| 摘要 |
A die 10 for reducing polyethylene pipe temporarily to enable it to be inserted in a pre-existing metal pipe is made of cast iron and has formations 20 by which the die is splittable into two portions. The formations receive cylindrical bars 14 which are squeezed together by a hydraulic squeeze off machine. Each formation is a U-shaped aperture with a saw cut 22 extending from the base of the U into the ligament beneath the formation. The saw cut acts as a stress raiser. In a modification only one formation is provided. The die is made of grey cast iron or some other brittle material. <IMAGE> |
