Abstract:
A wheel structure includes a support rack having two ends each provided with a roller and a control device. The control device is mounted on the respective end of the support rack and is urged on the roller to reduce the rotational speed of the roller. Thus, the rotational speed of the wheel structure can be efficiently controlled to the optimum state, thereby greatly facilitating a learner or a kid employing the wheel structure.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a wheel structure, and more particularly to a wheel structure whose rotational speed can be controlled to the optimum state.  
           [0003]    2. Description of the Related Art  
           [0004]    A conventional roller skate or scooter can provide an exercising an amusing effect to the user, so that the user can employ the roller skate or scooter to obtain an exercising effect or a funny amusement. However, the rotational speed of the rollers or wheels of the conventional roller skate or scooter cannot be adjusted or controlled, thereby easily causing danger to the user, especially to the learner or the kid, when the conventional roller skate or scooter is moved at a higher speed.  
         SUMMARY OF THE INVENTION  
         [0005]    The primary objective of the present invention is to provide a wheel structure whose rotational speed can be efficiently controlled to the optimum state, thereby facilitating a learner or a kid employing the wheel structure.  
           [0006]    Another objective of the present invention is to provide a wheel structure that is available for the roller skate or scooter. thereby facilitating the learner or the kid practicing the roller skate or scooter.  
           [0007]    A further objective of the present invention is to provide a wheel structure, wherein the control device produces a braking effect to the roller by the friction between the urging face of the push member and the plane portion of the roller, so as to reduce and control the rotational speed of the roller.  
           [0008]    In accordance with the present invention, there is provided a wheel structure, comprising:  
           [0009]    a support rack having two ends each provided with a roller and a control device; wherein:  
           [0010]    the roller is rotatably mounted on the respective end of the support rack;  
           [0011]    the control device is mounted on the respective end of the support rack and is urged on the roller to reduce the rotational speed of the roller.  
           [0012]    Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is an exploded perspective view of a wheel structure in accordance with the preferred embodiment of the present invention;  
         [0014]    [0014]FIG. 2 is an exploded perspective view of the wheel structure used for a roller skate in accordance with the preferred embodiment of the present invention;  
         [0015]    [0015]FIG. 3 is a perspective assembly view of the wheel structure used for a roller skate in accordance with the preferred embodiment of the present invention;  
         [0016]    [0016]FIG. 4 is a partially cut-away side plan cross-sectional assembly view of the wheel structure as shown in FIG. 1;  
         [0017]    [0017]FIG. 5 is a schematic operational view of the wheel structure as shown in FIG. 4 in use;  
         [0018]    [0018]FIG. 6 is a plan assembly view of the wheel structure in accordance with another embodiment of the present invention;  
         [0019]    [0019]FIG. 7 is a schematic operational view of the wheel structure as shown in FIG. 6 in use; and  
         [0020]    [0020]FIG. 8 is a perspective assembly view of the wheel structure used for a scooter in accordance with the preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Referring to the drawings and initially to FIGS. 1-5, a wheel structure in accordance with the preferred embodiment of the present invention is used for a roller skate  2  and comprises a support rack  10  secured on the bottom of a shoe  20  of the roller skate  2 .  
         [0022]    The support rack  10  has two ends  12  each provided with a roller  30  and a control device  50 . Preferably, each of the two ends  12  of the support rack  10  has a rectangular shape and is provided with a shaft  11  protruded outward therefrom.  
         [0023]    The roller  30  is rotatably mounted on the shaft  11  of the respective end  12  of the support rack  10  by a bearing  40 . The roller  30  has a first side formed with an annular flange  35 . The annular flange  35  of the roller  30  has a side formed with a plane portion  32  and has an inner wall formed with a toothed portion  33 . The roller  30  has a second side formed with a stepped recess  31  for receiving the bearing  40 .  
         [0024]    In addition, the shaft  11  of the support rack  10  is formed with an outer thread  110 , and a locking nut  112  is screwed on the outer thread  110  of the shaft  11  of the support rack  10  and is rested on the bearing  40  as shown in FIG. 4, so that the roller  30  is rotatably mounted on the shaft  11  of the respective end  12  of the support rack  10  by the locking nut  112 .  
         [0025]    The control device  50  is secured on the respective end  12  of the support rack  10  and is mounted in the annular flange  35  of the roller  30 . The control device  50  includes a cover  53 , a circular plate  52 , a push member  51 , and an adjusting member  54 .  
         [0026]    The cover  53  of the control device  50  is secured on the respective end  12  of the support rack  10 . The cover  53  has a first side having a center formed with a rectangular positioning hole  532  mounted on the respective rectangular end  12  of the support rack  10 . The cover  53  has a periphery formed with a through hole  531 .  
