| 摘要 |
PROBLEM TO BE SOLVED: To efficiently carry out a drawing work of a tube fixed to a structure by a relatively simple structure. SOLUTION: A plurality of slant surfaces 25 inclined along a retreat direction of a rod 13 are interspersed in a rotation direction of the rod 13 on a tip end portion of the rod 13 inserted into a tube 6. An engaging member 14 is provided every on a position corresponding to the slant surface 25 by surface contacting the engaging member 14 with the slant surface 25 in the state that a slide in a radial direction is only permitted. When the rod 13 is moved in retreat direction, the engaging member 14 slides in a radial direction by a guide of the slant surface 25 to press-contact to an inner surface of a tube 7. In contrast thereto, when the rod 13 is returned and moved in an advancing direction, a diameter-reducing block 10 urges the engaging member 14 in a direction that it is left from an inner surface of the tube 7 interlocked therewith and for forcedly leaving the engaging member 14 from the inner surface of the tube 7.
|
