  154  are provided on the body of the plastic chain guide support, and the spanning ridge portion includes a first spanning section between forward mounting hole  150  and intermediate mounting hole  152 , and a second spanning section between the intermediate mounting hole  152  and an aft mounting hole  154 .  
         [0024]     The ridge structure further includes at least one ridge portion  176  (see  FIGS. 3-7 ) disposed on a bottom surface of the plastic chain guide support substantially parallel to a direction of chain travel of the motorcycle, which may be referred to as a bottom ridge portion. Alternatively, the bottom ridge portion  176  may be oriented in another suitable direction. While typically the bottom ridge portion is formed independent of the remaining ridge portions in ridge structure  102 , it will be appreciate that in some embodiments, such as shown in  FIG. 8 , a bottom ridge portion  878  may be provided that is interconnected with other ridge portions such as ridge portions  170 ,  172 .  
         [0025]     Referring now to  FIG. 2 , a top view of the first example embodiment of the chain guide support is shown.  FIG. 2  shows the outer wall  110  and the inner wall  130  substantially parallel to each other and of approximately the same length. The bottom portion  120  is shown connecting the outer wall  110  and the inner wall  130 . Circular ridge portions  160 ,  162 , and  164  are shown projecting from the outer surface of the outer wall and circular ridge portions  166  and  168  are shown projecting from the outer surface of the inner wall. Spanning ridge portion  170  is shown projecting outward from the outer wall by approximately the same distance as the circular ridge portions and is shown intersecting circular ridge portions  160 ,  162 , and  164 . Spanning ridge portion  176  is shown projecting outward from the inner wall by approximately the same distance as the circular ridge portions and is shown intersecting circular ridge portions  166  and  168 .  
         [0026]     Referring now to  FIG. 3 , a schematic diagram of a left side view of the first example embodiment of the chain guide support is shown.  FIG. 3  shows that an outer perimeter of outer wall  110  is substantially aligned with the inner wall  130  (not shown), as viewed from the side. Further, opening  140  is shown to be substantially aligned with opening  144  and opening  142  is shown to be substantially aligned with opening  146 . Openings  140 ,  142 ,  144 ,  146  are shown having a generally trapezoidal shape with rounded corners, however other shapes are possible. For example, the openings could be circular, triangular, or rectangular among others. Mounting hole  150  is shown to be substantially aligned with mounting hole  156  and mounting hole  152  is shown to be substantially aligned with mounting hole  158 . Ridge portions  172  and  174  are shown arranged substantially parallel to each other and the front leading edge of the outer wall of the chain guide support. Bottom ridge portion  178  is shown projecting downward from the bottom of floor  120 . In some embodiments (see  FIG. 8 ), ridge portions  172  and  174  may intersect bottom ridge portion  178  in a manner similar to the intersection with spanning ridge portion  170 .  
         [0027]     Referring now to  FIG. 4 , a schematic diagram of a right side view of the first example embodiment of the chain guide support is shown. Spanning ridge portion  176  is shown intersecting circular ridge portions  166  and  168  at approximately the centerline of mounting holes  156  and  158 . A portion of the outer wall  110  is shown behind the inner wall  130 . In particular, mounting hole  154  is visible in  FIG. 4 .  
         [0028]     Referring now to  FIG. 5 , a schematic diagram of a bottom view of the first example embodiment of the chain guide support is shown. Ridge portions  172  and  174  are shown projecting outward from the outer wall  110  and tapering into the interface of the outer wall and the floor of the chain guide support prior to intersecting bottom ridge potion  178 .  
         [0029]     Referring now to  FIGS. 6 and 7 , schematic diagrams of a front and rear view of the first example embodiment of the chain guide support are shown respectively. In particular,  FIGS. 6 and 7  show how the various ridge portions of ridge structure  102  project outward from the surface of the outer wall  110 , inner wall  130 , and bottom portion  120  of the chain guide support. Ridge portions  172  and  174  are again shown tapering into the outer surface of the chain guide support, however in some embodiments, the ridge portions may end without tapering.  
         [0030]     Referring now to  FIG. 8 , a schematic diagram of a left side view of a second example embodiment of the chain guide support is shown. Chain guide support  800  is shown with an outer wall  810  including two openings  840  and  842  for the expulsion of debris. Opening  840  is shown having a substantially triangular shaped opening with rounded corners, while opening  842  is shown having a trapezoidal shape. Further, circular ridge portions  860  and  862  are shown intersected by a first section  870  of a spanning ridge portion at approximately the centerline of mounting holes  850  and  852 . Circular ridge portions  862  and  864  are shown intersected by a second section  872  of a spanning ridge portion. Further, the second section  872  of the spanning ridge portion is shown to substantially conform to the upper edge of outer wall  810  and is therefore curved so as to be upwardly concave. Ridge portions  874  and  876  are shown intersecting circular ridge portion  860  at the upper end. Further, ridge portions  874  and  876  are shown to be substantially parallel to each other and the leading edge of the chain guide support until intersecting at the lower edge of the chain guide support. Further, ridge portions  874  and  876  are shown intersecting bottom ridge portion  878 , which projects downward from the bottom surface of the chain guide support.  
         [0031]     Referring now to  FIG. 9 , schematic diagram of a left side view of a third example embodiment of the chain guide support is shown. Corresponding parts are labeled with references numbers similar to  FIG. 8 . For the sake of brevity, not all parts will be redescribed.  FIG. 9  shows chain guide support  900  with an outer wall  910  having three openings  940 ,  942 , and  944  each of different sizes and generally of trapezoidal shape. A spanning ridge portion is provided between mounting holes  950 ,  952 , and  954 , with a first section  970  and a second section  972 . Ridge portions  974  and  876  are shown to intersect circular ridge portion  960 , but not bottom ridge portion  978 .  
         [0032]     In some embodiments, the chain guide support may include variations in the features described above. For example, while the ridge structure is typically of a rectangular cross section throughout, it may alternatively be formed of a differently shaped cross section. In addition, the chain guide support may a different number of mounting holes, openings for expelling debris, etc. Further, the ridge structure may include more or fewer ridge portions than shown in the examples above. In some embodiments, all of the ridge portions may be of similar height and/or width. In other embodiments, some of the ridge portions may vary in height and width.  
         [0033]     It will be appreciated that the configurations disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.  
         [0034]     The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.