Patent Publication Number: US-2006011423-A1

Title: Bicycle force balancing mechanism with a brake arm actuation assembly and a pivot member for dual main brake cable segments

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is a continuation patent application of U.S. patent application Ser. No. 10/684,010, filed on Oct. 10, 2003, and claims priority thereto, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to bicycle braking systems, and in particular to a bicycle force balancing mechanism with a brake arm actuation assembly and a pivot member for dual main brake cable segments.  
      2. Description of the Prior Art  
      Bicycle trick or stunt riding has placed specialized requirements upon the design of rear brake assemblies. A rear brake assembly of a bicycle includes a rear hand brake lever mounted upon handlebars of the bicycle. The rear brake assembly further includes a pair of brake arms mounted to a bicycle frame for braking of a rear wheel of the bicycle. The brake arms are commonly of a U-brake configuration. Some form of cabling interconnects the rear hand brake lever to the brake arms. Squeezing of the rear hand brake lever imparts tension into such cabling which results in actuation of the brake arms. In this regard, brake pads are attached to each brake arm and are cooperatively configured to apply forces against rear wheel in a pinching manner for braking of the rear wheel. Design focus has been placed upon the cabling configuration between the rear hand brake lever and the rear brake arms.  
      Use of a cable detangler or cable decoupler allows for riders to do various tricks involving spinning of the handlebars without limitations of the brake cabling being twisted about the base of the handlebars after only a single rotation. As such, trick or BMX style bicycles are characterized as having a rear brake assembly with such a cable detangler. A cable detangler typically includes a detangler ball bearing set with inner and outer races. Squeezing of the rear hand brake lever pulls upon a cable (sometimes two cables) that terminates at one of the races of the detangler ball bearing set. A pair of rear main brake cables is routed to extend from the other race rearward along the bicycle frame to the rear brake arms. This configuration is commonly referred to as a dual rear brake cable configuration. As such, it is understood that the cable detangler allows for transmission of the cable tension initiated by the squeezing of the rear brake lever through the cable detangler while freeing the handlebars to spin in relation to the bicycle frame.  
      During a trick involving spinning of the handlebars, the inner and outer races of the cable detangler may tend to reciprocally “flop” or snap from position to position associated with the limits of such “play” in the ball bearing races. This flopping impairs the smooth spinning of the handlebars and often results in jerky movement and an undesirable audible clicking. Accordingly, there is a need in the art for an improved bicycle rear brake assembly configuration in comparison to the prior art.  
     SUMMARY OF THE INVENTION  
      An aspect of the present invention can be regarded as a dual cable force balancing mechanism for use with a pair of main brake cable segments and a pair of rear brake arms of a bicycle. The dual cable force balancing mechanism includes a brake arm actuation assembly defining a longitudinal axis positionable between the main brake cable segments. The brake arm actuation assembly is attachable to the rear brake arms. The dual cable force balancing mechanism further includes a pivot member including main attachment portions disposed about the longitudinal axis for respectively attaching the main cable segments. The pivot member is rotatably coupled to the brake arm actuation assembly for pivoting the pivot member with respect to the longitudinal axis.  
      It is contemplated that dual cable force balancing mechanism may be used with a bicycle having a cable detangler for allowing handlebars of the bicycle to freely rotate. The dual cable force balancing mechanism may be installed with the main brake cable segments connected to the cable detangler. The present invention recognizes that unequal tension in the main brake cable segments is a significant underlying cause of the cable flop phenomenon associated with the cable detangler when the handlebars are fully rotated. Such unequal tension may be a result of relative unequal lengths of the main brake cable segments that may result from loose manufacturing tolerances, improper installation, and defects in and wear of the various brake assembly components. The pivot member allows for the dual cable force balancing mechanism to “actively” compensate or adjust for unequal lengths of the main brake cable segments during rotation of the handlebars of the bicycle. This allows for the transmission of force between the dual cable force balancing mechanism and the cable detangler substantially equally through the two main brake cable segments to mitigate the cable flop phenomenon.  
