Patent Publication Number: US-7712749-B2

Title: Footwear

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit under 35 U.S.C.§119(a) of Korean Patent Application No. 2007-0071988, filed on Jul. 19, 2007 in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to footwear equipped with rollers in a bottom thereof. 
     2. Description of the Related Art 
     With the recent increase of leisure activities, roller skating using roller skate shoes such as roller skates, roller blades and inline skates are becoming popular. Generally, such roller skate shoes dedicatedly include a roller assembly at their bottoms. Therefore, in order to enjoy roller skating, a rider has to carry the roller skate shoes to a predetermined place and change his/her walking shoes into the roller skate shoes. After enjoying the roller skating, the rider now has to change back to the walking shoes. These processes are bothersome for the rider. 
     Nowadays, a variety of shoes equipped with rollers are being introduced to overcome such bother. A conventional roller shoe is disclosed in KR Utility Model No. 20-0378784 registered on May 3, 2005. 
     The conventional roller shoe is shown in  FIG. 1  (corresponding to  FIG. 3  in the publication). Since rollers  400  of the conventional roller shoe are rotatable by 360°, the rider can make a turn by 360°. However, in the conventional roller shoe, the rollers  400  cannot automatically return to the initial position after the turning. 
     Thus, the rollers  400  are often displaced from the initial position. When the rider starts in this state, the rider may even fall down because the rollers  400  would not roll smoothly and promptly due to resistance against the ground surface. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention has been made in view of the above-mentioned problems, and it is an aspect of the present invention to provide footwear enabling a rider to enjoy roller skating more safely and briskly, by having a function of returning rollers thereof automatically to their initial position. 
     In order to achieve the above-described aspects of the present invention, there is provided footwear comprising a main shoe body provided with a recess on a bottom thereof; an upper body fixed to the recess and having a plurality of magnets arranged at intervals in a circumferential direction; a lower body having a plurality of magnets arranged at intervals in a circumferential direction and connected with the upper body to be rotatable relative to the upper body; and rollers mounted to the lower body, wherein the magnets of the upper body and the lower body are arranged so as to return the rollers always to a regular position by magnetism acting between the magnets of the upper body and the magnets of the lower body. 
     The upper body and the lower body include four magnets respectively, arranged at constant intervals with alternate polarities. 
     A first sliding member is installed between the upper body and the lower body. 
     The first sliding member is a ball bearing. 
     A bearing cover provided with a ball bearing support groove is mounted to the upper body and the lower body respectively, and the ball bearing is supported by the bearing cover. 
     The upper body-and the lower body include a through-hole, respectively, and a screw member penetrates the through-hole of the lower body and is screw-connected with the through-hole of the upper body. 
     A second sliding member is mounted between a head of the screw member and the lower body. 
     The second sliding member is a ball bearing. 
     The lower body further includes a bearing cover having a ball bearing support groove, and the ball bearing is supported by the bearing cover of the lower body and another bearing cover having a ball bearing support groove. 
     The lower body includes twos roller recesses, and a roller rotation shaft support recess for a supporting rotation shaft of the rollers is formed on opposite sides of the respective roller recesses. 
     The lower body includes a separation prevention plate preventing separation of the rollers and having a window for allowing a body part of the rollers to pass through. 
     The recess is disposed at a rear side of the bottom, and two rows of rollers are additionally mounted to a front side of the bottom, the two rows of which a front row comprises two rollers and a rear row comprises one roller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The above aspect and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawing figures, wherein; 
         FIG. 1  shows main parts of a bottom of a conventional roller shoe; 
         FIG. 2  is a perspective view of a bottom of footwear according to an embodiment of the present invention; 
         FIG. 3  is an exploded view of the footwear shown in  FIG. 2 ; 
         FIG. 4  is an exploded view showing main parts of the footwear of  FIG. 2 ; 
         FIG. 5  is an exploded view of an upper body and a lower body of the footwear of  FIG. 4 , as seen from another direction; 
         FIG. 6(   a ) shows rollers of the footwear of  FIG. 2  as placed in the initial position; 
         FIG. 6(   b ) shows rollers of the footwear of  FIG. 2  as displaced from the initial position; and 
         FIG. 7  is a view-for-explaining the operation of the footwear of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawing figures. 
