Abstract: A self-locking, reusable carton is formed from a unitary blank of paperboard. The carton and blank have self-locking end closure flaps which are hingedly coupled to adjacent end edges of the side panels of the carton. The closure flaps include two flaps with L-shaped slits formed therein and a locking flap free of fold lines with a locking tab at the free end thereof. During assembly the locking flap is forced downwardly to place the locking tab in the L-shaped slits to lock the carton in its fully assembled configuration.

Abstract: A self-locking, reusable carton, formed from a unitary blank of paperboard, comprising a tubular body portion, a plurality of top closure flaps and a plurality of bottom closure flaps. The top closure flaps include two flaps having L-shaped slits therein and a locking flap having a reduced-width locking tab at the end for reception in the two L-shaped slits. The bottom closure flaps include first and second flaps, each having a set of two L-shaped slits therein, and third and fourth flaps, the third flap being received in one of the slits in the first flap and in one of the slits in the second flap, and the fourth flap being received in the other of the slits in the first flap and in the other of the slits in the second flap.

Abstract: A container formed from a single, unitary paper-board blank wherein certain side and bottom wall panels of the blank are provided with openings for receiving tabs on selected other top and bottom wall-forming flaps to lock the container in its erected, closed condition, when the blank is folded.