Abstract:
A board for balance training has an upper footstep surface, lower bearing surface and a progressive series of concentric, cylindrical sub-frames depending from the lower surface which enclose progressively smaller framed-in areas of the bearing surface within progressively smaller framed-in crown-cavities defined by each. This progressive series ranges extremes of a major in size to minor, with none, one or more intermediates. All at least but the major sub-frame are selectively removable from the board for clearing way for progressively larger framed-in crown-cavities. Any of the sub-frames permit a training ball to roll freely sandwiched between the board and ground unless stopped against any portion of that sub-frame. Selectively utilizing a minor sub-frame over, conversely, exclusion thereof in favor of any of the progressively larger sub-frames, progressively changes the level of difficulty for trainees standing on the upper footstep surface.

Description:
CROSS-REFERENCE TO PROVISIONAL APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 60/618,896, filed Oct. 14, 2004, the specification of which is incorporated herein by this reference. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to balance boards and, more particularly, to balance boards in connection with people involved in balance and fitness training like surfing, wind-surfing, wake boarding or skate boarding. 
     The prior art is replete with balance boards for balancing on balls—or in more difficult terminology, spherical rolling surfaces—with underside bearing surfaces formed as domes. E.g., U.S. Pat. No. 4,191,371—Armer, Jr. An issue with these prior art systems is that when a trainee causes the domed bearing-surface to climb up on the ball on the dome&#39;s periphery, gravity always wants to pull the board down such that the ball finds the high center. 
     It is an object of the invention to overcome these and other shortcomings with the prior art. 
     It is a further object of the invention to provide inserts to progressively make smaller the framed-in area under the board in which the training ball can operate. 
     A number of additional features and objects will be apparent in connection with the following discussion of preferred embodiments and examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the skills of a person having ordinary skill in the art to which the invention pertains. In the drawings, 
         FIG. 1  is a perspective view of a balance training apparatus in accordance with the invention, wherein a trainee is illustrated to show a manner of use; 
         FIG. 2  is an enlarged scale perspective view thereof; 
         FIG. 3  is an exploded bottom perspective view thereof, except including a progressive series of difficulty-changing training balls therefor (i.e., spherical rolling fulcrums); 
         FIG. 4  is an enlarged-scale bottom plan view of the board thereof; 
         FIG. 5  is a section view taken along offset line V-V in  FIG. 4 ; 
         FIG. 6  is a reduced-scale bottom perspective view the  FIGS. 4 and 5  version of the board combined with one selected training ball; 
         FIG. 7  is a bottom perspective view comparable to  FIG. 6  except showing the size of the crown cavity for  FIGS. 4 and 5  version of the board reduced in size by two progressive steps; 
         FIG. 8  is a perspective view comparable to  FIG. 2  except of an alternate embodiment of a board in accordance with the invention; and 
         FIG. 9  is an enlarged-scale bottom plan view of FIG.  8 &#39;s alternate embodiment of the board. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a first embodiment of balance training apparatus  20  in accordance with the invention, with a trainee shown adopting a stance thereon for one non-limiting preferred manner of use thereof. 
       FIG. 3  shows that such balance training apparatus  20  in accordance with the invention comprises a balance board  22  which includes a platform  25  and progressive series of cylindrical sub-frames  32 - 34 . Said balance training apparatus  20  further comprises a progressive series of training balls  42 - 44  or, again, spherical rolling fulcrums. 
     The platform  25  that has an upper footstep surface  52  and a lower bearing surface  54  surrounded by an edge border to be described more particularly below. The progressive series of sub-frames  32 - 34  have a progressive series of cylindrical inside diameters such that a major sub-frame  32  has the largest, a minor sub-frame  34  has the smallest, and an intermediate sub-frame  33  has of course an intermediate cylindrical inside diameter. 
       FIG. 4  shows that the progressive series of sub-frames  32 - 34  preferably nest inside each other as shown with respect to a common center. At least all but the major sub-frame  32  are removable. That is, each sub-frame  32 ,  33  or  34  encircles its own framed-in area of the bearing surface  54  and thereby defines its own framed-in crown cavity. For example, the major sub-frame  32  encircles a major framed-in area of the bearing surface  54  and thereby defines a major framed-in crown-cavity. Hence the minor sub-frame  34  must be removed to exposed all of the area of the bearing surface  54  framed-in by the intermediate sub-frame  33 . Correspondingly, both the minor and intermediate sub-frames  34  and  33  must be removed to expose all of the area of the bearing surface  54  framed-in by the major sub-frame  32 . 
