Abstract:
A mechanism to retrofit modern motorcycles with a foot operated clutch or to be installed as original equipment is disclosed. The mechanism has an escapement mechanism, such as a pawl and ratchet, for holding the clutch in disengaged condition when a rider applies positive pressure on a foot pedal without requiring the rider to hold the foot pedal down with his or her left foot. This frees the rider to balance the motorcycle. The mechanism then allows the clutch to be readily reengaged when the rider desires to move the motorcycle by applying further positive pressure to the foot pedal.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a foot operated clutch for a motorcycle. 
   2. Brief Description of the Prior Art 
   Modern motorcycles are typically provided with mechanical clutches in the drive train. The clutches are manually operated by action of a hand lever which drives a cable connected to the clutch. Gear selection is obtained by operation of a foot lever. Older motorcycles, those made in the 1940&#39;s and before, were provided with clutches which were foot operated and with hand operated gear selection levers. Such motorcycles include older Harley-Davidson (TM), Moto Guzzi (TM) and Indian (TM) motorcycles, among others. 
   Recently, there has been a growing nostalgic attraction for older motorcycles. However, there is an insufficient number of such machines available to satisfy the demand for them. In addition, because of short supply, older and collectable motorcycles are very expensive. Consequently, it has become desirable to retrofit more modern motorcycles with foot operated clutches and with hand operated gear selection levers. The retrofitted motorcycles imitate the older designs and satisfy the nostalgic appeal of the antique machines. 
   U.S. Pat. Nos. 2,094,163, 2,540,926, 3,856,123, 4,041,798, 4,056,268, 4,316,531, 4,543,850, and 5,662,195 are incorporated by reference herein. 
   BRIEF SUMMARY OF THE INVENTION 
   The device of the present invention is a foot operated clutch mechanism which may be installed as original equipment or used to retrofit an existing modern motorcycle. The device has structure that frees a rider from holding the clutch in disengaged condition. 
   A motorcycle is structured such that the foot brake is operated with a rider&#39;s right foot. When the motorcycle is stopped in traffic, for example at a stoplight, the rider applies the brake with the right foot and balances the motorcycle with the left foot. With a motorcycle gear selector, it is difficult to find the neutral position and it is therefore necessary to disengage the clutch. This creates a problem for a rider with a foot clutch because the left foot is needed to balance the motorcycle. 
   The present invention addresses the above-mentioned problem by providing an escapement mechanism, such as a pawl and ratchet, for holding the clutch in disengaged condition without requiring the rider to hold the clutch down with his or her left foot. This frees the rider to balance the motorcycle. The mechanism then allows the clutch to be readily reengaged when the rider desires to move the motorcycle. 
   It is thus an object of this invention to provide a foot operated clutch mechanism that can be used to retrofit existing hand clutch motorcycles or used as original equipment. Another object is to provide a foot operated clutch mechanism that selectively holds the clutch in disengaged condition and frees the rider to use his or her left foot to balance the motorcycle when needed. A further object is to provide a foot operated clutch mechanism that readily reengages the clutch and allows the rider to feather the clutch in an ordinary manner. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter. 
