these cylinders are then in turn mounted on the carriage 19 while guide rods 21 are mounted to be vertically movable on carriage 19 furthermore the two ends of a chain 23 are also fastened to carriage 19 wherein chain 23 runs over two sprocket wheels 24 of which the left sprocket wheel 24 as shown in fig1 is driven alternately in either direction by a motor 25 the right sprocket wheel 24 is mounted to be freely rotatable on guide rod 18 motor 25 is mounted on a part projecting from guide rod 18 gripper strips 20 have friction coating on their bottom surfaces and for the conveyance of pieces of material 10 10 39 and so forth they are brought into contact with the pieces of material in the direction of the arrow by lifting cylinder 22 and actually are placed on the two facing edge areas of pieces of material 10 10 39 and so forth which rest on mounting plates 26 the two mounting plates 26 are fastened at some spacing from one another on either side and parallel to the direction of conveyance of pieces of material 10 10 39 and so forth on the frame of the assembly conveyance device 17 moves the piece of material 10 as shown in fig1 to the right into a delivery position which is indicated by 10 39 and in which the piece of material can be picked.