Abstract:
A brake or clutch lever comprises a lever that pivots about an axis, a lever mounting structure from which the lever extends, and a thumbwheel having a cam thereon. The cam is disposed directly between the lever and the lever mounting structure. The thumbwheel rotates about an axis that is perpendicular to the axis of lever pivoting. Also provided is a method of adjusting a height of a brake or clutch lever. A grip portion of a brake or clutch lever is lifted away from a handlebar. A thumbwheel having a cam thereon is rotated about an axis that is perpendicular to a pivot axis of the brake or clutch lever. The brake or clutch lever is lowered toward the handlebar. A method of assembling a brake or clutch lever height adjuster is also provided.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to brake and clutch levers for motorcycles and the like, whose grip heights can be adjusted to accommodate different hand sizes. More particularly, the invention relates to brake and clutch lever height adjusters.  
         [0003]     2. Discussion of the Related Art  
         [0004]     Motorcycles, ATVs, and similar vehicles typically employ brake and clutch levers for actuating one or more brakes or clutches of the vehicle to change the vehicle&#39;s speed. Brake levers, for example, are normally attached to the right side of a handlebar adjacent the right handgrip. The brake lever is pulled toward the handlebar to activate the brake, typically by actuating a cable or by directly actuating a master cylinder. The grip height of some levers can be adjusted to accommodate different hand sizes. This is useful for customizing a brake system to the needs of an individual operator and/or in permitting different operators to drive the. vehicle.  
         [0005]     Some traditional brake lever height adjusters employ a setscrew that is positioned either between the lever and its mount or between sections of the lever to vary the spacing between those components and, thus, vary the grip height. These setscrews usually require tools for adjustment, and most alter the lever&#39;s mechanical advantage as a result of grip height adjustment. They are also aesthetically unattractive.  
         [0006]     Other brake lever height adjusters employ a thumbwheel that acts on an internal threaded linkage or similar structure. These systems are, generally speaking, very conspicuous to the casual observer and, hence, also aesthetically unattractive. They also tend to be relatively difficult to adjust with one hand. The adjustment mechanism also tends to be relatively complex because the thumbwheel acts on a pivoting linkage assembly rather than directly on the lever-mounting bracket or between sections of a lever.  
         [0007]     The need therefore has arisen to provide brake and clutch lever height adjusters that are relatively simple to manufacture, assemble, and use.  
         [0008]     The need has additionally arisen to provide aesthetically pleasing brake and clutch lever height adjusters.  
         [0009]     Much of the following description is directed towards brake levers for simplicity only. However, the inventive arrangements are analogous to clutch levers as well.  
       SUMMARY OF THE INVENTION  
       [0010]     In accordance with a first aspect of the invention, one or more of the above-identified needs is met by providing a brake or clutch lever that includes a lever that pivots about an axis, a lever mounting structure from which the lever extends, and a thumbwheel having a cam thereon. The cam is disposed directly between the lever and the lever mounting structure. The thumbwheel rotates about an axis that is perpendicular to the axis of lever pivoting.  
         [0011]     In accordance with a preferred embodiment of the invention, the brake or clutch lever height adjuster also includes a dog that is provided on the bottom surface of the thumbwheel. The dog maintains the thumbwheel in position in the absence of user-imposed rotational forces.  
         [0012]     The brake or clutch lever height adjuster does not alter the mechanical advantage or cable tension upon adjusting lever height.  
         [0013]     Also provided is a method of adjusting a height of a brake or clutch lever. For example, a grip portion of a brake lever is often lifted away from a handlebar. A thumbwheel having a cam thereon is rotated about an axis that is perpendicular to a pivot axis of the brake lever. The brake lever is lowered toward the handlebar.  
         [0014]     A method of assembling a brake or clutch lever height adjuster is also provided.  
         [0015]     The benefits provided by the inventive brake or clutch lever height adjuster are particularly (but by no means exclusively) applicable to motorcycles.  
         [0016]     In accordance with still other aspects of the invention, a method of making a brake or clutch lever height adjuster configured at least generally as described above and a method of using such brake or clutch lever height adjuster are additionally provided.  
