B65D 5/302

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 tongue-and-slot or like connections between sides and extensions of other sides {the tongue being a part of a lateral extension of a side wall combined with a slot provided in an adjacent side wall}