| 摘要 |
PROBLEM TO BE SOLVED: To improve the antislip effects of a car and a pedestrian by forming a large number of projection groups having directivity of at least one row or more and being formed in an amoebiform form such as an approximately oval shape to the surface of a cover receiving frame and arranging the projection groups approximately annularly in fixed rows or more. SOLUTION: A collar edge 5 is provided around the upper section of the outer circumference of a cover receiving stepped section 1a formed to the inner circumference of the cover receiving frame, and a large number of true circular projections 2 and amoebiform projections 3 are formed to a surface. The true circular projections 2 and the amoebiform projections 3 are arranged concentrically annularly while keeping mutual spaces and one row of projection groups are formed, and triple projection groups are formed to the surface of the collar edge 5. The amoebiform projections 3 are disposed so that axes determining directivity mutually differ, and recessed sections 4 are formed at places deviated from centers to top faces. The true circular projections 2 are formed in a true circular-shaped columnar form in a plan view. The amoebiform projections 3 are formed in a shape that the whole circumferences are connected continuously in a curved shape, and formed in an approximately oval shape, an approximately elliptical shape, an approximately ground shape or the like, and protruded in the columnar shape from the collar edge 5. Accordingly, an antislip effect to a tire and the sole of a shoe can be improved.
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