Abstract:
An adjuster is disclosed, to be placed “in-line” to a clutch disengagement system. The adjuster provides a means for lifting the pressure plate above the clutch pack without significantly affecting the operation or feel of the clutch disengagement system to the operator. Such an adjuster is particularly well suited for use with an automatic centrifugal clutch incorporating a friction disk that expands when rotated above a threshold speed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon provisional application 61/643,553 filed on May 7, 2012 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to a clutch system of the friction type placed in a power transmission system. The invention(s) were previously disclosed in provisional patent application 61/643,553. 
         [0003]    Typical clutch systems include a clutch input such as a clutch basket, a clutch output such as a center clutch, and one or more plates making up a clutch pack and disposed between the clutch input and clutch output. When the clutch pack is compressed, the clutch input and clutch output become rotationally coupled. The clutch pack is typically compressed by a pressure plate; the pressure plate typically providing a compressive force via a spring mechanism or through a centrifugally actuated mechanism. 
         [0004]    Typically, such clutch systems include a clutch disengagement system consisting of a lever mechanically coupled to the pressure plate such that when the lever is actuated, the pressure plate&#39;s compressive force on the clutch pack is removed, disconnecting the rotational coupling between the clutch input and clutch output. Clutch disengagement systems typically couple the lever to the pressure plate mechanically through a hydraulic actuation system or a cable actuation system. 
         [0005]    Most motorcycles incorporate a manual transmission coupled to the engine via a multi-plate clutch assembly. Typically, the multi-plate clutch is engaged/disengaged by the driver via a lever mounted on the handlebar. Although the lever operated clutch allows the driver to control the clutch engagement/disengagement, often times motorcycle drivers find the clutch lever difficult to operate smoothly. New riders have difficulty adjusting to smoothly engaging the clutch while operating the throttle to move the vehicle from a standing start. Experienced riders may need to partially disengage the clutch when traveling slowly to allow the engine to continue running without stalling. Motorcycle racers often have a difficult time controlling the engagement of the clutch and the application of the throttle to maximize acceleration. Off-road motorcycle racers often need to stop the rear wheel suddenly with the rear brake, causing the engine to stall if the clutch is not first disengaged. An automatic clutch can help overcome many of the problems associated with a manual clutch. 
         [0006]    U.S. patent application Ser. No. 12/412,245 discloses an automatic clutch system incorporating an expanding friction disk and is incorporated herein by reference. One of the benefits of the improved automatic clutch system is the ability for the operator to override the automatic engagement of the clutch via a clutch lever without a significant change in how the clutch lever responds due to the centrifugal mechanism in the automatic clutch. Such a clutch system requires the pressure plate to be lifted away from the clutch pack to function properly. In application Ser. No. 12/412,245, lifting the pressure plate away from the clutch pack is accomplished with an adjuster within the engine cases. 
         [0007]    However, for some motorcycle operators, the ability to adjust the position of the pressure plate without opening the engine cover to gain access to the clutch is important. Being able to adjust the position of the pressure plate externally allows the operator to make adjustments to the clutch system to compensate for clutch pack wear for example. By adjusting the position of the pressure plate so that it comes in contact with the clutch pack, allows the operator to quickly and easily configure the clutch so that when the engine is not spinning, the clutch is engaged. In this configuration, the clutch operation is similar to a manual clutch and allows the operator to “bump start” the engine. When the engine is off, with a gear selected and the clutch lever disengaged, rolling the motorcycle at sufficient speed and then suddenly releasing the clutch lever to engage the clutch, can start the engine. 
         [0008]    Clutch disengagement systems utilizing a cable for the mechanical connection between the lever and the pressure plate are well known in the art and typically incorporate a cable end adjuster to accommodate for wear or expansion of the clutch pack. Such clutch disengagement systems are typified by the system provided on the 2009 Honda CRF450R motorcycle model and whose operation and adjustment are disclosed in the 2009 Honda CRF450R Owner&#39;s Manual. 
