| 摘要 |
974,596. Blow-moulding hollow articles. F. STUBBE. Oct. 24, 1963 [Oct. 24, 1962], No. 42101/63. Heading B5A. In a process for the production of hollow bottle-like thermoplastic articles of regulated wall thickness, a tube of plastic material of varying wall thickness extruded from an extrusion press at a constant linear speed is located in a two-part blowing mould 23 mounted below the extrusion nozzle 12. The tube is cut off by the sharp edges of the mould parts 23, Fig. 9, or by a separate cutter and compressed air is introduced into the tube through the blowing nozzle 24 to form the article in the closed mould. The extrusion press comprises a worm 3 positioned in a heated plasticizing cylinder 2, to which granulated plastic material is supplied from a hopper, and the worm 3 is mounted so that it can be reciprocated axially together with its drive 7 by the hydraulically actuated piston and cylinder assemblies 9, 10 to act as an extrusion piston. During the downward movement of the worm 3 the ring 11 at its tip acts as a non-return valve to prevent material flowing back past the worm. The plastic material is fed to a distribution head 4 from which four nozzle heads 5 offset at 90 degrees are fed through channels 6. The nozzle heads 5 have exchangeable outer nozzle sleeve members 12 in which an axially reciprocating nozzle mandrel 15 is concentrically positioned. The outlet cross-section of the nozzle is controlled by the axial movement of the mandrel 15 actuated by the piston and cylinder assembly 20, 21 between positions controlled by stop nuts 18 and a magnetic lock 19. The tube of the required varying crosssection is produced at a constant linear speed by simultaneous variation of the speed of axial downward movement of the worm 3 with the axial movements of the nozzle mandrel 15 by means of a programme controlled hydraulic circuit including the electrically or magnetically operated throttle valves 38, 39, 45 and reversing valves 35, 42. The nozzle member 12 may be replaced by a flexible sleeve 50, Fig. 11, the outlet cross-section being controlled by an axially displaceable ring 51 actuated hydraulically as previously for the movable mandrel, or member 12 may be replaced by a mechanically operated diaphragm similar to an iris diaphragm.
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