Abstract:
The present invention relates to a unique convertible ride-on vehicle. The ride-on vehicle of the present invention includes at least one font wheel, at least two rear wheels mounted on a rear axle, a frame supported by the at least one front wheel and the at least two rear wheels, a torque input mechanism, a torque transfer mechanism for transferring torque from the torque input mechanism to the rear wheels. The ride-on vehicle of the present invention is convertible between a first, tricycle configuration in which the rear wheels are spaced apart on the rear axle and a second, bicycle configuration in which the rear wheels are in close proximity to each other. Finally, the present application discloses a clean, simple method and apparatus for adjusting the tension of a chain or belt utilized to drive a ride-on vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Patent Application Ser. No. 60/707,528, entitled “Trike to Bike” and filed Aug. 12, 2005. The disclosure of the above-mentioned provisional application is incorporated herein by reference in its entirety. 
    
    
     SUMMARY OF THE INVENTION 
     Generally, the present invention relates to a children&#39;s ride-on vehicle convertible from a training configuration to a more experienced rider configuration. More specifically, the present invention relates to a ride-on vehicle that is adapted to evolve between a tricycle configuration and a bicycle configuration. Tricycles exist for use by young children. For older children, bicycles, optionally fitted with stabilizing side wheels (a.k.a. “training wheels”) also exist. The present invention provides a solution to the new problem of adaptability and interchangeability of cycles, notably cycles for use by children. 
     As the motor skills of children develop, parents who purchased a tricycle are obliged to then fairly quickly purchase a bicycle fitted with removable stabilizing training wheels. Apart from the problem of cost, a learning problem may arise due to the physical change between a tricycle and a different bicycle product. The apparatus of the instant invention comprises an attachment which may be manufactured in at least two forms and utilized to convert a tricycle into a bicycle for use by a child in converting from a standard tricycle to a bicycle, the converted tricycle of the instant invention being designed for use by a child during the transition period between his riding a tricycle and his riding a conventional bicycle. 
     Thus, the present invention not only provides a two-wheeled ride-on vehicle for use by a small child in learning to ride a conventional bicycle, but does so in a conventional tricycle-type ride-on vehicle with a frame and feel with which the child is basically familiar and accustomed to. Also, a tricycle converted in accordance with the present invention produces an extremely low bicycle-type ride-on vehicle which may be readily handled by a small child with assurance that he will not fall from the greater height at which he would be riding if he was riding even a small bicycle of conventional design. A parent may convert his child&#39;s tricycle into a bicycle with a nominal effort and ultimately delay the greater expenditure involved in the purchase of a conventional bicycle until such time as the child has mastered riding the converted tricycle, at which time the child may easily make the transition to a conventional bicycle. 
     Further, in one form of the invention to be illustrated and described hereinafter more fully, a tricycle may be converted into a bicycle-like riding configuration in accordance with the present invention and thereafter back into a tricycle for use by younger children after an older child has mastered riding the converted tricycle and has been given a conventional bicycle. Additionally, the present invention may also be utilized in converting a tricycle once converted into a bicycle-like riding configuration back into a tricycle for use by younger children or further use by a child deemed not ready for the transition to a bicycle. Finally, the present invention incorporates a clean, simple method and apparatus for adjusting the tension of a chain or belt utilized to drive the children&#39;s ride-on vehicle of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, with the children&#39;s ride-on vehicle configured in a first, stabilized riding position. 
         FIG. 2  illustrates a front view of the children&#39;s ride-on vehicle of  FIG. 1 . 
         FIG. 3  illustrates a rear perspective view of the children&#39;s ride-on vehicle of  FIG. 1 . 
         FIG. 4  illustrates a perspective view of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, with the children&#39;s ride-on vehicle configured in a second, bicycle-like riding position. 
         FIG. 5  illustrates a front view of the children&#39;s ride-on vehicle of  FIG. 4 . 
         FIG. 6  illustrates a rear perspective view of the children&#39;s ride-on vehicle of  FIG. 4 . 
         FIG. 7  illustrates an exploded view of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 8  illustrates an exploded view of the crankcase assembly of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 9  illustrates an exploded view of one of the rear wheel assemblies of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 10  illustrates an exploded view of one of the rear axle bushings and frame members of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 11  illustrates a cut-away view showing the attachment of the crankcase to one of the frame members on a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 12  illustrates a perspective view of the attachment of frame members to the crankcase on a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 13  illustrates an exploded view of the front steering assembly of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 14  illustrates an isolated perspective view of the frame members, crankcase, rear axle, and pedal axle (“crank”) of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 15  illustrates a rear perspective view of the children&#39;s ride-on vehicle of  FIG. 14 . 
         FIG. 16  illustrates a rear perspective view of the children&#39;s ride-on vehicle of  FIG. 14  in a position in which the frame is rotated away from the crankcase and rear axle. 
         FIG. 17  illustrates a rear isolated perspective view of one of the rear wheel assemblies of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 18  illustrates a close-up rear perspective view of one of the rear wheel assemblies in proximity to the crankcase and rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 19  illustrates a rear isolated perspective view of the attachment of one of the rear wheel assemblies to the rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 20  illustrates a rear isolated perspective view of one of the rear wheel assemblies attached to the rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, the wheel assembly being positioned in the first, stabilized riding position. 
         FIG. 21  illustrates a rear isolated perspective view of one of the rear wheel assemblies, the frame members, crankcase, and rear axle, of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, the rear wheel assembly being positioned in the first, stabilized riding position and the frame members rotated back into position over the rear axle. 