         [0009]    The cable end adjuster allows the operator to increase or decrease the amount of lever “free-play”. Lever “free-play” is defined as the movement of the lever between an outward stopping point of the lever against the lever mounting bracket or perch and inward movement until further movement of the lever will result in lifting of the pressure plate. Typically, the cable adjuster is positioned so that the lever has some “free-play” movement. By adjusting the cable end adjuster for more “free-play”, the operator must move the lever further before the pressure plate begins to lift. With less “free-play”, the operator will not need to move the lever as far before the pressure plate begins to lift. The cable end adjuster can typically be adjusted to remove all “free-play” movement and further adjustment of the cable end adjuster will result in the pressure plate being lifted above the clutch pack. In this state, there is no lever “free-play” but the cable end adjuster has been used to create the necessary gap between the pressure plate and the clutch pack for the expanding friction disk to function as described in application Ser. No. 12/412,245. The disadvantage to this type of configuration is that the clutch lever has no “free-play” and can be more difficult for the operator to pull in to disengage the clutch system. 
         [0010]    For typical hydraulic clutch disengagement systems, no such provision exists for lifting the pressure plate through an in-line external adjuster. 
         [0011]    Hydraulic clutch disengagement systems are well known in the art and are typified by systems made by Magura and Brembo and are included on motorcycles such as those provided by KTM such as the KTM model year 2010 KTM 250 XCW. 
         [0012]    A typical hydraulic clutch disengagement system includes a master cylinder incorporating a reservoir for hydraulic fluid and a lever acting on a piston. A slave cylinder incorporates a bore and a piston; the piston typically acts upon the clutch throwout to lift the pressure plate for disengagement. A hydraulic line typically couples the master and slave cylinders and provides a conduit for the hydraulic fluid. 
         [0013]    When the clutch lever is in the disengaged position, typically an open port exists between the slave cylinder piston and the reservoir of the master cylinder. When the clutch lever is in the engaged position, the open port between the reservoir and the slave cylinder is closed and no self-adjustment can take place. The slave cylinder typically incorporates a spring that pushes the piston in the slave cylinder towards the pressure plate. Because an open port exists to the master cylinder reservoir, the slave cylinder is free to move inward or outward towards the pressure plate; when the clutch lever is in the disengaged position. 
         [0014]    Therefore a need exists for an adjustment mechanism, external to the engine cases, that can lift the clutch pressure plate to create a gap between the clutch pressure plate and clutch pack. 
         [0015]    For a cable actuated clutch disengagement system, the adjustment mechanism should be provided to allow a gap between the clutch pressure plate and clutch pack be created while maintaining clutch lever free play and use of the clutch lever. For hydraulically actuated clutch disengagement systems, the adjustment mechanism should maintain the use of the clutch lever while providing the capability to lift the clutch pressure plate to create a gap between the clutch pressure plate and clutch pack. 
         [0016]    It is therefore an object of the present invention to provide an adjuster mechanism, external to the engine cases, for a cable actuated clutch disengagement system that allows a gap between the pressure plate and clutch pack to be created while maintaining clutch lever “free-play”. 
         [0017]    It is another object of the invention to provide an adjuster mechanism, external to the engine cases, for a hydraulically actuated clutch disengagement system that allows a gap between the pressure plate and clutch pack to be created while maintaining the function of the hydraulically actuated clutch disengagement system. 
