| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to obtain a flexible pipe which bends flexibly in a direction necessary for insertion into the celom, is hardly bendable in the other directions exclusive of thereof and makes it possible to obtain excellent insertion by changing the inward projection length of projecting parts in a circumferential direction and differentiating the flexibility by the direction. SOLUTION: The projection length of the projecting parts 31 of a shell member to a pitch direction spacing of a helical pipe 10 from the inside surface of a net-like pipe 20 is change in the circumferential direction of the flexible pipe 1. In this embodiment, the projecting parts 31 are nearly flush with the inside surface of the helical pipe 10 and are lowest in the projection length in an upward direction and the projection length increases gradually therefrom to both right and left sides and is maximized in a downward direction. Such changes in the projection length of the projecting parts 31 may be arbitrarily formed by using an arbor of an external shape size smaller than the bore size of the helical pipe 10 and managing the position thereof at the time of extrusion molding. As a result, the helical pipe is characterized in that the pipe is extremely flexible and easily bendable in the upward direction and is less easily bendable in the other directions.
|
