Abstract: An improved cam mechanism bends carton blanks fed from the magazine of a packaging machine. The carton blanks each have a gripped portion attached to the packaging machine and a bendable portion extending from the gripped portion. The cam mechanism includes a rotatable shaft mounted on the packaging machine and at least one cam member mounted on the shaft. The cam member has a plurality of longitudinally extending side walls and apex portions interconnecting the side walls. Rotating the shaft about its longitudinal axis positions the side walls adjacent the gripped portions of the carton blank, and the apex portions radially displace the bendable portions of the carton blanks as the carton blanks are fed from the magazine.