Abstract:
A brake lever arm is mounted to a base member, with the base member fixed to a bicycle handlebar. The lever arm is pivotal about a pivot point on the base. The lever arm includes an adjusting mechanism that adjusts the position of the lever arm when the lever arm is in a brake dis-engaged position. The adjusting mechanism is slideable in grooves in the lever arm such that the adjusting mechanisms may be moved to positions that are differing distances away from the pivot point. The adjusting mechanism includes a contact member that engages a brake cable connected to the lever arm when the lever arm is moved from the brake disengaged position toward a brake engagement position. The position of the contact member with respect to the pivot point determines the effect movement of the lever arm has on the cable. In this manner, the adjusting mechanism adjusts the length of the stroke or travel of the lever arm from the brake disengaged position to the brake engagement position.

Description:
BACKGROUND OF THE INVENTION 
     A. Field of the Invention 
     The invention relates to a brake lever arm having an adjusting mechanism therein which adjusts the reach of the brake lever arm and the length of the movement of the brake lever arm. 
     B. Description of the Related Art 
     At one time, brake actuating mechanisms for bicycles were merely levers coupled to the handle bar of a bicycle with one end of a cable connected to the lever, and the opposite end of the cable being connected to a brake mechanism adjacent to one of the bicycle wheels. However, brake mechanisms and brake actuating mechanisms have become very sophisticated in recent years. 
     Brake actuating mechanisms usually include a lever arm mounted to a base member for pivotal movement. The base member is typically mounted to a handlebar of a bicycle. A cable extends from the brake mechanism to the lever arm. The lever arm pivots between a brake engagement position and a brake disengagement position. In the brake engagement position, the cable is pulled by the lever arm so that the brake mechanism is engaged to stop tire rotation. In the brake disengagement position, the cable tension is released and the brake mechanism is disengaged. Typically, in the brake disengagement position, the lever arm is spaced apart from the handlebar by a predetermined distance. In the brake engagement position, the lever arm is closer to the handlebar than it is in the brake disengagement position. 
     Until recently, the lever arm on brake actuation mechanisms were manufactured in accordance with a one size fit all approach. A single generic lever arm was expected to be used by all types of bicyclists. However, the needs of individual bicycle users differs from person to person. For instance, some bicyclists have small hands and some have large hands. Those bicyclists with small hands and short fingers have a short reach and therefore may have difficulty keeping the palm of their hands on a bicycle handlebar grip and  while reaching the lever arm. Conversely, a bicyclist with large hands may find that his fingers wrap too easily around the lever arm and may not have an optimal engagement with the lever arm. 
     Recently, brake actuation mechanisms have been introduced which include an adjustment mechanism which allows adjustment of the location of the lever arm when the brake mechanism is in a brake disengagement position. The brake disengagement position adjustment  is defined as the reach of a lever arm. Such reach adjustment mechanisms at least allow for some user adjustable features enabling a manufacturer to manufacture one component that may be used by a variety of bicyclists. 
     Such adjustable lever arms have a sever shortcoming in that the stroke of the lever arm is not adjusted accordingly. The stroke of the lever arm is defined as the total distance the lever arm moves from the brake disengagement position to the brake engagement position. The stroke length may be small or large depending on many things such as the brake mechanism used, how well the brake mechanism is adjusted, the length of the cable, to name a few. Adjustable lever arms appear to fail to provide for the lever arm stroke length. For instance, in the case where the stroke is relatively large and the adjustable lever arm is adjusted to accommodate small hands, the lever arm would be adjusted to be closer to the handlebar in the brake disengagement position. After such an adjustment, the lever arm might contact the handlebar before the brake is engaged causing a safety hazard for the bicyclist. 
     SUMMARY OF THE INVENTION 
     One object of the invention is to provide a brake lever arm with an adjustment mechanism which allows for adjustment of both the reach and the stroke of a bicycle brake lever arm. 