      According to various embodiments, the brake arm actuation assembly may include a pair of rear brake cable segments attachable to the rear brake arms. Each of the rear brake cable segments is disposed in mechanical communication with the pivot member. The brake arm actuation assembly may further include a hanger body. The hanger body is rotatably coupled to the pivot member. The hanger body includes rear attachment portions respective positionable about the longitudinal axis. The rear brake cable segments are attached to the hanger body respectively at the rear attachment portions. The hanger body may include a lip with the rear attachment portions disposed along the lip. The rear brake cable segments may be integrated into a single cable and the lip may be configured to engage the rear brake cable segments with the rear brake cable segments being looped about the lip. The hanger body may include a pivot member support and the lip may extend from the pivot member support. In another arrangement, the pivot member support includes first and second plates, and the lip extends between the first and second plates. The pivot member may be rotatably connected to and between the first and second plates. The rear brake cable segments may be rotatably attached to the hanger body respectively at the rear attachment portions. In an embodiment, the pivot member is a cross bar having opposing ends and a central portion. The pivot member is attached to the hanger body at the central portion, and the main attachment portions are respectively disposed adjacent the opposing ends. In another embodiment, the pivot member is a pulley and includes a central portion. The pivot member is attached to the hanger body at the central portion. The dual cable force balancing mechanism may further include a fastener rotatably coupling the pivot member to the hanger body. The main brake cable segments may be integrated into a single cable, and the pivot member is configured to engage the main brake cable segments with the main brake cable segments being looped about the pivot member. The pivot member includes a pivot pin element disposed between the main attachment portions and positionable orthogonal to the longitudinal axis, and the rear brake cable segments are joined at the pivot pin element. In an embodiment, the rear brake cable segments are cooperatively looped over the pin element with the pin element. In another embodiment, the rear brake cable segments are cooperatively wound about the pin element. The rear brake cable segments may take the form of a single spring wire. The pivot member may be rotatably attachable to the main brake cables.  
      According to another aspect of the invention, there is provided a bicycle. The bicycle includes a bicycle frame and a rear wheel supported by the bicycle frame. The bicycle further includes a rear brake assembly. The rear brake assembly includes a rear brake lever and a pair of main brake cable segments in mechanical communication with the rear brake lever. The rear brake assembly further includes a pair of rear brake arms in operable communication with the rear wheel. The rear brake assembly further includes a dual cable force balancing mechanism. The dual cable force balancing mechanism includes a brake arm actuation assembly defining a longitudinal axis positioned between the main brake cable segments. The brake arm actuation assembly is attached to the rear brake arms. The dual cable force balancing mechanism further includes a pivot member including main attachment portions disposed about the longitudinal axis. The main cable segments are respectively attached to the pivot member at main attachment portions, the pivot member being rotatably coupled to the brake arm actuation assembly for pivoting the pivot member with respect to the longitudinal axis.  
      According to various embodiments, the dual cable force balancing mechanism may include a pair of rear brake cable segments attached to the rear brake arms. Each of the rear brake cable segments is disposed in mechanical communication with the pivot member. The dual cable force balancing mechanism may be as described above. Further, the bicycle frame may include a seat post portion, and the dual cable force balancing mechanism may be disposed between the seat post portion and the rear brake arms. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a bicycle including a dual cable force balancing mechanism in accordance with an aspect of the present invention;  
       FIG. 2  is an enlarged exploded perspective view of the dual cable force balancing mechanism of  FIG. 1  as shown with portions of main brake cable segments and portions of rear brake cable segments;  
       FIG. 3  is a plan view of the dual cable force balancing mechanism of  FIG. 1  as assembled, as shown with portions of the main brake cable segments, the rear brake cable segments, and rear brake arms;  
       FIG. 4  is a plan view similar to the view of  FIG. 3 , however, of a dual cable force balancing mechanism according to another aspect of the present invention;  
       FIG. 5  is a plan view similar to the view of  FIG. 3 , however, of a dual cable force balancing mechanism according to another aspect of the present invention; and  
       FIG. 6  is a side view of the dual cable force balancing mechanism of  FIG. 5  as seen along axis  6 - 6  of  FIG. 5 ;  
       FIG. 7  is a plan view similar t the view of  FIG. 3 , however, of a dual cable force balancing mechanism according to another aspect of the present invention;  
       FIG. 8  is a top view of the dual cable force balancing mechanism of  FIG. 7  as seen along axis  8 - 8  of  FIG. 5 ;  
       FIG. 9  is a plan view similar t the view of  FIG. 3 , however, of a dual cable force balancing mechanism according to another aspect of the present invention; and  
       FIG. 10  is a top view of the dual cable force balancing mechanism of  FIG. 9  as seen along axis  10   −10  of  FIG. 9 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and not for purposes of limiting the same,  FIGS. 1-10  illustrate a bicycle with rear brake related elements in accordance with the aspects of the present invention.  
