METHOD DRAWING GLASS PREFORM AND APPARATUS FOR DRAWING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a method for drawing a glass preform which forms a less bending glass rod by drawing the glass preform and an apparatus for drawing the same. SOLUTION: This method for drawing the glass preform consists in discretely controlling the right and left numbers of revolutions of a pair of rollers 4 installed below the drawing apparatus in accordance with the deviation quantity between the central position of the heating and softening part of the glass preform 1 and the drawing axis of the drawing apparatus when hanging the glass preform 1 to the upper part of the drawing apparatus, softening the glass preform by heating, holding the drawn glass preform 1 with the rollers 4 and taking off the glass preform. The drawing apparatus has a supply mechanism for hanging the glass preform 1 in the upper part and sending the glass preform to a heating furnace at a prescribed speed, a heating section for softening the glass preform 1 by heating in the heating furnace and a take-off mechanism for holding the glass preform in the lower part with at least a pair of the rollers 4 and taking off the glass preform. The apparatus described above has a central position measuring instrument for measuring the central position of the heated and softened part of the glass preform 1 and a controller for discretely controlling the right and left numbers of revolutions of the rollers 4 in accordance with the deviation quantity between the measured central position and the drawing axis 6 of the drawing apparatus.