| 摘要 |
PROBLEM TO BE SOLVED: To provide a boring expanding tool which forms the construction hole of a metal expansion anchor having an undercut part in a base by one operation while the undercut part of the formed construction hole is exact and excellent in durability. SOLUTION: The tool has a fitting part 21 for a drill blade 2 at the tip, a propulsion shaft having a connection shaft 3, a fixed cylinder 4 housing the propulsion shaft arranged at the base end of the propulsion shaft 3, an inside cylinder 6 in which a transmission shaft 5 is inserted slidably into its base end side, an outside cylinder 7 which is inserted into its outside slidably in the axial direction with a tip surface projected by a prescribed distance from the tip surface of the fixed cylinder and arranged at the tip, a breaker 53 with fixing released by the movement of the outside cylinder 7 in the base end direction, and an eccentric screw 9 which is arranged on the base end side of the fixed cylinder 4, is inserted into the fixed cylinder on the outside, forms a lead angle in the right-left direction formed by a ball channel 91 engaged with a ball 71 fixed by the outside cylinder 7 along a peripheral surface, and has an eccentric hole 92 for the insertion of the propulsion shaft 3. COPYRIGHT: (C)2006,JPO&NCIPI
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