         FIG. 22  illustrates a close-up rear perspective view of both of the rear wheel assemblies, the frame members, the crankcase, and the rear axle, of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, the rear wheel assemblies being positioned in the first, stabilized riding position and the frame members rotated back into position over the rear axle. 
         FIG. 23  illustrates a rear isolated perspective view of one of the rear wheel assemblies in proximity to the crankcase and rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, where the rear wheel assembly has been rotated 180 degrees from its position in  FIG. 18 . 
         FIG. 24  illustrates a rear isolated perspective view of the attachment of one of the rear wheel assemblies to the rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 25  illustrates a rear isolated perspective view of one of the rear wheel assemblies attached to the rear axle of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, the wheel assembly being positioned in the second, bicycle-like riding position. 
         FIG. 26  illustrates an isolated perspective view of the children&#39;s ride-on vehicle of  FIG. 25  in a position in which the frame is rotated away from the crankcase and rear axle. 
         FIG. 27  illustrates an isolated perspective view of the children&#39;s ride-on vehicle of  FIG. 25 , with one of the rear wheel assemblies being positioned in the second, bicycle-like riding position and the frame members rotated back into position over the rear axle. 
         FIG. 28  illustrates an isolated perspective view of the children&#39;s ride-on vehicle of  FIG. 27 . 
         FIG. 29  illustrates a rear isolated perspective view of both of the rear wheel assemblies, the frame members, the crankcase, and the rear axle, of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention, the rear wheel assemblies being positioned in the second, bicycle-like riding position and the frame members rotated back into position over the rear axle. 
         FIG. 30  illustrates an isolated perspective view of a chain tension adjustment mechanism utilizing a portion of the sprocket and crank assembly of the children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. 
         FIG. 31  illustrates an isolated close-up perspective view of the chain tension adjustment mechanism of  FIG. 30 . 
         FIG. 32  illustrates a rear isolated bottom view of a children&#39;s ride-on vehicle in accordance with another embodiment of the present invention showing a rear wheel assembly, frame members, axle locks and a crankcase, the rear wheel assembly received and locked by the axle locks into slots in the frame members and the rear wheel assemblies being positioned in the first, stabilized riding position. 
         FIG. 33  illustrates an enlarged isolated bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing a close-up view of one side of the rear wheel assembly locked by the axle locks into one of the slots in one of the frame members. 
         FIG. 34  illustrates an enlarged isolated bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the axle lock of one frame member being released to permit entry or exit of the rear wheel assembly from the slot in the frame member. 
         FIG. 35  illustrates a close-up view of one of the slots and axle locks of one of the frame members of  FIGS. 32-34 . 
         FIG. 36  illustrates a rear bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the frame members rotated away from the crankcase and rear axle, and the rear wheel assembly removed from the slots. 
         FIG. 37  illustrates a close-up bottom view of one of the sides of the rear wheel assembly of the children&#39;s ride-on vehicle of  FIG. 36  being removed from the slot of a frame member. 
         FIG. 38  illustrates a bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the frame members rotated away from the crankcase and rear axle and, the rear wheel assembly completely removed from the slots of the frame members. 
         FIG. 39  illustrates a side view of the children&#39;s ride-on vehicle of  FIG. 32  showing the separation of the rear wheel assembly from the slots of the frame members. 
         FIG. 40  illustrates an isolated bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the separation of one side of the rear wheel assembly from the slot of the frame member. 
         FIG. 41  illustrates a bottom view of the children&#39;s ride-on vehicle of  FIG. 32  with the slide bushings positioned in their inner bicycle-like rider configuration and the wheels ready to be positioned in their inner bicycle-like rider configuration. 
         FIG. 42  illustrates an enlarged isolated bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing a wheel about half way transitioned from an outer side (stabilized configuration) of the slide bushing to an inner side (bicycle-like configuration) of the slide bushing by sliding the wheel along the slide bushing. 
         FIG. 43  illustrates a rear bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing one wheel completely transitioned to the inner side (bicycle-like configuration) of the slide bushing against the crank case. 
         FIG. 44  illustrates a rear bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing both rear wheels positioned inward on their respective slide bushings toward the crank case in the bicycle-like configuration. 
         FIG. 45  illustrates a rear bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the rear wheel assembly in the bicycle-like configuration and showing the exposed outer portions of the slide bushings of the rear wheel assembly being repositioned in the slots of the frame members. 
         FIG. 46  illustrates a rear isolated bottom view of the children&#39;s ride-on vehicle of  FIG. 32  showing the slide bushings of the rear wheel assembly repositioned in their respective slots and secured with the axle locks. 
         FIG. 47  illustrates a close-up isolated perspective view of the slide bushings of the children&#39;s ride-on vehicle of  FIG. 32  showing the a portion of a wheel, a slide surface, a flange, and flange teeth. 
         FIG. 48  illustrates an isolated close-up perspective view of a geared hub (on a portion of a wheel), a slide bushing, and the rear wheel axle of the children&#39;s ride-on vehicle of  FIG. 32 . 
         FIG. 49  illustrates a close-up view of torque projections extending from the rear axle of the children&#39;s ride-on vehicle of  FIG. 32 . 
     
    
    
     Like reference numerals have been used to identify like elements throughout this disclosure. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with the present invention, a children&#39;s ride-on vehicle is disclosed. The children&#39;s ride-on vehicle of the present invention is convertible from a training configuration to a more experienced rider configuration. 
