| 摘要 |
PURPOSE:To obtain the tough corrugated pipe excellent in connection and formability by a method in which while the projected part and/or the recessed part of every 1/4-1/2 round of a corrugated pipe, is enabled to be intermittently pushed into engagement in order by a plurality of endless belts, said pushing force is enabled to be regulated in each stage of moving the axis of the corrugated pipe. CONSTITUTION:A polyethylene beltlike body A is fed on the periphery of a rotary mandrel 4 from an extruder 2 and is wound spirally thereon, and when a polyethylene tubular body B is fed on said rear surface along the longitudinal direction of the beltlike body A from a reinforcing material-extruder 3, spirally projected ridges D are formed on the surface of a spiral pipe C. In the forming process of the spiral pipe C, a part of the beltlike body A to be secondarily wound is lapped onto the primarily wound beltlike body A, and said lapped parts are pushed and connected every about 1/2 round successively by each belt of the set 5 of endless belts. Since this connection is intermittently carried out by separate endless belts 5x, 5y..., the property of said connection is guaranteed by the sufficient time to be used therefor and the regulation of said pushing force. Since the cross section of the endless belt 5 correspondents to the spirally projected ridge, the corrugated pipe F with desired pressure resistant strength may be obtained. |
