Abstract:
A bicycle brake device includes first and second brake arms. The first brake arm includes a first brake arm mounting portion for mounting the first brake arm to a bicycle frame member, a first brake pad mounting portion, and a first control interface portion. Similarly, the second brake arm includes a second brake arm mounting portion for mounting the second brake arm to the bicycle frame member, a second brake pad mounting portion, and a second control interface portion. A biasing member is operatively coupled to the first brake arm so that the first brake pad mounting portion is biased in a selected direction. A bias communicating member is operatively coupled between the first brake arm and the second brake arm to communicate biasing force from the biasing member to the second brake arm.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to bicycle brakes and, more particularly, to a center-pull style bicycle brake with synchronized brake arms. 
     Typical center-pull bicycle brakes comprise first and second brake arms pivotably mounted to a bicycle frame member such as front fork or rear seat stay of the bicycle frame. Each brake arm includes a brake arm mounting portion for mounting the brake arm to the bicycle frame member, a brake pad mounting portion, and a control interface portion. The brake arm mounting portion is disposed between the brake pad mounting portion and the control interface portion such that the brake pad mounting portion is disposed below the brake arm mounting portion when the brake arm is mounted to the bicycle frame member. When the first and second brake arms are mounted to the bicycle frame member, the control interface portion of the first brake arm extends to the side of the bicycle frame member at which the second brake arm is mounted, and vice versa. First and second return springs usually are mounted between the respective first and second brake arm mounting portions and the bicycle frame member for biasing the first and second brake pad mounting portions away from the bicycle wheel rim. 
     After the first and second brake arms are mounted to the bicycle frame member, an intermediate control element such as a control wire is mounted to the first control interface portion of the first brake arm and to the second control interface portion of the second brake arm. A primary control element then is mounted to the center of the intermediate control element such that, when the primary control element is pulled upwardly, the first and second brake arms rotate against the biasing forces of the first and second return springs so that first and second brake pads mounted to the first and second brake pad mounting portions frictionally contact the bicycle wheel rim. 
     The friction caused by the structures used to mount the first and second brake arm mounting portions to the bicycle frame member sometimes is not equally balanced between the first and second brake arms. As a result, the rotation of the first and second brake arms is not properly synchronized, so the first and second brake pads do not contact the bicycle rim at the same time. Several attempts have been made to solve this synchronization problem. For example, JP 62-177592 discloses first and second gear wheels that engage gear teeth on the first and second brake arms to synchronously push the control interface portions of the first and second brake arms apart during operation of the brake; JP 63-112995 discloses first and second rollers respectively mounted to the first and second control interface portions of the first and second brake arms, wherein a cam mounted to the primary control element contacts the first and second rollers to synchronously push the first and second control interface portions of the first and second brake arms apart when the primary control element is pulled upwardly; JP 64-90890 discloses a pair of links with attached rollers that are pushed apart by a cam mounted to the primary control element, wherein the rollers synchronously push the first and second control interface portions of the first and second brake arms apart when the primary control element is pulled upwardly; JP 64-90891 discloses multiple links connected both in series and in parallel to the first and second brake arms and to the primary control element to synchronously push the first and second control interface portions of the first and second brake arms apart when the primary control element is pulled upwardly. However, such complicated structures add more friction and operating effort to the braking device, which only gets worse when the synchronizing assemblies are subjected to water, dirt, mud and other contaminants. 
