Abstract: A corrugated cardboard carton has opposed foldable outer flaps associated with the top and bottom ends thereof which overlap inner flaps in a conventional manner, with the opposed outer flaps being sealed together adjacent their free edges. To create a tamper-resistant seal between the outer flaps, the flaps terminate in free edges which effectively abut when the carton is closed, which free edges are defined by the inner facing layer and the intermediate corrugated layer of the board stock defining the flaps. The outer facing layer of the board stock defining the flaps is provided with a securing strip which is integral therewith and which projects outwardly beyond the free edge. This securing strip has cuts or openings therethrough. The outer facing layer of the flap also has an indicator strip, preferably of a bright color, formed on the exterior face thereof.

Abstract: A forming machine which permits a preformed corrugated board blank to be manually fed into one end of the machine, which blank has the rear flaps manually folded over and held until they are engaged by hold-down devices on the machine. The blank is moved through the machine by a drive belt and is sequentially acted upon by a folding structure which folds over the front corner tabs. A glueing device applies adhesive to the side flaps, and a further folding structure then folds over the side flaps for adhesive securement to the previously-folded corner flaps. The folding structure for the front corner tabs is nonpowered and includes levers for lifting the front tabs in response to movement of the tabs into engagement therewith, following which the front tabs are appropriately folded over while the side flaps pass beneath the lifting levers.