     One non-limiting example of the invention has the platform  25  constructed of plywood about one-and-one quarter inches ( ˜ 3 cm) thick. Likewise the sub-frames  32 - 34  are constructed of plywood, to a thickness of about one-and-three quarters inches ( ˜ 4½ cm) thick.  FIG. 5  shows that all the sub-frames  32 - 34  removably attached by bolts extending up through the sub-frames  32 - 34  to tighten in nut inserts commonly used widely in furniture construction. 
       FIG. 6  shows the balance board  22  affixed with the major sub-frame  32  only and disposed on top of the one the spherical rolling fulcrums (e.g.,  42 ).  FIG. 7  shows the balance board  22  affixed with the minor sub-frame  34 , as well as the intermediate and major sub-frames  33  and  32 , which in this case add little except mass to the dynamics of the balance training apparatus  20 . However,  FIGS. 6 and 7  show very different interaction between the major and minor sub-frames  32  and  34  with this selected training ball  42  (i.e., spherical rolling fulcrum). 
     The following table provides a non-limiting example of relative dimensions for diameters (i.e., O.D. stands for outside diameter, I.D. for inside diameter) that are preferred for the progressive series of sub-frames  32 - 34  and training balls  42 - 44 . 
                                     TABLE               FRAMES   O.D.   I.D.   BALLS   O.D.                   major   15½″   12½″ ({tilde over ( )}32 cm)   major   7″ ({tilde over ( )}18 cm)           ({tilde over ( )}40 cm)       inter-   12½″   9½″ ({tilde over ( )}24 cm)   intermediate   5″ ({tilde over ( )}13 cm)       mediate   ({tilde over ( )}32 cm)       minor   9½″   6½″ ({tilde over ( )}16 cm)   minor   2½″ ({tilde over ( )}6 cm)           ({tilde over ( )}24 cm)                    
It can be observed that the largest training ball  42  is larger than the inside diameter defined by the smallest sub-frame  34 .
 
     In use, the selected spherical rolling fulcrum  42 ,  43  or  44  is crowned by the platform  25  within the selected sub-frame  32 ,  33  or  34  such that the spherical rolling fulcrum  42 ,  43  or  44  is sandwiched between a ground surface and platform  25 . Moreover, the spherical rolling fulcrum  42 ,  43  or  44  is hemmed-in by the selected sub-frame  32 ,  33  or  34  in order to corresponding confine its interaction with only the area of the bearing surface  54  framed-in by that selected sub-frame  32 ,  33  or  34  (or the respective crown-cavity thereof). 
     It is a generally true rule that the spherical rolling fulcrum  42 ,  43  or  44  is free to roll sandwiched between the platform  25  and ground surface unless stopped against any portion of the selected sub-frame  32 ,  33  or  34 . However,  FIGS. 6 and 7  show very different results from application of the foregoing rule. That is, in  FIG. 7 , the spherical rolling fulcrum  42  has an outside diameter greater than the minor sub-frame  34 &#39;s cylindrical inside diameter. Indeed, the minor sub-frame  34  and spherical rolling fulcrum  42  are cooperatively sized such that the minor sub-frame  34  frictionally grips a circle on the spherical rolling fulcrum  42 . This frictional gripping stops virtually any possibility of the spherical rolling fulcrum  42  from being able to roll in the minor framed-in area of the bearing surface  54 . Accordingly, this limits the platform  25 &#39;s movement relative to the ground surface to teetering and twirling. Teetering is rocking about a horizontal axis as achieved by pumping legs up and down in alternation of each other (with balance of course). Twirling is spinning about a vertical axis and is more likely achieved by twist in the torso. 
     Preferably, at least the major and intermediate spherical rolling fulcrums  42  and  43  are inflatable. More preferential still is to utilize novelty soccer or basketballs which are commonly available in many reduced sized compared to regulation balls used in professional sports. It is an option to provide the balance training apparatus  20  in accordance with the invention with a manual air pump as well (not shown), with an inflation needle. Inflation of the training balls  42  and  43  is achieved with the air pump, whereas deflation is best practiced by disconnecting the needle and leaking out inflated air until the training ball  42  or  43  reaches the desired level of inflation. 