      Referring now to  FIG. 1 , there is depicted a perspective view of a bicycle  10  including a dual cable force balancing mechanism  12  in accordance with an aspect of the present invention. For ease of illustrating the present invention selected portions of the bicycle  10  are shown in phantom lining. The bicycle  10  includes a bicycle frame  14 . The bicycle frame  14  supports front and rear wheels  16 ,  18 . Handlebars  20  are rotatably coupled to the bicycle frame  14 . A front brake lever  22  is mounted to the handlebars  20 . The front brake lever  22  is cable connected to front brake arms  24 ,  26  which are configured to apply a braking force to the front wheel  16 . A rear brake lever  28  is further mounted to the handlebars  20 . The rear brake lever  28  is cable connected to a pair of rear brake arms  30 ,  32  that are configured to apply a braking force to the rear wheel  18 .  
      In the embodiment shown, a rear brake lever cable  34  is attached to the rear brake lever  28 . The rear brake cable  34  is split into a pair of segments  36 . As is common with BMX style bicycles, at a base of the handlebars  20  adjacent the bicycle frame  14  there is provided a cable detangler  38 . The cable detangler  38  allows for riders to do various tricks involving spinning of the handlebars  20  without limitations of the rear brake cabling being twisted about the base of the handlebars  20  after only a single rotation. The cable detangler  38  may include a detangler bearing set with inner and outer races. As seen in  FIG. 3 , the rear brake arms  30 ,  32  each include brake pads  62  which are configured to engage the rear wheel  18 . Squeezing of the rear brake lever  28  pulls upon the rear brake cable  34  and the segments  36  that are attached to one of the races of the cable detangler  38 . A pair of main cable segments  40 ,  42  is attached to the other race of the cable detangler  38 . This configuration is commonly referred to as a dual rear brake cable configuration. The main brake cable segments  40 ,  42  are routed to extend from the cable detangler  38  rearward along the bicycle frame  14  in mechanical communication with the rear brake arms  30 ,  32 . As such, it is understood that the cable detangler  38  allows for transmission of the cable tension initiated by the squeezing of the rear brake lever  28  through the cable detangler  38  while freeing the handlebars  20  to spin in relation to the bicycle frame  14 .  
      Referring now to  FIG. 2  there is depicted an enlarged exploded perspective view of the dual cable force balancing mechanism  12  of  FIG. 1  as shown with a portion of the main brake cable segments  40 ,  42  and portions of a pair rear brake cable segments  44 ,  46  of the pair of rear brake arms  30 ,  32  of the bicycle  10 . Referring additionally to  FIG. 3  there is depicted a plan view of the dual cable force balancing mechanism  12  of  FIG. 1  as assembled, as shown along with portions of the main brake cable segments  40 ,  42 , the rear brake cable segments  44 ,  46 , and the rear brake arms  30 ,  32 .  
      An aspect of the present invention can be regarded as the dual cable force balancing mechanism  12  for use with the pair of main brake cable segments  40 ,  42  and the pair of rear brake arms  30 ,  32  of the bicycle  10 . The dual cable force balancing mechanism  12  includes a brake arm actuation assembly  47  defining a longitudinal axis  50  positionable between the main brake cable segments  40 ,  42 . The brake arm actuation assembly  47  is attachable to the rear brake arms  30 ,  32 . The dual cable force balancing mechanism  12  further includes a pivot member  56  including main attachment portions  58 ,  60  disposed about the longitudinal axis  50  for respectively attaching the main brake cable segments  40 ,  42 . The pivot member  56  is rotatably coupled to the brake arm actuation assembly  47  for pivoting the pivot member  56  with respect to the longitudinal axis  50 .  
