| 摘要 |
PURPOSE:To enable to efficiently manufacture a duct with uniform thickness by a method wherein a hollow body is formed by blow-molding a parison, which is made by extrusion, in a mold after the shape of the inner wall of the mold and both its ends are cut off and an opening, to which a transparent plate is attached, is made on its side wall. CONSTITUTION:Firstly, an extrusion molder 15 is located above between a left and a right molding dies 13 and 14, both of which are in an open state. Secondly, a parison 17 made of polypropylene or the like is extruded from a nozzle 16 between the dies 13 and 14. Thirdly, the left and the right dies 13 and 14 are closed and a nozzle 19 is inserted into the dies 13 and 14 through the parison 17 in order to supply compressed air in the parison 17. Fourthly, after resin cools and solidifies, the dies 13 and 14 are open and a hollow body 20 is taken out of the dies. Fifthly, both ends of the hollow body 20 are cut off. Sixthly, an opening 23 is blanked by being guided with a patch 21 inserted in the interior of the hollow body 20 and further rivet holes are pierced. A segmented duct 11 is completed by making a transparent plate 25 made of polyvinyl chloride or the like, which is held between an annular metal sheet 26 and the side wall of the hollow body, the sheet 26 and the side wall into an integral body by means of rivets 27. |
