METHOD AND APPARATUS FOR SHAPING A NORMALLY RIGID PLASTIC PIPE

摘要

A normally rigid plastic pipe is shaped by softening a selected zone of the pipe, inserting into the softened zone a resiliently deformable mandrel and pressing axially on opposite sides of the mandrel. This expands the mandrel radially into frictional engagement with the softened pipe zone. Simultaneously the mandrel is shortened axially, thereby correspondingly expanding radially and shortening axially the softened portion of the pipe while proportionately thickening its side walls.