High strength open bottom packaging tray

Claim 1

In a generally rectangular molded tray for the packaging of fresh meat, fish or poultry in conjunction with a transparent overwrap film heat-sealed thereabout, said tray comprising upwardly and outwardly inclined side walls defining the rectangular configuration; a generally rounded corner between each adjacent side wall; and a peripheral lip extending outwardly from said side walls and defining the periphery of said tray, the improvement comprising: means for providing improved oxygen breathing through the bottom of the tray and for providing visibility through the bottom of the tray and for supporting the meat, fish or poultry at the bottom of said tray while maintaining a high humidity thereabout substantially without the formation of liquid pools, and also for protecting meat freshness and improving meat quality maintenance, said breathing and support means comprising a plurality of strong, substantially solid ribs having an inverted V-shaped cross-section with rounded apices, some of said ribs extending in one direction, and other of said ribs extending in a different direction, said ribs meeting and defining therebetween a plurality of open windows, said ribs having a section modulus in combination with said side walls such that the total strength is substantially equal to the beam strength of a tray of the same material of equal weight with a flat, imperforate bottom; and means to resist sidewall deformation from the inward pressure of wrapping film and to increase rigidity and strength at the location where said inverted V-shaped ribs join said side walls, said means comprising a curved portion in each of said side walls thereby defining in such side walls a straight upper portion, a curved center portion and a straight bottom portion, said bottom portion having a height equal to the height of said inverted V-shaped ribs.