Patent ID: 6386437
Filing Date: 2002-05-14
Classification: B65D

Abstract:
A collapsible bulk box that may be shipped in a folded-flat condition and opened into an erected condition by one person at a point of use, said box having a bottom structure that automatically moves to a closed position as the box is erected, comprising:a single blank scored to define a first pair of rectangular panels that form first and second opposed side walls in a completed box, a second pair of rectangular panels that form first and second opposed end walls in a completed box, and third and fourth rectangular panels that form diagonal corner panels connected between adjacent side and end walls in a completed box, said corner panels being bisected by a longitudinal fold line and foldably connected at opposite side edges thereof to opposite side edges of the side and end walls, and said side and end walls having top and bottom edges and opposite side edges; a glue panel extending along one side edge of the blank, said blank being folded upon itself along said longitudinal fold lines into a folded-flat condition, and said glue panel adhesively attached to an opposite side edge of the blank to form a flattened tubular structure; a pair of major bottom flaps foldably joined to the bottom edges of respective side walls along transverse fold lines, each major bottom flap having laterally projecting extensions on opposite side edges thereof and a free edge opposite the edge that is foldably connected to the associated side wall, said free edges on opposite major bottom flaps extending into close proximity to one another when the box is erected, each said free edge having offset portions defining a shoulder, said shoulders being interengaged to lock the major bottom flaps in their closed position when the box is erected, and the side edge of each extension includes, adjacent the free edge of the flap, an outer portion extending parallel to the longitudinal fold line at the side edge of the associated side wall, and an inner portion extending angularly from an inner end of the outer portion to the juncture of the longitudinal fold line at the side of that side wall and the fold line joining that flap to the side wall; a pair of minor bottom flaps foldably joined to the bottom edges of respective end walls along transverse fold lines, said minor bottom flaps each including a portion lying beneath an adjacent portion of one major bottom flap, and a portion lying above an adjacent portion of the other major bottom flap when the box is erected; and a diagonal fold line extending across one of said extensions of each said major bottom flap, defining a triangular corner panel on a side edge of each major bottom flap between the diagonal fold lines and the side edge and free edge of each major bottom flap, each said triangular corner panel being folded about the diagonal fold line and adhesively attached to a respective adjacent minor bottom flap, wherein the major and minor bottom flaps project externally of the tubular structure when said box is in its folded-flat condition, and when a force is exerted laterally inwardly on opposite longitudinally folded edges of the folded-flat box, the side and end walls open up away from each other and the bottom flaps automatically move into a closed position to form an erected box.