         [0027]    The circular plate  52  of the control device  50  is combined with the cover  53  by a screw member  56 . The circular plate  52  has a first side rested on a second side of the cover  53  and a second side formed with a tapered receiving recess  522 . The receiving recess  522  of the circular plate  52  has a center formed with a through hole  521  aligning with the through hole  531  of the cover  53 . The receiving recess  522  of the circular plate  52  has a periphery formed with at least one protruding rib  523 . The circular plate  52  has an outer wall rested on the toothed portion  33  of the roller  30 .  
         [0028]    The push member  51  of the control device  50  is movably mounted on the second side of the circular plate  52 . The push member  51  has a first end formed with a tapered head  510  rotatably mounted in the receiving recess  522  of the circular plate  52 . The tapered head  510  of the push member  51  has a periphery formed with at least one guide slot  513  for receiving the protruding rib  523  of the circular plate  52 . The tapered head  510  of the push member  51  has a side formed with an urging face  512  that can be moved to press the plane portion  32  of the annular flange  35  of the roller  30 . The push member  51  has a second end extended through the through hole  521  of the circular plate  52  and the through hole  531  of the cover  53 . Preferably, the second end of the push member  51  is formed with an outer thread  511 .  
         [0029]    The adjusting member  54  of the control device  50  is rotatably mounted on the first side of the cover  53  and is combined with the second end of the push member  51  for rotating the push member  51 . Preferably, the adjusting member  54  is formed with an inner thread  541  screwed on the outer thread  511  of the second end of the push member  51 .  
         [0030]    In operation, referring to FIGS. 4 and 5 with reference to FIGS. 1-3, the roller  30  is rotatably mounted on the shaft  11  of the respective end  12  of the support rack  10 , while the control device  50  is secured on the respective end  12  of the support rack  10  and is mounted in the annular flange  35  of the roller  30 .  
         [0031]    When the adjusting member  54  is rotated, the push member  51  is rotated by rotation of the adjusting member  54 , so that the protruding rib  523  of the circular plate  52  is detached from the guide slot  513  of the tapered head  510  of the push member  51  and is urged on the periphery of the tapered head  510  of the push member  51 , thereby forcing the push member  51  to move toward the roller  30  and to move from the position as shown in FIG. 4 to the position as shown in FIG. 5, such that the urging face  512  of the tapered head  510  of the push member  51  is urged on the plane portion  32  of the annular flange  35  of the roller  30 , thereby producing a braking effect to the roller  30  by the friction between the urging face  512  of the push member  51  and the plane portion  32  of the roller  30 , so as to reduce the rotational speed of the roller  30 .  
         [0032]    Alternatively, when the adjusting member  54  is rotated in the reverse direction, the push member  51  is rotated by rotation of the adjusting member  54 , so that the protruding rib  523  of the circular plate  52  is received in the guide slot  513  of the tapered head  510  of the push member  51 , thereby forcing the push member  51  to move away from the roller  30  and to move from the position as shown in FIG. 5 to the position as shown in FIG. 4, such that the urging face  512  of the tapered head  510  of the push member  51  is detached from the plane portion  32  of the annular flange  35  of the roller  30 , and the roller  30  can be rotated normally.  
         [0033]    Referring to FIGS. 6 and 7, a wheel structure in accordance with another embodiment of the present invention is shown, wherein the receiving recess  522  of the circular plate  52  is formed with a slit  60 , so that the circular plate  52  has a flexible feature and can be expanded outward when the receiving recess  522  of the circular plate  52  is compressed.  
         [0034]    In operation, when the adjusting member  54  forces the push member  51  to move away from the plane portion  32  of the roller  30 , the tapered head  510  of the push member  51  will push and compress the tapered receiving recess  522  of the circular plate  52 , so that the circular plate  52  can be expanded outward from the position as shown in FIG. 6 to the position as shown in FIG. 7, and the outer wall of the circular plate  52  is urged on the inner wall of the roller  30 , thereby producing a braking effect to the roller  30  by the friction between the outer wall of the circular plate  52  and the inner wall of the roller  30 , so as to reduce the rotational speed of the roller  30 . In addition, the outer wall of the circular plate  52  is rested on the toothed portion  33  of the roller  30  to enhance the friction effect.  
         [0035]    Referring to FIG. 8, the wheel structure in accordance with the preferred embodiment of the present invention is used for a scooter  70 , and the support rack  10  is secured on the bottom of the scooter  70 .  
         [0036]    Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.