TUBE EXTRUSION HEAD

摘要

1477616 Extruding bow moulding parisons HOOVER BALL & BEARING CO 6 March 1975 [18 March 1974] 9428/75 Heading B5A A plastics blow moulding parison is intermittently extruded from a die head accumulation chamber 42, defined between the die head mandrel 18 and a surrounding part 48 of the die head which is provided with a diverging piston surface 64 and which effects alternate accumulation 9 extrusion, upon axial displacement with respect to the mandrel 18 and with respect to and around both an upper die body part 36, and a lower die body part 50 to which the extrusion die 58 is attached. For extrusion the part 48 is downwardly displaced by a plurality of hydraulic or pneumatic power cylinders 82, which are carried by a stationary mounting plate 78 and the piston rods 86 of which are attached to the part 48 at a plate 78. For accumulation, upward displacement of the part 48, which may be assisted by the cylinders 82, is effected by the material continuously delivered from an extruder screw to the chamber 42, and acting against a lower resistance from the part 48 that that of extrusion of material through the extrusion outlet passage 44. A stationary plate 74 carries the die part 36, and carries the part 50 at a plurality of rods 80 around which the plate 78 slides during displacement of the part 48. The mandrel is provided with an air conduit 20 extending to a blow pin 22 and, during extrusion, is axially displaceable to vary the outlet 44 and wall thickness of the parison, by a programming cylinder 24. The diameter of the parison is variable by removable mounting of a tip 91 to the mandrel, and of a tip 58 and ring 54 to the die part 50 at a clamp ring 56. Heaters 60, 66, and 90 are provided.