Abstract:
A wheel assembly for a shoe. A housing is attached to a heel portion of the shoe and defined with an opening. A wheel section is mounted to the housing in a manner such that a pair of wheels of the wheel section can be moved between an operating position in which they are received in the opening of the housing to be partially exposed out of a lower surface of the housing and a non-operating position in which they are taken out of the opening of the housing to be seated on a rear end portion of the shoe. The wheel section includes the pair of wheels, a shaft for supporting the pair of wheels, and a support bracket having one end which is connected to the shaft and the other end which is connected to the shoe by a hinge pin.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates, in general, to a wheel assembly mounted to a shoe and, more particularly, to a wheel assembly for a shoe, which can implement cornering in a smooth manner, and can allow wheels to be moved as desired by a user between an operating position where the wheels are placed on a heel portion of the shoe to roll on a flat surface and a non-operating position where the wheels are placed on a rear end of shoe to be held detached from the flat surface.  
           [0003]    2. Description of the Prior Art  
           [0004]    In Korean Patent Application No. 2001-7012551, there is disclosed a shoe to a heel portion of which a wheel is mounted to give a user the ability to glide on flat surfaces one could only walk. Referring to FIG. 8, the conventional heeling device mounted to the shoe  900  comprises a mounting section defined with an opening, a shaft  910  supported by the mounting section, and a wheel  930  fitted around the shaft  910 .  
           [0005]    The wheel  930  is detachably mounted to the mounting section. Therefore, in the case that the shoe  900  is used to roll or slide on a flat surface, the wheel  930  is mounted to the mounting section, and in the case that the shoe  900  is used to walk or run on the flat surface, the wheel  930  as fitted around the shaft  910  is removed from the mounting section.  
           [0006]    However, the conventional heeling device mounted to the shoe suffers from defects as described below.  
           [0007]    First, while the user glides on the flat surface using the wheel  930 , when it is necessary to convert the heel-rolling state of the shoe  900  into a walking or running state, the user must remove and separately keep the wheel  930  from the shoe  900 . For this reason, the possibility of the wheel  930  to be lost is increased, and a sanitary problem is raised since it is the norm that the unclean wheel  930  is usually kept in a pocket.  
           [0008]    Second, in consideration of the fact that the single wheel  930  is fitted around the shaft  910 , since the wheel  930  has to support a weight of the user in a sufficient manner, the wheel  930  must have a substantial width. By this fact, when it is necessary for the shoe to implement cornering rather than going directly forward, because a difference is caused in rotational velocity between both ends of the wheel  930 , smooth cornering of the shoe  900  cannot be ensured, and partial wearing is provoked on a surface of the wheel  930 .  
           [0009]    Third, by the fact that the wheel  930  having a substantial width is closely mounted to the mounting section, heat produced in the mounting section due to sliding contact between the wheel  930  and the flat surface cannot be sufficiently dissipated and rather is transmitted to the foot of the user to deteriorate wearability of the shoe.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a wheel assembly for a shoe, which is simply constructed to allow the shoe to be conveniently converted from a heel-rolling or sliding state into a walking or running state to thereby be used as the conventional shoe without the need of removing a wheel from the shoe.  
           [0011]    Another object of the present invention is to provide a wheel assembly for a shoe, which is constructed to compensate a difference in rotational velocity caused between both ends of the wheel assembly when a user implements cornering, whereby partial wearing of the wheel assembly is reduced.  
           [0012]    Still another object of the present invention is to provide a wheel assembly for a shoe, which can easily dissipate frictional heat produced in a wheel part to thereby reduce the frictional heat transmitted to the foot of the user.  
           [0013]    In order to achieve the above object, according to one aspect of the present invention, there is provided a wheel assembly for a shoe, comprising: a housing attached to a heel portion of the shoe and defined with an opening; and a wheel section mounted to the housing in a manner such that a pair of wheels of the wheel section can be moved between an operating position in which they are received in the opening of the housing to be partially exposed out of a lower surface of the housing and a non-operating position in which they are taken out of the opening of the housing to be seated on a rear end portion of the shoe.  
           [0014]    According to another aspect of the present invention, the wheel section comprises the pair of wheels, a shaft for supporting the pair of wheels, and a support bracket having one end which is connected to the shaft and the other end which is connected to the shoe by a hinge pin.  
           [0015]    According to another aspect of the present invention, each of the wheels is rotatably supported by a ball bearing, and the wheels are structured to emit lights while they are rotated.  
           [0016]    According to another aspect of the present invention, both ends of the shaft are respectively formed with external threads, and a pair of cap elements are threadedly locked to the external threads; and a pair of flange portions having a predetermined height are integrally formed on a circumferential outer surface of the shaft at pre-selected locations, respectively.  
