| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of a mating degree of a main body and a tension screw in a primary tapping screw spike. SOLUTION: The primary tapping screw spike includes the main body, the tension screw and the drill head. Inside of the main body is hollow wherein the tension screw is inserted. The drill head is screwed to a head part of the tension screw, its rear part is driven by a tool, a male screw mating with a main body head part is provided at a middle stage and a screw part and a deformed part are provided at a main body external part. As a first feature, the mating part capable of holding a mating relation with the male screw of the tension screw when a hole is expanded by moisture is provided for an inner circumference of the main body head part. As a second feature, a stopper part for preventing ejection by looseness of the main body between an extended flange of the main body and a confronting surface of the tension screw is provided. COPYRIGHT: (C)2008,JPO&INPIT
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