       FIG. 1  illustrates a perspective view of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. In the view shown, the children&#39;s ride-on vehicle  100  is configured in a first, stabilized riding position. In the first, stabilized riding position, the rear wheels  150 A,  150 B of the ride-on vehicle  100  are spaced apart on the rear axle in a tricycle configuration. The children&#39;s ride-on vehicle  100  of the present invention includes a seat  110 , a steering assembly  120 , frame members  130 A,  130 B, a front wheel  140 , rear wheels  150 A,  150 B, a crankcase  160 , and a crank/pedal assembly  170 . 
       FIG. 2  illustrates a front view of the children&#39;s ride-on vehicle  100  of  FIG. 1 . As illustrated, in this, the first, stabilized riding position, the rear wheels  150 A,  150 B of the ride-on vehicle  100  are spaced apart on the rear axle in a tricycle configuration.  FIG. 3  illustrates a rear perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 1  in the first, stabilized riding position. As shown, the rear wheels  150 A,  150 B of the ride-on vehicle  100  are spaced apart along the rear axle  300  in a conventional tricycle configuration. In this, first, stabilized riding position, the rear wheels  150 A,  150 B of the ride-on vehicle  100  are also spaced apart (along the rear axle  300 ) from the crankcase  160 . 
       FIG. 4  illustrates a perspective view of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention, with the children&#39;s ride-on vehicle  100  configured in a second, bicycle-like riding configuration. In the second, bicycle-like riding configuration, the two rear wheels  150 A,  150 B of the ride-on vehicle  100  are positioned in close proximity to the crankcase  160  and to each other. This configuration allows a child to experience a riding configuration that is somewhat less stable (more challenging) than the first, stabilized riding position (described above), but is somewhat more stable than a conventional bicycle configuration (with perfectly aligned front and back wheels). 
       FIG. 5  illustrates a front view of the children&#39;s ride-on vehicle  100  of  FIG. 4 .  FIG. 6  illustrates a rear perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 4 . Again, in this, second, bicycle-like riding configuration, the two rear wheels  150 A,  150 B of the ride-on vehicle  100  are positioned in close proximity to the crankcase  160  and to each other. Also, the two rear wheels  150 A,  150 B of the ride-on vehicle  100  are positioned inside of frame members  130 A,  130 B (as opposed to outside of respective frame members  130 A,  130 B as shown in the first, stabilized riding position of  FIGS. 1-3 ). 
       FIG. 7  illustrates an exploded view of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. Although not shown herein, the crankcase  160  includes a chain or belt that connects the pedal sprocket/axle (“crank”) to the sprocket mounted on the rear axle  300 . Thus, when a child pedals the crank, the sprocket mounted on the rear axle  300  is driven by the chain/belt to turn the rear axle  300  and the rear wheels  150 A,  150 B mounted thereto.  FIG. 8  illustrates an exploded view of the crankcase assembly  160  of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. During conversion between its stabilized mode and its bicycle-like mode, the crankcase assembly of the children&#39;s ride-on vehicle  100  pivots relative to frame members  130 A,  130 B while maintaining the pedal crank axle  820  a constant distance from the rear axle  300 . The ability of the crank case assembly  160  to pivot about the pedal crank axle  820  will be discussed below. 
       FIG. 9  illustrates an exploded view of one of the rear wheel assemblies  900  of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. Each rear wheel assembly  900  includes a rear wheel  150 A/ 150 B, a rear wheel hub  930  and a stub axle  910 . Each stub axle  910  includes a flange  920  adapted to mount the stub axle  910  to the rear wheel hub  930  and ultimately to the rear wheel  150 A/ 150 B. 
       FIG. 10  illustrates an exploded view of one of the rear axle bushings  1000  and one of the frame members  130 A of the children&#39;s ride-on vehicle  100  of the present invention. Each rear axle bushing  1000  is attached to one of the frame members  130 A,  130 B and is adapted to rotationally receive the rear axle  300  of the children&#39;s ride-on vehicle  100 . As shown, and as described below, each of the frame members  130 A,  130 B includes a cut-out portion  1010  (notches) which allows the frame members  130 A,  130 B to be rotated with respect to the crankcase assembly  160 .  FIG. 11  illustrates a cut away view showing the attachment of the crankcase  160  to one of the frame members  130 A on a children&#39;s ride-on vehicle  100  of the present invention. 
       FIG. 12  illustrates a perspective view of the attachment of frame members  130 A,  130 B to the crankcase  160  on a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. As shown, each of the frame members  130 A,  130 B includes a slot  1200 A,  1200 B to receive the ends of rear axle  300 . The slots  1200 A,  1200 B also allow the crankcase  160  and rear axle  300  to pivot into an out of engagement with the frame members  130 A,  130 B. As discussed above, the crankcase assembly  160  maintains a constant distance between the pedal crank axle  820  and the rear axle  300 . The crank case assembly  160  pivots about the pedal crank axle  820  during conversion between vehicle modes. Pivoting about the pedal crank axle  820  allows the rear axle  300  to swing toward and away from the frame members  130 A,  130 B so that the rear axle  300  swings into and out of the slots  1200 A,  1200 B of the frame members  130 A,  130 B about the pedal crank axle  820 . 
       FIG. 13  illustrates an exploded view of the front steering assembly  120  of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. The front steering assembly  120  includes front fork  1310  and handlebars  1320 . The front fork  1310  is adapted to receive font wheel  140 . 