     The matters defined in the description such as a detailed construction and elements are nothing but the ones provided to assist in a comprehensive understanding of the invention. Thus, it is apparent that the present invention can be carried out without those defined matters. 
     As shown in  FIGS. 2 through 5 , footwear according to the embodiment of the present invention comprises a main shoe body  1 , an upper body  2 , a lower body  3 , and rollers  8 . 
     The main shoe body  1  has a recess  12  on a bottom  11  thereof. The recess  12  is disposed corresponding to a, heel. 
     The upper body  2  is fixed in the recess  12 . Referring to  FIG. 5 , four magnets  211 ,  212 ,  213  and  214  are mounted in the upper body  2 , being arranged at almost constant intervals in a circumferential direction. More specifically, the four magnets  211 ,  212 ,  213  and  214  are arranged at approximately 90.degree. intervals to alternately have opposite polarities, that is, in the order of N-S-N-S. Here, N denotes a positive pole and S denotes a negative pole. 
     In the same manner as the upper body  2 , the lower body  3  is also provided with four magnets  311 ,  312 ,  313  and  314  which are circumferentially arranged at almost constant intervals with alternate polarities. For convenient explanation, the polarities of magnets in the specification and the drawings are designated to correspond between the facing magnets. For example, the magnet  212  in  FIG. 5  has the negative pole S on the surface facing the magnet  312 , and the magnet  312  has the positive pole N on the surface facing the magnet  212 . 
     Additionally, a roller recess  32 , is formed on a bottom surface of the lower body  3 . Two roller recesses  32  are provided according to this embodiment. The lower body  3  is magnetically connected to the upper body  2 , being rotatable with respect to the upper body  2 . According to this, the magnets  311 ,  312 ,  313  and  314  of the lower body  3  are coupled with the magnets  211 ,  212 ,  213  and  214  of the upper body  2  to match with opposite polarities, as shown in  FIG. 5 . 
     According to the exemplary embodiment, the upper body  2  and the lower body  3  are provided with a first sliding member such as a ball bearing  4  disposed therebetween, for smooth rotation relative to each other. For this, the upper body  2  and the lower body  3  have bearing covers  22  and  33  including ball bearing support grooves  221  and  331 , respectively. The, ball bearing  4  is supported by the bearing covers  22  and  33 . 
     In addition, the upper body  2  and the lower body  3  have through-holes  21  and  31  respectively, penetrating the centers thereof. The upper body  2  and the lower body  3  can be connected not to separate from each other by a screw member  5  penetrating the through-holes  21  and  31 . While the through-hole  21  includes a female screw thread, the through-hole  31  does not. Therefore, the screw member  5  is fixedly connected only to the upper body  2  through screw-connection between the through-hole  21  and a male screw thread formed around an end thereof. In other words, the lower body  3  is rotatable relative to the screw member  5 . 
     For smooth rotation between the upper and lower bodies  2  and  3 , it is preferred that a second sliding member such as a ball bearing  6  is installed between a head of the screw member  5  and the lower body  3 . The lower body  3  has a bearing cover  34  including a ball bearing support groove  341 . The ball bearing  6  is supported by another bearing cover  7  and the bearing cover  34  having the ball bearing support groove  341 . 
     As shown in  FIG. 4 , the rollers  8  are mounted rotatably in the roller recess  32 . A roller rotation shaft support recess  321  for supporting a roller rotation shaft  81  is formed on opposite sides of the respective roller recesses  32 . It is preferred that diameter of the rollers  8  is not greater than 16 mm to effectively restrain generation of noise during roller skating. 
     In order for efficient stop using skidproof protrusions  100  and  101  during the roller skating, a protruded degree of the rollers  8  from the roller recess  32  is preferably less than about 8 mm. 
     A separation, preventive plate  9  is mounted to the lower body  3  to prevent separation of the rollers  8 . The separation preventive plate  9  has two windows  91  for the two rollers  8  to protrude through. The window  91  is sized to allow only a body part  82  of the rollers  8  but not the rotation shaft  81 . 
