Abstract:
A combination clutch and brake system that may be original equipment for or retrofitted to a motorcycle having a clutch, brake and stick shift mechanical rear box. The sole operating lever for applying the clutch and brake includes an adjustable cam and linkage arrangement whereby either the clutch or brake may be activated first or both activated substantially concurrently. The clutch is controlled by cam action and the brake by a adjustable linkage to the cam which legs the rotation of the cam.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates in general to motorcycles and in particularly to motorcycles having both foot clutch and foot brake systems. More particularly, it relates to a mechanical clutch and hydraulic brake systems for motorcycles. 
     2. Description of Related Art 
     In existing motorcycle clutch systems, a hand clutch lever is located on the handle bars and includes cable means for mechanically coupling the movement of the clutch to disengage and engage the clutch mechanism to allow shifting of the gears on those motorcycles having a mechanical shifted gear system. Other motorcycles with mechanical gear shifts employ one foot pedal for the clutch, again through cable arrangements for engaging and disengaging the hand shifted gears, while the other pedal is normally a brake pedal. In this arrangement, the throttle is controlled by hand on one side of the handle bar. 
     In an arrangement where one foot is used to engage and disengage the clutch and the other foot is used to engage and disengage the brake, constitutes somewhat of a hazard when a motorcycle is in stop and go traffic. In such situations, the motorcyclist would have to engage the clutch and shift the gear into neutral and then apply the brake and place the free foot on the ground to support the motorcycle. Also, the motorcyclists alternatively would engage the brake to slow down the motorcycle, then engage the clutch to shift into neutral and then fully apply the brake. With the motorcycle fully stopped, the motorcyclist would have to repeat the process in reverse, engage the clutch and shift into gear with the brake off and then accelerate. 
     Other arrangements have been provided by motorcycle manufacturer including automatic transmissions. In such arrangement, the transmission is controlled by a hand lever and the other hand operates the accelerator, such that only one foot is required for the brake with the other foot free to place on the ground. Still many motorcycle enthusiasts desire mechanical hand shifted transmissions where the usual arrangement is a foot pedal for the brake and a foot pedal for the clutch. 
     Moreover, many motorcycle manufacturers provide a hydraulic clutch system. Discussion of such a hydraulic clutch system is set out in U.S. Pat. No. 6,227,342 B1. 
     SUMMARY OF THE INVENTION 
     This invention sets forth a retrofit arrangement to provide a clutch/brake system, which allows a hand shift motorcycle rider the ability to routinely place a foot on the ground when coming to a complete stop and until take-off. This is accomplished by a single clutch/brake pedal, which may be located for the use of either the left foot or the right foot of the rider. Furthermore in three-wheel motorcycles, the combining of the clutch and brake operation by a single pedal would permit a handicap person having use of only one leg for various reasons to operate the three-wheel motorcycle in a completely safe manner. 
     The invention is accomplished by the movement of a foot lever through a cam arrangement to disengage the clutch and with further movement apply the brake while the clutch remains disengaged. This permits the motorcyclist to place one foot on the ground where it remains until the brake is released and the clutch engaged for taking off and accelerating the motorcycle. 
     Further, by adjusting the lag in the application of the brake after the clutch the brake may be partially applied before the clutch is disengaged. Such an arrangement would improve braking efficiency, the same as an automobile driver would apply the brakes before disengaging the clutch in a conventional stick shift mechanical gear box. In this arrangement the cam-brake linkage would initially apply the brake and upon further movement of the clutch/brake, the cam action would completely disengage the clutch. In starting after a stop, the gears would be shifted while the brake was applied and the clutch disengaged, then the clutch would be engaged just as the brake was released. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the clutch/brake assembly for retrofitting to an existing motorcycle. 
     FIG. 2 is an exploded view of the clutch/brake assembly in FIG.  1 . 
     FIG. 3 is a side elevation of the clutch/brake assembly in which neither the clutch nor brake is engaged. 
     FIG. 4 is a side elevation view of the clutch/brake assembly wherein the clutch if fully disengaged and the brake fully engaged. 
     FIG. 5 illustrates the relation between clutch lever, brake plunger and the cam with the clutch engaged and the brake released. 
     FIG. 6 is similar to FIG. 5 wherein the clutch is disengaged and the brake has not been applied. 
     FIG. 7 is similar to FIG. 6 with the clutch fully disengaged and the brake fully applied. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the Figures and particularly to FIGS. 1 and 2, there is illustrated a combination clutch and brake system  10 . System  10  includes mounting bracket  12  secured to the frame of a motorcycle (not shown). Clutch and brake actuator  13  includes sleeve  15  with central grease fitting  15   a . Rigidly attached at one end of sleeve  15  is clutch brake lever  14  with foot pedal  14   a . The opposed end of sleeve  15  has cam  16  rigidly attached. 