     Another disadvantage of prior art braking systems is that the biasing forces of the return springs must be overcome by the rider in order to operate the brakes. When synchronizing structures are used to synchronize the operation of the first and second brake arms, stronger return springs must be used to generate the greater biasing forces needed to overcome the additional friction created by the synchronizing structures and rotate the first and second brake arms so that the first and second brake pads are separated from the wheel rim. Such additional biasing forces further increase the effort required by the rider to operate the brakes. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to various features of a bicycle brake device. In one embodiment, a bicycle brake apparatus includes first and second brake arms. The first brake arm includes a first brake arm mounting portion for mounting the first brake arm to a bicycle frame member, a first brake pad mounting portion, and a first control interface portion. Similarly, the second brake arm includes a second brake arm mounting portion for mounting the second brake arm to the bicycle frame member, a second brake pad mounting portion, and a second control interface portion. A biasing member is operatively coupled to the first brake arm so that the first brake pad mounting portion is biased in a selected direction. A bias communicating member is operatively coupled between the first brake arm and the second brake arm to communicate biasing force from the biasing member to the second brake arm. Additional inventive features will become apparent from the description below, and such features alone or in combination with the above features and their equivalents may form the basis of further inventions as recited in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of an embodiment of a bicycle brake device attached to a front fork of a bicycle; 
         FIG. 2  is a right side view of the bicycle brake device; 
         FIG. 3  is a left side view of the bicycle brake device; 
         FIG. 4  is an exploded perspective view of the bicycle brake device; 
         FIG. 5  is a front view of a bias communicating member; 
         FIG. 6  is a partial cross-sectional view of the bicycle brake device in a brake-released position; 
         FIG. 7  is a partial cross-sectional view of the bicycle brake device in a brake-engaged position; 
         FIG. 8  is a bottom perspective view of another embodiment of a bicycle brake device; 
         FIG. 9  is a detailed view of top portions of the bicycle brake device shown in  FIG. 8 ; and 
         FIG. 10  is a perspective view of a bias communicating member used in the embodiments shown in  FIGS. 8 and 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is a front view of an embodiment of a bicycle brake device  10  attached to a front fork  14  of a bicycle,  FIG. 2  is a right side view of bicycle brake device  10 , and  FIG. 3  is a left side view of bicycle brake device  10 . Front fork  14  has a typical structure wherein a first fork leg  18  and a second fork leg  22  extend downwardly from a bridging member  26  that is attached to a steering tube  30 . Brake device  10  includes a first brake arm  34  and a second brake arm  38 , wherein first brake arm  34  is rotatably mounted to first fork leg  18  and second brake arm  38  is rotatably mounted to second fork leg  22 . As shown more clearly in  FIG. 4 , first brake arm  34  includes a first brake arm mounting portion  42  for mounting first brake arm  34  to first fork leg  18 , a first brake pad mounting portion  46  and a first control interface portion such as a first control element attachment location such as a first cable mounting portion  50 . First brake pad mounting portion  46  has a first brake pad mounting opening  52  for mounting a first brake pad  53  ( FIG. 1 ) in a well-known manner. Similarly, second brake arm  38  includes a second brake arm mounting portion  54  for mounting second brake arm  38  to second fork leg  22 , a second brake pad mounting portion  58  and a control interface portion such as a second control element attachment location such as a second cable mounting portion  62 . Second brake pad mounting portion  58  has a second brake pad mounting opening  60  for mounting a second brake pad  61  in a well-known manner. As shown in  FIGS. 1-3 , first brake pad  53  and second brake pad  61  are adapted to frictionally contact a rim portion  74  of a wheel  78 . 
     First brake arm mounting portion  42  includes a first mounting opening  66  for receiving a first mounting assembly  70  therethrough. First mounting assembly  70  includes a tubular first mounting base  82 , nuts  86 ,  90 , a tubular first bushing  94 , a washer  98 , a spacer  102 , a washer  106 , a tubular first pivot axle  110 , and a first mounting bolt  114 . First mounting base  82  includes a first mounting flange  118 , a first spring mounting portion  122 , a first bushing mounting portion  126  and a first threaded opening  130 . First mounting flange  118  is structured to be welded or otherwise attached to first fork leg  18 . First spring mounting portion  122  is structured to extend through a coil  134  of a biasing member such as a return spring  138 , and first bushing mounting portion  126  is structured to be inserted into an opening  142  in first bushing  94 . First bushing  94  includes a first flange  146  and a first arm mounting portion  150 , wherein first flange  146  abuts against nut  90 , and first arm mounting portion  150  extends through first mounting opening  66  in first brake arm mounting portion  42 . 
     First pivot axle  110  includes a first tubular portion  154 , a first flange  158 , and a first gate bridge supporting portion  162 . First tubular portion  154  extends through washer  106 , spacer  102 , washer  98 , first arm mounting portion  150  of first bushing  94 , and nuts  86  and  90  until first flange  158  abuts against washer  106 . A gate bridge  166  includes a first gate bridge loop  170  and a second gate bridge loop  174 , wherein first gate bridge loop  170  is structured to receive first gate bridge supporting portion  162  of first pivot axle  110  therein so that first gate bridge loop  170  abuts against first flange  158  of first pivot axle  110 . First mounting bolt  114  extends through first pivot axle  110  and screws into first threaded opening  130  in first mounting base  82  to axially fix first brake arm  34  to first fork leg  18  so that first brake arm  34  is supported by first bushing  94  for rotation around a first pivot axis X 1 . 
