Sole Structure for a Sports Shoe

Abstract

A sole structure for a sports shoe that controls bendability of a forefoot region of the sole structure. The sole structure includes an upper midsole disposed on an upper side of the forefoot region of the sports shoe and formed of a soft elastic material, a lower midsole disposed under the upper midsole and formed of a soft elastic material, and an outsole that is disposed on a lower surface of the lower midsole and that has sole bent grooves extending substantially in a sole width direction. Both the lower surface of the upper midsole and the upper surface of the lower midsole have corrugated mating surfaces that are formed of wavy shapes extending substantially in a sole longitudinal direction. Ridge lines and trough lines of the wavy shapes of the upper midsole extend substantially in the sole width direction. The ridge lines of the wavy shapes of the upper midsole of a relatively higher hardness are overlapped with the sole bent grooves of the outsole in a vertical direction.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates generally to a sole structure for a sports shoe, and more particularly, to the sole structure that can control bendability of a forefoot region by preventing an excessive bending of the forefoot region.[0002]EP3146862A2 discloses an article of footwear that includes a midsole having an undulating (i.e. zigzag) shape with alternating peaks and troughs in a sole longitudinal direction (see para. [0018] and FIGS. 1 and 2). The midsole has a gap formed between the adjacent peaks (i.e. above the trough between the adjacent peaks) and between the adjacent troughs (i.e. below the peak between the adjacent troughs). The gap between the adjacent peaks and the gap between the adjacent troughs extend across the entire width of the midsole (see para. [0018] and FIGS. 1 and 2).[0003]In the sole structure described in EP3146862A2, when the troughs of the undulating (or zigzag-shaped) midsole contact the ground surface a compressive fo...

AI Technical Summary

Benefits of technology

[0012]When the forefoot region of the sole structure is going to bend along the sole bent groove of the outsole at the time of bending of the sole structure, the thick part of the upper midsole or the lower midsole of a relatively greater hardness disposed at the sole bent groove is also going to bend at the same time. However, since such a thick part is a high-rigidity part, it has a greater bending resistance and it thus prevents an excessive bending locally along the sole bent groove of the sole structure. Thereby, bendability of the forefoot region can be controlled and an occurrence of an energy loss resulted from a locally excessive bending can be prevented.

[0015]When the forefoot region of the sole structure is going to bend along the sole bent groove of the outsole at the time of bending of the sole structure, the thick part of the upper midsole or the lower midsole disposed at the position on of the sole bent groove is also going to bend at the same time. However, since such a thick part is a high-rigidity part, it has a greater bending resistance and it thus prevents an excessive bending locally along the sole bent groove of the sole structure. Thereby, bendability of the forefoot region can be controlled and an occurrence of an energy loss resulted from the locally excessive bending can be prevented.

[0025]The upper surface of the lower midsole or the lower surface of the upper midsole without the corrugated surfaces may have a planar surface, and there may be formed a gap between the planar surface and the lower surface of the upper midsole or the upper surface of the lower midsole. Thus, when a load is transferred to the forefoot region of the sole structure, cushioning properties is improved.

Problems solved by technology

However, in the structure of EP3146862A2, at the time of bending of the midsole, an excessive bending is likely to occur locally at the troughs of the zigzag-shaped midsole.

An occurrence of such a locally excessive bending causes an energy loss.

In the structure of JP Pat. No. 3403952, since the soft upper midsole is exposed at the bottom portion of the sole bent groove, an excessive bending is similarly likely to occur to cause an energy loss at the time of bending along the sole bent groove.

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