Patent Publication Number: US-2013227859-A1

Title: Footwear

Description:
TECHNICAL FIELD 
     The present invention relates to footwear for alleviating pain in foot caused by hallux valgus. 
     BACKGROUND ART 
     In recent years, an increasing number of people are suffering from hallux valgus, which is developed by continuous use of shoes not fitting to feet such as high-heeled women&#39;s shoes. Hallux valgus refers to the symptom in which the big toe is in the laterally deviated state. That is, the tip of the big toe deflects toward the small toe side, while the root portion of the big toe is bent in a “V”-shape, to project toward the medial side in the foot width direction. As the symptom of the hallux valgus progresses, sharp pain may be caused by the root portion of the big toe being brought into contact with the insole of the shoe. This may hinder walking. 
     Conventionally, as footwear for alleviating such pain in the foot caused by hallux valgus, what is known is footwear in which a concave portion is formed at the insole at the position corresponding to the big toe (for example, see Patent Literature 1). The footwear is capable of reducing a weight load of a wearer acting on the big toe by the concave portion. Therefore, it can alleviate the pain in the foot while walking. 
     CITATION LIST 
     PATENT LITERATURE 
     Patent Literature 1: Japanese Examined Patent Publication No. 4-20608 
     SUMMARY OF INVENTION 
     Technical Problem 
     The conventional footwear can alleviate pain in the foot caused by hallux valgus. However, since the big toe itself is still in the laterally deviated state, the symptom of the hallux valgus itself cannot be improved. Further, since the lateral deviation portion of the big toe is brought into contact with the sidewall portion of the shoe, the pain in the foot cannot be fully alleviated. 
     The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide footwear capable of improving the symptom of hallux valgus while fully alleviating the pain in the foot caused by hallux valgus. 
     Solution to Problem 
     Footwear of the present invention for achieving the object stated above includes: a concave portion formed at an insole at a position corresponding to a first site ranging from a ball of a big toe to a tip of the toe for alleviating a weight load of a wearer acting on the big toe; and a pressing portion formed at the insole at a position corresponding to a second site being adjacent to a heel side of the ball of the big toe for pressing the second site, a reaction force occurring by the pressing causing the first site to sink in the concave portion. 
     With the footwear of the present invention, the concave portion formed at the insole at the position corresponding to the first site ranging from the ball of the big toe to the tip of the toe can reduce the weight load of the wearer acting on the big toe. Further, the pressing portion formed at the insole presses the second site being adjacent to the heel side of the ball of the big toe. The reaction force caused by the pressing allows the first site to sink in the concave portion. Accordingly, the big toe naturally enters the medially deviated state, to approximate the original normal state from the laterally deviated state. Thus, the symptom of hallux valgus can be improved. Furthermore, since it becomes possible to suppress the big toe from being brought into contact with the sidewall portion of the shoe, the pain in the foot can be further alleviated. 
     Further, it is preferable that the footwear further includes a lifting portion formed at the insole at a position corresponding to four toes except for the big toe, for lifting the four toes. 
     In this case, since the four toes except for the big toe are lifted by the lifting portion, the clearance between each adjacent ones of the four toes can be widened. Thus, even in the state where the first site of the big toe sinks in the concave portion as described above, the weight of the wearer can be supported by the four toes in a stable state. 
     Still further, it is preferable that the lifting portion is formed to become gradually high from a second toe toward a small toe both included in the four toes, to cause a straight line connecting top ends of the four toes to be substantially horizontal. 
     In this case, since the straight line connecting the top ends of the four toes lifted by the lifting portion becomes substantially horizontal, it becomes possible to allow the weight load of the wearer to act on the four toes substantially uniformly. Thus, the weight of the wearer can be supported by the four toes in a further stable state. 
     Still further, it is preferable that the lifting portion is provided with a projecting portion at the insole at a position corresponding to a clearance between a third toe and a fourth toe both included in the four toes, for widening the clearance. 
     In this case, since the projecting portion widens the clearance between the third toe and the fourth toe, the weight load of the wearer can be shared by a pair of two toes, i.e., the second toe and the third toe, and another pair of toes, i.e., the fourth toe and the small toe. Thus, weight of the wearer can be supported in a further stable state. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view showing an insole of footwear according to one embodiment of the present invention. 
         FIG. 2  is a cross sectional view taken along A-A in  FIG. 1 . 
         FIG. 3  is a cross sectional view taken along B-B in  FIG. 1 . 
         FIG. 4  is a cross sectional view taken along C-C in  FIG. 1 . 
         FIG. 5A  is a cross sectional view taken along D-D in  FIG. 1 . 
