Return mail container

A tamperproof return mail container for packaging a generally flat object, formed from a one-piece blank of paperboard or the like comprising a centrally located quadrilateral main panel of substantially the same dimensions as the packaged object, a plurality of side wall panels foldably attached to the edges of said main panel, said side wall panels each having a width substantially equal to the width of its attached main panel edge and a length substantially equal to the height of the packaged object, a first pair of top closure flaps designated respectively a mailing address flap and a return address flap foldably attached to two opposed side wall panels, said first pair of top closure flaps each having a width substantially equal to the width of its attached side wall panel and a length substantially equal to the full size of the first dimension of the packaged object wherein said first pair of top closure flaps are adapted to alternately overlap one another to cover the packaged object, said first pair of top closure flaps each further including at least one locking tab foldably attached along an outer free edge thereof and at least one tab receiving slot located substantially along the foldable connection between said top closure flap and side wall and opposite the locking tab attached to the outer free edge thereof, wherein said locking tabs have a nominal width substantially equal to the length of the attached foldable connection with integral locking ears projecting from each side thereof, and said tab receiving slots each have a length substantially equal to the nomimal width of said locking tabs and a width substantially equal to the thickness of the blank material from which the container is formed, and a second pair of top closure flaps foldably attached to the remaining opposed side wall panels, said second pair of top closure flaps each having a width substantially equal to the width of its attached side wall panel and a length no greater than about one-half the size of a second dimension of the packaged object, said second pair of top closure flaps each including notched portions at each side thereof near their free ends for accomodating an unused locking tab, wherein the container is prepared for mailing when the return address flap is folded over the packaged object and second top closure flaps to place the unused locking tab thereon in the region provided by the notched portions at one side of said second top closure flaps, and the mailing address flap is folded over the return address flap and the locking tab attached thereto is inserted in the tab receiving slot of said return address flap so as to position the integral locking ears thereof beyond the ends of said tab receiving slot, and the container is prepared for return mail, after severing the locking tab from the mailing address flap to open the container, with a reverse folding sequence wherein the return address flap is folded over the mailing address flap and the locking tab attached thereto is locked in the tab receiving slot of said mailing address flap.