| 摘要 |
An improved expansion screw and particularly an expansion screw for securely anchoring on various types of solid walls and hollow walls mainly includes a bolt and a nail tube. The nail tube has a front end fastened to a nut, a middle portion formed at least one expansion section which has carved slots formed thereon in an annular manner, and at least one <custom-character file="US20040067121A1-20040408-P00900.TIF" wi="20" he="20" id="custom-character-00001"/>-shaped slot formed annularly between the nut and the expansion section. Each <custom-character file="US20040067121A1-20040408-P00900.TIF" wi="20" he="20" id="custom-character-00002"/>-shaped slot has an expansion flap located therein. Every two neighboring <custom-character file="US20040067121A1-20040408-P00900.TIF" wi="20" he="20" id="custom-character-00003"/>-shaped slots are bridged by a longitudinal connection strip to form a bend section. When the bolt nut at the front end of the bolt is turned and driven to generate an inward compression, the expansion flap is forced to extend outwards and overlap with the annular ring at the front end of the nail tube, and the longitudinal connection strip is bent outwards on the bend section to form a double compression on the inner side of a construction hole in a wall to form a secured coupling. The multiple expansion section structure thus formed enables the invention be used in a wide variety of solid or hollow walls to form a secured fastening to minimize construction failure.
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