         FIG. 5B  is a cross sectional view taken along E-E in  FIG. 1 . 
         FIG. 5C  is a cross sectional view taken along F-F in  FIG. 1 . 
         FIG. 6  is a cross sectional view taken along G-G in  FIG. 1 . 
         FIG. 7  is a drawing-substituting photograph showing the state of a foot before wearing the footwear. 
         FIG. 8  is a drawing-substituting photograph showing the state of the foot wearing the footwear. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, with reference to the accompanying drawings, a description will be given of the preferred embodiment of the present invention.  FIG. 1  is a plan view showing a left-foot insole of footwear according to one embodiment of the present invention.  FIG. 2  is a cross sectional view taken along A-A in  FIG. 1 . In  FIG. 1 , an insole  3  of a shoe  1  being the footwear according to the present embodiment includes a concave portion  31  formed at the region corresponding to the big toe f 1  of the foot f, a pressing portion  32  formed so as to be adjacent to the concave portion  31 , and a lifting portion  33  formed at the region corresponding to the four toes f 2  to f 5  except for the big toe f 1 . Here, the “insole” refers to the element positioned at the bottom plane inside the footwear, and it includes a shoe insert placed on the bottom plane. 
     In planar view of  FIG. 1 , the concave portion  31  is formed at the region corresponding to a first site ranging from the ball f 1   a  of the big toe f 1  to the tip of the toe. As shown in  FIG. 2 , the cross-sectional shape of the concave portion  31  in the foot length direction (in the direction from the tip of toe to the heel) is formed so as to conform to the ventral side shape of the big toe f 1 . More specifically, in connection with the concave portion  31 , the portion corresponding to the ball f 1   a  of the big toe f 1  is depressed the most deepest, and the portion corresponding to the ventral portion f 1   b  of the big toe f 1  toward the tip of the toe is formed to be gradually shallower accordingly. 
     In planar view of  FIG. 1 , the pressing portion  32  is formed at the region corresponding to a second site adjacent to the heel side of the ball of the big toe f 1   a . The pressing portion  32  is configured to press the second site, so that the reaction force occurring by the pressing causes the first site to sink in the concave portion  31 . The pressing force to the second site is set to be greater than the force exerted by a level plane naturally pressing the second site when the foot f is placed on the level plane. 
     Further, such sinking of the first site is realized by using the phenomenon of the first site naturally sinking in response to the pressing, which is performed by the pressing portion  32 , acting on the tendon (abductor hallucis) connecting between the second site and the first site. The length L of the pressing portion  32  in the foot length direction is set to approximately 18 mm, and the length W in the foot width direction is set to approximately 50 mm. As shown in  FIG. 2 , the cross-sectional shape of the pressing portion  32  in the foot length direction is formed as an inclined plane becoming gradually higher from the concave portion  31  toward the heel side. 
       FIG. 3  is a cross sectional view taken along B-B in  FIG. 1 . As shown in  FIG. 3 , the pressing portion  32  is formed to have a cross-sectional shape in the foot width direction in which the portion from the lateral side (the left side in  FIG. 3 ) to the center portion is substantially, flat and the end on the medial side (the right side in  FIG. 3 ) projects upward. 
     In planar view of  FIG. 1 , the lifting portion  33  is formed at the region ranging from the tip of each of the second toe f 2 , the third toe f 3 , the fourth toe f 4  and the small toe f 5 , through the root portion of the four toes f 2  to f 5 , to the peripheral portion of the root portion of the four toes f 2  to f 5  on the heel side. 
       FIG. 4  is a cross sectional view taken along C-C in  FIG. 1 . As shown in  FIG. 4 , the lifting portion  33  is formed to have a cross-sectional shape in the foot length direction of an inclined plane, which becomes gradually higher from the heel side (the left side in  FIG. 4 ) toward the tip (the right side in  FIG. 4 ) of the four toes f 2  to f 5 . Thus, the lifting portion  33  lifts the four toes f 2  to f 5 . The lifting force is set to be greater than the force of a level plane naturally pressing the four toes  12  to f 5  when the foot f is placed on the level plane. 
       FIG. 5A  is a cross sectional view taken along D-D in  FIG. 1 ,  FIG. 5B  is a cross sectional view taken along E-E in  FIG. 1 , and  FIG. 5C  is a cross sectional view taken along F-F in  FIG. 1 . In  FIGS. 5A to 5C , the cross-sectional shape of the lifting portion  33  in the foot width direction is formed as an inclined plane being continuous from the concave portion  31 , i.e., becoming gradually higher from the second toe f 2  toward the small toe f 5 . As shown in  FIG. 5A , the inclination angle of the lifting portion  33  is set such that a straight line X connecting the top ends on the dorsal side of the four toes f 2  to f 5  becomes substantially horizontal. 
