PROBLEM TO BE SOLVED: To provide a fastener for a weed prevention sheet, excellent in durability and fixing strength with ground.SOLUTION: This fastener of a weed prevention sheet includes a head part fitting with a rotary tool, and a column like shaft part extending from the center of lower surface of the head part. The shaft part has a 5 to 15 mm diameter, a sharp tip end with 100 to 500 mm length in an axial direction, spiral screw threads formed at its outer circumference from the tip end of the shaft part to the position at or more than 1/2 of shaft directional length, and a part where the screw threads are not formed from the lower surface of the head part up to a position apart by ≥5 mm from the head part. A diameter (d1) of inscribed circle of the head part is larger than the diameter (d2) of the shaft part, the interval of the adjacent screw threads in the shaft direction is 3 to 10 mm. the height of the screw threads is 1 to 3 mm, the fastener is formed of iron, and a hot dipping plated layer of a metal having a larger ionization tendency than that of the iron is formed on the iron surface.COPYRIGHT: (C)2013,JPO&INPIT【課題】耐久性及び地面との固定強度に優れた防草シートの留め具を提供する。【解決手段】回転工具に適合する頭部と、該頭部の下面中央から延びる円柱状の軸部とを備え、前記軸部は、直径が5~15mmで先端が尖り、軸方向の長さが100~500mmで、外周には螺旋状のネジ山が前記軸部の先端から軸方向長さの1/2以上形成され、かつ前記頭部の下面から5mm以上離れた位置まではネジ山が形成されず、前記頭部の内接円の直径(d1)は前記軸部の直径(d2)より大きく、隣り合うネジ山の軸方向の間隔が3~10mm、ネジ山の高さが1~3mmであり、かつ前記留め具が鉄からなり、該鉄表面には鉄よりイオン化傾向の大きい金属の溶融めっき層が形成されている、防草シートの留め具。【選択図】図1
