Container with prismatic top - has additional fold line in one inclined side to allow concave folding

摘要

The container has a prismatic top with converging sides and a central sealing rib, being made from a single sheet of material. The sides have an oblique height A, and the rib a height B. The first side has an additional fold line (30) parallel to and below the upper one (26) where it joins the rib (24), and at a distance X below the line determined by the formula X = A - B2 This allows the first side to be folded in a concave shape along the additional line, so as to fold the top down without distortion of the other side (22). Folding the top flat can be effected by exerting a horizontal force towards the second side, against the first side and at right angles to the rib. A group of containers are assembled all the same way round into a set, and wrapped in an oblong cardboard sheet, to hold the tops flats.