Abstract:
Personal transportation devices having at least first and second foot platform units that are each fore-aft self-balancing. Various connector structures are disclosed that permit movement and/or positioning of the foot platform units at difference distances or spacings from one another. The spacing may be releaseably set or free moving or other. The connecting structure may maintain a parallel relationship between the two foot platform units, in the line of direction of travel of the device. The foot platform units may move laterally or longitudinally or both, depending on the embodiment, from one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/247,757, filed Oct. 29, 2015, entitled Self-Balancing Vehicle with Separatable Balancing Modules and having the same inventor as above, and U.S. Provisional Application No. 62/292,825, filed Feb. 8, 2016, entitled Self-Balancing Vehicle with Changeable Relative Position of Foot Placement Sections and having the same inventor as above. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to fore-aft self-balancing transportation devices that include two independently movable platform sections, one each for the right and left foot of a rider. 
       BACKGROUND OF THE INVENTION 
       [0003]    The prior art includes U.S. Pat. No. 8,738,278 issued to Shane Chen (the inventor herein) for a Two-Wheel, Self-Balancing Vehicle with Independently Movable Foot Placement Sections. This patent is hereby incorporated by reference as though disclosed in its entirety herein. The &#39;278 patent teaches fore-aft self-balancing of two independently movable (i.e., fore-aft rotatable) foot platforms, as well as drive motors, control circuitry, and other components for operation of such a device. 
         [0004]    In the &#39;278 patent, the two wheels are maintained in a fixed position relative to one another. They do not move laterally (to the side) relative to one another and they do not move longitudinally (in the direction of travel) relative to one another. 
         [0005]    To accommodate different riding preferences (a wider or narrower stance, for example) and to increase the variety of riding experiences, there is a need for the lateral distance between the foot platforms to be adjustable and/or variable. 
         [0006]    Furthermore, if there is a “bump” in a pathway, it is generally easier to ride over it if one wheel encounters it first, rather than both at the same time. In the device of the &#39;278 patent, bumps or dips, such as pronounced sidewalk seams or items laid across a sidewalk (i.e., garden hose, steel construction plates, etc.), are contacted by both wheels at the same time. This tends to cause a rider to be thrown forward off the platforms. If by contrast, one wheel could be extended forward, crossing is easier because a rider can shift his/her weight to the stable foot (the one not immediately encountering the obstacle), allowing the less weighted foot/leg to absorb or avoid the shock of the collision. Once over the obstacle, the rider can transfer weight to that forward foot allowing the rear foot to be less weighted when it contact the obstacle. Thus, there is a need, in a two foot platform self-balancing device where there is at least one wheel associated with each foot platform, to be able to move one foot platform forward or rearward (in the line of direction of travel) relative to the other. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, it is an object of the present invention to provide a self-balancing personal transportation device where the lateral distance between the foot platform units is changeable. 
         [0008]    It is another object of the present invention to provide a self-balancing personal transportation device where the longitudinal distance (i.e., in the line of direction of travel) between the foot platform units is changeable. 
         [0009]    It is also an object of the present invention to improve or enhance the riding experience in a self-balancing personal transportation device having two foot platform units and to make overcoming an obstacle in a pathway easier. 
         [0010]    These and related objects of the present invention are achieved by use of a self-balancing vehicle with adjustable or movable positioning of foot platforms as described herein. The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIGS. 1-2  are perspective views of a first embodiment of a self-balancing transportation device with movable foot platform units, the platform units in the extended position. 
           [0012]      FIGS. 3-4  are views of the transportation device of  FIGS. 1-2  yet with the foot platform units in a contracted or stowage position. 
           [0013]      FIGS. 5-7  illustrate another embodiment of a self-balancing transportation device with movable foot platform units. 
           [0014]      FIG. 8  is a plan view of yet another embodiment of a self-balancing transportation device with movable foot platform units. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIGS. 1-4 , a first embodiment of a transportation device  10  with adjustable position foot platform units in accordance with the present invention is shown. 
         [0016]    Device  10  may include two foot platforms units  20 , 40  that receive the left and right foot of a user, respectively. The foot platform units (“FPUs”) may be constructed in similar fashion and include the same or similar components. They are each independently fore-aft self-balancing (like the two platform sections of the &#39;278 patent) and include suitable components to achieve this function. These components may include a position (i.e., gyroscopic) sensor, battery, drive motor and control circuitry. The control circuitry instructs the motor to drive the wheel towards FPU balancing based on position data from the sensor. Suitable self-balancing components and arrangements are known in the art. 
         [0017]    In  FIG. 2 , the sensor  31 , 51 , battery  32 , 52  and control circuitry  34 , 54  are shown in phantom lines because they are within housing  24 , 44 , respectively. The drive motor  36 , 56  is preferably a hub motor within wheel  26 , 46 , respectively. 
         [0018]    Each FPU may include a foot platform  22 , 42  and housing  24 , 44 . Platform side walls  25  (shown in  FIG. 1  in phantom lines) may extend upwardly from the outside and/or inside edges of the platforms. These sidewalls help to position a user&#39;s foot and to permit a user to exert a lateral force to slide the FPUs towards or away from one another. While sidewalls are only shown on FPU  20 , the sidewalls may also be provided with FPU  40 . Housing  24 , 44  supports the platforms  22 , 42 , houses the self-balancing components, and may provide internal structural support. 
         [0019]    A connector or connecting structure  50  is preferably provided between the two foot platform units. Connector  50  may have a shaft or rod like configuration and is preferably telescoping or the like such that FPUs  20 , 40  can be moved from an extended position (shown in  FIGS. 1-2 ) to a contracted position (shown in  FIGS. 3-4 ), and vice versa. Connector  50  may include a main rod  51  and two retractable sheaths  52 , 54 . In  FIGS. 3-4 , rod  51  has penetrated into a complementary space within the two housings, as have the retractable sheaths. 
