Suction control in a suction/blowing mold system
AssigneeFischer-W. Muller Blasformtechnik GmbH
InventorsRudolf Küpper, Heinz-Hugo Willach, Hubert Müller
Life of this patent
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Abstract
A plastic hollow preform is drawn through a mold passage formed in a closed mold by applying a generally constant suction to a downstream end of a conduit having an upstream end connected to an output end of the mold passage. A flow cross section of the conduit is varied between its upstream and downstream ends so as to vary a rate at which the preform is drawn through the passage by the suction. The flow cross section is varied by displacing a valve element in the conduit between positions in which it differently blocks flow through the conduit.
Claims9
A molding method comprising the steps of:
- drawing a plastic hollow preform through a mold passage formed in a closed mold by applying a generally constant suction to a downstream end of a conduit having an upstream end connected to an output end of the mold passage;
- and
- varying a flow cross section of the conduit between its upstream and downstream ends and thereby varying a rate at which the preform is drawn through the passage by the suction.
A molding apparatus comprising:
- a closable mold forming when closed a nonstraight passage having an intake end and an output end;
- extruder means for forming a hollow plastic preform and feeding it to the intake end of the passage;
- a suction conduit having an upstream end connected to the output end of the passage and a downstream end;
- pump means connected to the downstream end of the conduit for applying a generally constant suction thereto;
- a valve element in the conduit intermediate its ends movable for varying a flow cross section of the conduit;
- and
- control means connected to the conduit and to the extruder means for moving the valve element, varying suction applied through the conduit to the passage in accordance with a position of the preform relative to the mold, and thereby varying a rate at which the preform is drawn through the passage by the suction.
Dependencies are inferred from the claim text.