           [0017]    According to another aspect of the present invention, the support bracket has a configuration of a plate, and, by bending and riveting both ends of the plate, the support bracket is defined with a shaft insertion groove through which the shaft is inserted and a pin insertion groove through which the hinge pin is inserted, and wherein the support bracket is defined at substantially a middle portion thereof with a slot which extends in a lengthwise direction of the support bracket.  
           [0018]    According to still another aspect of the present invention, the housing has a pair of semi-cylindrical shaft receiving grooves which are defined at both axial ends of the opening so that both ends of the shaft can be received in the shaft receiving grooves, respectively, and a pair of hinge holes which are defined at a rear end of the housing so that both ends of the hinge pin can be inserted through the hinge holes, respectively.  
           [0019]    According to yet still another aspect of the present invention, the rear end portion of the shoe is formed with an engaging projection so that the engaging projection can be close-fitted into the slot defined in the support bracket to hold the wheel section to the non-operating position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:  
         [0021]    [0021]FIG. 1 is a partially broken-away side view illustrating a shoe to which a wheel assembly in accordance with an embodiment of the present invention is mounted;  
         [0022]    [0022]FIGS. 2 a  and  2   b  are a perspective view and a sectional view illustrating the wheel assembly according to the present invention;  
         [0023]    [0023]FIG. 3 is an exploded perspective view illustrating a wheel section which constitutes the wheel assembly according to the present invention;  
         [0024]    [0024]FIG. 4 is a perspective view illustrating a housing which constitutes the wheel assembly according to the present invention;  
         [0025]    [0025]FIGS. 5 a  and  5   b  are a bottom view and a rear view illustrating an unfolded operating position of wheels of the wheel assembly according to the present invention;  
         [0026]    [0026]FIGS. 6 a  and  6   b  are a bottom view and a rear view illustrating a folded non-operating position of the wheels of the wheel assembly according to the present invention;  
         [0027]    [0027]FIG. 7 is a side view illustrating a state wherein the wheels of the wheel assembly slide on a flat surface;  
         [0028]    [0028]FIG. 8 is a side view illustrating a shoe to which the conventional wheel is mounted;  
         [0029]    [0029]FIG. 9 is a partial bottom view of FIG. 8; and  
         [0030]    [0030]FIGS. 10 a  and  10   b  are views for comparing the present invention with the conventional art. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts.  
         [0032]    [0032]FIG. 1 is a partially broken-away side view illustrating a shoe to which a wheel assembly in accordance with an embodiment of the present invention is mounted; and FIGS. 2 a  and  2   b  are a perspective view and a sectional view illustrating the wheel assembly according to the present invention.  
         [0033]    As shown in the drawings, a wheel assembly in accordance with an embodiment of the present invention, designated by the reference numeral  10 , comprises a housing  30  attached to a heel portion  51  of a shoe  5 , and a wheel section  20  for selectively positioning a pair of wheels  210  and  210 ′ in the housing  30  and on a rear end portion  53  of the shoe  5 .  
         [0034]    The housing  30  attached to the heel portion  51  of the shoe  5  is defined with an opening in which the pair of wheels  210  and  210 ′ can be accommodated. A pair of semi-cylindrical shaft receiving grooves  310  are defined at both axial ends of the opening so that both ends of a shaft  230  can be received in the shaft receiving grooves  310 , respectively, and a pair of hinge holes  330  are defined at a rear end of the housing  30  so that both ends of a hinge pin  259  can be inserted through the hinge holes  330 , respectively. The rear end portion  53  of the shoe  5  is formed with an engaging projection  350 . The engaging projection  350  is formed to have a size and a shape which allow the engaging projection  350  to be close-fitted into a slot  257  defined in a support bracket  250  as will be described later in detail. Hence, due to the fact that the engaging projection  350  is close-fitted into the slot  257 , the support bracket  250  including the pair of wheels  210  and  210 ′ can be securely held with respect to the rear end portion  53  of the shoe  5  (see FIGS. 2 b  and  4 ).  
         [0035]    As can be readily seen from FIG. 3, the wheel section  20  comprises the pair of wheels  210  and  210 ′, the shaft  230  for supporting the pair of wheels  210  and  210 ′, and the support bracket  250 .  
         [0036]    The wheels  210  and  210 ′ are rotatably supported by ball bearings  215  while being fitted around the shaft  230 . In this preferred embodiment of the present invention, the wheels  210  and  210 ′ may be structured to emit lights while they are rotated. As the wheel  210  and  210 ′, a wheel of a narrow width, similar to those used in an in-line skate, may be used.  
