| 摘要 |
PURPOSE: To increase the wall thickness of a trigonal pyramid-shaped corner part where three wall surfaces consisting of a plate part and rising parts cross each other in the production of a hollow double wall product equipped with the plate part and the rising parts bent from the periphery of the plate part. CONSTITUTION: A parison is arranged between opened molds 11, 12 to be held by clamping both molds and the part becoming the other wall of the parison in a trigonal pyramid-shaped corner part 6 is deformed so as to protrude by a slide member 15 to form a recessed part and the leading end surface thereof is welded to the part becoming one wall of the parison to form a welded part 8. Subsequently, a compressed fluid is introduced into the parison to expand the parison along cavities 11a, 12a and the outer surface of the slide member 15 and a recessed rib 7 wherein one end side is integrally molded along with other wall 2 and the other end side is welded to one wall 1 by the welded part 8 in the trigonal pyramid-shaped corner part is formed. |
