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 is slidable in grooves formed on the lever arm such that the adjusting mechanism may be selectively moved to a plurality of positions located at differing distances away from the pivot point. An adjusting screw extends through a portion of the base and, in one embodiment, contacts a portion of the adjusting mechanism. In another embodiment, the adjusting screw contacts a portion of the lever arm. Movement of the adjusting screw allows for positioning of the lever arm to define a brake dis-engagement position. The adjusting mechanism includes a contact member that is contactable with a brake cable connected to the lever arm. Depending on the adjustment of the adjusting screw and the adjusting mechanism, when the lever arm is located in the brake dis-engagement position, the cable does not contact the contact member. The cable contacts the contact member as the lever arm is moved from the brake dis-engagement position to a brake engagement position. The position of the contact arm with respect to the pivot point determines the amount of leverage of the lever arm effects on the cable.

Description:
This application is a continuation-in-part of application Ser. No. 08/598,578, filed Feb. 12, 1996, now abandoned. 
    
    
     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 a cable connected to the lever, 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 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 requiring other adjustments, such as a cable adjustment, not so easily made. 
     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 support portion mounted for pivotal movement on the pivot point from a brake dis-engagement position to a brake engagement position, the support portion formed with a slot therein, and the handle portion formed with a cable connector. Mounted within the slot is an adjusting mechanism, the adjusting mechanism having 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. 
     Alternatively, the support portion is formed with a first slot and the adjusting mechanism confined to selective movement along the first slot. 
     Preferably, the support portion of the lever arm is formed with a second slot generally parallel to the first slot, and the adjusting mechanism is formed with a pair of protrusions which extend into the first slot and the adjusting mechanism includes a screw extending though the first slot. 
     Preferably, the lever arm is formed with first and second sides, the first slot is formed in the first side and the second slot is formed in the second side with the adjusting mechanism disposed between the first and second sides. The first slot and the second slot are generally aligned with one another, and the first slot is longer than the second slot. 
     Preferably, the adjusting mechanism includes a contact member and the cable contact point is 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. 
     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 denote 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. 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, 3B and 3C 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, 1B 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. 13A is a fragmentary side view of a brake lever arm in accordance with another embodiment of the present invention; 
     FIG. 13B is an end view of the brake lever arm depicted in FIG. 13A, with portions of the brake lever arm removed for clarity; 
     FIG. 14 is a fragmentary side view of the brake lever arm depicted in FIGS. 13A and 13B, showing features of a brake lever arm adjusting mechanism in a first position within the brake lever arm; 
     FIG. 15 is a fragmentary side view of the brake lever arm depicted in FIGS. 13A, 13B and 14, showing features of the brake lever arm adjusting mechanism in a second position within the brake lever arm; 
     FIG. 16 is an end view similar to FIG. 13B, showing an alternative configuration of a fine adjusting mechanism of the brake lever arm depicted in FIGS. 13A, 13B, 14 and 15; 
     FIG. 17 is a back view of a lever arm shown removed from the brake lever arm depicted in FIGS. 13A, 13B, 14 and 15; 
     FIG. 18 is a side view of the brake lever arm adjusting mechanism shown removed from the brake lever arm depicted in FIGS. 13A, 13B, 14 and 15; and 
     FIG. 19 is a cross section view of the brake lever arm adjusting mechanism taken along the line XIX--XIX in FIG. 18. 
    
