positioning station 8 the positioning station 8 is equipped in its upper part with a conveyor member 11 comprising a frame formed by vertical bars 12 linked by crossbars 13 supporting a slide 14 and on which one or two tables 15 and 23 move each table supports a series of telescopic suction heads 16 and 17 in this example two tables 15 and 23 are provided preferably movement of the tables 15 and 23 is obtained with a linear motor and the movement of the table 15 is controllable independently of the movement of the table 23 the lower part of the positioning station 8 is provided with a series of front stops 18 which can be retracted and with a series of lateral stops 19 some of which can be moved laterally and vertically fig2 is a schematic plan view of fig1 wherein an inserting operation of a reinforcement 20 into a box blank 21 has been illustrated in the embodiment illustrated in this figure the feed station 2 comprises three introduction members or adjustable feeders 6 a 6 b and 6 c arranged side by side across the width of the assembly device 1 these adjustable feeders 6 a to 6 c are.