| 摘要 |
PURPOSE:To restrain a tension change during screening, by detecting the extent of a tension change during screening and by controlling the braking force of the 1st drawer in accordance with the extent of the variation of tension. CONSTITUTION:An optical fiber 1 supplied from a suplier 2 is passed between the pressing belt 4 and the roll 3 of the 1st drawer 5 and drawn along a vertically movable roll 13. At this time, tension is applied to the fiber 1 by means of a spring 14. The fiber 1 is further passed between the pressing belt 7 and the roll 6 of the 2nd drawer 8 and coiled around a coiler 12. When the drawing speed of drawers 5, 8 are different from each other, the position of the roll 13 is vertically moved. The roll position is detected with a sensor 15 and inputted in a feedback circuit 16. When the roll 13 is moved upward, the braking force of the powder brake of the drawer 5 is reduced to increase the feeding speed of the fiber 1 and to move the roll 13 downward. When the roll 13 is moved downward, the braking force of the powder brake of the drawer 5 is increased to reduce the feeding speed of the fiber 1 and to move the roll 13 upward. Thus, the roll 13 is held at a constant position. |