         [0018]    A preferred embodiment of the present invention for cable actuated clutch disengagement systems is disclosed in  FIGS. 5 through 8 . A preferred embodiment of the present invention for hydraulically actuated clutch disengagement systems is disclosed in  FIGS. 9 through 12 .  FIGS. 1A and 1B  depict a typical clutch system positioned relative to the present invention.  FIGS. 2 through 4  depict a clutch assembly similar to what is disclosed in U.S. patent application Ser. No. 12/412,245 with the clutch pressure plate positioned in three typical states. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1A  depicts a typical clutch system employing a hydraulically actuated clutch disengagement system positioned relative to the present invention; 
           [0020]      FIG. 1B  depicts a typical clutch system employing a cable actuated clutch disengagement system positioned relative to the present invention; 
           [0021]      FIG. 2  depicts a clutch assembly similar to what is disclosed in U.S. patent application Ser. No. 12/412,245 with the pressure plate positioned to form a gap between the pressure plate and clutch pack; 
           [0022]      FIG. 3  depicts the clutch assembly in  FIG. 2  with the clutch disengagement system activated to increase the distance between the pressure plate and clutch pack; 
           [0023]      FIG. 4  depicts the clutch assembly in  FIG. 2  with the pressure plate positioned in contact with the clutch pack and thus eliminating the gap created by the present invention; 
           [0024]      FIG. 5  is an isometric view depicting the present invention configured for use and disposed within a typical cable actuated clutch disengagement system; 
           [0025]      FIG. 6  is a section view detailing the present invention&#39;s internal components configured to a cable actuated clutch disengagement system, wherein the clutch disengagement system is not actuated and the novel adjuster mechanism is adjusted to lift the pressure plate to create an installed gap; 
           [0026]      FIG. 7  is a section view detailing the present invention&#39;s internal components configured to a cable actuated clutch disengagement system, wherein the clutch disengagement system is actuated and the novel adjuster mechanism is adjusted to lift the pressure plate to create an installed gap; 
           [0027]      FIG. 8  is a section view detailing the present invention&#39;s internal components configured to a cable actuated clutch disengagement system, wherein the clutch disengagement system is not actuated and the novel adjuster mechanism is adjusted to allow the pressure plate to contact the clutch pack and eliminate the installed gap; 
           [0028]      FIG. 9  is an isometric view of the present invention configured for use in a hydraulically actuated clutch disengagement system; 
           [0029]      FIG. 10  is a section view of the present invention configured for use in a hydraulically actuated clutch disengagement system, wherein the clutch disengagement system is not actuated and the novel adjuster mechanism is adjusted to lift the pressure plate to create an installed gap; 
           [0030]      FIG. 11  is a section view of the present invention configured for use in a hydraulically actuated clutch disengagement system, wherein the clutch disengagement system is actuated and the novel adjuster mechanism is adjusted to lift the pressure plate to create an installed gap. 
           [0031]      FIG. 12  is a section view of the present invention configured for use in a hydraulically actuated clutch disengagement system, wherein the clutch disengagement system is not actuated and the novel adjuster mechanism is not adjusted to lift the pressure plate to create an installed gap; 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    Reference throughout this specification to “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
         [0033]    Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
         [0034]    The present invention provides for a novel, external adjustment mechanism suitable for use in a clutch system that requires a gap to be formed between the pressure plate and clutch pack; such as disclosed in application Ser. No. 12/412,245. A preferred embodiment is disclosed for both cable actuated clutch disengagement systems and hydraulically actuated clutch disengagement systems. 
         [0035]      FIG. 1  discloses the novel adjuster  100  positioned in line relative to the clutch disengagement system  107 . The clutch disengagement system  107  is coupled to the clutch  106  through the actuator  104  and throwout  105 . The actuator  104  is connected to the engine case  108 . The clutch override assembly  102  can be actuated for the purpose of engaging or disengaging the clutch  106 . The novel adjuster  100  is positioned between the upper clutch conduit  101  and lower clutch conduit  103  and thus between the clutch override assembly  102  and actuator  104 . 
         [0036]    Clutch disengagement systems are well known in the existing art and can be configured for a cable-mechanical clutch disengagement system or a hydraulic-fluid clutch disengagement system. In a cable-mechanical clutch disengagement system the clutch override assembly  102  is usually comprised of a lever and perch allowing the clutch input assembly to be attached and anchored to the vehicle. In a hydraulic clutch disengagement system the clutch override assembly  102  is usually comprised of a master cylinder, lever and mounting means allowing attachment to the vehicle. 