      It is contemplated that dual cable force balancing mechanism  12  may be used with the bicycle  10  having the cable detangler  38  for allowing the handlebars  20  of the bicycle  10  to freely rotate. The dual cable force balancing mechanism  12  may be installed with the main brake cable segments  40 ,  42  connected to the cable detangler  38 . The present invention recognizes that unequal tension in the main brake cable segments  38  is a significant underlying cause of the cable flop phenomenon associated with the cable detangler  38  when the handlebars  20  are fully rotated. Such unequal tension may be a result of relative unequal lengths of the main brake cable segments  40 ,  42  that may result from loose manufacturing tolerances, improper installation, and defects in and wear of the various brake assembly components. The pivot member  56  allows for the dual cable force balancing mechanism  12  to “actively” compensate or adjust for unequal lengths of the main brake cable segments  40 ,  42  during rotation of the handlebars  20  of the bicycle  10 . The pivot action of the pivot member  56  is indicated in  FIG. 3  with the curved double-headed arrows. This pivot action allows each of the two main brake cables  40 ,  42  to transmit a substantially equal force from the cable detangler  38  to the brake arm actuation assembly  47  to mitigate the cable flop phenomenon. As such, the pivot action allows the dual cable force balancing mechanism  12  to perform a force balancing in the transfer of tension initiated by the pulling of the rear brake lever  28  to actuate the rear brake arms  30 ,  32 .  
      In further detail according to various embodiments, the main brake cable segments  40 ,  42  are formed and routed to be generally parallel adjacent the dual cable force balancing mechanism  12 . The main brake cable segments  40 ,  42  are engaged with the dual cable force balancing mechanism  12  with the main brake cable segments  40 ,  42  adjacent the dual cable force balancing mechanism  12  being generally aligned with the longitudinal axis  50 .  
      The main brake cable segments  40 ,  42  may be engaged to the pivot member  56  in a variety ways. In this regard, in the embodiment shown, the pivot member  56  takes the form of a cross bar having opposing ends  64 ,  66  and a central portion  68 . The main attachment portions  58 ,  60  are respectively disposed adjacent the opposing ends  64 ,  66 . A fitting  70  is attached to each of the opposing ends  64 ,  66  with a fastener  72 . The fittings  70  and the pivot member  56  are cooperatively configured to respectively capture and clamp the main brake cable segments  40 ,  42  at the main attachment portions  58 ,  60 . The fasteners  72  may each be received in fastener engagement holes  74  formed in the pivot member  56 . The main attachment portions  58 ,  60  may each include a groove  76  as shown in  FIG. 2 . Each groove  76  is formed to respectively accommodate and receive the main brake cable segments  40 ,  42  for secure engagement and desired positioning of the main brake cable segments  40 ,  42 .  
      Though not shown it is contemplated that the main brake cable segments  40 ,  42  may include barrel adjusters at either of their ends to adjust the relative lengths of the main brake cable segments  40 ,  42  so as to fine tune the tension in the main brake cable segments  40 ,  42 . However, it is understood that the incorporation of the pivot element  56  and its pivoting action advantageously compensates for differential relative lengths in the main brake cable segments  40 ,  42  to maintain a substantially equal tension.  
      The brake arm actuation assembly  47  may include the pair of rear brake cable segments  44 ,  46 . The rear brake cable segments  44 ,  46  may be attachable to the rear brake arms  30 ,  32 . Each of the rear brake cable segments  44 ,  46  may be disposed in mechanical communication with the pivot member  56 . The brake arm actuation assembly  47  may further include a hanger body  48 . The hanger body  48  is rotatably coupled to the pivot member  56 . The hanger body includes rear attachment portion  52 ,  54  respectively positionable about the longitudinal axis  50 . The rear brake cable segments  44 ,  46  are attached to the hanger body  48  respectively at the rear attachment portions  52 ,  54 .  