       FIG. 6  is a cross sectional view taken along G-G in  FIG. 1 . As shown in  FIG. 6 , in the lifting portion  33 , a projecting portion  33   a  is formed at the region corresponding to the clearance between the third toe f 3  and the fourth toe f 4 . The projecting portion  33   a  is configured to widen the clearance between the third toe f 3  and the fourth toe f 4 . 
     With the shoe  1  according to the present embodiment structured as described above, the insole  3  is provided with the concave portion  31  at the portion corresponding to the first site ranging from the ball f 1   a  of the big toe f 1  to the tip of the toe. Therefore, the weight load of the wearer acting on the big toe f 1  can be reduced, and the pain in the foot f can be alleviated. Further, the pressing portion  32  formed at the insole  3  presses the second site adjacent to the heel side of the ball of big toe f 1   a . The reaction force caused by the pressing allows the first site to sink in the concave portion  31 . Accordingly, the big toe f 1  naturally enters the medially deviated state, to approximate the original normal state from the laterally deviated state. Thus, the symptom of hallux valgus can be improved. Furthermore, since it becomes possible to suppress the big toe f 1  from being brought into contact with the sidewall portion of the shoe  1 , the pain in the foot f can be further alleviated. 
     Further, since the four toes f 2  to f 5  except for the big toe f 1  are lifted by the lifting portion  33 , the clearance between each adjacent ones of the four toes f 2  to f 5  can be widened. Thus, even in the state where the first site of the big toe f 1  sinks in the concave portion  31 , the weight of the wearer can be supported by the four toes f 2  to f 5  in a stable state. 
     Still further, since the straight line X connecting the top ends on the dorsal side of the four toes f 2  to f 5  lifted by the lifting portion  33  becomes substantially horizontal, it becomes possible to allow the weight load of the wearer to act on the four toes f 2  to f 5  substantially uniformly. Thus, the weight of the wearer can be supported by the four toes f 2  to f 5  in a further stable state. 
     Still further, since the projecting portion  33   a  formed at the lifting portion  33  makes it possible to widen the clearance between the third toe f 3  and the fourth toe f 4 , the weight load of the wearer can be shared by a pair of two toes, i.e., the second toe f 2  and the third toe f 3 , and another pair of two toes, i.e., the fourth toe f 4  and the small toe f 5 . Thus, the weight of the wearer can be supported in a further stable state. 
     Note that the present invention is not limited to the embodiment described above. For example, though a shoe has been exemplarily shown as the footwear in the embodiment described above, the present invention is applicable also to footwear such as sandals, straw sandals, split-toed socks, wooden clogs or slippers. 
       FIGS. 7 and 8  show the result of comparison verification as to the change in hallux valgus of a foot between before and after wearing the shoe according to the embodiment described above.  FIG. 7  is a drawing-substituting photograph showing the state of a foot before wearing the shoe, and  FIG. 8  is a drawing-substituting photograph showing the state of the foot wearing the shoe. The shoe in the photograph is shown only by the insole, so that the foot can be easily observed. 
     With the foot shown in  FIG. 7 , it can be seen that the big toe is in the laterally deviated state, that is, the tip of the big toe is deflected toward the small toe, and the root portion of the big toe is bent in a “V”-shape, to project toward the medial side in the foot width direction (the left side in  FIG. 7 ). 
     On the other hand, as compared to  FIG. 7 , the root portion of the big toe shown in  FIG. 8  is suppressed from being projecting toward the medial side in the foot width direction, and it can be seen that the symptom of hallux valgus is improved. Further, it can be seen that, in connection with the four toes except for the big toe shown in  FIG. 8 , the clearance between each adjacent ones of the toes is widened, as compared to  FIG. 7 . In particular, it can be seen that the widened clearance between the third toe and the fourth toe is considerably wider than the clearance shown in  FIG. 7 . 
     REFERENCE SIGNS LIST 
       1 : SHOE (FOOTWEAR) 
       3 : INSOLE 
       31 : CONCAVE PORTION 
       32 : PRESSING PORTION 
       33 : LIFTING PORTION 
       33   a : PROJECTING PORTION 
     f 1 : BIG TOE f 1   a : BALL OF BIG TOE 
     f 2 : SECOND TOE 
     f 3 : THIRD TOE 
     f 4 : FOURTH TOE 
     f 5 : SMALL TOE 
     X: STRAIGHT LINE