discernible from fig1 in particular the shaft denoted 34 is coupled to the shaft 11 of the suction roller 7 by way of an interposed train of gears 37 38 and 39 functioning also as means by which to adjust the timing between the rotation of the suction roller 7 and that of the tension varying means 30 in such a way that the three cylindrical rods 31 can be made to alternate cyclically and at the same frequency as the cutting means 5 between a first limit position radially behind the surface 20 of the suction roller 7 and a second limit position radially beyond the selfsame surface 20 by passing through the aforementioned gaps 23 in operation the continuous strip 4 advances at a predetermined linear speed along the feed path p through a gumming station 40 and a guide roller 41 ultimately reaching the outer surface 20 of the suction roller 7 which in order to distance the leaves 3 separated at the cutting station 10 is caused to rotate at a peripheral speed greater than the linear speed of the advancing strip 4 this difference in speed causes the strip 4 positioned upstream of the cutting station.