摘要 |
A rotary flap tucker (10) comprising a tube sector having a smaller arc length end, a larger arc length end, a longitudinal edge (12), and an edge which helically advances generally from the small arc length end to the large arc length end. The tube sector has end plates (30, 40) each with an edge contoured to avoid contact with a carton flap as the flap tucker rotates about its center axis which is aligned with the carton travel direction. The leading edge (66) of a flap (64) entering the flap tucker follows the helical edge of the flap tucker as it rotates without contacting the flap for a majority of the rotation. Rotation brings the flap tucker's longitudinal edge (12) in contact with the flap along a majority of the flap's length. Continued rotation plows the majority of the length of the flap simultaneously, thereby preventing the flap from misaligning on the carton when the flap is closed. The outside surface of the rotating flap tucker runs against the closed flap of the advancing carton, preferably along the carton's center line.
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