Method and apparatus for multiple blow molding with rotary turntable

Claim 1

A blow molding apparatus comprising a rotary indexing turntable, means to rotatably index the turntable at a predetermined number of circumfrentially spaced stations, said turntable having at least one partible mold mounted therewith for each of first and second indexing stations, means to provide opened molds at said first and second stations, first means to form a first parison operatively positioned at said first station, and second means to form a second parison operatively positioned at said second station circumfrentially spaced from said first station, said first and second parisons being formed at about the same time, means to position said first parison and means to position said second parison between the parted sections of each of the respective molds at the respective first and second stations, means to close said opened molds on said extruded and positioned parisons at the respective first and second stations, first means and second means to introduce air under pressure to the interior of each of the respective parisons to expand the parisons to conform to the interior of the respective molds so as to form hollow objects therein, means to cool each of said objects during rotation of the turntable and circumfrential transfer of tHe molds from said respective first and second stations, and means for removing the formed objects from the opened molds so as to permit other extruded parisons to be positioned therebetween, and wherein said first parison forming means comprises a first extruder and first die means and wherein said second parison forming means comprises a second extruder and second die means, said die means being spaced from said respective molds, and wherein said rate of first extrusion is about equal to the rate of said second extrusion, and means to interconnect the first extruder to each of said means to position said parisons between the respective opened molds, so as to simultaneously position said first and second parisons, said means to simultaneously position said first and second parisons comprising cam means mounted with said interconnecting means and switch means operatively mounted with said cam means to be actuated thereby, whereby the first extrusion rate is proportional to the rate of actuating said switch means, said switch means being interconnected to first parison severing and gripping means and first parison lowering means and to second parison severing and gripping means and second parison lowering means, so that upon actuation of said switch means said first parison and said second parison are simultaneously severed from the respective extruder die means, gripped and then lowered into position between the opened partible molds.