     Shoulder bolt  18  seats inside sleeve  15  and threaded into tap  18   a  on mounting bracket  12  with O-rings  19  sealing sleeve  15  at each end. Clutch and brake actuator  13  is free to oscillate about shoulder bolt  18 . Clutch rod  30  is secured by shoulder bolt  31  through aperture  31   a  and threaded into tap  31   b  in mounting bracket  12 . Clutch rod  30  is free to rotate around shoulder bolt  31 . At the other end of clutch rod  30  is slot  35  and recess  36  (best seen in FIGS. 5,  6  and  7 ). Cable  37  has cable lugs  38  attached at one end and seats in recess  36  and extends through slot  35  and through aperture  32  in cable guide  34  and extends to the clutch assembly of the motorcycle (not shown). Clutch rod  30  is positioned to engage cam  16  such that clockwise rotation (as viewed in FIG. 1) will cause clutch rod  30  to rotate counterclockwise to disengage the clutch in the clutch assembly (not shown). 
     Brake cylinder  20  is mounted to mounting bracket  12  by bolt  25  through apertures  25   a  in brake cylinder  20  and into taps  25   b  in mounting bracket  12 . A bolt, similar to bolt  25  would be mounted through tap  25   c  in brake bracket  26  and into tap  25   d  (not shown), but see FIGS. 3 and 4. 
     Operating rod  21  extends from brake cylinder  20 , which activates an internal plunger in brake cylinder  20  to activate the hydraulic brake system of the motorcycle (not shown). Threaded onto operating rod  21  is sliding brake controller  22 , which has threaded slot  40  and elongated slot  41 . Sliding brake controller  22  is coupled to cam  16  by cam shoulder bolt  23 , which extends through elongated slot  41  and threaded into tap  16   a.    
     Foot peg  50  is secured in threaded aperture  52  of mounting bracket  12 . Return spring  55  is secured at one end in tap  53  of foot peg  50  and the other end of return spring  55  is attached in tap  56  of clutch brake lever  14 . Thus, return spring  55  holds clutch brake lever  14  seated against foot peg  50  when no pressure is being applied to foot pedal  14   a.    
     Further referring to FIGS. 4,  5 ,  6  and  7 , the operation of combined clutch and brake system  10  will be described. In the initial position of brake clutch lever  14 , the clutch is fully engaged and shoulder bolt  23  attached to cam  16  is in the rear most position in slot  41  of sliding brake controller  22  and the distance span between brake cylinder  20  and sliding brake controller  22  by operating rod  21 , is indicated as D 1  in FIG.  5  and the brake is not applied. In this position, the motorcycle is moving down the roadway. When the rider is ready to shift gears or come to a stop, clutch brake lever  14  is rotated forwardly in the applying motion by depressing pedal  14   a . With this action, shoulder bolt  23  on cam  16  rotates with cam  16  and moves from the rear of slot  41  to the front of slot  41 . Further clockwise rotation of cam  16  by further depressing pedal  14   a  moves clutch rod  30  counterclockwise, thus pulling cable  37  forward thereby disengaging the clutch (not shown) attached to cable  37 . Referring to FIG. 6, it will be observed that cam  16  has rotated clockwise and cam shoulder bolt  23  is now positioned at the forward most position in slot  41  of sliding brake controller  22 . At this point, the clutch has been disengaged and the brake has not been applied and the rider is free to shift the gears to suit the road conditions being encountered. Upon continued rotation of cam  16  with clutch brake lever  14 , cam shoulder bolt  23  of cam  16  pushes sliding brake controller  22  towards brake cylinder  20  with operating rod  21  moving within brake cylinder  20  to push the internal brake plunger and apply hydraulic pressure to the brake system causing the motorcycle to slow or stop and the clutch remains disengaged. With the brake fully applied, FIG. 7 illustrates the position of cam  16 , sliding brake controller  22  and the distance span of operating rod  21  between sliding brake controller  22  and brake cylinder  20  is reduced from D 1  to D 2  with operating rod  21  engaging the internal plunger of brake cylinder  20  to apply the hydraulic brakes. Upon releasing pressure on foot pedal  14   a , return spring  55  contracts and operating lever  14  rotates rearwardly in the return motion releasing the brake and engaging the clutch. 
     By adjusting the depth that operating rod  21  is threaded into threaded slot  40  would require further movement of operating rod  21  before moving the internal plunger of brake cylinder  20  to apply hydraulic pressure to the brakes. In this manner, the clutch would remain disengaged and clutch brake lever  14  would be further rotated before the brakes would be applied. Further, by unthreading operating rod  21  from threaded slot  40 , the distance D 1  in FIG. 5 would be increased and cam shoulder bolt  23  would be positioned intermediate the ends of elongated slot  41 . Upon initial rotation of clutch brake lever  14 , thereby rotating cam  16  clockwise, the travel of cam shoulder bolt  23  in elongated slot  41  would engage the forward most end of elongated slot  41  moving sliding brake controller  22  and operating rod  21  to engage the internal plunger of brake cylinder  20 , initiating braking before clutch rod  30  has moved to disengage the clutch of the motorcycle. Thus maintaining the gears engaged to aid in slowing the motorcycle by allowing the gear to be engaged through part of the braking of the motorcycle. 
     Thus it will be recognized that the combination clutch and brake system  10 , by relatively simple adjustments, can be made to disengage the clutch before the brake is applied and to disengage the clutch and engage the brake at the same time or engage the brake and then disengage the clutch. 
     The ability to make adjustments to the combination clutch and brake system permits safer operation of the motorcycle over city streets, on the highway, in mountain regions and through rugged terrain. Further, the combination clutch and hydraulic brake systems may be utilized for either the left or right foot of the rider.