Abstract: The container of the present invention includes polygonal sidewalls with at least some of the upper edges of the side walls each having a container locking flap thereon and with at least one other of the side walls being free from locking flaps. The lid has polygonal edge walls sized to matingly fit over the upper edges of the container side walls. Each of the edge walls of the lid are provided with a lid lock flap which folds upwardly and inwardly with respect to the edge walls and which terminates in an upwardly presented edge spaced downwardly from the top of the lid. When the lid is placed over the top of the container, the lock flaps of the container retentively engage the upwardly presented edges of the lid lock flaps.The lid may be removed after the first locking by severing the lid lock flaps from the lid with a knife or other cutting instrument.

Abstract: The method for forming a polygonal container from a blank comprises placing the blank over a polygonal cone having the same number of sides as the side walls of the polygon to be formed. The blank is inverted during placement over the cone so that the upper edges of the container side walls engage the sides of the cone and so that the bottom closure portion of the container is presented upwardly. The bottom closure is folded inwardly along preformed folding lines into a configuration comprising a plurality of triangular bottom panels equal in number to the side panels and a plurality of interconnecting webs each extending between a pair of adjacent bottom panels. Each bottom panel is hingedly connected to one of the side panels and is inclined upwardly from the lower edge of the side panel to which it is connected to form an acute angle therewith.

Abstract: A method and means is provided for securing the bottom closure of a polygonal container having a plurality of side panels and a strong weight supporting bottom formed by a plurality of generally triangular bottom panels and a plurality of interconnecting webs between the panels. The method comprises inserting a fin head assembly within the container, the fin head assembly having a plurality of vertically disposed fin plates which are registered in alignment with the junctures between the side edges of the bottom panels. The fin plates are then inserted into the junctures between the side edges of the bottom panels so that each fin plate is embraced between the double thickness of the web panels which are between the side edges of the bottom panels. The fin plates hold the bottom panels and webs in place so that a clip may be placed over the circular array of ribs formed by the double thickness web panels, thereby holding the web panels and the bottom panels in a predetermined configuration.