Abstract A hollow structure of thermoplastic material which is light in weight and exhibits excellent mechanical strength property and heat insulation property is produced by forming a resin path by a die body and a core member for the extrusion of the hollow structure comprising an outer shell having a plurality of spaces at an opening thereof and diaphragms, extruding the thermoplastic resin into the core member from the die equipped with a gas path having at least two circuits communicating with said spaces, blowing gas alternately into the spaces within the extruded hollow structure through said circuits to expand and move the diaphragms to fuse alternate diaphragms with their adjoining diaphragms or outer shell so that the hollow sections can be formed into isolated chambers for each of the alternate gas blows while preventing the substantial expansion of the outer shell of the hollow body by contact with a cooling unit following the die.
A METHOD FOR MANUFACTURING A HOLLOW STRUCTURE OF THERMOPLASTIC RESIN COMPRISING THE STEPS OF FORMING A RESIN PATH BY A DIE BODY AND A CORE MEMBER FOR THE EXTRUSION OF THE HOLLOW STRUCTURE COMPRISING AN OUTER SHELL HAVING A PLURALITY OF SPACES AT AN OPENING THEREOF AND DIAPHRAGMS, EXTRUDING THE THERMOPLASTIC RESIN FROM THE DIE EQUIPPED WITH A GAS PATH INTO SAID CORE MEMBER HAVING AT LEAST TWO CIRCUITS COMMUNICATING WITH SAID SPACES, BLOWING GAS ALTERNATELY INTO THE SPACES WITHIN THE EXTRUDED HOLLOW STRUCTURE THROUGH SAID CIRCUITS TO EXPAND AND MOVE THE DIAPHRAGMS AND FUSE ALTERNATE DIAPHRAGMS WITH THEIR ADJOINING DIAPHRAGMS AND OUTER SHEETS OF SAID SHELL SO THAT THE HOLLOW SECTIONS CAN BE FORMED INTO ISOLATED CHAMBERS FOR EACH OF THE ALTERNATE GAS BLOWS TO PREVENT THE OUTER SHELL OF THE HOLLOW BODY FROM EXPANDING SUBSTANTIALLY BY CONTACTING SAME WITH A COOLING UNIT FOLLOWING SAID DIE BODY.
Claim 2
Independent Claim
148 words
A METHOD FOR MANUFACTURING A HOLLOW STRUCTURE OF THERMOPLASTIC RESIN COMPRISING THE STEPS OF FORMING A RESIN PATH BY A DIE BODY AND A CORE MEMBER FOR THE EXTRUSION OF THE HOLLOW STRUCTURE COMPRISING AN OUTER SHELL HAVING A PLURALITY OF SPACES AT AN OPENING THEREOF AND DIAPHRAGMS, EXTRUDING THE THERMOPLASTIC RESIN FROM THE DIE EQUIPPED WITH A GAS PATH INTO SAID CORE MEMBER HAVING AT LEAST TWO CIRCUITS COMMUNICATING WITH SAID SPACES, BLOWING GAS ALTERNATELY INTO THE SPACES WITHIN THE EXTRUDED HOLLOW STRUCTURE THROUGH SAID CIRCUITS TO EXPAND AND MOVE THE DIAPHRAGMS AND FUSE ALTERNATE DIAPHRAGMS WITH THEIR ADJOINING DIAPHRAGMS AND OUTER SHEETS OF SAID SHELL SO THAT THE HOLLOW SECTIONS CAN BE FORMED INTO ISOLATED CHAMBERS FOR EACH OF THE ALTERNATE GAS BLOWS TO PREVENT THE OUTER SHELL OF THE HOLLOW BODY FROM EXPANDING SUBSTANTIALLY BY CONTACTING SAME WITH A COOLING UNIT FOLLOWING SAID DIE BODY.