         [0017]     Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understand, however, that the detailed description and specific examples, while indicating the preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which:  
         [0019]      FIG. 1  is a side elevation view of a brake lever and a brake lever height adjuster made in accordance with a preferred embodiment of the invention installed on a motorcycle handlebar and showing the lever in its deactuated or at-rest position;  
         [0020]      FIG. 2  is an exploded view of the lever of  FIG. 1 ;  
         [0021]      FIG. 3  is a sectional view of the lever of  FIG. 1  through line  3 - 3  showing the brake lever height adjuster in a first position to affect a first squeeze lever height;  
         [0022]      FIG. 4  is fragmentary sectional view corresponding to  FIG. 3  and showing the brake lever height adjuster in a second position to affect a second squeeze grip height;  
         [0023]      FIG. 5  is a top plan view of a thumbwheel of the brake lever height adjuster;  
         [0024]      FIG. 6  is a bottom plan view of a thumbwheel of the brake lever height adjuster;  
         [0025]      FIG. 7  is a side elevation view of the lever or  FIG. 1 , showing a grip height adjustment operation;  
         [0026]      FIG. 8  is a partial exploded view of a brake lever and a brake lever height adjuster made in accordance with an alternative embodiment of the invention; and  
         [0027]      FIG. 9  is a partial exploded view of a clutch lever and a clutch lever height adjuster made in accordance with another alternative embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     1. A First Preferred Embodiment of a Brake Lever Height Adjuster  
         [0029]     A wide variety of different brake and clutch lever height adjusters for a variety of different applications could be constructed in accordance with the invention as defined by the claims. Hence, while a preferred embodiment of the invention will now be described with reference to a motorcycle brake lever height adjuster for ease of reference, it should be understood the invention is in no way so limited. It is also usable with clutches as well as with brakes, and also with a variety of different vehicles, such as bicycles and ATVs. It is also usable with a variety of other brake or clutch systems, such as direct hydraulic, cable hydraulic, and cable actuated brake and clutch systems.  
         [0030]     Referring now to  FIGS. 1-4 , a brake lever height adjuster  10  constructed in accordance with one embodiment of the invention is shown as being used on a brake lever  12  installed on a conventional motorcycle including handlebars  13 . The brake lever  12  is positioned on the handlebar  13  adjacent an inboard end  16  of a right handgrip  14  in the illustrated embodiment, although it could also be positioned on the handlebar  13  adjacent an inboard end  16  of a left handgrip  18 . It is mounted on the handlebar  13  by a bracket  20  shown only schematically in  FIG. 1  and only in phantom that also bears or includes a master cylinder  21  (also shown only schematically in  FIG. 1  and only in phantom). The lever  12  of this embodiment is a two-piece lever  12 . A mounting structure that includes an actuator  22  supports the lever  12 , and the lever height adjuster  10  is positioned directly between the actuator  22  and the lever  12 . (Alternatively, the lever  12  could be a one-piece lever  12 , and the height adjuster  10  could be positioned between the lever  12  and its mounting bracket  20  or other support). The actuator  22  and lever  12  are held together by a pivot pin  26  that also mounts the lever  12  on the mounting bracket  20  so as to permit the lever  12  to pivot as a whole about a horizontal pivot axis to reduce the lever height and apply the master cylinder  21 .  
         [0031]     Still referring to  FIGS. 1 and 2 , the actuator  22  includes a lower actuator portion  28 , a central adjuster mounting portion  30 , and an upper lever mounting portion  32  having an opening  34  formed therethrough. An inboard surface  36  of the actuator portion  28  is configured to rest against a master cylinder piston (not shown) and to apply the master cylinder  21  upon lever actuation. A stop lug  38  is formed on the upper end of the lever mounting portion  32  for reasons detailed below.  
