Patent ID: 7819791

Claim:
A system for forming a carton having concave sides, comprising: a pair of capture lugs for processing a carton blank, each of the capture lugs including lip means shaped for holding opposed ends of the carton blank and squeezing the carton blank such that the carton blank bulges when held between the capture lugs, the capture lugs being attached to a conveyor means whereby the carton blank is positioned between the capture lugs when the conveyor means moves the carton blank; and pre-breaking means positioned adjacent to the conveyor means and shaped for softening at least one curved score line along the carton blank when the carton blank is bulged between the capture lugs, the at least one curved score line corresponding to one of the concave sides of the carton, the pre-breaking means shaped for softening the curved score line for subsequent folding of a side of the carton blank along the score line to form the carton having concave sides, the pre-breaking means further comprises a plate having a gradual curved edge that supports the carton blank along the at least one curved score line of the carton blank while the carton blank is being pre-broken over the curved edge, the curved edge comprising a first and second end portions and a central portion, the first and second end portions having a curve angle which is greater than a curve angle of the central portion.