Sole Structure for a Shoe

Abstract

The sole structure 1 has an upper plate, a lower midsole located under and fixedly attached to the upper plate, and having a laterally extending groove opening to the bottom side of the lower midsole, and a bending restriction member formed in a bent shape and spanning the groove longitudinally between the front edge and the rear edge of the opening of the groove. During the beginning phase of sole bending, the bending restriction member allows for the sole to bend till the bending restriction member gradually extends toward a straight shape from the bent shape and becomes taut between the front edge and the rear edge of the opening of the groove. During the advanced phase of the sole bending, when the bending restriction member experiences a force from the taut state, it functions so as to restrict the sole from bending.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates generally to a sole structure for a shoe, and more particularly, to an improved sole structure for decreasing an energy loss during running.[0002]Mizuno proposed a sole structure such as shown in WO 2006 / 070549 for improving bendability of a sole forefoot region of a shoe. The sole structure is comprised of a longitudinally extending upper plate disposed on an upper side of the sole forefoot region and a longitudinally extending lower plate disposed under and located away from the upper plate and having an undulated shape such that a longitudinal path length of the lower plate is greater than a longitudinal path length of the upper plate.[0003]In this case, during bending deformation of the sole forefoot region, the lower plate can further extend due to the undulated shape of a greater longitudinal path length and as a result the lower plate does not hinder bending deformation of the sole forefoot region, thus improving ...

AI Technical Summary

Benefits of technology

[0018]A sole structure for a shoe according to a first aspect of the present invention comprises a sole having a laterally extending groove that is formed on a bottom surface of the sole, and a bending restriction member that is formed in a bent shape and that spans the groove longitudinally between a front edge and a rear edge of an opening of the groove. In the beginning phase of bending of the sole, the bending restriction member allows for the sole to bend till the bending restriction member gradually extends toward a straight shape from the bent shape and becomes taut between the front edge and the rear edge of the opening of the groove. Thereafter, in an advanced phase of bending of the sole, when the bending restriction member experiences a force that pulls the bending restriction member in a longitudinal direction from its taut state, it functions so as to restrict bending of the sole.

[0019]According to the first aspect of the present invention, in the beginning phase of sole bending, the bending restriction member in the bent shape spanning the groove longitudinally between the front and rear edge of the groove allows for the sole to bend till the bending restriction member gradually extends toward the straight shape from the bent shape and becomes taut between the front and rear edge of the groove. Therefore, in the beginning of the push off phase of running, bending resistance of the sole becomes relatively small thus allowing for the sole to bend smoothly. As a result, an energy loss at the beginning of the push off phase can be decreased.

[0020]Thereafter, in the advanced phase of bending of the sole, the bending restriction member experiences a force that pulls it in the longitudinal direction from its taut state and the bending restriction member functions so as to restrict bending of the sole. Therefore, in the latter half of the push off phase of running, bending resistance of the sole becomes relatively large thus restraining the sole from bending. As a result, an energy loss in the latter half of the push off phase can be decreased.

Problems solved by technology

As a result, the push off motion of the sole forefoot region cannot be conducted in a smooth (i.e. rapid, secure and efficient) manner.

However, since the sole structure is so constructed as to make the sole rear foot region bend relative to the sole forefoot region, the bending properties of the sole forefoot region itself is not necessarily preferable.

Additionally, during the period from (b) to the middle of (b) and (c) of the push off phase, the shoe of a small bending resistance also generates an energy loss, but such an energy loss is neglectable.

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