     In one aspect of the present invention, a brake lever mechanism includes a base member formed with a cable guide and the base member having a pivot point defined thereon spaced apart from the cable guide. The brake lever also includes a lever arm formed with a handle portion and a support portion, the . The support portion is mounted for pivotal movement on the pivot point from a brake dis-engagement position to a brake engagement position, the . The support portion is formed with a first slot therein, and the handle portion is formed with a cable connector. Mounted within the first slot is an adjusting mechanism, the . The adjusting mechanism having  has a cable contact point, wherein the adjusting mechanism adjusts the relative position between the cable contact point and the pivot point. 
     Preferably a fine adjusting mechanism extends through a portion of the base member for engagement with the support portion. The fine adjusting mechanism adjusts the relative position between the lever arm and the cable guide with the lever arm in the brake dis-engagement position. 
     Alternatively, the fine adjusting mechanism extends through a portion of the base member for engagement with the adjusting mechanism, wherein the fine adjusting mechanism adjusts the relative position between the lever arm and the cable guide with the lever arm in the brake dis-engagement position. 
     Preferably, the support portion of the lever arm is formed with a second slot generally parallel to the first slot. The adjusting mechanism is formed with a pin extending through the first slot and the adjusting mechanism includes a screw extending though  through the second slot. 
     Preferably, the first slot extends lengthwise in the support portion from a point proximate the pivot point to a point further away from the pivot point. 
     Preferably, the adjusting mechanism includes a first portion having at least one pin member which extends through the first slot in the support portion, and the . The adjusting mechanism further includes a contact member attached to the first portion, with the cable contact point being formed on the contact member. 
     Preferably, the cable guide includes an aperture extending through a portion of the base member and a cable length adjusting member encircling one end of the aperture on threads formed on the base member. 
     Preferably, the support portion of the lever arm includes generally parallel first and second support portions spaced apart from one another. extending from the lever portion, the slot having parallel first and second slots formed in the first and second support portions, respectively, the  The adjusting mechanism being  is disposed between the first and second support portions, and the adjusting mechanism having a pin which extends through the first and second slots . 
     Preferably, the  the support portion of the lever arm further comprises third and fourth slots. The first and second support portions are formed with the first, second, third and fourth slots generally parallel to the first and second slot, respectively, and the  each other. The adjusting mechanism includes a pin extending through the first and fourth slots, and a screw extending through the second and third slots. and the adjusting mechanism includes threaded member engaging the screw extending though the fourth slot. 
     These and other objects, features, aspects and advantages of the present invention will become more fully apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings where like reference numerals denoted corresponding parts throughout, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side elevation of a brake lever arm attached to a handlebar in accordance with a first embodiment of the present invention; 
         FIG. 1B  is a side elevation similar to  FIG. 1 , but showing the opposite side of the brake lever arm; 
         FIG. 1C  is a side elevation 
         FIG. 2  is a section of the brake lever arm taken along the line II-II in  FIG. 1A , looking in the direction of the arrow, and shown on a slightly enlarged scale, showing details of an adjusting mechanism disposed within the brake lever arm; 
         FIGS. 3A ,  3 B and  3 C are views of the adjusting mechanism depicted in  FIG. 2 , shown removed from the brake lever arm; 
         FIGS. 4-6  are fragmentary side elevations with phantom line details showing an alternate embodiment of the brake lever arm depicted in  FIGS. 1A ,  1 B and  2  with the adjusting mechanism in a first position, where  FIG. 4  shows the brake lever arm in a brake disengagement position,  FIG. 5  shows the brake lever arm in an intermediate position, and  FIG. 6  shows the brake lever arm positioned in engagement with a handlebar grip; 
         FIGS. 7-9  are fragmentary side elevations, similar to  FIGS. 4-6 , showing the brake lever arm adjusting mechanism in a second position, where  FIG. 7  shows the brake lever arm in a brake disengagement position,  FIG. 8  shows the brake lever arm in an intermediate position, and  FIG. 9  shows the brake lever arm positioned in engagement with the handlebar grip; 
         FIGS. 10-12  are fragmentary side elevations, similar to  FIGS. 4-6 , showing the brake lever arm adjusting mechanism in a third position, where  FIG. 10  shows the brake lever arm in a brake disengagement position,  FIG. 11  shows the brake lever arm in an intermediate position, and  FIG. 12  shows the brake lever arm positioned in engagement with the handlebar grip; 
         FIG. 13  is a fragmentary side view of the brake lever arm in accordance with another alternate embodiment of the present invention; and 
         FIG. 14  is a fragmentary side view of the brake lever arm in accordance with yet another alternate embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIGS. 1A and 1B , there is shown a bicycle brake mechanism  5  that includes a base  10  that is connected to a bicycle handlebar  15 . The handlebar  15  also includes a grip  20  to accommodate a bicyclist&#39;s hand (not shown). A pivot pin  25  extends through the base  10  and a lever arm  30 . The lever arm  30  pivots freely about the pivot pin  25 . 
