Patent Document

CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/574,862, filed May 27, 2004, and which is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD  
       [0002]     This invention relates to hang glider wheels that include a hub with a noncircular aperture for attachment to a member having a noncircular cross section.  
       BACKGROUND OF THE INVENTION  
       [0003]     Hang gliders typically include a basetube. The basetube is typically the lowest horizontal bar on a hang glider. The basetube is typically part of a “control bar” that extends downward from a hang glider wing. In flight, the basetube is the preferred place for the hands of the pilot who is controlling the hang glider.  
         [0004]     The prior art includes cylindrical basetubes, i.e., tubular structures with a circular cross-section. Cylindrical basetubes are typically straight, although “speedbar”-style basetubes have become common, where the basetube is bent in gentle curves (usually fore and aft) to allow the hands and wrists a more comfortable, ergonomic grasp. The curves of a “speedbar” basetube are not unlike the curves of a “curling bar” in weight lifting, which similarly improve the alignment of the hands and wrists when using the bar for leverage.  
         [0005]     A cylindrical basetube may be equipped with wheels. The wheels allow the hang glider to roll instead of lurching to a stop when the glider is dropped to the ground by a pilot during landing. The wheels also allow the glider to be rolled from one place to another without the need to lift and carry it.  
         [0006]     Basetubes that are airfoil shaped, instead of circular in cross section, improve hang glider performance compared to cylindrical basetubes.  
       SUMMARY OF THE INVENTION  
       [0007]     An apparatus for a hang glider control bar basetube having a noncircular cross sectional shape is provided. The apparatus includes a wheel hub having an inner surface that defines a noncircular aperture sufficiently sized and shaped to circumscribe the basetube for nonrotatably mounting the hub to the basetube. A wheel is rotatable about the periphery of the hub so that the basetube functions as an axle for the wheel. The hub thus functions as an adapter to enable a wheel to rotate about a member having a noncircular cross section. In a preferred embodiment, the noncircular aperture is substantially airfoil-shaped to conform to the exterior surface of a basetube having an airfoil-shaped cross section.  
         [0008]     In a preferred embodiment, the hub has a selectively variable opening extending from the periphery of the hub to the aperture to facilitate installation of the hub to the basetube.  
         [0009]     The above features and advantages, and other features and advantages, of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a schematic perspective view of a hang glider;  
         [0011]      FIG. 2  is a schematic perspective view of the basetube of the hang glider of  FIG. 1  with a hub and wheel operatively connected thereto;  
         [0012]      FIG. 3  is a schematic side view of the hub of  FIG. 2 ;  
         [0013]      FIG. 3   a  is a schematic side view of another hub for use with the basetube of  FIG. 2 ;  
         [0014]      FIG. 4  is a schematic perspective view of an unassembled wheel;  
         [0015]      FIG. 5  is a schematic perspective view of the hub of  FIG. 3   a  with a wheel subcomponent engaged therewith;  
         [0016]      FIG. 6  is another schematic perspective view of the hub and wheel subcomponent of  FIG. 5 ; and  
         [0017]      FIG. 7  is a schematic perspective view of an alternative wheel hub configuration. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Referring to  FIG. 1 , a hang glider  8  is schematically depicted. Exemplary hang glider construction is disclosed in U.S. Pat. No. 3,995,799, issued Dec. 7, 1976 to Bartolini, and U.S. Pat. No. 4,116,407, issued Sep. 26, 1978 to Murray, each of which is hereby incorporated by reference in its entirety. The hang glider  8  includes a wing  9  and a triangular control bar  11  that extends downward from the wing  9 . A basetube  10  forms the generally horizontal base of the control bar  11 . Although a triangular control bar is depicted in  FIG. 1 , a control bar of any shape may be employed within the scope of the claimed invention. The basetube  10  is characterized by an airfoil cross-sectional shape. The basetube  10  may be integrally formed with the control bar  11 , may be connected to the rest of the control bar  11  via releasable fasteners, etc.  
