| 摘要 |
PROBLEM TO BE SOLVED: To provide a tube boring device having excellent work efficiency, and easily boring with small force. SOLUTION: A cylindrical member 15 and a feed screw sleeve 23 integrated with the cylindrical member 15 are rotatably supported by a main body 2 and a main body cap 11. An O-ring 20 is disposed between the main body and the cylindrical member, thereby preventing rotations with weak force. A lead shaft 31 is inserted in the feed screw sleeve so as to be screwed by a first thread portion 34, and under that, a drill holder 41 wherein a drill 51 is integrally attached to a second thread portion 35 is screwed. The pitch of the first thread portion is larger than that of the second thread portion. When rotating a shaft member, first, the feed screw sleeve is not rotated by friction force of the O-ring. Relative rotations are generated in a space with the shaft member, and the shaft member is descended. Descending speed at that time is fast. When the drill is stuck to piping, the feed screw sleeve is integrally rotated with the shaft member, and the drill is descended in regard to the shaft member without descending the shaft member. The speed is slower than before. COPYRIGHT: (C)2005,JPO&NCIPI
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