| 摘要 |
946,371. Extruding thermoplastic tubing. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. June 27, 1962, No. 24681/62. Heading B5A. Thermoplastic material is extruded through a die head comprising a mandrel 8 rotating within a die 7 and formed with a skirt 8D cooperating with a skirt 10A on a bush 10 to define a sinuous path for the thermoplastic material. The extruder screw 3A to which the mandrel 8 is secured, feeds the thermoplastic material through a breaker plate 9, thence along the sinuous path and over the conical surface 8c of the mandrel to the extrusion orifice 13. A dome shaped collar 12 on the mandrel shank 8A prevents accumulation of plastic material at the end of the screw. The extruded tube may be expanded against a calibrating die surface by compressed air supplied through a bore 14 in the mandrel 8. Alternatively the die may be rotated instead of the mandrel. Specifications 862,941, 867,566 and 867,576 are referred to.
|