         [0019]     Referring to  FIG. 2 , wherein like reference numbers refer to like components from  FIG. 1 , a wheel apparatus  14  includes a hub  18 A and a wheel  22 . The hub  18 A is nonrotatably mounted to the basetube  10 . The hub  18 A rotatably supports and retains the wheel  22  at the periphery of the hub  18 A. The basetube  10  functions as an axle for the wheel apparatus  14 , and is at least partially coextensive with the axis of rotation of the wheel  22 . The hub  18 A includes a generally circular periphery  26 , as shown in  FIG. 3 . An inner surface  30 A defines a generally airfoil-shaped interior aperture  32 A that substantially conforms to the exterior contour of the basetube  10 . The hub  18 A has a variable opening  34  extending from the inner surface  30 A to the periphery  26  to receive the basetube  10  into the aperture  32 A, as shown in  FIG. 2 . The hub  18 A includes a living hinge  38  about which a first portion  42 A of the hub  18 A is pivotable with respect to a second portion  46  of the hub  18 A to selectively increase or decrease the size of the opening  34 . The aperture  32 A is sufficiently sized and shaped such that, when the basetube is received in the aperture  32 A and the portions  42 A,  46  are pivoted about the living hinge  38  to close the opening  34 , the inner surface  30 A circumscribes the basetube so that the hub  18 A is circumjacent the basetube. At least a portion of the inner surface  30 A of the aperture  32 A contacts at least a portion of the exterior surface (depicted at  48  in  FIG. 2 ) of the basetube  10  to nonrotatably retain the hub  18 A on the basetube  10 .  
         [0020]     The generally airfoil-shaped aperture  32 A of hub  18 A includes a semicircular portion  50  to allow unimpeded passage of cables, strings, and other control devices from one side of the wheel hub to the other. In the embodiment depicted, a variable geometry (VG) string (not shown) is routable through portion  50 . Referring to  FIGS. 2 and 3 , the basetube  10  in the embodiment depicted includes a guide  52  mounted thereon that retains and guides the VG string. Guide  52  at least partially extends through portion  50  when the hub  18 A is mounted to the basetube  10 . Referring to  FIG. 3a , wherein like reference numbers refer to like components from  FIGS. 2 and 3 , hub  18 B is substantially identical to hub  18 A, except that hub  18 B does not have portion  50  for a VG string and VG string guide. The shape of aperture  32 B is substantially identical to the cross-sectional shape of the basetube. Hub  18 B is configured to be mounted to the basetube  10  a distance apart from hub  18 A.  
         [0021]     In an alternative embodiment, and within the scope of the claimed invention, the opening  34  and the living hinge  38  can be eliminated, such that the hub is circumferentially continuous. In such an embodiment, the hub  18 B may be installed by inserting the end of the basetube into the aperture  32 B prior to the basetube being attached to the rest of the control bar and hang glider. The opening  34  and the living hinge  38  allow the hub to be installed to the basetube after the hang glider is completely assembled.  
         [0022]     In another alternative embodiment, and within the scope of the claimed invention, the hub  18 B comprises two or more separable sub-components that join to form the interior aperture and circular periphery.  
         [0023]     The hub  18 B may include asymmetrical channels and additional holes, grooves, apertures, etc., within the scope of the claimed invention. The purpose and function of these additional features would include, but not be limited to, the ability of the hub to fit over or around structures added to the airfoil basetube, such as cleats or other hardware.  
         [0024]     Referring to  FIG. 4 , wherein like reference numbers refer to like components from  FIGS. 1-3   a,  the wheel  22  comprises two subcomponents  58 , each including a semicircular or semiannular inner surface  62  and a semicircular or semiannular outer surface  66  interconnected by spokes  70 . Each subcomponent  58  includes fastening components, namely a threaded fastener  74  and a threaded hole  78 . The threaded fastener  74  of each subcomponent is engageable with the threaded hole  78  on the other subcomponent to operatively connect the subcomponents to one another and thereby form the wheel  22 .  