       FIG. 14  illustrates an isolated perspective view of the frame members  130 A,  130 B, crankcase  160 , rear axle  300 , and pedal axle (“crank”) of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention.  FIG. 15  illustrates a rear isolated perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 14 . 
       FIG. 16  illustrates a rear isolated perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 14  in a position in which the frame members  130 A,  130 B are rotated away from the crankcase  160  and rear axle  300 . Thus a user can reconfigure the ride-on vehicle  100  from the first, stabilized riding configuration of  FIGS. 1-3  to the second, bicycle-like riding configuration of  FIGS. 4-6  by rotating the frame members  130 A,  130 B away from the crankcase  160  and rear axle  300  and reconfiguring the rear wheel assemblies  900  as described in detail below. 
       FIG. 17  illustrates a rear isolated perspective view of one of the rear wheel assemblies  900  of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention. As mentioned above with respect to  FIG. 9 , the rear wheel assembly  900  includes stub axle  910 . Stub axle  910  includes and orifice  1700  adapted to receive a spring-loaded button (a “valco button”) that is integrated into rear axle  300 .  FIG. 18  illustrates a rear isolated perspective view of one of the rear wheel assemblies  900  in proximity to the crankcase  160  and rear axle  300  of a children&#39;s ride-on vehicle in accordance with an embodiment of the present invention. As illustrated, rear axle  300  includes a spring-loaded button  1810  adapted to mate with orifice  1700  of stub axle  910 . Alternatively, the features of stub axle  910  (orifice  1700 ) could be included on the rear axle  300  and the rear axle  300  (spring-loaded button) features located on the stub axle  910 . 
       FIG. 19  illustrates a rear isolated perspective view of the attachment of one of the rear wheel assemblies  900  to the rear axle of a children&#39;s ride-on vehicle  100 . As shown, spring-loaded button  1810  on rear axle  300  is pressed inward to allow rear axle  300  to slide inside of stub axle  910  until the spring-loaded button  1810  emerges from orifice  1700  to lock the rear wheel assembly  900  and the rear wheel  150 B to the rear axle  300 . Thus, when rear axle  300  rotates, rear wheel  150 B rotates therewith. Also, the receipt of spring-loaded button  1810  into orifice  1700  fixes rear wheel  150 B longitudinally on rear axle  300 .  FIG. 20  illustrates a rear isolated perspective view of one of the rear wheel assemblies  900  attached to the rear axle  300  of a children&#39;s ride-on vehicle  100  in accordance with the present invention, the wheel assembly  900  being longitudinally positioned in the first, stabilized riding position of  FIGS. 1-3 . 
       FIG. 21  illustrates a rear isolated perspective view of one of the rear wheel assemblies  900  attached to the rear axle  300  of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention, the wheel assembly  900  being positioned in the first, stabilized riding configuration (of  FIGS. 1-3 ). In this position, as compared with  FIGS. 16-20 , the frame members  130 A,  130 B have been rotated back downward toward the crankcase  160  and rear axle  300 .  FIG. 22  illustrates a rear isolated perspective view of both of the rear wheel assemblies  900 , the frame members  130 A,  130 B, the crankcase  160 , and the rear axle  300 , of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention, the rear wheel assemblies  900  (including rear wheels  150 A,  150 B) being positioned in the first, stabilized riding position (of  FIGS. 1-3 ) and the frame members  130 A,  130 B rotated back down into position over the rear axle  300 . 
     To transition from the first, stabilized riding configuration (of  FIGS. 1-3 ) to the second, bicycle-like riding configuration (of  FIGS. 4-6 ), the user pivots the frame members  130 A,  130 B away from the crankcase  160  and rear axle  300  and removes the wheel assemblies  900  by depressing the spring-loaded button  1810  on rear axle  300 . The stub axles  910  of the rear wheel assemblies  900  can then be slid off of the rear axle  300 . Next, as illustrated in  FIG. 23 , the rear wheel assembly  900  is rotated 180 degrees from its position shown in  FIG. 18  (i.e., the wheel assembly is reversed with stub axle  910  extending outward). 
     As shown in  FIGS. 23 ,  24 , and  25 , spring-loaded button  1810  on rear axle  300  is pressed inward to allow rear axle  300  to slide inside of stub axle  910  until the spring-loaded button  1810  emerges from orifice  1700  to lock the rear wheel assembly  900  to the rear axle  300 . The other rear wheel assembly  900  (including wheel  150 A) is attached to the other side of rear axle  300  in a likewise manner. This wheel reversal method allows the mounting of the rear wheel assemblies  900  in close proximity to crankcase  160  and to each other. In another embodiment of the present invention (discussed in greater detail below), rear wheels  150 A,  150 B can be permanently connected to the rear axle  300 . In these embodiments, reconfiguration is accomplished by simply sliding wheels  150 A,  150 B along the rear wheel axle  300  which never requires wheel removal from or wheel reversal on the rear axle  300 . 
