Natural ventilation type footwear

Claim 1

An article of footwear, comprising: an outsole; an upper attached to an upper surface of the outsole, said upper having a heel end, a toe end, and two opposing side walls, wherein a rectangular slot is formed in each opposing side wall; an insole located in said upper and having an upper surface and an outer lateral surface, said upper surface having a plurality of openings located therein, said outer lateral surface having a plurality of passages therein, said openings and said passages being in communication with each other; a vent frame member attached to each opposing side wall of the upper and having a rectangular boundary frame which defines an opening aligned with one of the rectangular slots and an inner peripheral wall, a groove located in the inner peripheral wall of the boundary frame, and a plurality of alternating vent holes and blind parts located in the opening defined by the boundary frame, the vent holes of each vent frame member communicating with the passages located in the outer lateral surface of the insole; and a shutter member located in each of the vent frame members, and having opposing edge portions which are slidably engaged in the groove of each of the vent frame members and a plurality of vent holes and blind parts, each of said shutter members being movable between a position where the vent holes of the shutter member are aligned with the vent holes of one of the vent frame members, and a position where the blind parts of the shutter member are aligned with the vent holes of one of the vent frame members.