         [0037]    The wheel section  20  of the present invention has the pair of wheels  210  and  210 ′. In this regard, referring to FIG. 10 a , when assuming a user goes around a corner having a short radius, an outside rotation radius is substantially greater than an inside rotation radius, and therefore, an outside end of a wheel must be rotated at a velocity greater than that of an inside end of the wheel. In spite of these considerations, in the conventional art, since the single wheel  930  having a large width is used, the inner and outer ends of the wheel  930  are rotated at the same velocity. Accordingly, a partial wearing phenomenon occurs in the wheel  930  due to a difference in rotational velocity between the inner and outer ends of the wheel  930 , whereby smooth cornering of the wheel  930  cannot be ensured.  
         [0038]    However, in the present invention, by the fact that the pair of wheels  210  and  210 ′, that is, the inner wheel  210 ′ and the outer wheel  210  are fitted around the shaft  230  by way of their respective ball bearings  215 , even though a rotational velocity difference is caused between the outer and inner wheels  210  and  210 ′, smooth and calm cornering of the wheels  210  and  210 ′ is ensured, and partial wearing does not occur in any of the outer and inner wheels  210  and  210 ′. Also, because a gap is sufficiently secured between the pair of wheels  210  and  210 ′, heat produced due to the rotation of the wheels  210  and  210 ′ can be easily dissipated into the surrounding air.  
         [0039]    The shaft  230  are structured to ensure that the wheels  210  and  210 ′ are reliably rotated and to sufficiently stand a load applied by a weight of the user. Referring to FIG. 3, both ends of the shaft  230  are respectively formed with external threads  231 , and a pair of cap elements  235  are threadedly locked to the external threads  231 . A pair of first flange portions  233  are integrally formed on a circumferential outer surface of the shaft  230  at pre-selected locations, respectively. A pair of second flange portions are also formed on circumferential outer surfaces of the cap elements  235 , respectively. Consequently, after fitting the wheels  210  and  210 ′ around the shaft  230  which is formed with the first flange portions  233 , by threadedly locking the cap elements  235  to the external threads  231  of the shaft  230 , the wheels  210  and  210 ′ are securely maintained while being intervened between the first flange portions  233  of the shaft  230  and the second flange portions of the cap elements  235 .  
         [0040]    The support bracket  250  is formed by riveting a plate-shaped sheet material using rivets  255 . In the case of defining in advance the shaft insertion groove  251  in which the shaft  230  is to be inserted, it is impossible to properly insert the shaft  230  through the shaft insertion groove  251  due to the presence of the first flange portions  233  which are formed on the shaft  230 . Thus, before riveting the support bracket  250 , the shaft  230  is inserted through the shaft insertion groove  251 . Thereafter, riveting of the support bracket  250  is conducted.  
         [0041]    As shown in the drawings, a front end of the support bracket  250  is defined with the shaft insertion groove  251 , and the rear end of the support bracket  250  is defined with the pin insertion groove  253  through the hinge pin  259  is inserted. Also, the support bracket  250  is defined at substantially a middle portion thereof with the slot  257  which extends in a lengthwise direction of the support bracket  250 . Both ends of the hinge pin  259  which is inserted through the pin insertion groove  253  are also fitted through the pair of hinge holes  330  of the housing  30 , so that the support bracket  250  can be rotated about the hinge pin  259 .  
         [0042]    By the construction of the wheel assembly  10  according to the present invention, while the user glides on a flat surface using the wheels  210  and  210 ′, if the user wants to convert the heel-rolling state of the shoe  5  into a walking or running state, the wheels  210  and  210 ′ which are accommodated in the opening of the housing  30  are taken out of the opening by the user&#39;s fingers, and then, the support bracket  250  is rotated about the hinge pin  259  so that the slot  257  of the support bracket  250  is closely engaged with the engaging projection  350 . Accordingly, because the wheels  210  and  210 ′ do not project out of a lower surface of the shoe  5  and instead positioned on the rear end portion of the shoe  5 , the shoe  5  can be used as usual. On the contrary, if the user wants to convert the walking or running state of the shoe  5  into the heel-rolling state, by disengaging the support bracket  250  from the engaging projection  350  and then accommodating the wheels  210  and  210 ′ into the opening of the housing  30 , the user can glide on the flat surface using the wheels  210  and  210 ′ which project out of the lower surface of the shoe  5 .  
         [0043]    As apparent from the above description, the wheel assembly for a shoe according to the present invention, constructed as mentioned above, provides advantages in that the shoe equipped with the wheel assembly can be used to roll or slide on a flat surface using a pair of wheels and can be used as the conventional shoe through simple manipulation without the need of removing the wheels from the shoe.  
         [0044]    Further, when a user implements cornering using the wheels, since it is possible to compensate a difference in rotational velocity between both wheels, partial wearing of the wheels is prevented, and smooth cornering is ensured.  
         [0045]    Moreover, due to the fact that a gap is sufficiently secured between the pair of wheels, frictional heat produced in the wheels can be easily dissipated into the immediate environment, whereby it is possible to prevent the frictional heat from being transmitted to the foot of the user.  
         [0046]    Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.