Wmf Container Corporation

Leesona Corporation

Edward E Batson

John H Kurz

An apparatus for forming frangible score lines in rigid plastic sheet material. The apparatus utilizes a flat surface having a serrated edge having points and notches. The rigid plastic sheet material is laid on the flat surface. A scoring means is positioned to strike downwardly on the sheet material whereby the points of the serrated edge of the flat surface will extend into the sheet material a distance further than the notches of the serrated edge to thus form a corrugated fracturable score line in the plastic sheet material. The apparatus is useful for forming score lines in lids for drink cups intended for fast food service.

Apparatus for scoring rigid plastic sheet material

According to this invention, there is provided a method and apparatus for making an article, such as a lid for a plastic food container made of plastic having frangible score lines. The article is formed of a sheet of plastic material having substantially constant thickness with score lines defining an offset portion thereof which is connected to the remaining sheet material by a segment that is thinner than said sheet material and being rupturable for the removal of said offset portion. The periphery of the inwardly directed portion of said offset portion overlaps the periphery of the outwardly directed portion of the offset portion on the opposite side of said sheet material. The fracturable score lines are corrugated along their length by a plurality of successive grooves and ridges with the grooves extending deeper into the material than the ridges.

Plastic closure with score lines

A method for making an article, such as a plastic food container lid having frangible score lines. The article is formed of a sheet of plastic material having substantially constant thickness with score lines defining an offset portion thereof which is connected to the remaining sheet material by a segment that is thinner than the sheet material and being rupturable for the removal of the offset portion. The periphery of the inwardly directed portion of the offset portion overlaps the periphery of the outwardly directed portion of the offset portion on the opposite side of the sheet material. The fracturable score lines are corrugated along their length by a plurality of successive grooves and ridges with the grooves extending deeper into the material than the ridges.

Method for scoring rigid plastic sheet material

A trim press employs a hammer assembly to deliver a hammer blow to the punch of the press at the moment the punch begins to apply shearing pressure to material being trimmed. A spring system applies a steadily increasing spring loading to the hammer as the punch carrying platen moves downwardly in its operating stroke toward the die. A latch assembly, triggered by an abutment on the die, unlatches the hammer at the time the punch engages the material so that the downward velocity of the punch due to the downward movement of the platen is increased by a hammer blow as the punch moves through the material being trimmed. The spring system is operable to restore the hammer to its latched position during the upward stroke of the platen.

Trim press having hammer drive for punch

An extruder or the like, continuously issues a heated plastics material in the form of an elongated web, which is moved sequentially to molding and article severing stations. The products cut out are moved to lip rolling printing and drying stations. Articles such as containers are formed by the mechanism which includes a turntable assembly for varying the length of the web travel path between an extruder and forming station to thereby control the residual heat in the web at the time of forming, and a molding drum with improved plug assist devices which are air powered and also include air emitting ports to move the web into intimate engagement with the mold cavities as a final forming step under controlled conditions which assure that the pressure is applied at exactly the proper time. The system includes a lip curling system which feeds containers severed from the web in stepwise fashion through forming roll sections and releases them in timed relation to indexible mandrels. The system further includes a printing assembly which utilizes offset printing mechanism in combination with the mandrels, and associated ink drying mechanism, to print the containers prior to releasing or ejecting them.

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Mesa, AZ, United States of America

Edward E Batson