| 摘要 |
<p>PURPOSE:To integrally bond the ring-shaped ridges formed to the leading ends of the side edge parts of a flat plate-shaped metal strip plate and to strongly bond adjacent strip plates mutually by a method wherein the strip plate is spirally wound while bent by a roll processing machine and the side edge parts of adjacent strip plates are mutually butted to coat the outer peripheral surfaces thereof with a molten resin. CONSTITUTION:When a flat plate-shaped metal strip plate 1 is sent into a roll processing machine 3 to be passed between rolls 31-36, the strip plate 1 is gradually bent to form a trough part 12 at the center thereof and, at the same time, both side edge parts thereof are curled into a circular arc shape to form ring-shaped ridges 13. Subsequently, the strip plate 1 is held between control rolls 37a, 37b and bent by bending rolls 38, 39 to be curved into a desired curvature and a spiral pipe is wound and molded. Next, the molten resin extruded from an extruder 6 is fused to the inner peripheral surface of the trough part 12 from the gap of the strip plate 1 and, thereafter, the outer peripheral surfaces of the side edge parts of the adjacent strip plate 1 are integrally coated with the molten resin extruded from an extruder 7 and, at least, the outer peripheral surfaces of the trough part 12 and the ridge parts on both sides thereof are integrally coated with the molten resin extruded from an extruder 8.</p> |
