B65D 5/247

Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper by folding-up portions connected to a central panel from all sides to form a container body, e.g. of tray-like form with adjacent sides interconnected by gusset folds {and being maintained in erected condition by integral mechanical locking means formed on, or coacting with, the gusset folds, e.g. locking tabs, tongue and slit }