     The upper portion of first brake arm  34  bends laterally inwardly from first brake arm mounting portion  42  and forms first cable mounting portion  50  at a distal end thereof. First cable mounting portion  50  includes plate-shaped, parallel and arcuate first and second end bead mounting claws  182  and  186  that form a substantially vertically-oriented cable receiving slot  190  therebetween. First end bead mounting claw  182  forms a first cable end bead receiving opening  194  for receiving a cable end bead  198  ( FIG. 1 ) therein, and second end bead mounting claw  186  forms a second cable end bead receiving opening  202  for receiving cable end bead  198  therein. 
     A spring contacting surface  204  is formed on the laterally inner side surface of first brake arm  34  between first brake arm mounting portion  42  and first brake pad mounting portion  46  for contacting a first spring end  205  of return spring  138 . A pair of parallel, spaced-apart roller mounting ears  206  and  210  with corresponding mounting openings  214  and  218  are disposed on first brake arm  34  between first brake arm mounting portion  42  and first cable mounting portion  50 . Mounting opening  214  is unthreaded, whereas mounting opening  218  is threaded. Mounting ears  206  and  210  are spaced apart for receiving a tubular spacer  222  and a tubular roller  226  therebetween. Roller  226  is rotatably mounted between roller mounting ears  206  and  210  by a screw  230  that extends through mounting ear  206  and spacer  222  and screws into threaded mounting opening  218 . Roller  226  functions as a movement interface member in a manner discussed below. 
     Second brake arm mounting portion  54  includes a second mounting opening  234  for receiving a second mounting assembly  238  therethrough. Second mounting assembly  238  is substantially the same as first mounting assembly  70 . Second mounting assembly  238  includes a tubular second mounting base  242 , nuts  246 ,  250 , a tubular second bushing  254 , a washer  258 , a spacer  262 , a washer  266 , a tubular second pivot axle  270 , and a second mounting bolt  274 . Second mounting base  242  includes a second mounting flange  278 , a second spring mounting portion  282 , a second bushing mounting portion  286  and a second threaded opening  290 . Second mounting flange  278  is structured to be welded or otherwise attached to second fork leg  22 . Second spring mounting portion  282  is structured to engage a second spring end  294  of return spring  138 , and second bushing mounting portion  286  is structured to be inserted into an opening  298  in second bushing  254 . Second bushing  254  includes a second flange  302  and a second arm mounting portion  306 , wherein second flange  302  abuts against nut  250 , and second arm mounting portion  306  extends through second mounting opening  234  in second brake arm mounting portion  54 . 
     Second pivot axle  270  includes a second tubular portion  310 , a second flange  314 , and a second gate bridge supporting portion  318 . Second tubular portion  310  extends through washer  266 , spacer  262 , washer  258 , second arm mounting portion  306  of second bushing  254 , and nuts  246  and  250  until second flange  314  abuts against washer  266 . Second gate bridge loop  174  of gate bridge  166  is structured to receive second gate bridge supporting portion  318  of second pivot axle  270  therein so that second gate bridge loop  174  abuts against second flange  314 . Second mounting bolt  274  extends through second pivot axle  270  and screws into second threaded opening  290  in second mounting base  242  to axially fix second brake arm  38  to second fork leg  22  so that second brake arm  38  is supported by second bushing  254  for rotation around a second pivot axis X 2 . 
     A bias communicating member  322  is structured and dimensioned to be mounted within a vertical mounting groove  326  formed in second brake arm mounting portion  54  of second brake arm  38 . In this embodiment, second pivot axis X 2  intersects mounting groove  326  so that bias communicating member  322  pivots around a bias communicating member pivot axis B that is coaxial with second pivot axis X 2 . As shown in  FIGS. 4 and 5 , bias communicating member  322  comprises a bias communicating member mounting portion  330 , a first brake arm interface portion  334 , and an axially thin, rod-shaped second brake arm interface portion  338 , wherein bias communicating member mounting portion  330  is disposed between first brake arm interface portion  334  and second brake arm interface portion  338 . As a result, second brake arm interface portion  338  is disposed between second brake arm mounting portion  54  and second brake pad mounting portion  58  of second brake arm  38  when bias communicating member  322  is mounted in mounting groove  326 . Bias communicating member mounting portion  330  is formed as a generally annular member having an opening  342  dimensioned to receive second arm mounting portion  306  of second bushing  254  therethrough. The end portion of first brake arm interface portion  334  is formed as an axially thick paddle  346  for engaging roller  226  mounted to first brake arm  34 . As shown in  FIG. 5 , first brake arm interface portion has  334  a first brake arm interface end  350 , and second brake arm interface portion  338  has a second brake arm interface end  354 . A distance D 1  from bias communicating member pivot axis B to first brake arm interface end  350  is greater than a distance D 2  from bias communicating member pivot axis B to second brake arm interface end  354 . 