      The pivot member  56  may be attached to the hanger body  48  at the central portion  68 . This may be accomplished through any number of ways. For example, as shown a fastener  78  is disposed through the pivot member  56  at the central portion  68  and is engaged with the hanger body  48 .  
      The hanger body  48  may include a lip  80 . The rear attachment portions  52 ,  54  are disposed along the lip  80 . In this regard, the rear attachment portions  52 ,  54  take the form of curved surfaces along an inner portion of the lip  80 . The hanger body  48  may further include a pivot member support  82  and the lip  80  may extend from the pivot member support  82 . The hanger body  48 , in particular the pivot member support  82 , may be integrally formed with the lip  80 . The rear brake cable segments  44 ,  46  may be integrated into a single cable. The lip  80  may be configured to engage the rear brake cable segments  44 ,  46  with the rear brake cable segments  44 ,  46  being looped about the lip  80 .  
      As shown in  FIG. 3 , the rear brake cable segments  44 ,  46  are respectively attached to the rear brake arms  30 ,  32 . In this regard, the rear brake arms  30 ,  32  may each include a cable end  84  and an opposing brake pad end  86 . The brake pad ends  86  each respectively support the brake pads  62 . Fasteners  88  may be used to clamp down and attach the rear brake cable segments  44 ,  46  to the cable ends  84 . It is contemplated that the rear brake cable segments  44 ,  46  may be integrally formed as shown.  
      According to another aspect of the present invention, there is provided the bicycle  10  including the bicycle frame  14 , the rear wheel  18  supported by the bicycle frame  14 , and a rear brake assembly including the rear brake lever  28 , the main brake cable segments  40 ,  42 , the rear brake arms  30 ,  32 , the rear brake cable segments  44 ,  46 , and the dual cable force balancing mechanism  12 . The bicycle frame  14  may include a seat post portion  90  as shown in  FIG. 1 , and the dual cable force balancing mechanism  12  may be disposed between the seat post portion  90  and the rear brake arms  30 ,  32 . It is contemplated that such positioning of the dual cable force balancing mechanism  12  results in the rear brake cable segments  44 ,  46  having an incident angle with the cable ends  84  of the rear brake arms  30 ,  32  to be substantially normal for providing a high degree of leverage. Thus, this facilitates that the effective moment arm of the brake arms  30 ,  32  may be relatively maximized, in comparison to positioning of the dual cable force balancing mechanism  12  at other locations of the bicycle  10 .  
      Referring now to  FIG. 4  there is depicted a plan view similar to the view of  FIG. 3 , however of a dual cable force balancing mechanism  92  according to another aspect of the present invention. The dual cable force balancing mechanism  92  is similar in configuration to the dual cable force balancing mechanism  12 , however with the differences noted, and like reference numerals indicate like structures. This embodiment contemplates that there is provided rear brake cable segments  96  that are discrete members. In this regard, the dual cable force balancing mechanism  92  includes a hanger body  94  that is configured to engage the rear brake cable segments  96 . The hanger body  94  includes rear attachment portions  98 ,  100 . Fasteners  102  and fittings  104  may be used to respectively clamp the rear brake cable segments  96  to the hanger body  92  at the rear attachment portions  98 ,  100 . The rear brake cable segments  96  may be rotatably coupled to the hanger body  94  as indicated by the double-headed arrows.  
      Referring now to  FIG. 5  there is depicted a plan view similar to the view of  FIG. 3 , however of a dual cable force balancing mechanism  106  according to yet another aspect of the present invention.  FIG. 6  is a side view of the dual cable force balancing mechanism  106  of  FIG. 5  as seen along axis  6 - 6 . The dual cable force balancing mechanism  106  is similar in configuration to dual cable force balancing mechanism  12 , however with the differences noted, and like reference numerals indicate like structures.  
