| 摘要 |
1,036,711. Extrusion heads. BAKER PERKINS GRANBULL Ltd. Aug. 15, 1962 [Aug. 23, 1961], No. 30444/61. Heading B5A. In a variable area extruder head having an outer nozzle 1 (Fig. 1, not shown) and an inner mandrel 3, time profile cam means 17 are arranged to effect relative movement between the nozzle 1 and mandrel 3 to vary the size of the outlet orifice 2. The plastic material is fed from a cylinder 4 by a piston 5 to the shaft of which is attached the linear cam 17. A follower 16 regulates the movement of the mandrel 3 by means of a piston and cylinder arrangement 11, 12 thus automatically varying the orifice size. The ends of the nozzle and of the mandrel may be either flared outwardly or inwardly. Alternatively in a twin head extruder the mandrels 23 (Fig. 3, not shown) may be controlled by a piston-operated rack 25 moving pinion 33 fixed to eccentric 27. The automatic operation of the mandrels is controlled through an electrically operated hydraulic circuit, Fig. 4 (not shown).
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