Container structure
US4497431A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 4, 1982 |
| Grant date | Feb 5, 1985 |
| Priority date | — |
| Expiry date | Jan 4, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S229/903
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A closed paperboard carton for containing hot foods includes an automatically openable vent responsive to presence of hot vapor emanating from the food to accommodate escape of the vapor. The vent comprises a tab portion formed in a wall of the carton, defined by at least a pair of equal-length knife cuts and having a region of connection with the wall. Vapors emanating from the hot food condense, and are absorbed by the inwardly facing wall surfaces of the paperboard carton. Absorption of condensed vapors in the region of the tab causes the inwardly facing surface of the tab to swell so that it curls outwardly and forms a vent. Once the vapor has substantially escaped, the inwardly facing wall surfaces tend to dry out, accompanied by uncurling of the tab to its original, vent-closing position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.