    
     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 generally parallel opposing sides 31 and 32. The side 32 includes a first slot 35 and a third slot 36, as shown in FIG. 1B. 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. 1A and 1B). 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, 3B and 3C. The adjusting mechanism 40 includes a main body 54 which has a generally U-shape in cross-section, as shown in FIG. 3C. 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 60a 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 58a 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 38a, 38b and 38c to accommodate a screw head 58a 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 58a 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 58a extends into one of the three rounded sections 38a, 38b or 38c, 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 38a, 38b or 38c 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 first slot 35 has also been formed in the side 31 and the pin 56 extends into the first slot 35 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 58a disposed in the rounded section 38a. In FIGS. 7-9 the adjusting mechanism 40 is shown in a second position with the head 58a disposed in the rounded section 38b. In FIGS. 10-12 the adjusting mechanism 40 is shown in a first position with the head 58a disposed in the rounded section 38c. 
     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 center 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 Al is constant in FIGS. 4, 5 and 6 where the adjusting mechanism 40 is positioned with the screw head 58a disposed in the first rounded portion 38a 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 58a of the screw 58 being positioned in the second rounded portion 38b 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 58a disposed in the second rounded portion 38b 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 58a of the screw 58 is disposed in the third rounded section 38c 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 58a disposed in the third rounded portion 38c 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 38a, 38b or 38c. 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. 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 embodiment of the present invention is shown in FIGS. 13A, 13B, 14, 15, 16, 17, 18 and 19. In this embodiment, a lever arm 130 includes a support portion S and a handle portion H supported by a pivot pin 25 which extends through a base 10. A central axis of the pivot pin 25 defines a pivot point about which the lever arm 130 pivots with respect to the base 10. The base 10 is generally the same as the base 10 described above with respect to the first embodiment. The support potion S includes has a first side 132 (FIG. 17) and a second side 131 (FIG. 13A). The lever arm 130 is formed with a first slot 135 on the first side 132, shown in FIGS. 14, 15 and 17, and a second slot 38 on the second side 131. The second slot 38 is similar to the second slot 38 described above with respect to FIGS. 1, 4, 5 and 6. The second slot 38 includes the three rounded sections 38a, 38b or 38c, also described above. The first slot 135 is generally parallel to the second slot 38 but, as is shown in FIG. 17, the first slot 135 is longer than the second slot 38. It should be noted that in FIG. 17, the lever arm 130 has been removed from the remainder of the bicycle brake mechanism for greater clarity. 
     As with first embodiment, the base 10 shown in FIGS. 13A and 13B includes a cable adjusting mechanism 50 (referred to in the claims as a cable length adjusting member) at a distal end of the base 10. The distal end of the base 10 is formed with an aperture 210 that extends through the base 10. The cable adjusting mechanism 50 encircles one end of the aperture. 
     Between the sides 131 and 132 of the lever arm 130 there is an adjusting mechanism 140 which is shown removed from the lever arm 130 in FIGS. 18 and 19. The adjusting mechanism 140 includes a contact body 160 shown in FIG. 18 and 19 that is disposed between portions of a main body 154. The main body 154 has a first side 154a that completely covers a lower portion of one side of the contact body 160. A second side 154b of the main body 154 covers only a portion of an opposite side of the contact body 160, as is shown in phantom in FIG. 18. The contact body 160 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 an upper portion of the contact body 160 in a manner similar to that described above. The recess 62 is configured to contact a brake cable in a manner as described above with respect to the first embodiment with respect to the description of FIGS. 5 through 12. Specifically, the recess 62 is configured to engage a cable when the handle portion H is moved to a brake engagement position thus defining a cable contact point 200, as shown in FIGS. 13A and 19. It should also be understood that one end of a cable may be connected to a cable connector 205 as shown in FIG. 13A (and also shown in FIGS. 4 through 12). 
     The contact body 160 is further formed with two generally rectangularly shaped protrusions 165 and 166. The protrusions 165 and 166 extend into the first slot 135 as is indicated in FIGS. 14, 15 and 18. It should be appreciated that the first slot 135 is superimposed in phantom over the adjusting mechanism 140 along with the second slot 38. 
     A screw 58 extends through both the first slot 135 and the second slot 38. The screw 58 has a head 58a that is larger than the second slot 138 and therefore contacts the outer surface of the side 131, as shown in FIGS. 13A and 19. The screw 58 further extends through the adjusting mechanism 140. The screw 58 extends through a threaded hole 154c in the second side 154b. The screw 58 extending through the first and second slots 135 and 38 and through the threaded hole 154c provided a means for securing the adjusting mechanism 140 within the support portion H. Upon loosening the screw 58, the adjusting mechanism 140 can be moved between three positions (described above). One position is shown in FIG. 14 and another position is shown in FIG. 15. The screw 58 and the protrusions 165 and 166 limit the up and down movement of the adjusting mechanism along the length of the first and second slots 135 and 38. The effects of this configuration are generally the same as described above. 
     As was described above, the screw 52 extends through a hole 10 a formed in the extending portion 46 of the base 10. The adjusting screw 52 contacts the main body 154 of the adjusting mechanism 140 and provides fine adjustment of the stopping position (brake disengagement position) of the lever arm 130, as is shown in FIGS. 14 and 15. As can be seen in FIG. 13B, the screw 52 is slightly offset from the center of the extending portion 46 of the base 10. The screw 52 therefore engages the main body 154 at a position shown generally in FIG. 19, with the screw 58 in the first portion 38a of the second slot 38 (FIG. 18). 
     In an alternate configuration of the present invention, the screw 52 could be positioned at a location further offset from the center of the extending portion 46&#39;, as shown in FIG. 16. In FIG. 16, the screw extends generally perpendicular into the drawing and engages the side 131 of the lever arm 130. Therefore, regardless of the position of the adjusting mechanism 140, the adjustment of the screw 52 is constant since the screw 52 engages the lever arm 130 in FIG. 16, not the adjusting mechanism 140. 
     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.