         [0032]     The lever  12  includes an outboard grip portion  40  and an inboard mounting portion  42 . The grip portion  40  of the lever  12  extends generally parallel to the handgrip  14  when the lever  12  is in its at-rest position and is spaced from the handgrip  14  by an average height whose thickness can be varied by operation of the lever height adjuster  10 . The mounting portion  42  includes two generally circular projections  44  each defining an opening  46  therein. The two circular projections  44  slidingly receive the grip mounting portion  32  of the actuator  22 . The diameter of the opening  34  in the actuator  22  is substantially the same as the diameter of the openings  46  in the mounting portion  42  of the lever  12  such that they can all receive a bushing  48  through which the pivot pin  26  passes. An inboard facing notch  50  is formed in the upper portion of the mounting portion  42  so as to receive the stop lug  38  of the actuator  22 . The notch  50  also receives on end a torsion spring  52  that surrounds the bushing  48 . The opposite end of the torsion spring  52  rests on the inboard portion of the actuator  22  so to bias the actuator  22  and lever  12  toward one another. The torsion spring  52  holds the mounting portion  42  and the actuator  22  together and biases the lever  12  as a whole toward the master cylinder  21 .  
         [0033]     The adjuster mounting portion  30  of the actuator  22  includes an arcuate outer surface  54  against which an end of the torsion spring  52  rests. It also includes a generally upwardly facing planar thumbwheel support surface  56  configured to support a thumbwheel  58  of the lever height adjuster  10 . A stepped bore  60  extends downwardly though the thumbwheel support surface  56 . The bore  60  has an upper portion  62  having a first diameter, a threaded central portion  64  having a second diameter that is smaller than the first diameter, and a lower portion  66  having a third diameter substantially equal to the first diameter. The bore  60  receives a screw  68  from below that is threaded into a tapped bore  70  in a post  72  on the underside of the thumbwheel  58 . The post  72  is received in the upper portion  62  of the bore  60 . A spring  74  in the lower portion  66  of the bore  60  surrounds the screw  68  so as to bias the screw  68  and thumbwheel  58  downwardly. Referring now to  FIGS. 5 and 6 , dogs  76  are provided on the bottom surface of the thumbwheel  58  so as to engage detents (not shown) on the thumbwheel support surface  56 . The dogs  76  maintain the thumbwheel  58  in position in the absence of user-imposed rotational forces on the thumbwheel  58  while allowing the thumbwheel  58  to rise against the force of the spring  74  and rotate upon the imposition of those actuating forces. The thumbwheel  58  is rotated about an axis that is perpendicular to the axis of the brake lever  12  pivoting.  
         [0034]     Referring back to  FIGS. 1-4 , a lug  80  on the bottom surface of the mounting portion  42  of the lever  12  rests on the upper surface of the thumbwheel  58 , hence setting the height of the lever  12 . Hence, the thumbwheel  58  acts directly on the lever  12  and the actuator  22  rather than an intermediate structure. This height is adjusted by making the thumbwheel  58  of non-uniform thickness so that it presents a cam  82  on its upper surface, and the lug  80  hence acts as a cam follower. The cam  82  could be formed by a continuous ramp on the upper surface of the thumbwheel  58 , hence providing for infinitely variable grip height adjustment between the maximum height determined by the point of maximum thumbwheel thickness and the minimum height determined by the point of minimum thumbwheel thickness. In the preferred embodiment, which is best seen in  FIGS. 5-6 , however, the thumbwheel  58  is circumferentially divided into arcuate sections  84  of a number of discreet thicknesses, and hence provides a number of discreet adjusted positions. Three such sections  84  are provided in the illustrated embodiment, but fewer or more sections could be provided. The transition between each set of adjacent sections is preferably ramped rather than stepped to facilitate thumbwheel rotation even if the lug  80  is in light contact with the thumbwheel  58  during adjustment.  
         [0035]     Rotation of the thumbwheel  58  sets the height of the lever  12  by bringing a selected one of the three arcuate sections  84  of the cam  82  into contact with the lug  80  on the mounting portion  42 . This rotation is facilitated by nubs  86  on the outer periphery of the thumbwheel  58 . Preferably, the thumbwheel  58  is dimensioned relative to the width of the lever  12  so that the thumbwheel  58  protrudes beyond the side of the lever  12  only as necessary for adequate operator access. Because the remainder of the thumbwheel  58  and the adjuster  10  as a whole are hidden from view of the casual observer, the adjuster  10  does not significantly alter the aesthetics of the lever  12 .  