     Consequently, is an aspect of the invention that the major training ball  42  is selectively inflatable to a selected inflation pressure in order to obtain an optimized frictional grip between the minor sub-frame  34  and major training ball  42  (i.e., major spherical rolling fulcrum). 
     To turn now to  FIG. 6 , here the major sub-frame  32  is expansively larger than the selected spherical rolling fulcrum  42 &#39;s outside diameter. Therefore, utilizing the major sub-frame  32  to the exclusion of the progressively smaller sub-frames  33  or  34  frees up the chances of relative rolling between the spherical rolling fulcrum  42  and major framed-in area of the bearing surface  54 , unless and until stopped by abutment against the major sub-frame  32 . In consequence, this arrangement of things allows the platform  25 &#39;s possible movement relative the to the ground to include translation as well as teetering and twirling. Translation is linear displacement along the ground (e.g., from one spot to another, but not necessarily in a straight line). It may be readily reckoned that there is only a limited extent of linear displacement possible before the training ball  42  limits out against the major sub-frame  32 . Nevertheless, the training dynamic between the  FIG. 7  arrangement of things and the  FIG. 6  one is readily apparent. 
     The foregoing is highly desirable because this variability in the balance training apparatus  20  in accordance with the invention provides trainees with an indeterminate number of levels of training difficulty. 
     To turn to matters of the platform  25 &#39;s planform, and its edge border, the drawings show that the platform  25  has spaced cantilevered shoulders  60  projecting oppositely beyond over not only the minor sub-frame  34  but also the major sub-frame  32 . The continuations of the upper footstep surface  52  over to the shoulders  60  are fashioned with grip areas which are intended to encourage trainees to adopt a preferred stance on the platform  25 . Their feet preferably would be planted on the grip areas, with legs straddling the center of the sub-frames  32 - 34  (e.g., the center of geometry of the platform  25  too).  FIG. 1  provides illustration of one such preferred stance and/or manner of training. 
     Generally each shoulder  60  extends in a plane generally between spaced parallel sides  62  and a transverse end  64 . However, the each shoulder  60  further comprises a pair of spaced diagonal edges  66 , and these originate in the parallel sides  62  of the respective shoulder  60  and terminate in the transverse end  64 . That way, these diagonal edges  66  eliminate sharp corners between the sides  62  and transverse end  64 . Accordingly, trainees more safely ground out the platform  25  on the diagonal edges  66  on the ground surface than if there were sharp corners. Grounding out is considered a wipe out because if such were done in reality on a wake board, surf board, snow board or whatever, surely then the rider would have wiped out (fallen, wrecked). Conversely, stepping off the grip areas and tromping on the flanked center in order to keep one&#39;s balance is, while perhaps bad form, not always going to correspond with wiping out. In reality, perhaps such would have corresponded to some chance of recovery. 
       FIGS. 8 and 9  show an alternate embodiment of the platform  125  in accordance with the invention, one with narrower shoulders  60  and more simulative of a surfing experience on a surf board or the like. 
     Other matters in view of this description of the invention include a remark on what has been described here for convenience in this written description as the ground surface. The ground surface can be anything base support surface (planar or not, flat or not), including without limitation outdoor pavement, indoor tiled or carpeted or hard/soft wood floors, beach-side boardwalks, or perhaps even compacted beach sand. However, the ground surface can greatly affect the training dynamics of the balance training apparatus  20  in accordance with the invention. Needless to say, smooth pavement will provide harder experience than shag carpet, which is where perhaps novices should start. 
     Whereas preferably the major and intermediate training balls  42  and  43  are inflatable, it is correspondingly preferred if the minor training ball  44  has a solid construction of a suitable polymeric or resinous material. 
     Wherein preferably the framed-in areas of the bearing surface  54  are flat, because the training experience is totally different, the invention does not exclude a domed bearing surface (this is not illustrated). Since it is preferred to make the bearing surface  54  flat, it is a significant aspect of the invention that trainees can train first with a minor sub-frame  34  and a frictionally-captured major-size training ball  42  before progressively advancing to more difficult combinations. In the more difficult combinations of, say for example, the major sub-frame  32  and the major training ball  42  inflated hard, when a wipe out is about to occur at least the training ball  42  (or  43  and/or  44  for that matter) stops against the major sub-frame  32  to more safely terminate the failed training experience than if the sub-frame  32  (or  33  and/or  34  for that matter) were not there at all. 
     The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.