| 摘要 |
1,156,727. Extrusion dies. E. I. DU PONT DE NEMOURS & CO. 18 July, 1966 [19 July, 1965], No. 32161/66. Headings B5A and B5B. A cross-head extrusion die comprises rotatable die members 24, 26, the former of which is attached to a shaft 22 axially adjustable by transverse movement of an annular wedge 30 and provided at the downstream end of inlet 10 with a converging portion which allows a thrust on shaft 22 to be created which is opposite to the thrust of the extruding material on die member 24. Wedge 30 is moved by rotating bolt 36 and axial movement of shaft 22 is produced via a block 38 which houses bearing 44 and abuts a cover plate 40 fixed to the shaft. Leakage of material between shaft 22 and housing 14, 16 is prevented by an upstream seal comprising a fixed metal ring 52 and a metal ring 54 which rotates with shaft 22 and is urged into contact with ring 52 by means of a spring 56 and a basically similar downstream seal 52A, 54A &c. Die member 26 is rotated via spur gear 28. The die is particularly intended for the production of tubular netting or ribbed tubular film. Materials specifically mentioned are polyamides, polyesters, polyvinylhalides and copolymers thereof with vinyl acetate or vinylidene chloride, cellulose acetate and natural or synthetic rubbers, thermosetting reins possibly mixed with thermoplastic resins, viscose, cupra-ammonium cellulose or a protein material, e.g. derived from soya bean.
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