       FIG. 26  illustrates an isolated perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 25  in a configuration in which the frame members  130 A,  130 B are rotated away from the crankcase  160  and rear axle  300 . Next, as illustrated in  FIG. 27 , the frame members  130  are rotated toward the crankcase  160  and into contact with the rear axle  300  to assume the second, bicycle-like riding configuration.  FIG. 28  illustrates an isolated rear perspective view of the children&#39;s ride-on vehicle  100  of  FIG. 25 , with only one of the rear wheel assemblies  900  (including wheel  150 B) being positioned in the second, bicycle-like riding configuration (with the frame members  130 A,  130 B rotated back into position over the rear axle  300 ).  FIG. 29  illustrates a rear isolated perspective view of both of the rear wheel assemblies  900 , the frame members  130 A,  130 B, the crankcase  160 , and the rear axle  300 , of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention, the rear wheel assemblies  900  being positioned in the second, bicycle-like riding position (of  FIGS. 4-6 ) and the frame members  130 A,  130 B rotated back into position over the rear axle  300 . As shown, in this second position, the rear wheel assemblies  900  are in close proximity to crankcase  160  and to each other. 
       FIG. 30  depicts a drive chain/belt tension adjustment mechanism  3000  in accordance with the present invention. As shown, the chain/belt tension adjustment mechanism  3000  is attached to the pedal bars  3030 . Chain tension adjustment mechanism  3000  comprises a sprocket  830  (shown in  FIGS. 7-8 ) connected to pedal crank axle  820 . The adjustment mechanism also has a top bushing  3020  fixed with respect to the crank case  160  and a selectively positionable bottom bushing  3010  linearly movable with respect the crank case  160 . The bottom bushing  3010  is also configured to be linearly moveable with respect to the fixed top bushing  3020 . As explained with reference to  FIG. 31  below, when the bottom bushing  3010  is moved linearly away from the rear axle  300 , crank axle  820  and crank axle sprocket  830  are also moved away from the rear axle sprocket  840  to tighten the belt or chain on the sprockets  830 ,  840 . 
       FIG. 31  illustrates an isolated close-up perspective view of the chain tension adjustment mechanism  3000  of  FIG. 30 . The bottom bushing  3010  includes elongated openings  3110 . Both fixed top bushing  3020  and selectively positionable bottom bushing  3010  include teeth or interlocking splined portions  3130 . The elongated openings  3110  and interlocking splined portions  3130  allow a user to linearly adjust the bottom bushing  3010  with respect to the fixed top bushing  3020 . Movement of the bottom bushing  3010  toward the front wheel  140  of the children&#39;s ride-on vehicle  100  causes the chain/belt within crank case  160  to be tightened. Movement of the bottom bushing  3010  toward the rear wheels  150 A,  150 B of the children&#39;s ride-on vehicle  100  causes the chain/belt to be loosened. After adjustment, the interlocking spline portions  3130  help maintain the relative position between the top bushing  3020  and the bottom bushing  3010  before fasteners are tightened into bottom openings  3110 . 
     While the invention has so far been described in detail and with reference to one specific embodiment thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. For example, as explained below, the rear wheels  150 A,  150 B may be slidably mounted to the rear axle  300  so that a user could change from the first, stabilized riding configuration of  FIGS. 1-3  to the second, bicycle-like riding configuration of  FIGS. 4-6  by simply pivoting the frame members  130 A,  130 B away from the crankcase  160  and rear axle  300  (shown generally in  FIG. 16  and discussed in greater detail below), and sliding the rear wheels  150  together and then pivoting the frame members  130 A,  130 B toward the crankcase  160  and into engagement with rear axle  300 . In other words, the wheels  150 A,  150 B are pivoted away from the frame members  130 A,  130 B by pivoting the crank case  160 , the rear axle  300 , and the wheels  150 A,  150 B away from frame members  130 A,  130 B. The wheels  150 A,  150 B can then be slid along rear axle  300  without interference from frame members  130 A,  130 B. When the appropriate wheel spacing between wheels  150 A,  150 B has been achieved, the wheels  150 A,  150 B along with the rear axle  300  and crank case  160  are again pivoted toward the frame members  130 A,  130 B and locked into their new configuration. 
     One significant advantage of this additional embodiment described above (where the children&#39;s ride-on vehicle  100  is reconfigured simply by sliding the rear wheels  150 A,  150 B back and forth along the axle  300 ) is that even though the wheels  150 A,  150 B could, if necessary, be removed from rear axle  300 , transformation between riding configurations can be accomplished without removing the wheels  150 A,  150 B from the rear axle  300 . 
       FIG. 32  illustrates a rear isolated bottom view of a children&#39;s ride-on vehicle  100  in accordance with an embodiment of the present invention showing a rear wheel assembly  3200 , frame members  130 A,  130 B and a crankcase  160 , the rear wheel assembly  3200  received and locked in the frame members  130 A,  130 B in the first, stabilized riding configuration (tricycle mode).  FIG. 33  illustrates an enlarged isolated bottom view of one side of the children&#39;s ride-on vehicle  100  of  FIG. 32  showing a close-up view of the rear wheel assembly  3200  locked by respective axle locks  3300 A,  3300 B into one of the slots  1200 A,  1200 B in frame members  130 A,  130 B. Specifically, the rear wheel assembly  3200  includes a rear axle  300 , slide bushings  3335 A,  3335 B and rear wheels  150 A,  150 B slidably mounted on the rear axle  300 . 
       FIG. 32  and  FIG. 33  show slide bushings  3335 A,  3335 B on each end of the rear axle  300 . Each slide bushing  3335 A,  3335 B has corresponding slide surfaces  3340 A,  3340 B surrounding corresponding cores  3370 A,  3370 B. Each core  3370 A,  3370 B has a pair of corresponding flanges  3375 A and  3375 B extending from corresponding ends of the slide surfaces  3340 A,  3340 B. That is,  3370 A includes a pair of flanges  3375 A on each of its linear ends (with the wheel  150 A captured there between). Furthermore, each pair of flanges  3375 A,  3375 B has corresponding flange teeth  3380 A,  3380 B thereon for transferring torque to the wheel  150 A,  150 B. This method of torque transfer will be discussed in more detail below. 
