| 摘要 |
This invention relates to a method and an apparatus for the production of pipes. In the extrusion of plastic pipes, a circular mould cavity is formed of chill moulds (1, 2) which are semicircular in cross-section and the junction faces of which are pressed against each other. In order to keep the chill moulds tightly against each other, it is known to provide the edge area of the chill moulds (1, 2) with counter pieces (4) which have locking surfaces (5) whereon a press force is exerted by means of a rail of a U-shaped cross-section. In this known solution, great friction forces are created between the locking surface (53 and the rail, and the diameter of the mould increases in a direction perpendicular to the junction faces. These disadvantages are avoided in the present invention wherein the apparatus comprises locking means (6) which follow the movement of the chill moulds (1, 2) and grip the locking surfaces (5) of the chill moulds. (Figure 4) |
