| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw piercingly fitted to a coping, a colorbest(R), and a sheathing roof board from above the coping in a roof structure having the roof board as thick as T1, the colorbest(R) as thick as T2 laid on the roof board, and the coping as thick as T3 laid on the vest substantially in the condition of T1=T2=T3. SOLUTION: The screw has a plate-shaped head and a shank extending from the head together, and constituting a self-drill screw provided with a drill at the extremity of the shank and also constituting the front end part including the drill, tail end including the head, and a middle part positioned therebetween. A screw thread is formed only in the middle part. Next formulas are expressed, L1≥T3+T2, approximately L2=T3+T2, approximately L3=T1, L1 stands for length of the front end, L2 stands for length of the middle, and L3 stands for length of the tail end. COPYRIGHT: (C)2004,JPO
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