Feed synchronising in machine coating boards with plastics film - using electrical shaft connecting reel and coating cylinder drives

摘要

Film reels are driven be a transmission from a motor connected by an electrical shaft to the drive of the pressing rollers in a plant for coating boards on one side or both with a layer of plastics film e.g. melamine. The value of the control signal is derived by comparison of the actual value and the nominal value of a measurement of the motion of the films running from the reels and through the pressing rollers. The tension on the film is damped by one or more compensating rollers. A further control signal value for the drive is obtained by measuring the sag in the fil, which is transmitted to the control unit. Makes it possible to process brittle melamine films from the reel in a continuously working plant. The film is drawn with the minimum of tension and without jolting. The invention ensures that the variable imbalance, the variable inertia and the variable bearing friction between full and empty reels do not affect the tension on the film.