Apparatus for converting successive prefabricated blanks into envelopes has a pair of shiftable advancing rolls which transport successive blanks into the nip of two rotary cylindrical holders one of which supports a first folding tool and the other of which supports a first tongs. The tool cooperates with the tongs to fold one major panel of the blank over the other major panel, and such folding is assisted by a suitable guide which is adjacent to the path of movement of successive blanks downstream of the holders. Successive blanks are thereupon engaged and entrained by an orbiting suction head which transports the blanks into the range of a second folding tool cooperating with a second tongs to fold one flap of one of the major panels over the adjacent portion of the other major panel. The suction head is mounted on a rotary cylindrical holder which further carries the second folding tool. The flap which is folded by the second tool and second tongs is coated with adhesive during transport between the first and second folding tools. A transfer conveyor thereupon transports successive blanks past a second paster which applies adhesive to another flap of the one major panel before the second flap is folded over the other major panel.
