Abstract:
A Device is fitted to a traditional bicycle to facilitate a riding style in which the rear wheel of the bicycle can slid sideways or drifted in a controlled manner by harnessing the rider&#39;s backward pedaling motions to thrust a block of UHMW plastic downward to the road surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of provisional patent application Ser. No. 62/283,907, filled on Sep. 15, 2015 by the present inventor. 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    None. 
       SEQUENCE LISTING 
       [0003]    None. 
       BACKGROUND OF THE INVENTION 
     Field of Invention 
       [0004]    Drifting is a style of riding or driving vehicles in which the available traction of one or more of the rear wheels is exceeded causing the rear of the vehicle to assume a sliding motion while the front tire or tires maintain largely static traction with the road surface. Most drifting is performed with motorized vehicles which have the ability to use engine power to overwhelm available traction between the tires and the road surface. Practitioners of car and motorcycle drifting take great pride in their ability to navigate turns vehicles which would appear to a lay person to be skidding dangerously out of control. Bicycle drifting is extraordinarily difficult because even the strongest cyclist cannot administer sufficient thrust to the rear wheel of a bicycle to cause it to lose traction. Skidding the rear wheel with the rear brake can induce a brief sensation of drifting, but since bicycles do not travel are high speeds the bicycle quickly slows to a stop. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0005]    To facilitate the drifting of bicycles the available traction of the rear tire to the road surface must be reduced while the front tire of the bicycle must retain most or all of its traction to the road surface. The traction must be reduced in a controlled manner such that the rider can actively add or subtract to the traction of the rear tire to the road surface. If the rider were to lose too much rear wheel traction, the bicycle would be liable to slide out from underneath him in a manner appreciably similar to a bicyclist crashing on a patch of ice. Additionally, the sudden and inadvertent addition of traction to the rear wheel of a sliding bicycle could cause the bicycle to suddenly tip over and crash. 
         [0006]    To selectively reduce the traction of the rear tire of the bicycle with the pavement, a block of plastic, likely composed of UHMW Polyethylene is pressed again the pavement in close proximity to the contact point with which the rear tire contacts the pavement. UHMW Polyethylene has both high abrasion resistance and it slides readily on pavement. As the block of UHMW is pressed against the pavement with increasing force the rear tire of the bicycle with gradually be lifted from the road surface. Even before the tire lifts fully from the road, the tire&#39;s traction with the road surface will be significantly reduced. Since UHMW slides so well once the traction of the traction tire to the road&#39;s surface is sufficiently reduced the rider will be able to controllably drift the rear of the bicycle around turns. 
         [0007]    Replacement of the UHMW Polyethylene with other slipper materials or even one or more rolling elements is certainly possible provided they slide readily on the road surface. 
         [0008]    The block of UHMW Polyethylene may be pressed against the road surface by any number of mechanisms and energized by either stored energy or the exertions of the bicycle rider. While an electromechanical mechanisms or hand powered mechanism are certainly possible, the rider back pedaling the bicycle&#39;s crankset appears to be the ideal method of generated the force and displacement necessary to lift the rear of the bicycle. In one embodiment of the design, a disc with multiple protrusions is affixed to the inside surface of the bicycle&#39;s front chain ring. A member with a cavity hooks onto one of the protrusions on the disc when the chain ring is rotated opposite of usual pedaling motion and is moved accordingly toward the ground. As the member moves it down, it in turn pushes downward on an assembly rotating about the rear axle of the bicycle. The assembly rotating about the rear axle of the bicycle has on its end a universal joint of such to which is affixed a block of UHMW plastic which is driven onto the surface of the roadway on which the bicycle is trans versing. Alternative embodiments of this invention in which mechanisms move the UHMW block by capturing the motion of chain ring teeth which rotate about the bicycle&#39;s bottom bracket can certainly be easily envisioned. The capacity to engage or disengage the mechanism so that when not engaged the bicycle can freely be backpedaled would make possible sense in some embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1 . View of Bicycle fitted with Drifting Mechanism 
           [0010]      FIG. 2 . Exploded Isometric View of Lower Rear Section of Bicycle 
           [0011]      FIG. 3 . View of Lower Rear Section of Bicycle, Mechanism Not Engaged 
           [0012]      FIG. 4 . View of Lower Rear Section of Bicycle, Mechanism Engaged 
           [0013]      FIG. 5 . View of Bicycle with Drifting Mechanism Engaged 
       
    
    
     REFERENCE NUMERALS 
       [0014]      
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                  5-Frame 
                  9-Handlebars 
               
               
                   
                 10-Rear Wheel 
                 11-Front Wheel 
               
               
                   
                 12-Crank 
                 18-Pedals 
               
               
                   
                 22-Connecting Member 
                 23-Pegged Disc 
               
               
                   
                 24-Connecting Rod 
                 25-UHMW Polyethylene Plastic Block 
               
               
                   
                 26-Axis of Rotation 
                 27-Compression Spring 
               
               
                   
                 29-Tension Spring 
                 30-Slotted Rod 
               
               
                   
                 31-Pin 
                 32-Shoulder Bolt 
               
               
                   
                 33-Running Surface 
                 35-Protruding Feature 
               
               
                   