     A threaded opening  358  is formed in second brake arm  38  between second brake arm mounting portion  54  and second brake pad mounting portion  58  for receiving an adjustment member in the form of an adjustment screw  362  therein. The tip of adjustment screw  362  contacts second brake arm interface portion  338  of bias communicating member  322  for adjusting the relative position between second brake arm interface portion  338  and second brake arm  38  in a continuous manner. 
     A passage  366  in the form of an opening is formed in second brake arm  38  between second brake arm mounting portion  54  and second cable mounting portion  62 . In this embodiment, passage  366  is formed as a substantially circumferentially-closed opening such as a completely circumferentially-closed opening. Passage  366  is dimensioned such that it is capable of receiving the portion of first brake arm  34  above first brake arm mounting portion  42  therethrough. As a result, when brake device  10  is viewed along first pivot axis X 1  and second pivot axis X 2 , first brake arm  34  intersects second brake arm  38  so that first cable mounting portion  50  of first brake arm  34  and second cable mounting portion  62  of second brake arm  38  are located on opposite sides of the intersection. 
     Second cable mounting portion  62  of second brake arm  38  extends upwardly from passage  366  and includes a cable mounting wall  370  with a side surface  374 , wherein a generally horizontally-oriented threaded opening  378  is formed at side surface  374  for receiving a cable mounting bolt  382  ( FIG. 1 ) therein. First cable mounting portion  50  and second cable mounting portion  62  are configured such that, when brake device  10  is viewed perpendicular to first and second pivot axes X 1  and X 2  and first and second pivot axes X 1  and X 2  are horizontal, cable receiving slot  190  in first brake arm  34  substantially aligns with side surface  374  on second brake arm  38 . 
     As shown in  FIGS. 1-3 , in this embodiment, an intermediate control element comprises a generally triangular control plate  386 , a first intermediate control wire  390 , and a second intermediate control wire  394 . First intermediate control wire  390  has a first end attached to the lower right vertex of control plate  386  and a second end that extends through cable receiving slot  190  in first cable mounting portion  50  of first brake arm  34  and attaches to cable end bead  198 . Second intermediate control wire  394  has a first end attached to the lower left vertex of control plate  386  and a second end attached to side surface  374  of second cable mounting portion  62  of second brake arm  38  by cable mounting bolt  382 . A primary control element in the form of a primary control wire  398  is attached to the upper vertex of control plate  386 . 
     Operation of the device is shown in  FIGS. 6 and 7 , wherein  FIG. 6  is a partial cross-sectional view of brake device  10  in a brake-released position, and  FIG. 7  is a partial cross-sectional view of brake device  10  in a brake-engaged position. When primary control wire  398  is pulled upwardly, first cable mounting portion  50  of first brake arm  34  and second cable mounting portion  62  of second brake arm  38  are pulled upwardly, thereby causing first brake arm  34  to rotate counterclockwise and causing second brake arm  38  to rotate clockwise. During that time, the tip of adjusting screw  362  presses against second brake arm interface portion  338  of bias communicating member  322 , and paddle  346  of first brake arm interface portion  334  of bias communicating member  322  presses against roller  226  attached to first brake arm  34  to synchronize the movement of first brake arm  34  and second brake arm  38 . Thus, bias communicating member  322  also functions as a synchronizing member that communicates rotational force between first brake arm  34  and second brake arm  38  so that first brake arm  34  moves synchronously with second brake arm  38 . 
