High strength open bottom packaging trays

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 a pair of upwardly and outwardly inclined side walls, each said side wall forming a long side of said tray; a pair of upwardly and outwardly incLined end walls, each said end wall being adjacent to ends of said side walls, and thereby forming the rectangular configuration of said tray; a generally rounded corner between each said side wall and each said end wall; and a peripheral lip extending outwardly from said side and end 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 primary ribs having an inverted V-shaped cross-section with rounded apices, some of said primary ribs extending in one direction, and other of said primary ribs extending in a different direction, said primary ribs meeting and defining therebetween a plurality of open windows, said ribs having a section modulus in combination with said end and 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 increase rigidity and strength comprising a peripherally extending annular transition zone between said end and side walls and said primary ribs.