| 摘要 |
PURPOSE:To obtain a strong corrugated pipe by pressingly joining with pressing force, which is controlled at respective stages in the axial shifting of the corrugated pipe, for long time enough for joining by a method wherein projecting portions or recessed portions are engagingly pressed with a plurality of specified endless belts intermittently in regular succession. CONSTITUTION:A spiral pipe C is continuously made by spirally and pilingly winding a band-like body A and a pipe-like body B, both of which are respectively supplied from both extruders, round a rotating mandrel 4. In the spiral pipe C, the overlapped parts of the band-like body A are pressingly joined to each other over every nearly semicircular peripheries of respective belts of an endless belt set 5. Since the joining of the overlapped parts is intermittently done by the separate endless belts 5x, 5y..., the band-like body is pressingly joined for long time enough for joining and pressing force can be controlled at respective stages in the axial shifting of a corrugated pipe, resulting in fully ensuring the bonding property between the bodies irrespective of the fact whether the bodies are made of non-rigid synthetic resin or rigid synthetic resin. Further, due to the control of the pressing force and the shaping action of the belt 5x, the section of the pipe-like body B is held in the predetermined perfect circular form and consequently the desired strength to pressure of the pipe is obtained. |
