Patent ID: 8650665

Claim:
A bottom periphery length adjustment mechanism comprising: a slide adjuster, wherein the slide adjuster comprises a band and a buckle that are formed of a synthetic resin and an engagement claw of the buckle is engaged with a serrated engagement groove provided on an outer surface of the band so that, in an engaged state, the band non-retractably approaches the buckle; the buckle comprises a buckle body that comprises a bottom plate and a ceiling frame facing to each other and two side plates for connecting the bottom plate to the ceiling frame, an inside of the buckle serving as a band insertion space; and an operating plate that is horizontally provided on an inner side of the ceiling frame and has, on an under surface at one end, the engagement claw engageable with the engagement groove of the band, the other end functioning as a pressing part for releasing the engagement, the operating plate being supported by a connecting shaft between the two side plates or the ceiling frames at an intermediate point between the engagement claw and the pressing part to render the operating plate swingable around the intermediate point as a fulcrum; a height of the pressing part is equal to or lower than that of the ceiling frame; the buckle is fixed to a backside of the bottom through the ceiling frame; and when the band approaches the buckle, the periphery of the bottom shrinks, and when the band moves away from the buckle, the periphery of the bottom expands.