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
       [0015]      FIG. 1  depicts a bicycle which includes a front wheel  11  which is steered by handlebars  9  which rotate about in axis in the frame  5 . A rear wheel  10  rotates about an axis  26  in the frame  5  and is propelled by pedals  18  which turn a crank  12  which rotates in the frame  5 . Rotation of the cranks  12  about the bottom bracket  34  in the frame  5  causes the rotation of the pegged disc  23 . Rotations of the pegged disc  23  is translated into the motion of the connecting rod  24 . Motion of the connecting rod  24  ultimately results in the movement of the UHMW Polyethylene block  25  as it is revolved around an axis of rotation  26  and constrained in this motion by the connecting member  22 . 
         [0016]      FIG. 2  depicts an exploded view of the lower rear portion of the entire bicycle depicted in  FIG. 1 . Note the small portion of the front wheel  11  visible, the portion of the frame  5  partially visible, and the rear wheel  10  also partially visible. The axis of rotation  26  about which the rear wheel  10  and the connecting member  22  rotate in the frame  5  is clearly visible. Note the protruding feature  35  on the connecting member  22  which contacts the frame  5  when the mechanism is not engaged. Connecting the connecting member  22  to the UHMW polyethylene bock  25  is a slotted rod  30  which is pinned onto the connecting member  22  with a pin  31  on which it may rotate. The UHMW polyethylene block  25  pops onto the slotted rod  30  for easy replacement and it facilitates the rotation of said block to conform to the orientation of the bicycle to the ground or running surface. Pushing the connecting member  22  towards the running surface is the connecting rod  24  which is connected to the connecting member  22  with a shoulder bolt  32 . A compression spring  27  pushes the connecting rod  24  in a counter clockwise rotation so that the forked top profile of the connecting rod  24  engages with the pegs protruding from the pegged disc  23 . The pegged disc  23  is rotated in a counter clockwise motion about the bottom bracket  34  by the crank  12  onto which the two pedals  18  are affixed to engage and modulate the drifting mechanism. The bottom bracket  34  is firmly fastened into the frame  5 . The UHMW polyethylene block  25  is retracted from the road surface by pedaling the crank  12  in a clockwise motion which in turn turns the pegged disc  23  in a clockwise motion. The tensioned spring  29  connected to the frame  5  and the compression member  22  pulls the UHMW polyethylene block  25  upward as the pegged disc  23  is no longer pushing down the connecting rod  24 . 
         [0017]      FIG. 3  depicts a view of the lower rear portion of the entire bicycle depicted in  FIG. 1 . Note the small portion of the rear wheel  10  visible, the portion of the frame  5  partially visible, and a cross section view of the running surface  33  on which the bicycle moves. The axis of rotation  26  about which the rear wheel  10  and the connecting member  22  rotate in the frame  5  is clearly visible. Note the protruding feature  35  on the connecting member  22  is in contact with the frame  5 . The connecting member  22  is retracted upward so there is no contact between the UHMW polyethylene bock  25  and the running surface  33 . The connecting rod  24  is not engaged to the pegged disc  23  so provided the pegged disc  23  is motionless or not rotated in a counter clockwise rotation the connecting rod  24  will not be pushed downward. Notice that in this orientation the compression spring  24  is compressed as it functions to press the notched top of the compression rod  24  into the pegged disc  23 . Rotation of the pegged disc  23  is a result of the rotation of the crank  12  by the two pedals  18 . 
         [0018]      FIG. 4  is a view of the assembly in  FIG. 3  but with the mechanism engaged to lift the rear wheel  10  from the running surface  33  which will allow the rear of the bicycle to drift sideways in relation to the bicycle&#39;s forward motion. Note the gap between the protruding feature  35  on the connecting member  22  and the bicycle&#39;s frame  5 . The gap is opened up by the rotation of the connecting member  22  about an axis of rotation  26 . This counter clockwise rotation tensions the tension spring  29  which is connected to the connecting member  22  and the frame  5 . The counter clockwise rotation of the connecting member  22  is caused by the downward thrust of the connecting rod  24  to which it is connected by the shoulder bolt  32 . The connecting rod is driven downward by its engagement with the pegged disc  23  whose pegs press into the recess in the top of the connecting rod  24 . The pegged disc  23  is rotated in a counter clockwise manner and held in this orientation by the rider using the pedals  18  to orient the crank  12  which rotates about the bottom bracket  34 . 
         [0019]      FIG. 5  is a full view of the bicycle as it travels on the running surface  33  with the mechanism engaged to lift the rear wheel  10  from the running surface. Notice the significant gap between the rear wheel  10  and the running surface  33 . No gap exists between the front wheel  11  and the running surface  33  as they remain in firm contact. Steering motions to the handlebars  9 , road surface variations, and the movement of the rider&#39;s mass would cause the frame  5  to move somewhat independently of the bicycle&#39;s customary path of travel whenever the UHMW polyethylene plastic block  25  is exerting significant pressure on the running surface  33 . Note that the rear of the bicycle is essentially supported by the connecting rod  24  and will remain this way as long as the pegged disc  23  is maintained in its orientation by the rider keeping the crank  12  from rotating. Careful pedaling of the pedals  18  allows the rider complete control over how firmly the UHMW polyethylene plastic block is thrust onto the road surface.