| 摘要 |
Plastic trays used for baking shrink when in an oven such that lids which attached to the tray prior to baking no longer fit the tray after baking. Since the shrinkage of the tray is known for the temperature range expected during baking, a lid having two sets of locking tabs at different perimeters can be used to secure the lid to the tray. The first perimeter and locking tabs are used before the tray is baked and the second perimeter and locking tabs used after the tray baked. In this manner a tray with food therein can have a lid secured thereto before baking when the tray is one size and the same lid secured thereto after baking. The lid is removed during baking and reapplied after baking thus protecting the food in the tray before and after baking. Alternatively the tray may have two lid engaging perimeters for attaching the trays to the lids. The first tray perimeter used before baking and the second after baking. The lid would have one perimeter for engaging the tray before and after baking. The location for attaching the trays to the lids can be located anyplace around the trays and lids. The means for attaching the trays to the lids may be by inserting a concave portion into a concave portion, by inserting a portion of the tray or lid under tabs of the lid or tray or any other means of inserting lockingly securing the trays and lids together. The trays and/or lids may change size for a variety of reasons, including thermal expansion and contraction, thermoplastic shrinkage, or load stresses. The dual size containers will fit the lid to the tray before and after the size changes.
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