Apparatus for curling rims of articles

Claim 1

APPARATUS FOR FORMING A RIM ON A THIN-WALLED THERMOPLASTIC CONTAINER, COMPRISING A MOLD HAVING A CAVITY, AN UPSTANDING ANNULAR PROJECTION SURROUNDING AN UPPER MARGIN OF THE MOLD CAVITY, A DIE BLOCK HAVING A MANDREL DISPOSED OPPOSITE TO SAID MOLD CAVITY ANDBEING PROVIDED WITH AN ANNULAR RECESS ENCIRCLING SAID MANDREL AND ALIGNED WITH SAID UPSTANDING PROJECTION, MEANS FOR CLAMPING HEATED THERMOPLASTIC MATERIAL INTERMEDIATE OF AND IN A CIRCUMFERENTIAL MANNER OUTSIDE THE MANDREL AND MOLD PERIPHERY, MEANS FOR RELATIVELY SHIFTING SAID MOLD AND MANDREL TOWARD EACH OTHER TO THEREBY DRAW PREDETERMINED AREAS OF THE MATERIAL INTO THE MOLD CAVITY AND FOR POSITIONING SAID ANNULAR PROJECTION AND RECESS IN COOPERATIVE RELATIONSHIP, THE MAXIMUM DIMENSION OF SAID RECESS BEING LESS THAN SAID PROJECTION WHEREBY TO CLAMP AN UPPER MARGINAL PORTION OF SAIOD PREDETERMINED DRAWN AREAS ON SUBSTANTIALLY OPPOSITE SIDES OF SAID ANNULAR PROJECTIN TO SEAL SAID ARTICLE FROM THE REMAINDER OF THE WEB AND ENCLOSE SAID UPPER MARGINAL PORTION WITHIN A SEALED CHAMBER, MEANS FOR ESTABLISHING A POSITIVE FLUID PRESSURE ACROSS SAID DRAWN MATERIAL TO EXPAND THE SAME AGAINST THE INNER PERIPHERY OF THE MOLD AND COMPLETE THE FORMATION OF THE CONTAINER, CHANNEL MEANS CONNECTING PORTS FORMED IN THE FEMALE MOLD WITH SAID SEALED CHAMBER UPON THE EXPANSION OF PREDETERMINED DRAWN AREAS AGAINST THE INNER PERIPHERY OF THE FEMALE MOLD, THE AIR BETWEEN SAID PREDETERMINED DRAWN AREAS AND SAID FEMALE MOLD IS FORCE THROUGH SAID PORTS AND CHANNEL MEANS INTO SAID SEALED CHAMBER TO CAUSE SAID OUTER MARGINAL PORTION TO ASSUME A PREDETERMINED CROSS SECTIONAL CONFIGURATION RELATIVE TO SAID CONTAINER AXIS, SAID DIE BLOCK ADJACENT SAID RECESS AND SAID ANNULAR PROJECTIN HAVING COMPLEMENTARY CUTTING EDGES FOR SEVERING THE CONTAINER AND ITS UPPER MARGINAL PORTION FROM THE REMAINDER OF THE WEB, THE CONTINUED MOVEMENT OF AT LEAST A PORTION OF SAID ANNULAR PROJECTION ENGAGING AND CURLING THE SEVERED FREE END OF SAID UPPER MARGINAL PORTION TO COMPLETE THE ULTIMATE RIM CONFIGURATION.