Appts. to produce corrugated pipe having small inner surface - composed of parallel rotary shafts with two bearing boards arranged along a cylinder with flat rolls mounted on top end portions of shafts, etc.

摘要

The novelty is that parallel rotary shafts supported by 2 bearing boards are arranged along a cylinder, flat rolls are mounted on the top end portions of the shafts and grooved rolls are mounted on the root end portions of the shaft to form an inner tubular die to form a corrugated pipe with an outside die.