Plastic object blow molding method and apparatus

Claim 1

IN THE FORMATION OF REDUCED DIAMETER UPPER PORTION AND ENLARGED BOTTOM DIAMETER CONTAINERS BY EXTRUDING A TUBULAR PARISON AND EXPANDING THE PARISON BY INTERNAL AIR PRESSURE WITHIN A MOLD COMPRISING A PAIR OF CAVITATED SECTIONS ADAPTED TO PINCH TOGETHER THE WALLS OF THE PARISON ALONG A BOTTOM DIAMETER IN AN AXIAL PLANE OF THE FORMED CONTAINER, THE METHOD THAT INCLUDES: (1) EXTRUDING ONE EXTENT OF THE PARISON HAVING AT OPPOSITE SIDES OF SAID PLANE A RELATIVELY LESSER WALL THICKNESS THROUGHOUT A LENGTH OF THE PARISON WHICH FORMS SAID REDUCED DIAMETER PORTION OF THE CONTAINER, AND (2) EXTRUDING ANOTHER CONTAINER BOTTOM-FORMING EXTENT OF THE PARISON OF LOCALIZED RIB-LIKE INCREASED WALL THICKNESS AT OPPOSITE SIDES OF SAID PLANE WHICH ARE GREATER THAN THE FIRST MENTIONED WALL THICKNESS AND GREATER THAN THE WALL THICKNESS OF THE LAST MENTIONED EXTENT IN SAID PLANE, (3) INTERNALLY BLOWING SAID PARISON EXTENT TO CONFORMANCE WITH THE INSIDE WALLS OF SAID MOLD SO AS TO CAUSE SAID LOCALIZED RIB-LIKE INCREASED WALL THICKNESSES TO FORM AXIAL RIBS IN THE THINNER WALLS OF THE BLOWN CONTAINER AT OPPOSITE SIDES OF SAID PLANE.