| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly crime-preventive screw free from easy turn and removal with external force. SOLUTION: This fastener comprises a male screw 6 consisting of a head portion 7 having a groove to which the front end of a tool such as a driver is applied, and a rod portion 9 to be inserted into a cylindrical portion 3 of a female screw 1, and the female screw 1 consisting of the cylindrical portion 3 into which the rod portion 9 of the male screw 6 is inserted, and a dome-shaped head portion 2 having no groove. At least one columnar protrusion 4 is provided on a reverse face 5 of the head portion of the female screw to improve the crime-preventive property of the fastener. COPYRIGHT: (C)2009,JPO&INPIT
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