Method and apparatus for producing double-walled containers

Claim 1

APPARATUS FOR FORMING DOUBLE-WALLED PLASTIC ITEMS WHICH COMPRISES, IN COMBINATION, PLASTICATING MEANS, PARISON DIE MEANS WHICH COMPRISE A FIRST INNER MANDREL PROVIDED WITH A COOLING CHANNEL THEREIN SO ADAPTED AS TO COOL SAID MANDREL, A SECOND INNER MANDREL CONCENTRICALLY DISPOSED ABOUT SAID FIRST INNER MANDREL SO AS TO FORM AN INNER ANNULAR AREA, AN OUTER MANDREL CONCENTRICALLY DISPOSED ABOUT SAID SECOND INNER MANDREL SO AS TO FORM AN OUTER ANNULAR AREA, SAID FIRST INNER MANDREL EXTENDING INTO THE CAVITY OF SAID MOLDING MEANS, MOLD CAVITY MEANS, SAID PLASTICATING MEANS COMMUNICATING WITH SAID FIRST AND SECOND ANNULAR AREAS ADJACENT SAID PARISON DIE MEANS, SAID ANNULAR AREAS BEING ADAPTED TO DIRECT ANNULAR FLOW OF PLASTIC MATERIAL INTO SAID MOLD CAVITY MEANS, SAID MOLD CAVITY MEANS BEING POSITIONED IN ALIGNMENT WITH SAID PARISON DIE MEANS, AND MEANS COMMUNICATING WITH SAID MOLDING MEANS TO APPLY FLUID PRESSURE IN SAID MOLDING MEANS BETWEEN SAID INNER AND OUTER ANNULAR AREAS.

Claim 3

A METHOD OF FORMING FLUID INSULATED DOUBLE-WALLED ITEMS WHICH COMPRISES THE STEPS OF (A) EXTRUDING AN INNER PARISON OVER A MANDREL AND SIMULTANEOUSLY EXTRUDING AN OUTER PARISON ABOUT AND SPACED FROM SAID INNER PARISON SO AS TO PROVIDE ONE WITHIN THE OTHER; (B) CLOSING A MOLDING MEANS AROUND SAID PARISONS; AND (C) INJECTING FLUID INTO THE SPACE BETWEEN SAID PARISONS SO AS TO BLOW SIMULTANEOUSLY SAID OUTER PARISON AND INNER PARISON TO ITS DESIRED FORM.

Claim 4

A METHOD OF FORMING FLUID INSULATED DOUBLE-WALLED ITEMS WHICH COMPRISES THE STEPS OF (A) EXTRUDING AN INNER PARISON OVER A MANDREL AND SIMULTANEOUSLY EXTRUDING AN OUTER PARISON ABOUT AND SPACED FROM SAID INNER PARISON SO AS TO PROVIDE ONE WITHIN THE OTHER; (B) CLOSING A MOLDING MEANS AROUND SAID PARISONS; AND (C) INJECTING FLUID INTO THE SPACE BETWEEN SAID PARISONS SO AS TO BLOW SIMULTANEOUSLY SAID OUTER PARISON AND INNER PARISON TO ITS DESIRED FORM.