         [0037]    In the improved clutch disengagement system  107 , the novel adjuster  100  is placed between the clutch override assembly  102  and actuator  104  interrupting the continuous conduit and creating the upper clutch conduit  101  and lower clutch conduit  103 . In one embodiment the novel adjuster  100  is positioned closer to the clutch input assembly  102 . In another embodiment the novel adjuster  100  positioned closer to the actuator  104 . In yet another embodiment the novel adjuster is positioned equidistant from the clutch override assembly  102  and actuator  104   
         [0038]      FIG. 1B  discloses an end adjuster  109  between the clutch override assembly  102  and upper clutch conduit  101 . The end adjuster  109  allows the clutch disengagement system  107  to have additional adjustment to accommodate displacement of the upper clutch conduit  101  that can exist when the novel adjuster is used in a cable-mechanical clutch disengagement system allowing the operator to adjust the starting point of the lever. 
         [0039]    The actuator  104  represents either a mechanical cam system in a cable-mechanical clutch disengagement system or a slave cylinder with slave piston in a hydraulic clutch disengagement system. In another embodiment the actuator  104  is comprised of a rack and pinion assembly. 
         [0040]    In another embodiment the novel adjuster  100  can be configured with a hydraulic clutch disengagement system where the hydraulic clutch disengagement system is employed to act on a mechanical cam system rather than a slave cylinder. 
         [0041]      FIG. 2  depicts the clutch  106  being similar to what is disclosed in U.S. patent application Ser. No. 12/412,245. The clutch  106  includes a pressure plate  202  with springs  203  which bias the pressure plate  202  in the inward direction  211 . The clutch  106  includes a throwout top assembly  206  disposed between the pressure plate  202  and throwout  105 . When the throwout  105  moves in the outward direction  210  the pressure plate  202  also moves in the outward direction  210 . 
         [0042]      FIG. 2  depicts the clutch  106  in a state where the pressure plate  202  has been positioned to create the installed gap  204  between the pressure plate  202  and clutch pack  205 . 
         [0043]      FIG. 3  depicts the clutch  106  from  FIG. 2  in a state where the pressure plate  202  has been moved further in the outward direction  210 . In  FIG. 3  the operator has activated the clutch override assembly  102  disclosed in  FIG. 1  further lifting the pressure plate  202  from the position in  FIG. 2  consequently increasing the installed gap  204  to accommodate clutch disengagement. A disengaged gap  302  is formed between the pressure plate  202  and clutch pack  205 . The disengaged gap includes the installed gap  204  from  FIG. 2 . 
         [0044]      FIG. 4  depicts the clutch  106  from  FIG. 2  in a state where the pressure plate  204  is positioned in the inward direction  211  to eliminate the installed gap  204  creating no gap  401  and allowing the pressure plate  202  to contact the clutch pack  205  via the springs  203 . With the pressure plate  202  touching the clutch pack  205  and transmitting force from the springs  203  to the clutch pack  205 , the clutch  106  is in a state where it can be bump started. 
         [0045]      FIGS. 5 through 8  disclose a novel cable adjuster  500  configured as part of a clutch cable assembly  510 . In this embodiment, the novel cable adjuster  500  is designed to be “in-line” of a typical clutch cable assembly. The components of the novel cable adjuster  500  visible in  FIG. 5  are the male adjuster  503 , the female adjuster  505  and the locknut  504 . In this embodiment, the male adjuster  503  threads into the female adjuster  505  to set the distance between the two components. The locknut  504  can be used to prevent relative rotational movement between the male adjuster  503  and the female adjuster  505 . In another embodiment, grooves in a male adjuster and a circlip are used to set the distance between the two components. 
