| 摘要 |
PURPOSE:To simultaneously make two U-shaped pieces and reduce working cost, by extruding a thermoplastic resin pipe of cross section shaped like a hollow gourd and by cutting off the pipe along the narrow part of the cross section. CONSTITUTION:After a thermoplastic resin pipe of cross section shaped like a hollow gourd is extruded, the resin pipe is cut off along the narrow part of the gourd-shaped cross section so that two U-shaped pieces are simultaneously and continuously manufactured. To form the resin of cross section shaped like a hollow gourd, the extrusion is effectd by using a die having a gourd-shaped material discharge port 1 or by the like. Extrusion may be performed to provide notches on one or both of the inside and outside of the resin pipe in two facing positions on the narrow part and divide the pipe along the notches to facilitate the cutting-off, shape each cut-off end like a wedge and facilitate the fitting of the U-shaped piece on a protective piece. |