     The lever arm  30  has a U-shaped cross-section, as shown in FIG.  2 . The lever arm  30  is therefore  has a generally hollow interior and has  defined by generally parallel opposing sides  31  and  32 . The side  32  includes a first slot  35  and a third slot  36 , as shown in FIG.  1 B. The side  31  includes a second slot  38 , which has an irregular shape, as will be described in greater detail below. Disposed between the two sides  31  and  32  is an adjusting mechanism  40 , which is also described in greater detail below. 
     The lever arm  30  is also formed with a cable retainer  42  which accommodates and retains the ball end  44  of a cable (not shown in FIGS.  1 A and  1 B). In  FIGS. 1A and 1B  the ball end  44  of the cable end is shown but the cable is not shown for greater clarity. The cable C is shown in  FIGS. 4-12 , and is described in greater detail below. 
     With reference to  FIGS. 1A and 1B , the base  10  also includes an extending portion  46  which has a distal end  48 . The distal end  48  is formed with a threaded bore  49  through which a cable adjusting mechanism  50  extends. An adjusting screw  52  extends through the extending portion  46 , as is described in greater detail below. 
     The adjusting mechanism  40  is shown in cross section in  FIG. 2 , and is also shown removed from the lever arm  30  in  FIGS. 3A ,  3 B and  3 C. The adjusting mechanism  40  includes a main body  54  which has a generally U-shape in cross-section, as shown in FIG.  3 C. The main body  54  includes a pin  56  extending though holes formed on either side of the main body  54  and a screw  58  also extending though the main body  54 , the screw  58  engaging threads formed in the main body  54 . The screw  58  also extends through a contact body  60 . The pin  56  is fitted tightly within the main body  54  by, for instance, press fitting the pin  56  in holes formed in the main body  54 . 
     The contact body  60  generally has a T-shape, as shown in  FIG. 3B , the lower portion  60 a of the contact body  60  extending into the interior of the main body  54 . The contact body  60 , as indicated in  FIG. 2 , is made of a resin or plastic material. The upper portion of the contact body  60  is formed with a recess  62  that extends the length of the upper portion of the contact body  60 . 
     With the adjusting mechanism  40  disposed within the lever arm  30 , the pin  56  extends into the first slot  35  formed in the side  32 . Further, the screw  58  extends into the third slot  36  formed in the side  32  and the head  58 a of the screw  58  extends through the second slot  38  formed in the side  31 . When the screw  58  is loosened, the adjusting mechanism  40  is able to slide freely within the length of the slots  35 ,  36  and  38 . 
