| 摘要 |
<p>The non-bendable straight tube part (20) of at least one segment has longitudinal movement restricting protrusions (30) which are provided on and protrude from the outer peripheral surface (20a) of the non-bendable straight tube part (20) and which are provided with a gap provided therebetween, the gap having a width equal to the width of an affixation member (50). In order to restrict the circumferential movement of the affixation member (50) relative to the non-bendable straight tube part (20), the non-bendable straight tube part (20) further has a circumferential movement restricting protrusion (40) which is provided on and protrudes from the outer peripheral surface (20a) so as to rectilinearly extend from one end to the other end of the non-bendable straight tube part (20).</p> |
