GB1238718A - - Google Patents

Abstract

1,238,718. Automatic speed control. E.I. DU PONT DE NEMOURS & CO. Oct.23, 1968 [Oct. 23, 1967], No. 50252/68. Heading G3R. In a web-winding apparatus, in which a web 11 is fed by a speed controlled assembly 13 to a take-up roller 16 driven by a motor 17 through an adjustable clutch 18, the clutch being energized in accordance with a control signal proportional to the ratio of the speed of assembly 13 to the speed of roller 16 so as to maintain constant tension in the web 11, the web is initially fed at a low speed until the roll 12 of wound material reaches a predetermined value when the speed is increased automatically. This allows the use of a smaller motor 17 since it is not required to wind at high speed when the roll 12 is small. The feed rollers 13 are driven by a motor 41 through a second clutch 38 energized by a speed controller 39 in accordance with a datum setting of a potentiometer 44 in series with a resistor 45. The winder is started by closing switch 37 to energize relays 40, 46 to fully energize both clutches 18, 38. The speeds of rollers 14, 16 are detected by tachometer generators 19, 20. As soon as 20 produces an output a relay 28 connects a controller 21, receiving inputs from both tachometer generators, to a controller 22 to reduce the energization of clutch 18 as the roll 12 increases. While the assembly 13 is accelerating a compensator 31 derives a rate of change of speed signal which is added to the input of controller 22 to increase the clutch energization. A roller 35 senses the size of roll 12 and adjusts a potentiometer 36 accordingly to vary the voltage applied to a relay 42; when the roll is of a predetermined size relay contacts 30 close to short the resistor 45 thus increasing the datum level at controller 39 to increase the speed. The relay 42 is adjustable.