Collapsible sidewall structure for stackable bin

Claim 1

In a collapsible storage bin having a collapsible six-fold sidewall structure which is horizontally of generally rectangular shape and defines a vertically extending opening therethrough, and upper and lower pallet-like supports removably engaged with the respective upper and lower edges of said sidewall structure for closing off said sidewall structure and defining a storage compartment therein, said sidewall structure including a pair of substantially parallel sheet-like side walls joined together by a pair of sheet-like end walls, the end and side walls having adjacent vertical edges joined together by a corner fold structure which permits relative horizontal swinging movement between the adjacent end and side walls, and each said end wall having a center fold structure extending vertically thereacross substantially midway between the vertical end edges thereof for dividing the end wall into two plate-like wall portions which are horizontally relatively swingably movable about said center fold structure, the improvement comprising: each said side and end wall being constructed as a multi-ply laminate having substantially coextensive inner and outer layers fixedly secured to and substantially coextensively overlying opposite side faces of an intermediate layer; each said inner and outer layer being constructed of plastic and having substantially parallel inner and outer plastic facing sheets joined together by a plurality of substantially parallel plastic ribs which extend transversely between and are rigidly joined to said facing sheets, said ribs and sheets cooperating to define therebetween a plurality of elongated and substantially parallel channels which are enclosed between said facing sheets, the ribs and channels of at least one of said inner and outer layers being elongated substantially vertically; and said intermediate layer being constructed as a sheet of light-weight rigid plastic foam.