Apparatus for forming protrusions with enlarged head portions in thermoplastic sheet material
Abstract
Abstract METHODS AND APPARATUS FOR FORMING PROTRUSIONS WITH ENLARGED HEADS IN THERMOPLASTIC SYNTHETIC PLASTIC SHEETS WHEREIN A MALE PART ON ONE DIE ENTERS A FEMALE PART ON ANOTHER DIE HAVING A STRETCHABLE, RESILIENT, BELL-SHAPED LINER WITH A RECIPROCABLE BOTTOMING PIN THEREIN WHICH IS PUSHED INWARDLY BY THE MALE DIE PART TO DISTORT THE LINER SO THAT THE OUTER PORTIONS OF THE SIDE WALL OF THE LINER ARE COLLAPSED INWARDLY AND FORM THE REDUCED NECK ON THE PROTRUSION FORMED IN THE PLASTIC WEB BY THE MALE AND FEMALE PARTS. THE SIDE WALL OF THE LINER IS SHAPED TO FORM A BUTTON-SHAPED HEAD IN THE PLASTIC WEB WHEN THE PRESSURE OF THE DESCENDING MALE DIE ON THE SHEET ASSISTS IN MOVING OUTER PORTIONS OF THE SIDE WALL OF THE LINER INWARDLY TO FORM THE REDUCED NECK. THE PROTRUSIONS FORMED ARE PARTICULARLY USEFUL AS FASTENERS FOR EGG CARTONS AND ARE FORMED IN CONVENTIONAL DIFFERENTIAL PRESSURE THERMOFORMING MACHINES AS A PART OF THE OVERALL OPERATION OF FORMING THE EGG CARTON ITSLF.
Inventors
- 👤 Gaylord W Brown
Bibliographic Details
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