       FIG. 33  shows one of the two rear axle receivers  1210 A,  1210 B of  FIG. 32  that include respective slots  1200 A,  1200 B for receiving the slide surfaces  3340 A,  3340 B of the slide bushings  3335 A,  3335 B and one or the other of the flanges  3375 A,  3375 B of the slide bushings  3335 A,  3335 B. The rear axle receivers  1210 A,  1210 B (mounted at the ends of frame members  130 A,  130 B respectively) also include respective axle locks  3300 A,  3300 B for releasably securing the slide bushings  3335 A,  3335 B of the rear wheel assembly  3200  to the frame members  130 A,  130 B in the slots  1200 A,  1200 B. The axle locks  3300 A,  3300 B include respective slot latches  3320 A,  3320 B that extend across the openings of the slots  1200 A,  1200 B, contacting the slide surfaces  3340 A,  3340 B to retain the slide bushings  3335 A,  3335 B of rear wheel assembly  3200  in the slots  1200 A,  1200 B. The axle locks  3300 A,  3300 B also include respective finger actuators  3310 A,  3310 B that are connected to the slot latches  3320 A,  3220 B for retracting the slot latches  3320 A,  3320 B from the openings in slots  1200 A,  1200 B against the force of a respective springs  3350 A,  3350 B. The finger actuators  3310 A,  3310 B extend from within a cutout  3360 A,  3360 B in the frame members  130 A,  130 B.  FIG. 34  illustrates an enlarged isolated bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 32  showing the axle lock  3300 B of one frame member  130 B being released to permit entry or exit of the rear wheel assembly  3200  from the slot  1200 B in the frame member  130 B. 
     Springs  3350 A,  3350 B normally bias the slot latches  3320 A,  3320 B to extend into the openings of the slots  1200 A,  1200 B to contact the slide surfaces  3340 A,  3340 B and prevent their escape from the slots  1200 A,  1200 B. Furthermore, the ends of the slot latches  3320 A,  3320 B may be tapered so that the slide bushings  3335 A,  3335 B may be inserted into the slots  1200 A,  1200 B (without engaging the finger actuators  3310 A,  3310 B), and locked in the slots  1200 A,  1200 B against removal. In other words, the slot latches  3320 A,  3320 B would be forced back from the opening of the slots  1200 A,  1200 B by pressing the slide surfaces  3340 A,  3340 B against the tapered ends of the slot latches  3320 A,  3320 B to automatically push/retract the slot latches  3320 A,  3320 B from the openings of the slots  1200 A,  1200 B against the force of the springs  3350 A,  3350 B. 
       FIG. 35  illustrates a close-up view of one of the rear axle receivers  1210 A of  FIG. 32  including a slot  1200 A, and an axle lock  3300 .  FIG. 35  also shows the tapered slot latch  3320 A extending into the opening of the slot  1200 A and the bearing surface  3510 A in the slot  1200 A which the slide surface  3340 A contacts.  FIG. 36  illustrates a rear bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 32  showing the rear wheel assembly  3200  pivoted with respect to the frame members  130 A,  130 B and removed from the slots  1200 A,  1200 B.  FIG. 37  illustrates a close-up bottom view of one side of the children&#39;s ride-on vehicle  100  showing slide surface  3340 A of the rear axle assembly removed from slot  1200 A.  FIG. 37  also shows the rear wheel hub  930 A 1  on the slide surface  3340 A and hub teeth  3710 A 1  for engaging flange teeth  3380 A of the slide bushing  3335 A when the children&#39;s ride-on vehicle  100  is configured in the bicycle configuration (discussed further below). Generally, rear wheel  150 A includes wheel hubs  930 A 1  (inside),  930 A 2  (outside) and rear wheel  150 B includes wheel hubs  930 B 1  (inside),  930 B 2  (outside). In addition, each wheel hub  930 A 1 ,  930 A 2 ,  930 B 1 ,  930 B 2  includes respective hub teeth  3710 A 1 ,  3710 A 2 ,  3710 B 1 ,  3710 B 2  for respectively engaging the flange teeth  3380 A, (at either end of slide surface  3340 A) and  3380 B (at either end of slide surface  3340 B) of the slide bushings  3335 A,  3335 B to generate propulsion. Propulsion of the children&#39;s ride-on vehicle  100  will be discussed in greater detail below. 
       FIG. 38  illustrates a bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 32  with the rear wheel assembly  3200  pivoted further with respect to the frame members  130 A,  130 B and removed from slots  1200 A,  1200 B (illustrating the maximum separation from rear axle receivers  1210 A,  1210 B of frame members  130 A,  130 B). In addition,  FIG. 39  illustrates a side view of the children&#39;s ride-on vehicle  100  of  FIG. 38  showing the maximum separation of the rear axle and the wheels  150 A,  150 B from the frame members  130 A,  130 B.  FIG. 39  best shows how the rear axle and the wheels  150 A,  150 B pivots (along with the crank case  160 ) until the wheels  150 A,  150 B have cleared the frame members  130 A,  130 B in the axial direction. After the crank case  160  and wheels  150 A,  150 B have been pivoted away from the frame members  130 A,  130 B and have cleared the frame members  130 A,  130 B, the position of the wheels  150 A,  150 B can be adjusted along the rear axle  300  by sliding the wheels  150 A,  150 B together (into the bicycle configuration) or apart (into the stabilized configuration) by sliding the respective slide bushings  3335 A,  3335 B along the rear axle  300 . 