     Referring to  FIG. 2 , two rows of rollers are further mounted to a front side of the bottom  11  of the footwear. A front row of the two rows includes two rollers  111  and  112 , and a rear row does one roller  113 . Preferably, the rollers  111  and  112  of the front row and the roller  113  of the rear row are arranged almost in the middle of the width of the bottom  11 . 
     The skidproof protrusions  100  and  101  are formed on front and rear ends of the bottom  11  so that the rider can stop by tilting the footwear forward or backward during roller skating. 
     The operation of the above-structured footwear will now be described with reference to  FIGS. 6 and 7 . 
       FIG. 7  is a view for explaining the relative operations of the upper body  2  and the lower body  3 , as seen in an arrowed direction B of  FIG. 5 . More particularly, FIG.  7 ( a ) shows the lower body  3  placed in the initial position while  FIG. 7(   b ) shows the lower body  3  as rotated by about 30° clockwise from the initial position. For convenience in explanation, the upper body  2  and its magnets  211 ,  212 ,  213  and  214  are indicated by a solid line and the lower body  3  and its magnets  311 ,  312 ,  313  and  314  by a dotted line. 
     In the initial position as shown in  FIG. 7(   a ), the lower body  3  and the upper body  2  are connected with each other magnetically. In other Words, the four magnets  211 ,  212 ,  213  and  214  of the upper body  2  are magnetically coupled with the magnets  311 ,  312 ,  313  and  314  of the lower body  3 , respectively. 
     When changing the skating direction with the footwear in contact with the ground surface, the lower body  3  is turned by a predetermined angle, for example, by about 30° clockwise as shown in  FIG. 6(   b ) and  FIG. 7(   b ). 
     After the turn, when the rollers  8  are separated from the ground surface by lifting a heel of the footwear slightly away from the ground surface, the lower body  3  is automatically rotated in an arrowed direction C due to magnetism, thereby returning to the initial position as shown in  FIG. 6(   a ) and  FIG. 7(   a ). More specifically, the lower body  3  is returned to the initial position by the magnetism acting respectively between the magnets  211  and  311 , the magnets  212  and  312 , the magnets  213  and  313 , and the magnets  214  and  314 . 
     Now, the rider can keep roller skating, putting the heel down back to the ground. 
     Since the lower body  3  can automatically return to the initial position in this way, the rollers  8  are placed always in a regular position ( FIG. 6(   a )). In other words, after the turn, simply by lifting the heel of the footwear away from the ground surface, the rider can return the rollers  8  to the regular position, that is, to head in an advancing direction ‘A’. 
     For stop in the middle of the roller skating, on the other hand, the rider tilts the roll footwear er shoe so that the skidproof protrusions  100  and  101  are contacted with the ground surface. 
     Here, the roller diameter not greater than 16 mm is advantageous in restraining generation of noise during the roller skating. Also, the interval not greater than 8 mm between the ground surface and the shoe bottom helps smooth stop. 
     Although the respectively four magnets are provided to the upper body  2  and the lower body  3  with alternate polarities in this embodiment, the present invention is not limited to this configuration. For example, two magnets may be mounted to the upper body  2  in the order of N-S, while another two magnets are mounted to the lower body  3  in the opposite order, that is, in the order of S-N. 
     Alternatively, the upper body  2  may be mounted with six magnets arranged in the order of N-S-S-N-S-S and the lower body  3  in the order of S-N-N-S-N-N. 
     As described above, the present-invention is not limited to certain configuration but may adopt other various configurations as long as it can keep the rollers  8  in the regular position by applying the magnetic coupling, between the upper body  2  and the lower body  3 . 
     With the footwear according to the embodiment of the present invention, the rollers can immediately return to their initial positions from any displaced position, thereby enabling more prompt and safe roller skating. Furthermore, the rollers are able to turn by 360° without a turning radius. In addition, since respectively five rollers are provided at proper places of the shoe bottom, the rider can feel almost the same wearing comfort as general walking shoes and enjoy roller skating stably and safely. 
     While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.