     When primary control wire  398  is released, return spring  138  biases first brake arm  34  clockwise to move first brake pad  53  to the brake released position. The clockwise rotation of first brake arm  34  is communicated to paddle  346  of first brake arm interface portion  334  of bias communicating member  322  via roller  226 , thereby causing bias communicating member  322  to rotate counterclockwise. The counterclockwise rotation of bias communicating member  322  is communicated to adjusting screw  362  in second brake arm  38  via second brake arm interface portion  338 , thereby causing second brake arm  38  to rotate counterclockwise to move second brake pad  61  to the brake released position. Unlike prior art brake devices, only one return spring is required to rotate both first brake arm  34  and second brake arm  38  to the brake released positions. Second brake arm  38  is unbiased except for the biasing force from return spring  138  received from bias communicating member  322 . As a result, less operating force is required to operate brake device  10 . Furthermore, since distance D 1  from bias communicating member pivot axis B to first brake arm interface end  350  is greater than a distance D 2  from bias communicating member pivot axis B to second brake arm interface end  354 , bias communicating member  322  functions as a lever that provides a mechanical advantage so that the biasing force of return spring  138  is efficiently communicated from first brake arm  34  to second brake arm  38 . Finally, the position of first brake pad  53  relative to second brake pad  61  may be adjusted easily using adjusting screw  362  to assure symmetrical positioning of first brake pad  53  and second brake pad  61  relative to wheel  78 . 
     Since cable receiving slot  190  in first brake arm  34  substantially axially aligns with side surface  374  on second brake arm  38  when brake device  10  is viewed perpendicular to first and second pivot axes X 1  and X 2 , first intermediate control wire  390  likewise axially aligns with second intermediate control wire  394 . As a result, the axial forces applied to first brake arm  34  and second brake arm  38  by first intermediate control wire  390  and second intermediate control wire  394  are balanced, and torsional forces applied to first intermediate control wire  390  and second intermediate control wire  394  are reduced, thereby reducing wear on the control wires. Furthermore, in this embodiment, first intermediate control wire  390  and second intermediate control wire  394  are substantially axially centered relative to first brake arm  34  and second brake arm  38  when brake device  10  is viewed perpendicular to first and second pivot axes X 1  and X 2 . This configuration further balances the axial forces applied to first brake arm  34  and second brake arm  38 . 
     While the above is a description of various embodiments of inventive features, further modifications may be employed without departing from the spirit and scope of the present invention. For example, bias communicating member  322  need not be mounted within mounting groove  326 . Bias communicating member  322  could be mounted outside second brake arm  38 , or bias communicating member  322  could be mounted on or about first brake arm  34 . Other adjusting members could be provided for adjusting the relative position between second brake arm  38  and second brake arm interface portion  338  of bias communicating member  322 . For example a spacer or some other member or structure could be disposed between second brake arm  38  and second brake arm interface portion  338  for adjusting the relative position between second brake arm  38  and second brake arm interface portion  338  in a discrete or step-wise manner. Passage  366  need not be formed as a bounded opening as long as passage  366  accommodates the passage of first brake arm  34  therethrough. 
     While brake device  10  was operated using primary control wire  398 , control plate  386 , first intermediate control wire  390  and second intermediate control wire  394 , the bias communicating function and/or the synchronizing function performed by bias communicating member  322  may be applied to other braking devices. For example  FIGS. 8-10  illustrate another embodiment of a brake device  10 ′ that includes inventive features. This embodiment includes a first brake arm  34 ′ and a second brake arm  38 ′. First brake arm  34 ′ and second brake arm  38 ′ share many features as first brake arm  34  and second brake arm  38  in the first embodiment, so only the differences will be described. 
     In this embodiment, first brake arm  34 ′ and second brake arm  38 ′ are operated by a piston-operating hydraulic cylinder  400  that receives hydraulic fluid from a hydraulic fluid line  404  and includes a piston  406  (shown schematically in  FIG. 9 ) that selectively extends and retracts a T-shaped piston shaft  408  in response to the pressure of hydraulic fluid received through hydraulic fluid line  404 . Piston shaft  408  is biased toward a retracted position by a return spring (not shown) disposed within hydraulic cylinder  400  in a well-known manner. To accommodate this structure, first brake arm  34 ′ includes a first control interface portion  412 , and second brake arm  38 ′ includes a second control interface portion  416 . First control interface portion  412  includes parallel and arcuate first and second shaft mounting claws  420  and  424  that form a substantially vertically-oriented slot  428  therebetween. First shaft mounting claw  420  forms a first cartridge bearing receiving recess  432  for receiving a first cartridge bearing  436  therein, and second shaft mounting claw  424  forms a second cartridge bearing receiving opening  440  for receiving a second cartridge bearing  444  therein. First cartridge bearing  436  and second cartridge bearing  444  are rotatably supported on opposite ends of the T-shaped piston shaft  408 . 
