Apparatus for producing hollow plastic articles

Claim 1

IN AN APPARATUS FOR THE PRODUCTION OF HOLLOW THERMOPLASTIC ARTICLES, IN COMBINATION, AN EXTRUDING MACHINE INCLUDING AN EXTRUSION NOZZLE HAVING A VERTICAL AXIS AND ARRANGED TO DISCHARGE A PLASTIC TUBE VERTICALLY DOWNWARDLY; A CONVEYOR ARRANGED TO ADVANCE IN A PREDETERMINED PATH HAVING A STRAIGHT HORIZONTAL PORTION ADJACENT TO BUT SPACED FROM AND EXTENDING SUBSTANTIALLY AT RIGHT ANGLES TO THE AXIS OF AND BELOW SAID NOZZLE; A PLURALITY OF SPACED HOLDERS SECURED TO SAID CONVEYOR; AN ELONGATED BLOWING MANDREL MOUNTED IN EACH OF SAID HOLDERS AND MOVABLE WITH REFERENCE TO THE RESPECTIVE HOLDER IN DIRECTIONS AT RIGHT ANGLES TO THE AXIS THEREOF, EACH MANDREL WHICH IS TEMPORARILY LOCATED IN SAID STRAIGHT PORTION OF SAID PATH EXTENDING UPWARDLY FROM SAID CONVEYOR AND ITS AXIS BEING AT LEAST NEARLY PARALLEL WITH THE AXIS OF SAID NOZZLE; AN OPEN-AND-SHUT BLOW MOLD DISPOSED BETWEEN SAID NOZZLE AND SAID HORIZONTAL PORTION OF SAID PATH AND DEFINING A MOLD CAVITY WHICH REGISTERS WITH SAID NOZZLE WHEN THE MOLD IS SHUT SO THAT A LENGTH OF PLASTIC TUBE MAY BE ACCOMMODATED AND EXPANDED IN SAID MOLD CAVITY; ADVANCING MEANS FOR INTERMITTENTLY ADVANCING SAID CONVEYOR THROUGH SUCH DISTANCES THAT, DURING EACH INTERVAL BETWEEN INTERMITTENT ADVANCES OF SAID CONVEYOR, ONE OF SAID MANDRELS IS HELD IN VERTICAL POSITION AND REGISTERS AT LEAST APPROXIMATELY WITH SAID NOZZLE AND WITH SAID MOLD CAVITY WHEREBY SAID ONE MANDREL MAY EXTEND INTO ONE END OF THE TUBE IN SAID MOLD CAVITY TO EXPAND THE SAME, SAID ONE MANDREL BEING HELD BY SAID CONVEYOR IN VERTICAL POSITION, AT LEAST FOR A SHORT PERIOD OF TIME, DURING TRAVEL AWAY FROM REGISTRY WITH SAID NOZZLE; AND CENTERING MEANS FOR AUTOMATICALLY CENTERING SAID ONE MANDREL INTO ACCURATE REGISTRY WITH SAID NOZZLE.