Abstract:
A self-balancing transportation device having improved shock absorbing ability and operation. Several embodiments are disclosed including a single wheel or wheel structure device with foot platforms disposed for angular movement about an axis of rotation that is non-collinear with the axis of rotation of the drive wheel. Single and multiple wheel devices are disclosed as well as devices having independently movable foot platforms, and devices having load platforms that rotate independently and are movable longitudinally with respect to one another, among other embodiments.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of provisional application No. 62/309,935, filed Mar. 17, 2016, for an Angular Suspension System for Self-Balancing Vehicles by the inventor herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to self-balancing transportation devices and, more specifically, to suspension in such devices. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various prior art self-balancing devices are known. They include the Segway (disclosed in U.S. Pat. No. 6,302,230, among others), the Hovertrax or hoverboard (disclosed in U.S. Pat. No. 8,738,278), and the Solowheel (disclosed in U.S. Pat. No. 8,807,250). These devices contribute to the art of fore-aft self-balancing vehicles and are hereby incorporated by reference. 
         [0004]    A problem exists in providing suspension in these devices. Conventional suspension, for example, a typical automobile suspension system, involves a vertical shaft and a spring the biases against depression of the vertical shaft. There is a certain amount of horizontal displacement with this up-down movement of the vertical shaft and spring. This movement is inconsequential for the function of vertical suspension, but it is consequential with respect to shifting force and/or weight horizontally. 
         [0005]    Since device driving and control in a self-balancing device depends on fore-aft weight distribution, subtle weight or force changes horizontally, i.e., fore-aft, will influence the control and driving of the vehicle. 
         [0006]    Thus, a need exists to provide appropriate, effective and cost-efficient suspension in self-balancing vehicles. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, it is an object of the present invention to overcome the shortcomings of the prior art. 
         [0008]    It is another object of the present invention to provide a self-balancing transportation device with enhanced suspension. 
         [0009]    It is also an object of the present invention to provide a self-balancing transportation device with rotational and/or angular displacement of the load support surface when a shock inducing force is applied to the device. 
         [0010]    These and related objects of the present invention are achieved by use of a self-balancing transportation device with angular movement of foot platform as described herein. 
         [0011]    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 
         [0012]      FIG. 1  is a perspective view of a self-balancing transportation device having suspension in accordance with the present invention. 
           [0013]      FIGS. 2-3  are perspectives view of another embodiment of a self-balancing transportation device with suspension in accordance with the present invention. 
           [0014]      FIGS. 4-5  are also perspectives view of another embodiment of a self-balancing transportation device with suspension in accordance with the present invention. 
           [0015]      FIGS. 6-7  are perspectives view of yet another embodiment of a self-balancing transportation device with suspension in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring to  FIG. 1 , a perspective view of one embodiment of a self-balancing transportation device  10  with suspension in accordance with the present invention is shown. 
         [0017]    Device  10  preferably includes a wheel  11  having a tire  14  mounted on rim  15 , and two foot platforms  20 , 30  located on opposite sides of the wheel and rigidly connected to each other by platform coupling member  42 . Device  10  is configured for self-balancing operation. A position sensor  16 , preferably a gyroscopic sensor and/or accelerometer, may be provided on or in the foot platforms. The self-balancing system may include position sensor  16 , an electronic control circuit, a battery and a drive motor  12 . The battery and control circuit may be located on the wheel frame and/or within the wheel housing or within the foot platforms or otherwise situated. These components and their use and implementation are known in the art. 
         [0018]    Device  10  preferably has two platform attachment arms  21 , 31  (only  21  is visible in the perspective of  FIG. 1 , yet  31  is symmetrically arranged with  21 ) that are fixedly coupled to a shaft upon which wheel  11  rotates. In the orientation of  FIG. 1 , these arms extend forward and downward from the center of wheel  11  (i.e., from the axis of rotation of the wheel). Foot platforms  20 , 30  are preferably coupled near the end of arms  21 , 31 , respectively. 
         [0019]    The foot platforms  20 , 30  are preferably coupled to their respective arms with a shaft and torsion spring assembly  25 . This assembly provides lateral support along the front of the foot platform while allowing the platform to rotate along axis  50  when a sufficient force is applied counter to the torsion spring. This rotation provides suspension and, accordingly, the strength of the torsion spring may be selected with the weight range of an intended rider in mind (child, adult, etc). The spring strength is preferably sufficient to provide a secure, predictable platform position to a rider, while also allowing shock absorbing movement when an external potentially destabilizing force is applied to the wheel. 
         [0020]    The device&#39;s self-balancing systems maintain a substantially level orientation of the foot platforms relative to horizontal, while the foot platforms undergo angular movement relative to the wheel. The angular platform movement provides suspension without the horizontal or fore-aft play associated with vertical suspension, thus delivering better operator control of the device. 
         [0021]    While  FIG. 1  illustrates platform arms  21 , 31  extending forward, thus positioning axis  50  forward of the axis of rotation of wheel  11 , alternatively, axis  50  (and hence the orientation of arms  21 , 31 ) may be positioned rearward of the axis of wheel  11 . Axis  50  and the axis of rotation of wheel  11  are preferably parallel to one another. 
         [0022]    Referring to  FIGS. 2-3 , perspectives view of another embodiment of a self-balancing transportation device  110  with suspension in accordance with the present invention is shown. 
