Cap

Abstract

In a cap including a top plate that is circular in shape; and a side wall becoming larger in a tapered shape from an outer perimeter of the top plate toward a lower end having a ring-like shape, on an outer surface of the side wall, a plurality of knurls extending in a direction from the outer perimeter toward the lower end are arranged side by side, and on an inner surface of the side wall, grooves formed inside the respective knurls and an inner thread having a screw shape are provided, and the inner thread is split by the grooves. Each of the knurls has a ridgeline substantially in parallel with a vertical direction with respect to the top plate, and bottom surfaces of the respective grooves are provided in parallel with the ridgeline. Lower ends of the respective knurls are spaced apart from the lower end of the side wall.

Dependencies are inferred from the claim text.