RIB-PLANE CONVERTER JOINT AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To manufacture a rib-plane converter joint easily and inexpensively through a series of steps including extrusion molding. SOLUTION: A ribbed portion 16 and a non-ribbed portion 18 are formed continuously with the same inside diameter, and the non-ribbed portion 18 with no flat strength by ribs 22 is provided with a greater wall thickness for reinforcement. The ribbed and non-ribbed portions 16 and 18 are formed through pipe extrusion by an extruder and pipe withdrawal by ribbed and non-ribbed blocks. The pipe withdrawal speed is controlled, and each molding block is supplied with proper amounts of synthetic resin material depending on the ribbed and non-ribbed portions 16 and 18.