         [0020]    The connector  50  may be configured such that the FPUs may be positioned at a desired lateral distance from one another and the connector releasably secure in that position with the FPUs at the distance. A rotating latch or biased pins or expanding rotary wedge or other suitable mechanism (known in the art) may be used to releasable set a desired spacing. The connector may also be configured such that the FPUs are not set at a fixed distance and a rider can expand and reduce the FPU spacing during use by exerting an outward or inward force through his or her feet. 
         [0021]    In the embodiment of  FIGS. 1-4 , the axis of rotation of wheels  26 , 46  is preferably co-linear. Furthermore, in a preferred embodiment, the axis of connector  50  is preferably co-linear with the axis of the wheels  26 , 46 . 
         [0022]    Further, since each FPU is independently tiltable (in fore-aft), turning is achieved by the rider leaning forward or backward on one FPU more than the other, in the same way that devices of the &#39;287 patent turn. 
         [0023]    It should also recognized that connector  50  may be configured such that rod  51  is releasable decouplable from the FPUs to minimize size for stowage or to allow the FPUs to be operated individually without a connector. 
         [0024]    Referring to  FIGS. 5-7 , another embodiment of a transportation device  110  in accordance with the present invention is shown. Device  110  includes two self-balancing FPUs  120 , 140  that may be the same or similar to FPUs  20 , 40  of device  10 . The FPUs of device  110  preferably include similar components such as a battery, position sensor, control circuitry and drive motor (hub based or otherwise). 
         [0025]    In device  110 , the connecting structure  150  is preferably configured such that it maintains a parallel relationship between the FPUs, while permitting one FPU to be moved forward or backward longitudinally relative to the other FPU. In the embodiment of  FIGS. 5-7 , the connection structure  150  also permits the FPUs to be independently fore-aft rotated to achieve turning of the device. 
         [0026]    For example, in  FIGS. 5-7 , device  110  has three rods (or elongated members)  161 - 163  that extend between the FPUs and are pivotally coupled (through pivots  171 ) to plates  165 , 166  which are secured to FPUs  120 , 140 , respectively. Support or frame members  168  preferably hold rods  161 - 163  at a fixed spacing from one another. Rods  161 - 163  are preferably sufficiently strong to maintain the parallel relationship of the FPUs, yet sufficiently flexible that the FPUs may rotate in fore-aft relative to each other. Steel or strong plastic or other materials may be suitable for this. In such a configuration, the plates  165 , 166  are non-rotatably coupled to their respective FPUs and rotation comes from the flexibility of the connector rod material. 
         [0027]    It should be noted that the number of connector rods  161 - 163  could vary as long as the strength and flexibility characteristics are maintained to allow a substantially parallel FPU relationship and independent fore-aft rotation. Furthermore, it should be noted that in place of the mildly flexible, parallel-position maintaining structure of  FIGS. 5-7 , connector  150  could be implemented with a torsion bar or the like that possesses both sufficient rigidity and flexibility (particularly directional flexibility). A suitable torsional bar is described in U.S. Pat. No. 8,157,274 entitled Torsional Flexible Connecting Structure for Transporting Device, by Chen. 
         [0028]    Referring to  FIG. 7 , in the embodiment of device  110  described above, plate  166  is non-rotatably mounted to FPU  140 . In an alternative embodiment, the connecting, parallel-position maintaining rods  161 - 163  could be made of a more rigid/less flexible material and plates  165 , 166  could be rotatably mounted to the FPUs. For example, the plates could be mounted about a central pivot  169 . This would allow the FPUs to rotate fore-aft relative to one another, and move forward and backward longitudinally, while maintaining the parallel relationship of the FPUs. Pivot  169  is preferably both equidistant from rods  161 - 163  and co-linear with the axis of the wheels  126 , 146 . 
         [0029]    Referring to  FIG. 8 , top plan view of yet another embodiment of a transportation device  210  in accordance with the present invention is shown. Device  210  is similar to that of devices  10 , 110  discussed above and includes FPUs  220 , 240  that function in the same or similar manner. 
         [0030]    The FPUs preferably have sidewalls  225 , 245  discussed above with reference to  FIG. 1 .  FIG. 8  discloses a connector structure  250  that preferably maintains the FPUs in a parallel arrangement and permits fore-aft rotation and longitudinal movement of the FPUs relative to one another (as was the case with device  110 ). Device  210  also provides telescoping of connector  250  so that the distance between the FPUs can be altered, either on the fly or set to a desired spacing. 
         [0031]    In one embodiment of device  210 , the distance between the FPUs is biased by a spring internal to connector  250  to a minimum distance. However, if the rider sees a bump coming in the path, the rider may exert an outward (lateral) pressure on the FPUs to increase the distance between them (applying force opposite the contracting spring) and then place one FPU in front of the other so that the wheels  226 , 246  of the FPUs contact the obstacle in series rather that in parallel, which is a more stable manner in which to ride over an obstacle. Sidewalls  225 , 245  assist with foot-supplied application of lateral force. 
         [0032]    In another embodiment of device  220 , the connector  250  may have no bias spring and be configured to allow rider controlled sliding of the telescoping connector  250  while riding (to enhance the riding experience). In yet another embodiment, the telescoping connector  250  may be configured such that the spacing between the FPUs may be user selected and released secured at a desired spacing. 
         [0033]    Connector  250  may include the housing shown  FIG. 8  which house multiple (at least a pair) of connecting shafts that are each telescoping and to the same amount (to maintain parallel FPU alignment). The FPUs may be pivotally connected (through a pivot similar to  169  or the like) to connector  250  to achieve independent fore-aft rotation of the FPUs. 
         [0034]    While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.