   The invention summarized above comprises the constructions hereinafter described, the scope of the invention being indicated by the subjoined claims. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated, corresponding reference characters refer to corresponding parts throughout the several views of the drawings in which: 
       FIG. 1  is a left side view of the device of the invention installed on a motorcycle; 
       FIG. 2  is a partial perspective view of the device of the invention installed on a motorcycle, in phantom; 
       FIG. 3  is a perspective view of the device of the invention; 
       FIG. 4  is an exploded view of the device of the invention; 
       FIG. 5  is a front detail view of the device of the invention; 
       FIG. 6  is a partial cross-sectional view of the device of the invention taken along the plane  6 — 6  in  FIG. 5 ; 
       FIG. 7  is a back detail view of the device of the invention shown in  FIG. 5 ; 
       FIG. 8  is a front detail view of the device of the invention similar to  FIG. 5 ; 
       FIG. 9  is a back detail view of the device of the invention similar to  FIG. 7 ; 
       FIG. 10  is a front detail view of the device of the invention similar to  FIGS. 5 and 8 ; 
       FIG. 11  is a partial cross-sectional view of the device of the invention taken along the plane  11 — 11  in  FIG. 10 ; and, 
       FIG. 12  is a back detail view of the device of the invention similar to  FIGS. 7 and 9 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a foot operated clutch mechanism  20  of the invention is shown installed on a conventional modern motorcycle  22 . Foot operated clutch mechanism  20  activates a clutch  24  through a clutch activating rod or link  26  and a clutch lever  27 . Foot operated clutch mechanism  20  includes a mounting plate  28  which is provided with a plurality of mounting holes  30  which accept mounting bolts to attach the foot operated clutch mechanism to the frame of motorcycle  22 , as shown. Mounting plate  28  may also be equipped with a conventional foot rest  32 . 
   Foot operated clutch mechanism  20  is operated through a foot lever  34  and pedal  36  which drive a rod lever  38  through an intermediate member  40 , as best seen in  FIG. 3 . It will be appreciated that foot lever  34 , pedal  36 , intermediate member  40  and rod lever  38  are joined to act as a unit without relative movement between these elements. Rod lever  38  drives clutch activating rod  26  through an adjustable tie rod end  42 . 
   Turning to  FIG. 4 , the operating elements  34 ,  36 ,  38  and  40  receive a keyed shaft  44  in a bore  46 . Operating elements  34 ,  36 ,  38  and  40  are fastened to keyed shaft  44  by use of suitable fasteners, such as a machine screw  48 . Keyed shaft  44  is journaled in a bearing  50  in mounting plate  28  and extends transversely therethrough. When keyed shaft  44  is passed through bearing  50 , a key way  52  with a drive key  54  is positioned on the same side as operating elements  34 ,  36 ,  38  and  40  with drive key  54  received in a drive slot (not shown) in the inner portion of bore  46  to complete a driving connection between operating elements  34 ,  36 ,  38  and  40  and keyed shaft  44 . It will be appreciated that other equivalent structures may be used to fix shaft  44  to elements  34 ,  36 ,  38  and  40 . For example, shaft  44  may be tapered and/or pressed into bore  46 . Shaft  44  may also be splined or may have a square or other shape to mate with a similar shape in bore  46 . Combinations of these structures may also be used. 
   Keyed shaft  44  has two ratchets  56  and  58  installed thereon by conventional means as described herein for the other structures on keyed shaft  44 . When keyed shaft  44  is installed in bearing  50 , ratchets  56  and  58  remain are on the opposite side of mounting plate  28 . Keyed shaft  44  had a slotted end  60  which extends beyond ratchets  56  and  58 , as shown. A housing  62  has a central bore  64  therein which receives slotted end  60  of keyed shaft  44  therethrough. As shown in  FIG. 4 , slotted end  60  of the keyed shaft  44  has a transverse slot  65  therein. Housing  62  may be attached to mounting plate  28 , as shown in  FIG. 3 , by the use of suitable fasteners such as machine screws, not shown. 
   The right side of housing  62  contains a slotted cam  66 . As shown in  FIG. 4 , slotted cam  66  has a transverse slot  67  therein. Slotted cam  66  has a bore  68  for receipt of slotted end  60  of keyed shaft  44 . When slotted end  60  of keyed shaft  44  and slotted cam  66  are positioned with their slots,  61  and  67  in communication, they are joined by a keeper  69  held by a suitable fastener, such as a machine screw  70 , as shown. It will be appreciated that other equivalent structures may be used to fix cam  66  to shaft  44 . For example, shaft  44  may be tapered and/or pressed into cam  66 . Shaft  44  may be splined or may have a square or other shape to mate with a similar shape in cam  66 . Combinations of these structures may also be used. 