     The adjusting mechanism  40  is configured to move to three positions within the lever arm  30 . Correspondingly, the second slot  38  is formed with three rounded sections  38 a,  38 b and  38 c to accommodate a screw head  58 a formed on the end of the screw  58 . In order to change the position of the adjusting mechanism  40 , the screw  58  must be loosened so that the head  58 a of the screw  58  extends above the surface of the side  31  of the lever arm  30 . With the screw  58  loose, the adjusting mechanism  40  is able to slide within the confines of the first slot  35  and the second slot  38 . The screw  58  may be tightened so that the head  58 a extends into one of the three rounded sections  38 a,  38 b or  38 c, each of the rounded sections corresponding to the three positions, which are described in greater detail below. It should be appreciated that the second slot  38  may be provided with only two rounded sections or may be formed with four or more rounded sections to provide corresponding numbers of adjustment positions for the adjusting mechanism  40 . It should further be appreciated that the screw  58  may be replaced with a spring loaded pin which may be urged by a spring into the rounded sections  38 a,  38 b or  38 c and by pushing on the spring loaded pin, the adjusting mechanism  40  may be moved into a desired position. 
       FIGS. 4 through 12  depict the present invention in an alternate embodiment where the firsta fourth slot  35 a has also been formed in the side  31  and thea pin  56 a extends into the firstfourth slot  35 a formed in the side  31 . Further, the cable C connects to the lever arm  30  in an alternate manner. 
     In  FIGS. 4-12 , the three positions of the adjusting mechanism  40  are depicted. For instance, in  FIGS. 4-6  the adjusting mechanism  40  is shown in a first position with the head  58 a disposed in the rounded section  38 a. In  FIGS. 7-9  the adjusting mechanism  40  is shown in a second position with the head  58 a disposed in the rounded section  38 b. In  FIGS. 10-12  the adjusting mechanism  40  is shown in a first position with the head  58 a disposed in the rounded section  38 c. 
     With reference to  FIG. 4 , various measurements are indicated.  FIG. 4  shows the lever arm  30  in a first brake disengagement position where the lever arm  30  is a distance D 1  away from the handlebar grip  20 . A brake lever arm distance L is defined from the carrier of the pivot pin  25  to the center of the cable end  44 . It should be noted that the brake lever arm distance L is constant throughout all of the various positions depicted in  FIGS. 4 through 12 . 
     It should further be noted that for all measurements shown in  FIGS. 4  though  12 , the adjusting screw  52  is held in a constant position to define the various the brake disengagement positions, described below. 
       FIG. 5  shows the brake lever arm  30  in an intermediate position between the brake engagement and brake disengagement positions. A first adjustable lever distance A 1  is defined from the center of the pivot pin  25  to the recess  62  where the cable C contacts the contact body  60 . It should be appreciated that the first adjustable lever distance A 1  is constant in  FIGS. 4 ,  5  and  6  where the adjusting mechanism  40  is positioned with the screw head  58 a disposed in the first rounded portion  38 a of the second slot  38 . 
       FIG. 7  shows the brake lever arm in a second brake disengagement position, where the lever arm  30  is a distance D 2  away from the handlebar grip  20  due to the head  58 a of the screw  58  being positioned in the second rounded portion  38 b of the slot  38 . 
       FIG. 8  shows the brake lever arm in an intermediate position. A second adjustable lever distance A 2  is defined from the center of the pivot pin  25  to the recess  62  where the cable C contacts the contact body  60 . It should be appreciated that the second adjustable lever distance A 2  is constant in  FIGS. 7 ,  8  and  9  where the adjusting mechanism  40  is positioned with the screw head  58 a disposed in the second rounded portion  38 b of the second slot  38 . 
       FIG. 10  shows the brake lever arm in a third brake disengagement position, with the adjusting mechanism  40  in a third position where the head  58 a of the screw  58  is disposed in the third rounded section  38 c of the slot  38 . In  FIG. 10 , the lever arm  30  is a distance D 3  away from the handlebar grip  20 . 
       FIG. 11  shows the brake lever arm in an intermediate position. A third adjustable lever distance A 3  is defined from the center of the pivot pin  25  to the recess  62  where the cable C contacts the contact body  60 . It should be appreciated that the third adjustable lever distance A 3  is constant in  FIGS. 10 ,  11  and  12  where the adjusting mechanism  40  is positioned with the screw head  58 a disposed in the third rounded portion  38 c of the second slot  38 . 
