Abstract: This apparatus separates downturned flaps of paperboard cases, which flaps are joined by tabs and lying over sides of the case, without requiring the use of a knife or other sharp instrument for cutting. The apparatus has a conveyor for moving the case through the apparatus. There is a first device for engaging one of the flaps. A first thrust device is positioned proximate to the conveyor and connected to the flap engaging device for moving it against the side of the case over which the one of the flaps lies, and below the flap. There is a device operatively coupled to the flap engaging device for moving it along the side of the case until at least a portion of the flap engaging device extends between the flap and the side against which it lies. A device for retracting the flap engaging device is connected thereto and does so with sufficient force to break the tab joining the flap to another one of the flaps of the case. The flap engaging device is preferably frustum shaped.