       FIG. 40  illustrates an enlarged bottom view of one side of the children&#39;s ride-on vehicle  100  of  FIG. 39  showing the separation between the slide bushing  3335 A and the rear axle receiver  1210 A. The wheels  150 A,  150 B of the device are ready to be adjusted along the rear axle  300  from the tricycle arrangement of  FIGS. 38-40  into the bicycle configuration.  FIG. 41  illustrates a bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 38  with the slide bushings  3335 A,  3335 B slid into their inner (bicycle) configuration. Adjustment of the slide bushings  3335 A,  3335 B between the position shown in  FIG. 38  and the position shown in  FIG. 41  is accomplished by holding the slide bushings  3335 A,  3335 B and sliding them toward the crank case  160  along the rear axle  300 . The wheels  150 A,  150 B are also slid inward (toward each other along with their respective slide bushings  3335 A,  3335 B. 
       FIG. 42  illustrates an enlarged bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 41  showing how a wheel  150 A is slid along the slide surface  3340 A toward the middle of the slide bushing  3335 A. In the children&#39;s ride-on vehicle  100 , wheels  150 A,  150 B are respectively mounted slidably on the slide bushings  3335 A,  3335 B so that the inner portions (not shown) of wheel hubs  930 A 1 ,  930 A 2 ,  930 B 1 ,  930 B 2  respectively bear against and slide along slide surfaces  3340 A,  3340 B of the slide bushings  3335 A,  3335 B. In other words, wheels  150 A,  150 B are slidably mounted on the slide bushings  3335 A,  3335 B between the pairs of flanges  3375 A,  3375 B. The slide bushings  3335 A,  3335 B, in turn, are slidably mounted between the ends of the rear axle  300 . Again,  FIG. 42  shows that each end of the slide bushings  3335 A,  3335 B includes respective flanges  3375 A,  3375 B with flange teeth  3380 A,  3380 B thereon for transferring torque to the wheels  150 A,  150 B. Again, the torque transfer will be discussed in greater detail below. 
       FIG. 43  illustrates a rear bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 42  with both slide bushings  3335 A,  3335 B in the bicycle configuration. One wheel  150 A, however, is completely slid inward along the slide bushing  3335 A toward the crank case  160  into the bicycle configuration while the other wheel  150 B remains in an outward position on its respective slide bushing  3335 B. In the configuration of  FIG. 43 , a portion of the slide surface  3340 A of the slide bushing  3335 A is exposed on the outer side of wheel  150 A. The wheel  150 B has not yet been slid inward toward the crank case  160  along the slide surface  3340 B into the bicycle configuration in the same way wheel  150 A has already been positioned.  FIG. 44  illustrates a rear bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 43  with both wheels  150 A,  150 B completely slid together along their respective slide bushings  3335 A,  3335 B toward the crank case  160  into the bicycle configuration. 
       FIG. 44  also shows how, after the wheels  150 A,  150 B have been completely slid together, outer portions of slide bushings  3335 A,  3335 B extend outwardly past the wheels  150 A,  150 B to expose outer portions of slide surfaces  3340 A,  3340 B. The rear axle  300  is dimensioned such that in the configuration of  FIG. 44 , the exposed outer portions of the slide bushings  3335 A,  3335 B are aligned with the slots  1200 A,  1200 B of the rear axle receivers  1210 A,  1210 B. The alignment between the slide bushings  3335 A,  3335 B and the rear axle receivers  1210 A,  1210 B is such that when the rear axle  300 , crank case  160 , and wheels  150 A,  150 B are pivoted back toward the frame members  130 A,  130 B, the slide bushings  3335 A,  3335 B can be received in the slots  1200 A,  1200 B of the rear axle receivers  1210 A,  1210 B and locked by the axle locks  3300 A,  3300 B. 
       FIG. 45  illustrates a rear bottom view of the children&#39;s ride-on vehicle  100  of  FIG. 44  showing the exposed outer portions of the slide bushings  3335 A,  3335 B being repositioned in the slots  1200 A,  1200 B of their respective frame members  130 A,  130 B in the bicycle configuration (where the rear axle  300 , crank case  160 , and wheels  150 A,  150 B have been pivoted all the way back into contact with the frame members  130 A,  130 B).  FIG. 46  illustrates a rear bottom view of the children&#39;s ride-on vehicle  100  of the present invention showing the wheels  150 A,  150 B in the bicycle configuration with the slide bushings  3335 A,  3335 B fully repositioned in their respective slots  1200 A,  1200 B and secured with their respective axle locks  3300 A,  3300 B. 