     The various positions of the lever arm distance D 1 , D 2 , and D 3  represent the reach of the lever arm  30 . 
     As is shown in the figures, the following relationships are true:
         A 1 &gt;A 2 &gt;A 3 ;   D 1 &lt;D 2 &lt;D 3 ; and   L=constant throughout.       

     There are several geometrical relationships that are fundamental to the operation of the bicycle brake mechanism  5 . First, the reach distance D 1 , D 2  or D 3  is easily adjusted by moving the adjusting mechanism  40  into any one of the three rounded sections  38 a,  38 b or  38 c. Adjustment of the reach distance D 1 , D 2  or D 3  also alters the stroke length or total movement of the lever arm  30  due to the setting of the adjustable lever distances A 1 , A 2  or A 3 . The adjustable lever distances alter the stroke length of the lever arm  30  by contacting the cable at a points having differing distances from the pivot pin  25 . The movement of the cable C is directly proportional to the size of the adjustable lever distances A 1 , A 2  or A 3 . Hence, for the reach distance D 1 , the adjustable lever distance A 1  has a relatively large value and therefore, as the lever arm  30  moves, the cable C will move about the pivot pin  25  a corresponding short stroke length until the brake mechanism (not shown) is engaged. For the reach distance D 2 , the adjustable lever distance A 2  has an intermediate value and therefore, as the lever arm  30  moves, the cable C will move about the pivot pin  25  a corresponding intermediate stroke length until the brake mechanism (not shown) is engaged. For the reach distance D 3  the adjustable lever distance A 3  has a relatively small value and therefore, as the lever arm  30  moves, the cable C will move about the pivot pin  25  a corresponding long stroke length until the brake mechanism (not shown) is engaged. 
     Comparing the three positions of the adjusting mechanism  40  it is shown in the present invention that as the reach (D 1 , D 2  or D 3 ) gets smaller, the corresponding stroke length also decreases since the distance (either A1, A2 or A3) from the pivot pin  25  increases. Conversely, as the reach (D 1 , D 2  or D 3 ) gets larger, the corresponding stroke length also increases since the distance (either A1, A2 or A3) from the pivot pin  25  decreases. 
     Also, the brake disengage position distance D 1  provides a short reach for a bicyclist, with the lever arm  30  being relatively close to the handlebar grip  20 . Similarly, the brake disengage position distance D 3  provides a long reach for a bicyclist, with the lever arm  30  being at a relatively large distance from the handlebar grip  20 . 
     The adjusting screw  52  is shown contacting the adjusting mechanism  40 . However, alternatively, the adjusting screw  52  may be configured to contact one or both of the sides  31  and  32 . For instance, in  FIG. 1C , the adjusting screw  52  is shown contacting side  32 . The adjusting screw  52  is mounted in the present invention in part to provide for fine adjustment of the reach of the lever arm  30 . 
     Another alternate embodiment is depicted in  FIG. 13 , where an adjusting mechanism  40 a is mounted within a lever arm  30 a by the screw  58 . In this embodiment, the screw is completely removed before the adjustment mechanism  40 a may be moved to different positions. Once in position, the screw  58  must be re-installed. 
     In yet another embodiment depicted in  FIG. 14 , two screws  58  are used to secure an adjusting mechanism  40 b into position in a lever arm  30 b. 
     There are numerous advantages in the present invention. For instance, the present invention provides a simple and easy way to adjust the reach of a lever arm. The present invention also provides a simple and easy way to adjust the stroke length of a lever arm. The present invention provides a simple and easy means for simultaneously adjusting both the reach and the stroke of a lever arm. 
     The present invention also provides a means for fine adjusting a lever arm into a brake disengage position to accommodate various sized bicyclists with differing size hands. 
     Various details of the invention may be changed without departing from its spirit nor its scope. Furthermore, the foregoing description of the embodiments according to the present invention is provided for the purpose of illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.