| 摘要 |
PURPOSE:When the heating means is reciprocated, the device for measuring the outer diameter of the parent material is allowed to follow the hating means always from behind whereby the parent material for optical fiber is drawn with high accuracy in a uniform outer diameter. CONSTITUTION:The parent material for optical fiber 2 is heated with burner 4 and locally drawn in order. When holder 6 moves, the outer diameter- measuring device 5 follows the burner 4 a few millimeters behind to detect the outer diameter of the parent material 2 immediately after heating. The signals are sent in order to the computing and controlling unit 7 where the difference between the set values and the observed values is calculated. The control signals based on the difference are given to the motor 3f for driving the major shaft of the rotary drawing means 3, gas feeder 8 and the motor 12 for driving the holder. Thus, the drawing speed, the flame energy of the burner 4, the movement speed of the burner 4 and the movement speed of the device for measuring the outer diameter 5 are controlled. The mechanism can do automatic drawing without localized neckings. |
