Seesaw- motion footwear sole

Abstract

A footwear sole having a dual-structure midsole, in which a seesaw movement can be performed to enhance an exercise effect during walking. The seesaw-motion footwear sole includes a main midsole having a convex projection in the central portion of the underside thereof to define a walking axis; a sub-midsole coupled to the underside of the main midsole and made of a softer material than that of the main midsole in order to exhibit a primary shock absorbing function, wherein the sub-midsole allows the main midsole to perform a seesaw movement on the basis of the walking axis in backward and forward directions during walking; and an outsole coupled to the sub-midsole. The seesaw-motion footwear sole can be applied to a variety of shoes such as running shoes, and can advantageously provide an excellent exercise effect, which is superior to that provided by heelless shoes of the prior art.

1 . A seesaw-motion footwear sole, comprising:
 a main midsole having a convex projection in a central portion of an underside thereof to define a walking axis;   a sub-midsole coupled to an underside of the main midsole and made of a softer material than that of the main midsole in order to exhibit a primary shock absorbing function, wherein the sub-midsole allows the main midsole to perform a seesaw movement on a basis of the walking axis in backward and forward directions when walking; and   an outsole coupled to the sub-midsole.   
     
     
         2 . The seesaw-motion footwear as claimed in  claim 1 , wherein the main midsole includes a shank embedded therein, the shank having an elastic plate shape in order to maintain a shape of the main midsole. 
     
     
         3 . The seesaw-motion footwear as claimed in  claim 2 , wherein the main midsole and the sub-midsole are configured to mate and couple with each other, in which a portion of a coupling surface of the sub-midsole convexly projects and a corresponding portion of the main midsole is concavely recessed. 
     
     
         4 . The seesaw-motion footwear as claimed in  claim 3 , wherein the portion of the sub-midsole that convexly projects, projects by varying amounts in response to load distributions thereon. 
     
     
         5 . The seesaw-motion footwear as claimed in  claim 1 , wherein the sub-midsole has a polyol cloth having a waterproofing function attached to an outer surface thereof. 
     
     
         6 . The seesaw-motion footwear as claimed in  claim 5 , wherein the sub-midsole is configured to be thinnest in a portion corresponding to the walking axis of the main midsole.