   Housing  62  also has a peripheral bore  72  therethrough, as shown in  FIGS. 6 and 11 . A piston or plunger  74  is received in peripheral bore  72  and extends transversely therethrough to the right side of housing  62 . As shown, bore  72  and piston  74  have circular cross-sections. It will be appreciated, however, that they may be constructed with non-circular cross-sections if desired. Piston  74  is biased to the right by a spring  76  which is captured in bore  72 , as shown in  FIG. 6 . The left end of piston  74  extends through to the left side of housing  62 , as shown in  FIGS. 6 and 11 . A pawl  78  is attached to the left end of piston  74 , by conventional means as described herein, and is biased in the clockwise direction by a spring  80  anchored in the housing  62 , as shown in  FIGS. 5 ,  6  and  10 . As shown in  FIGS. 4 ,  6  and  11 , pawl  78  may be secured to the left end of piston  74  by suitable spacers and fasteners. As shown in  FIGS. 5 ,  7 ,  10 , and  12 , housing  62  may have a spring loaded detent  82  which engages cam  66 , as described herein. Pawl  78 , ratchets  56  and  58 , and cam  66  provide an escapement mechanism for device  20 , as described herein. 
   OPERATION OF THE DEVICE 
   To operate the device to disengage the clutch of a motorcycle on which the device of the invention is installed the rider rotates foot lever  34  in the counterclockwise direction by applying positive force to pedal  36  by use of the left foot. Intermediate member  40  and rod lever  38  also rotate in the counterclockwise direction and pull clutch activating rod  26  to the left as shown in  FIG. 3 . Clutch activating rod  26  disengages the clutch of the motorcycle when so moved by operating clutch lever  27 . It will be appreciated that the modern hand lever and cable connection have been previously removed from clutch lever  27 . 
   As intermediate member  40  and rod lever  38  move in the counterclockwise direction they move keyed shaft  44  in the counterclockwise direction also. Ratchets  56  and  58  are joined to keyed shaft  44  and carried in a counterclockwise direction by keyed shaft  44 . Ratchet  58  moves from the position shown in  FIG. 5  to the position shown in  FIG. 8 . As shown, pawl  78  glides over the surface of ratchet  58  and engages a notch  84  in the ratchet  58 . Cam  66 , also joined to keyed shaft  44 , moves from the position shown in  FIG. 7  to the position shown in  FIG. 9  and is held in that position by detent  82 . As shown in  FIG. 8 , pawl  78  prevents keyed shaft  44  from rotating in a clockwise direction and fixes clutch activating rod  26  to hold motorcycle clutch lever  27  and clutch  24  latched in the disengaged position. The left foot of the rider is thus free to hold the motorcycle steady by resting on the road surface, for example when stopped at a stoplight, as device  20  maintains clutch  24  locked in the disengaged position. 
   To reengage motorcycle clutch  24  the rider applies additional positive force to foot pedal  36  to rotate mechanism  34 ,  40  and  38  an addition distance in the counterclockwise direction. This movement releases pawl  78  from ratchet  58  as keyed shaft  44  and ratchet  58  rotate in the counterclockwise direction from the position shown in  FIG. 8  to the position shown in  FIG. 10 . Cam  66  is also rotated by keyed shaft  44  from the position shown in  FIG. 9  to the position shown in FIG.  12  and is prevented by a stop  86  from further counterclockwise rotation. In this position, a cam surface  88  on cam  66  depresses piston  74  and moves it to the left, as shown in  FIG. 11 . In this position, pawl  78  is freed from engagement with ratchet  58  and glides over a relieved portion  90  on ratchet  56 . The force of an internal spring (not shown) of motorcycle clutch  24  retracts clutch activating rod  26  and clutch  24  reengages. The engagement of clutch  24  can be feathered in the normal manner by maintaining some foot positive pressure on foot pedal  36  as clutch activating rod  26  is retracted by the internal spring of clutch  24 . As clutch  24  reengages, cam  66  moves from the position shown in  FIG. 12  to the position shown in  FIG. 7 . Spring  76  restores piston  74  to the position shown in  FIG. 6  and device  20  is ready for a next cycle of use to disengage clutch  24 . 
   In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.