     Second control interface portion  416  likewise includes parallel and arcuate first and second shaft mounting claws  448  and  452  that form a substantially vertically-oriented slot  456  therebetween and having sufficient width to receive hydraulic cylinder  400  therein. First shaft mounting claw  448  forms a first cartridge bearing receiving recess (not shown, but similar to first cartridge bearing receiving recess  432 ) for receiving an annular first bushing  460  therein, and second shaft mounting claw  452  forms a second cartridge bearing receiving opening (not shown, but similar to second cartridge bearing receiving opening  440 ) for receiving an annular second bushing (not shown, but similar to first bushing  460 ) therein. First bushing  460  is mounted to a first mounting shaft  464  that extends from the side of hydraulic cylinder  400 , and the second bushing is similarly mounted to a second mounting shaft (not shown) extending from the opposite side of hydraulic cylinder  400 . 
     In this embodiment, a bias communicating member  470  is structured and dimensioned to be mounted within a vertical mounting groove  474  formed in first brake arm mounting portion  42 ′ of first brake arm  34 ′. In this embodiment, first pivot axis X 1  intersects mounting groove  474  so that bias communicating member  470  pivots around a bias communicating member pivot axis B that is coaxial with first pivot axis X 1 . Bias communicating member  470  comprises a bias communicating member mounting portion  478 , an axially thin, rod-shaped first brake arm interface portion  482 , and a second brake arm interface portion  486 , wherein bias communicating member mounting portion  478  is disposed between first brake arm interface portion  482  and second brake arm interface portion  486 . As a result, first brake arm interface portion  482  is disposed between first brake arm mounting portion  42 ′ and first brake pad mounting portion  46  of first brake arm  34 ′ when bias communicating member  470  is mounted in mounting groove  474 . Bias communicating member mounting portion  478  is formed as a generally annular member having an opening  490  dimensioned to receive first arm mounting portion  150  ( FIG. 4 ) of first bushing  94  therethrough. Second brake arm interface portion  486  is formed as an axially thick paddle cam for engaging a thin rod-shaped cam follower  494  mounted to second brake arm  38 ′ between second brake arm mounting portion  54 ′ and second control interface portion  416 . 
     When hydraulic cylinder  400  extends piston shaft  408  to bias first brake arm  34 ′ to rotate counterclockwise, the side of first brake arm  34 ′ presses against first brake arm interface portion  482  of bias communicating member  470 , and second brake arm interface portion  486  of bias communicating member  470  presses against cam follower  494  attached to second brake arm  38 ′ to communicate biasing force from piston shaft  408  to second brake arm  38 ′ and to synchronize the movement of first brake arm  34 ′ and second brake arm  38 ′. 
     When hydraulic cylinder  400  retracts piston shaft  408  to bias second brake arm  38 ′ to rotate counterclockwise, the counterclockwise rotation of second brake arm  38 ′ is communicated to second brake arm interface portion  486  of bias communicating member  470  via cam follower  494 , thereby causing bias communicating member  470  to rotate clockwise. The clockwise rotation of bias communicating member  470  is communicated to first brake arm  34 ′ via first brake arm interface portion  482  of bias communicating member  470 , thereby causing first brake arm  34 ′ to rotate clockwise to move first brake pad  53  to the brake released position and to synchronize the movement of first brake arm  34 ′ and second brake arm  38 ′. 
     The size, shape, location or orientation of the various components may be changed as desired. Components that are shown directly connected or contacting each other may have intermediate structures disposed between them. Separate components may be combined, and vice versa. The functions of one element may be performed by two, and vice versa. The function of one element may be performed by another, and functions may be interchanged among the elements. The structures and functions of one embodiment may be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Terms of degree such as “substantially,” “about” and “approximately” as used herein include a reasonable amount of deviation of the modified term such that the end result is not significantly changed. Thus, the scope of the invention should not be limited by the specific structures disclosed or the apparent initial focus or emphasis on a particular structure or feature.