Abstract: A continuous web of paper is fed from a reel by a driven roller and a cooperating pressure roller and cut into sheets by a pair of rotating knives. The shafts on which the driven roller and one of the knives are mounted, are drivingly connected by a presettably variable ratio gear box and the drive is obtained from a main motor which is connected to the driven roller shaft. A differential gear is positioned between the main motor and the driven roller, the shafts of which are connected to two of the input/outputs of the differential gear. The casing of the differential gear is connected to an auxiliary motor which is connected to a speed regulator. The speed of the web and the rotational speeds of the driven roller and the knife shaft are monitored and compared with the desired sheet length and a signal indicative of any error between the desired and actual sheet length is used to control the speed regulator.