     The present invention children&#39;s ride-on vehicle  100  is propelled by a rider turning the pedals with their feet. Propulsion force from the rider&#39;s feet is transferred to at least one of the rear wheels  150 A,  150 B in the following manner. The pedals are pivotally connected to a pedal crank axle  820  that is in turn connected to a first pulley or sprocket  830 . The first pulley or sprocket  830  is connected to a belt or chain (not shown) that is linked with and turns a second pulley or sprocket  840  connected to the rear axle  300  to rotate the rear axle  300 .  FIG. 47  illustrates an enlarged perspective view of an extended end of a slide bushing  3335 B of the children&#39;s ride-on vehicle  100  of  FIG. 32  showing the flange  3375 B, flange teeth  3380 B, and a portion of the slide surface  3340 B.  FIG. 48  illustrates an enlarged perspective view of the core  3370 B of the slide bushing  3335 B and the rear axle  300  of the children&#39;s ride-on vehicle  100  of  FIG. 32 . The core  3370 B has an axial opening  4810 B through which the rear axle  300  passes to enable the slide bushing  3335 B to slide along the rear axle  300 . 
       FIG. 49  illustrates a an enlarged view of the rear axle  300  of the children&#39;s ride-on vehicle  100  of the present invention showing the rear axle  300  having radially extending torque projections  4910 B extending from the rear axle  300 . The axial opening  4810 B also has receiving slots  4820 B communicating with the axial opening  4810 B for slidably and axially receiving the torque projections  4910 B of the rear axle  300 . Therefore, when the rear axle  300  turns, the torque projections  4190 B interlock with the receiving slots  4820 B of the core  3370 B to rotate the core  3370 B. The flange teeth  3380 B of the rotating core  3370 B also rotate along with the core  3370 B. Therefore, when a rider turns the pedals the rear axle  300  rotates to rotate the flange teeth  3380 B of the core  3370 B. Torque is then transferred to the wheel  150 B when, for example, the flange teeth  3380 B interlock with the hub teeth  3710 B of wheel hubs  930 B 1 ,  930 B 2  as shown in  FIG. 43 . 
     As the children&#39;s ride-on vehicle  100  of the present invention is transformed between the first, stabilized riding mode (tricycle) and the first, bicycle mode, wheels  150 A,  150 B are driven by different combinations of hub teeth  3710 A and  3710 B with interlocking flange teeth  3380 A and  3380 B. Wheel  150 A for example, as shown in  FIG. 42 , in transitioning to the tricycle mode, is slid away from the crank case  160  such that hub teeth  3710 A (not shown in  FIG. 42 ) on hub  930 A 2  engages with flange teeth  3380 A. On the other hand, as shown in  FIG. 42 , in transition to the bicycle mode, wheel  150 A is slid toward the crank case  160  such that hub teeth  3710 A (not shown in  FIG. 42 ) on the opposite side of wheel  150 A on hub  930 A 1  engage with flange teeth  3380 A on the opposite end of slide surface  3340 A. Wheel  150 B is alternately driven in a similar manner. For example, as shown in  FIG. 44 , wheel  150 B has been slid toward the crank case  160  into the bicycle mode such that hub teeth  3710 B (not shown in  FIG. 44 ) on hub  930 B 1  engage flange teeth  3380 B (not shown in  FIG. 44 , but shown in  FIG. 43 ). Similarly, as shown in  FIG. 44 , wheel  150 B must be slid away from the crank case  160  to the first stabilized riding mode such that hub teeth  3710 B (not shown in  FIG. 44 ) on the opposite side of wheel  150 B on hub  930 B 2  engage flange teeth  3380 B on the opposite end of slide surface  3340 B. 
     In the configurations discussed above, the propulsion mechanism of the children&#39;s ride-on vehicle  100  drives both wheels. However, even though the present invention is capable of operating satisfactorily driving both wheels in the first, stabilized riding mode (tricycle), there are reasons why the ride-on vehicle may operate more efficiently if, for example in the first, stabilized riding mode, only one wheel is driven. When a vehicle turns, generally one rear wheel covers a larger distance than the other rear wheel. If at the same time the wheels are forced, for example, by a mechanical linkage (axle  300 ) to rotate at the same speed, wheel hop may occur in much the same way it occurs in a tight turning 4-wheel drive vehicle. To insure maximum ease of handling the ride-on device of the present invention can include a mechanism for driving both wheels in the bicycle configuration while driving only one wheel in the first, stabilized riding (tricycle) configuration. 
     As discussed above, the ride-on vehicle  100  generally drives both wheels  150 A,  150 B in the first, stabilized (tricycle) riding mode by respective engagement between hub teeth  3710 A and flange teeth  3380 A and between hub teeth  3710 B and flange teeth  3380 B. To eliminate propulsion to one or the other of the wheels  150 A,  150 B, engagement between hub teeth  3710 A and flange teeth  3380 A or engagement between hub teeth  3710 B and flange teeth  3380 B can be eliminated. This disengagement can be accomplished by eliminating any one of hub teeth  3710 A, flange teeth  3380 A, hub teeth  3710 B or flange teeth  3380 B on the outer sides of the wheels  150 A,  150 B. Such elimination would also not interfere with propulsion of both wheels  150 A,  150 B in the bicycle mode because unlike the first, stabilized riding mode, propulsion in bicycle mode involves hub teeth  3710 A, flange teeth  3380 A, hub teeth  3710 B and flange teeth  3380 B on the inner sides of the wheels  150 A,  150 B. 
     Thus, it is intended that the present invention cover the modifications and variations of this invention that come within the scope of the appended claims and their equivalents. For example, it is to be understood that terms such as “left”, “right” “top”, “bottom”, “front”, “rear”, “side”, “height”, “length”, “width”, “upper”, “lower”, “interior”, “exterior”, “inner”, “outer” and the like as may be used herein, merely describe points of reference and do not limit the present invention to any particular orientation or configuration.