         [0023]    Device  110  includes a wheel  111  and two foot platforms  120 , 130  located on opposite sides of the wheel. A housing  118  may cover portions of wheel  111 . Foot platforms  120 , 130  are preferably coupled to the housing/frame at pivot  156 . The platforms and pivot are preferably configured such that the platforms rotate about axis  150 . Coupling member  142  may fixedly connect the two platform sections and be situated above coil spring  125  that provides suspension. 
         [0024]    A bottom housing section  119  may be located below the platforms. This housing may encase the drive motor, battery and a control circuit. Position sensor  116  is provided on or in platforms  120 , 130  or in a part of the vehicle not movable relative to platforms  120 ,  130  as discussed above for device  10 . 
         [0025]    Axis  150  is preferably below the axis of rotation of wheel  111 . While axis  150  is shown forward of (to the right) and below the axis of wheel rotation, it may alternatively be place rearward. 
         [0026]      FIG. 2  discloses leg contact member  161 . These may be forms, pads or other structure/materials that provide cushion, positioning and/or enhance friction, or other, to a rider&#39;s lower leg. Indicator and/or pathway lights  163  may also be provided. Leg contact members and lights are known in the art. 
         [0027]      FIG. 3  illustrates device  110  yet with the bottom housing removed or compressed and a movable leg contact support  145  mounted to the platforms and arranged to move with the platforms during a suspension event. In this manner, contact of the rider&#39;s lower legs with the leg contact members is not significantly altered by a shock force. 
         [0028]      FIGS. 1-3  illustrate single wheel devices. It should be recognized that while one tire  14  is shown on rim  15 , two or more tires (providing, for example, enhance lateral stability) could be provided on rim  15  or on multiple rims that are coupled together. These arrangements may be referred to as a “single wheel structure” because although there is more than one tire, they operate similar to a single wheel, for example, similar to a single wheel with a wider tire. 
         [0029]    It should also be recognized that position sensor(s) could detect side-to-side tilt. This measure may be used to affect the driving of wheel  11 , 111 , for example, reducing speed as a rider leans into a turn, etc. 
         [0030]    It should further be noted that different drive motor arrangements may be used without departing from the present invention. For device  10  of  FIG. 1 , a hub motor may be a suitable motor, while for device  110  of  FIG. 2 , a friction-drive motor (located below the foot platforms) or other motor may be used. Various motor arrangements are known in the art. 
         [0031]    Referring to  FIGS. 4-5 , perspective views of another embodiment of a self-balancing transportation device  210  with suspension in accordance with the present invention are shown. 
         [0032]    Device  210  preferably includes two wheels  211  that may be configured in the same or similar manner as wheel of  FIG. 1 . Accordingly, wheels  211  include a motor, position sensor, electronic control circuit (separate or shared) and a battery (separate or shared). Each wheel preferably has an associated platform  220 , 230  and each platform is coupled through an attachment arm  221 , 231 , respectively. These components are preferably configured as their counterparts in wheel  11 . Thus, arms  221 , 232  extend forward of the axis of rotation  251  of the wheel and couple through a shaft and torsion spring assembly  225  to their respective platforms. The shaft and torsion spring assembly establishes an axis of rotation  250  for each foot platform. 
         [0033]    A connecting rod or shaft  242  preferably joins the two foot platforms  220 , 230  in a manner that maintains a coaxial relationship and provides fore-aft rotation of the individual foot platforms. Connecting rod  242  may also serve as a handle. 
         [0034]    With two independently movable foot platforms, a rider may turn device  210  by applying more drive (i.e., platform rotation) to one wheel, and spin device  210  by applying opposing forces, as is the case with devices of the &#39;278 patent discussed above. 
         [0035]      FIGS. 4-5  illustrate more forward lean on platform  220 .  FIGS. 4-5  also illustrate a relationship of the platform axes of rotation  250  and the wheel axes of rotation  251 . Again, the platform axis is preferably forward or rearward of the wheel axis, and axis  250  and axis  251  are preferably arranged in parallel. 
         [0036]    Referring to  FIGS. 6-7 , perspective views of yet another embodiment of a self-balancing transportation device  310  with suspension in accordance with the present invention are shown. Device  310  includes wheels  311 , foot platforms  320 , 330  and attachment arms  321 , 331  arranged similar to that of device  10  and  210 . Device  310 , however, includes supplemental coupling arms  322  and a joining or bridge member  345 . 
         [0037]    Supplemental coupling arms  322 , 332  and bridge members are preferably arranged to maintain a substantially parallel relationship between the wheel and foot platforms, yet permit them to move fore-aft relative to one another such that a rider may “push” or “slide” one wheel forward of the other, thereby adding to the riding experience and permitting, for example, cracks in a pathway (such as typical sidewalk recesses) to be encountered one wheel at a time, which is far less de-stabilizing than both wheels at the same time, among other benefits. 
         [0038]    Joining or bridge member  345  may also serve as a handle. 
         [0039]    In any of the above embodiments, the spring(s) may be damped to absorb shock. Damping may be achieved using methods known in the art, such as by incorporating hydraulics or by adding low-rebound materials to the spring system. 
         [0040]    While taught in devices have two foot platforms (one each for the right and left foot), the present invention may also be practiced in a self-balancing device having one platform used by both feet or in a seated or otherwise arranged self-balancing device. Important elements include an axis of angular movement or rotation for the platform or structure that bears the majority of the load (rider and/or cargo) that is space from the axis of rotation of the wheel(s). 
         [0041]    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.