Molding apparatus having a vented female mold member for forming foamed egg cartons
US4419068A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 11, 1982 |
| Grant date | Dec 6, 1983 |
| Priority date | — |
| Expiry date | Mar 11, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An egg carton made from expanded polystyrene with a nonexpanded skin on one side includes integrally formed cover and tray portions interconnected together by a pair of hinges adjacent opposite sides of a hingeband. The tray is divided into a plurality of cells by a plurality of partitions. At least some of the partitions have a top flap portion hinged to the top of the partition by the skin of the polystyrene. Each cell further has a pliant inside surface provided by one or more grooves in the interior cell walls. A post extending from the inside surface of the cover is formed opposite a tray support surface using a thermo molding method by which a protrusion in a top mold is inserted into a nonvented cavity of a bottom mold. A pair of integrally molded hinge posts extend above the hingeband a distance less than the width of the hingeband between hinges and seat into a groove in the hingeband when the top is in closure relationship to the tray.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.