         [0046]    In addition  FIG. 5  discloses the inner cable  501 , lower housing  502 , upper housing  506 , lower end  507  and upper end  508  as can be found in the prior art. The lower end  507  allows the inner cable to be connected to the actuator  104  and the upper end  508  allows the inner cable to be connected to the clutch override assembly  102  such that when the clutch override assembly  102  is activated the actuator  104  is able to position the pressure plate  202  via the throwout  105 . The novel cable adjuster  500  is positioned between the lower housing  502  and upper housing  506  along the inner cable  501 . 
         [0047]    As depicted in  FIG. 6 , a ferrule  601  is firmly attached to the inner cable  501  in such a way that it will not move when a load is placed against it. The cable  501 , lower housing  502 , upper housing  506 , lower cable end  507  and upper cable end  508  are all of typical construction as found on many modern motorcycle cable actuated clutch systems. The male adjuster  503  has external threads formed along its outer surface. The female adjuster  505  has female threads formed inside of female adjuster  505  corresponding to the threads of the male adjuster  503  so that the male adjuster  503  can be threaded into the female adjuster  505 . When the female adjuster  505  is rotated while the male adjuster  503  remains stationary relative displacement between the female adjuster  505  and male adjuster  503  takes place. 
         [0048]      FIG. 6  depicts the novel cable adjuster  500  adjusted in the outward direction  210  positioning the pressure plate  202  as depicted in  FIG. 3  and thus forming the installed gap  204  also shown in  FIG. 3 . The female adjuster  505  contains a pressure face  602  which applies force to the ferrule  601  corresponding to the outward direction  210 . As the female adjuster  505  is adjusted in the outward direction  210  it positions the ferrule  601  and in turn moves the inner cable  501  in the outward direction  210 . The adjuster space  606  signifies the displacement that has taken place between the male adjuster  503  and female adjuster  505  to create the installed gap  204  shown in  FIG. 2 . The lock nut  504  is tightened against the face  603  of the female adjuster  505  to maintain the relative displacement between the female adjuster  505  and male adjuster  503 . In this state, there is tension in the inner cable  501  between the ferrule  601  and the lower end  507  to position pressure plate  202 . However, there is no tension in the cable between the ferrule  601  and upper end  508 . In this state, the operator is able to adjust the clutch lever free play to their preference because the novel cable adjuster  500  has been used to create a gap between the pressure plate  202  and clutch pack  205 . 
         [0049]      FIG. 7  depicts the novel cable adjuster  500  and cable assembly  510  where the clutch override assembly  102  in  FIG. 1B  has been actuated advancing the inner cable  501  in the outward direction  210  creating the disengagement space  701  between the ferrule  601  and pressure face  602 . The disengagement space  701  depicted in  FIG. 7  corresponds to the disengaged gap  302  formed between the pressure plate  202  and clutch pack  205  shown in  FIG. 3 . 
         [0050]      FIG. 8  depicts the novel cable adjuster  500  and cable assembly  510  configured for bump starting. The female adjuster  505  has been adjusted in the inward direction  211  relative to the male adjuster  503  thus eliminating the contact between the pressure face  602  and ferrule  601  resulting in the separation gap  801  between the ferrule  601  and pressure face  602 . The separation gap  801  depicted in  FIG. 8  corresponds to the pressure plate  202  position shown in  FIG. 4  where the pressure plate  202  is contacting the clutch pack  205  for engagement creating no gap  401 . 
         [0051]      FIGS. 9 through 12  disclose a novel hydraulic adjuster  900  configured to be “in-line” in a typical hydraulically actuated clutch disengagement system between a clutch override assembly  102  and actuator  104  shown in  FIG. 1A . 
         [0052]    The components of the novel hydraulic adjuster  900  visible in  FIG. 9  are the body  901 , adjuster  902 , upper hydraulic line  903 , upper banjo bolt  904 , lower hydraulic line  905  and lower banjo bolt  906  and are all of typical construction as found on many modern motorcycle hydraulically actuated clutch disengagement systems. 
