| 摘要 |
PURPOSE:To prevent buckling of a guide tube with constitution though relatively simplified by providing an insertion hole tilting in a direction approaching the center line of an insertion part in accordance with the insertion hole advancing to a side of the guide tube. CONSTITUTION:When a curved part 6 is curved, a flexing piece 8, exposed in its internal surface, approaches a protecting sheath 37 of a guide tube 35. When both the piece and sheath are brought into contact, the guide tube 35 is bent. On the contrary, the guide tube 35 is tilted in a direction of the center line X1 of an insertion part 2 along an insertion hole 31 in its tilt and drawn by the amount of that tilt to a part near the center line X1, so that a distance between the guide tube 35 and an internal surface of the flexing piece 8 increases. Consequently, bending by contact of the guide tube 35 with the flexing piece 8 is decreased extremely small, while the radius of curvature of the bending increases even for the temporary bending, so that the guide tube 35 is decreased in its interference with the flexing piece 8, being prevented from buckling. |