         [0025]     Referring to  FIGS. 5 and 6 , wherein like reference numbers refer to like components from  FIGS. 1-4 , the periphery  26  of the hub  18 B is characterized by an annular outer surface  82 , also referred to herein as a “bearing surface,” between two flanges  86  extending radially outward from bearing surface  82  to form a track  90 . The wheel is connected to the hub  18 B by connecting the two subcomponents  58  to one another via the fastening elements  74 ,  78  so that the inner surfaces  62  of the subcomponents  58  cooperate to form a circular or annular surface that engages, or contacts, the annular outer surface  82 . The wheel subcomponents  58 , when connected to one another, compress the hub  18 B to close the opening  34 , as depicted in  FIG. 6 . Alternatively, and within the scope of the claimed invention, other means may be employed to close the opening  34 . For example, the hub could be compressed manually, and fasteners may be employed so that opening  34  remains closed prior to installation of the wheel. In the embodiment depicted, the bearing surface  82  rotatably supports the wheel by directly contacting inner surfaces  62  such that inner surfaces  62  are slidable with respect to the bearing surface  82 . However, and within the scope of the claimed invention, the hub  18 B and bearing surface  82  may rotatably support the wheel indirectly, with friction-reducing components, such as rollers, positioned interjacent the bearing surface  82  and the inner surfaces  62 .  
         [0026]     Flanges  86  restrict axial movement of the wheel by physical part interference to retain the wheel  22  to the hub  18 B. Those skilled in the art will recognize a variety of other means to restrict axial movement of the wheel  22  with respect to the hub  18 B that may be employed within the scope of the claimed invention. For example, the hub  18 B may include one or more flanges at the periphery, and the wheel  22  may include one or more grooves in which the one or more flanges is inserted in a tongue-and-groove style configuration.  
         [0027]     Those skilled in the art will recognize a variety of materials that may be employed to form the hub. In a preferred embodiment, the hub comprises a polymeric material such as nylon. It should be noted that, although the hubs depicted in the figures are one-piece, a hub may be an assembly of different components within the scope of the claimed invention.  
         [0028]     Referring to  FIG. 7 , wherein like reference numbers refer to like components from  FIGS. 1-6 , an alternative hub  18 B′ is depicted. The hub  18 B′ includes a first subcomponent  94 A that includes a surface  96 A that forms approximately one half of bearing surface  82 ′. The first subcomponent  94 A also includes one flange  86 A. The hub  18 B′ includes a second subcomponent  94 B that includes a surface  96 B that forms the remainder of the bearing surface  82 ′. The second subcomponent  94 B also includes a flange  86 B. The subcomponents  94 A,  94 B are separable at split line  100 , enabling a unitary, one piece wheel (not shown) to be mounted to the hub  18 B′. Thus, a user may install only the first subcomponent  94 A to the basetube. Surface  96 A has a flange  86 A on only one side, and is accessible for mounting a one-piece wheel on the other side. The one-piece wheel is mountable to the first subcomponent  94 A via the end of the basetube prior to installation of the basetube to the control bar. After mounting the one-piece wheel to the first subcomponent  94 A such that the inner surface of the wheel engages surface  96 A, the second subcomponent  94 B may be installed on the basetube such that the one-piece wheel engages surface  96 B. The subcomponents are then fastened together, such as by mechanical fasteners (not shown). Flange  86 A and flange  86 B then restrict axial movement of the one-piece wheel with respect to the hub  18 B′.  
         [0029]     Alternatively, and within the scope of the claimed invention, the embodiment of  FIG. 7  may be characterized by the absence of a living hinge and variable opening so that surfaces  96 A and  96 B are circumferentially continuous, resulting in a circumferentially continuous outer surface  82 ′. In such an embodiment, the hub  18 B′ is connected to a basetube by inserting the end of the basetube through the aperture  32 B.  
         [0030]     Other means of connecting the wheel to the hub may be employed within the scope of the claimed invention. For example, a wheel may be permanently, rotatably connected to the hub to form an assembly, and the hub may be connected to the basetube by inserting the end of the basetube through the noncircular aperture.  
         [0031]     Various features shown and described in accordance with the different embodiments of the invention illustrated may be combined.  
         [0032]     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.

Technology Category: 7