         [0036]     Significantly, the brake lever height adjuster  10  does not alter the mechanical advantage. That is, the ratio of the output force produced by the brake lever  12  to the applied input force is not altered when the brake lever height is adjusted. Similarly, if the lever  12  were to be used in a cable actuated system, cable tension would not be altered when the brake lever height is adjusted.  
         [0037]     2. Assembly and Use of the Brake Lever Height Adjuster  
         [0038]     The lever  12  is assembled by mounting the thumbwheel  58  into the upper portion  62  of the bore  60  in the thumbwheel support surface  56  of the actuator  22  by inserting the screw  68  and spring  74  into the lower portion  66  of the bore  60 . The torsion spring  52  is then positioned between the mounting portion  30  of the actuator  22  and the mounting portion  42  of the lever  12  to form an assembly having aligned openings  34  and  46 , and the assembly is mounted on the mounting bracket  20  by inserting the bushing  48  and the pin  26  through the aligned openings  34  and  46  and inserting the pin  26  into mating bores (not shown) in the mounting bracket  20 . At this time, the inboard surface of the actuator portion  28  of the actuator  22  rests against the master cylinder piston (not shown), and the lever  12  rests in a position in which the grip portion  40  of the lever  12  is spaced from the handgrip  14  by an average height Hi as seen in  FIG. 1 .  
         [0039]     The brake lever height can be adjusted with one hand by pushing the brake lever  12  away from the handlebar  13  with the user&#39;s index finger (indicated by the arrow A of  FIG. 7 ). The extent of this pivoting is limited by engagement between the stop lug  38  on the lever mounting portion  32  of the actuator  22  and the outboard end of the notch  50  in the mounting portion  42  of the lever  12 . The operator then rotates the thumbwheel  58  about its axis by placing the thumb on the edge of the thumbwheel  58  and rotating it, as is indicated by the arrow B of  FIG. 7 . The radially spaced nubs  86  on the edge of the thumbwheel  58  provide a friction surface to facilitate rotation of the thumbwheel  58 . This rotation moves one section of the thumbwheel  58 , such as the section of maximum thickness, out of alignment with the lug  80  while moving another section  84 , such as the section  84  of minimum thickness, into alignment with the lug  80 . As a result, when the operator releases the lever  12  to let the lug  80  swing back into contact with the thumbwheel  58 , the grip portion  40  of the lever  12  assumes a new height H 2  (not shown) that is different from the initial height H 1 .  
         [0040]     Referring now to  FIG. 8 , a partial exploded view of a brake lever  12  and a brake lever height adjuster  10  made in accordance with an alternative embodiment of the invention is depicted, in which the function thereof is as previously described. However, the screw  68  and spring  74  used to hold the thumbwheel  58  in the assembly of the previous figures has been replaced by an anti-rattling bushing  88  by techniques known to those skilled in the art. For example, a rubber bushing  88  is preferred.  
         [0041]     Referring now to  FIG. 9 , a partial exploded view of a clutch lever  12 ′ and a clutch lever height adjuster  10 ′ made in accordance with an alternative embodiment of the invention is depicted, in which the function thereof is as previously described, except the brake lever  12  and brake lever height adjuster  10  have been respectively replaced by a clutch lever  12 ′ and a clutch lever height adjuster  10 ′ by techniques known to those skilled in the art, and in which like numerals generally depict like components. As with  FIG. 8 , the screw  68  and spring  74  used to hold the thumbwheel  58  in the assembly of the previous figures of the brake has been replaced by an anti-rattling bushing  88 ′ by techniques known to those skilled in the art. In addition, a first pivot hole  90  for cable attachment, a second pivot hole  92  for bushing and pin attachment to the clutch assembly, and a lever pivot screw  94  are provided by techniques known to those skilled in the art.  
         [0042]     As indicated above, many changes and modifications may be made to the present invention without departing from the spirit thereof. The scope of some of these changes is discussed above. The scope of others will become apparent from the appended claims.