      Among other things, this embodiment features that the main brake cable segments  108 ,  110  are integrated into a single cable. The dual cable force balancing mechanism  106  includes a pivot member  112  rotatably coupled to a hanger body  114 . The pivot member  112  may take the form of a pulley. The pivot member  112  includes a central portion  116  and the pivot member  112  is attached to the hanger body  114  at the central portion  116 . A fastener  118 , such as a pin, may be used to couple the pivot member  112  with the hanger body  114 . The pivot member  112  is configured to engage the main brake cable segments  108 ,  110 . In this regard, the pivot member  112  may be configured to engage the main brake cable segments  108 ,  110  with the main brake cable segments  108 ,  110  being looped about the pivot member  112 . The pivot member  112  includes main attachments portions  120 ,  122  which are disposed along a radially outward facing peripheral groove  124  (as seen in cross section in  FIG. 6 ). The hanger body  114  may include a pivot member support including first and second plates  126 ,  128 . The pivot member  112  is rotatably connected to and between the first and second plates  126 ,  128 . A lip  130  extends between the first and second plates  126 ,  128 . The lip  130  may be configured to engage the rear brake cable segments  44 ,  46 . The lip  130  includes rear attachment portions  132 ,  134  of the hanger body  114 .  
      Referring now to  FIG. 7  there is depicted a plan view similar to the view of  FIG. 3 , however of a dual cable force balancing mechanism  136  according to yet another aspect of the present invention.  FIG. 8  is a top view of the dual cable force balancing mechanism  136  of  FIG. 7  as seen along axis  8 - 8 . The dual cable force balancing mechanism  136  is similar in configuration to dual cable force balancing mechanism  12 , however with the differences noted, and like reference numerals indicate like structures.  
      Among other things, this embodiment features a pivot member  138  that may be rotatably coupled to the main brake cable segments  40 ,  42  as indicated with double-headed arrows. In this regard, the main brake cable segments  40 ,  42  may pass through rotatable fasteners  140  located at main attachment portions  142 , as shown in  FIG. 8 . The pivot member  138  may include a pivot pin element  144  disposed between the main attachment portions  142  and positionable orthogonal to the longitudinal axis  50 . In this embodiment, there are provided rear brake cable segments  146  that are integrally formed and are joined at the pivot pin element  144 . The rear brake cable segments  146  may be formed of a single spring wire. The rear brake cable segments  146  are cooperatively wound about the pin element  144 . In this embodiment, the dual cable force balancing mechanism  136  includes a brake arm actuation assembly  148  that is simply formed of the rear brake cable segments  146 . In this form, it is contemplated that the pivot member  138  may rotate with respect to the brake arm actuation assembly  148  about the pivot pin element  144 . Advantageously, the use of a spring wire may serve a dual purpose of not only transferring force from the main brake cable segments  40 ,  42  to the rear brake arms  30 ,  32 , but also may act as a return spring for positioning the rear brake arms  30 ,  32  prior to and after actuation.  
      Referring now to  FIG. 9  there is depicted a plan view similar to the view of  FIG. 3 , however of a dual cable force balancing mechanism  150  according to yet another aspect of the present invention.  FIG. 10  is a top view of the dual cable force balancing mechanism  150  of  FIG. 9  as seen along axis  10   −10 . The dual cable force balancing mechanism  150  is similar in configuration to dual cable force balancing mechanism  150 , however with the differences noted, and like reference numerals indicate like structures.  
      Among other things, this embodiment features a pivot member  152  that may be coupled to the main brake cable segments  40 ,  42  at main attachment portions  154 . The pivot member  152  may include a pivot pin element  156  disposed between the main attachment portions  154  and positionable orthogonal to the longitudinal axis  50 . In this embodiment, there are provided rear brake cable segments  158  that are integrally formed and are joined at the pivot pin element  156 . The rear brake cable segments  146  are cooperatively loop over the pivot pin element  156 . In this embodiment, the dual cable force balancing mechanism  150  includes a brake arm actuation assembly  160  that is simply formed of the rear brake cable segments  158 . In this form, it is contemplated that the pivot member  138  may rotate and be disposed in sliding contact with the brake arm actuation assembly  160  at the pivot pin element  156 .  
      While an illustrative and presently preferred embodiments of the various aspects of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.