         [0053]    The upper hydraulic line  903  connects to the clutch override assembly  102 . The lower hydraulic line  905  connects to the actuator  104  such that when the clutch override assembly  102  is activated the actuator  104  is able to position the pressure plate  202  via the throwout  105  by displacing hydraulic fluid within the system. 
         [0054]      FIG. 10  discloses sealing washers  1001  being used in conjunction with the upper banjo bolt  904  and lower banjo bolt  906  which provide a sealed connection between the upper hydraulic line  903 , lower hydraulic line  905  and body  901  as can be found in the prior art. 
         [0055]      FIG. 10  depicts the inner bore  1002  and threaded adjuster hole  1004  of the body  901 . The inner bore  1002  contains the floating piston  1003  with floating piston seal  1006 . The floating piston seal  1006  separates the fluid on either side of the piston seal  1006 . The adjuster  902  has an externally threaded section  1012  allowing the adjuster  902  to thread into the body  902  via the threaded adjuster hole  1004 . The adjuster  902  contains an adjuster seal  1007  for the purpose of sealing the portion of the inner bore  1002  between the adjuster  902  and floating piston  1003 . Lastly, the adjuster  902  has a column  1008  extending the length of the adjuster  902  for the purpose of providing necessary separation between the floating piston  1003  and adjuster seal  1007  allowing the inlet port  1011  to open into the inner bore  1002  without the floating piston  1003  blocking the inlet port  1011 . 
         [0056]    The clutch override assembly  102  is operable to displace the actuator  104  via hydraulic fluid. The floating piston  1003  is therefore operable to displace hydraulic fluid within the inner bore  1002  in either direction. When the floating piston  1003  is acted on by clutch override assembly  102  the floating piston  1003  displaces the pressure plate  202 . When the floating piston  1003  is positioned via the adjuster  902  in a direction corresponding to the outward direction  210  the pressure plate  202  is displaced in the outward direction  210 . 
         [0057]      FIG. 10  shows the adjuster  902  threaded into the threaded adjuster hole  1004  of the body  901 . The column  1008  of the adjuster  902  is contacting the floating piston  1003  and has positioned the floating piston  1003  such that the position of the pressure plate  202  is positioned as shown in  FIG. 2  creating the installed gap  204 . Turning the adjuster  902  clockwise pushes the floating piston  1003  displacing the pressure plate  202  to create the installed gap  204 . 
         [0058]      FIG. 11  depicts the system in a state where the clutch override assembly  102  is actuated with the novel hydraulic adjuster  900  adjusted as disclosed in  FIG. 10 . The position of the adjuster  902  is the same as shown if  FIG. 10 . However, in  FIG. 11  the operator has actuated the clutch override assembly  102  causing the floating piston  1003  to be displaced further in a direction corresponding to the outward direction  210  signified by the piston gap  1100  between the column  1008  and floating piston  1003 . The position of the floating piston  1003  in  FIG. 11  corresponds to the position of the pressure plate  202  in  FIG. 3  resulting in the disengaged gap  302  between the pressure plate  202  and clutch pack  205 . 
         [0059]      FIG. 12  depicts the novel hydraulic adjuster  900  in a state where the clutch override assembly  102  not actuated and the novel hydraulic adjuster  900  is not configured to position the pressure plate  202 . Specifically, the adjuster  902  is not positioning the floating piston  1003  creating a column space  1200  between the adjuster  902  and floating piston  1003 . In this state the position of the floating piston  1003  corresponds to the position of the pressure plate  202  depicted in  FIG. 4  where pressure plate  202  is contacting the clutch pack  205  for engagement creating no gap  401 . 
         [0060]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. For example, for one skilled in the art, the present invention could be adapted for use in other types of vehicles that use clutch disengagement systems. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.