Carton blank erecter and feeder

Apparatus including a plurality of blank feeders for simultaneously feeding blanks to respective bottom forming mandrels, each of the blanks being folded in a flat form and being unfoldable to a tubular form of square cross section by unfolding the blank to the tubular form and fitting the unfolded blank around the mandrel, each of said plurality of blank feeders comprising:

• a magazine having a delivery opening at one end and accommodating flat blanks arranged closely side by side from said one end toward the other end thereof,
• transport means having a path of transport extending from said delivery opening as a starting end to a terminal end along a circular arc having a central axis parallel to the widthwise direction of the blank in the delivery opening, said transport means comprising a suction member, a transport arm having said suction member attached to a forward end thereof, and a rotatable shaft rotatably supporting a base end of said transport arm, said rotatable shaft having an axis which is aligned with a central axis of said circular arc;
• said suction member comprising a plurality of suction cups arranged at different distances from said central axis for gripping one side of the blank, so that unfolding of the blank by movement of said suction member along said circular arc causes a greater separation of a gripped side of the blank at the furthest end of the blank from said central axis than at the nearest end of the blank from said central axis;
• unfolding means for unfolding each blank from the flat form to the tubular form while the blank is being transported by the transport means, said unfolding means having first and second blank unfolding claws disposed at edge portions of said delivery opening so as to individually engage with opposite ends of the blank in the delivery opening;
• and
• means for feeding the opened carton to a mandrel.