GB1097162A - Web winding process and apparatus - Google Patents

Abstract

1,097,162. Controlling clutches. E. I. DU PONT DE NEMOURS & CO. May 11, 1966 [May 12, 1965], No. 20945/66. Heading F2L. [Also in Division G1] In order to maintain a uniform tension in winding a web on to a roll driven by a motor through an adjustable magnetic clutch, the clutch current is adjusted as a function of the difference between the rotational speed of the roll and the linear speed of the web, and is also adjusted to take account of such things as starting, accelerating to operating speed, stopping, and friction effects, and to maintain the tension when the roll is stationary. As shown, a web 11 is advanced by a roller 14 driven by a motor 41 through a magnetic clutch 38 and is wound on to a mandrel 16 driven by a motor 17 through a magnetic clutch 18. Tachometergenerators 19, 20 driven by the rolls 14, 16 supply signals to an inverse speed generator 21 which supplies an output signal, which is inversely proportional to the ratio of the speed of mandrel 16 to the speed of roller 14, through a tension adjuster 32 (by which the desired tension level is set) to a clutch voltage controller 22 so as to increase the torque with increasing web roll radius. Change in the torque requirement during acceleration and deceleration is controlled by an acceleration-deceleration compensator 31 which is a detectoramplifier adapted to transmit to the clutch voltage controller 22 a signal proportional to the rate of increase or decrease of the output signals of the tachometer-generator 19. A friction compensator 25 is a manually-adjustable voltage divider feeding a portion of a bias voltage available from a supply A to the clutch voltage controller 22. As the friction generally decreases as the speed of the winding unit increases, a R.P.M. compensator 34 which derives a signal from the tachometer-generator 20 provides a gradually diminishing bias as the diameter of the web roll 12 increases. To increase the torque on starting a forcing torque compensator 29 provides a direct current impulse of preselected magnitude and duration. The magnitude of the impulse is controlled by a diameter-sensing potentiometer 36 to increase the magnitude as the size of the roll 12 increases to give a greater starting torque. A standing tension compensator 27 transmits to the clutch voltage controller 22 a portion of a bias voltage from a supply D and is operative during a stall or standing sequence to maintain a torque sufficient for the required tension of the web. A taper-adjuster 33 is a potentiometric device transmitting to the clutch voltage controller 22 a portion of a bias voltage from a supply C. The taper adjuster 33 controls the tension pattern, i.e. the change in tension within the roll from the core to the periphery. When adjuster 33 is set at a zero setting the roll is given a constant tension. The adjuster 33 includes a potentiometer Y responsive to adjustment of the tension adjuster 32 to ensure that the taper bias signal is a fixed percentage of the signal from the tension adjuster 32.