ELECTRIC FURNACE STRETCHING METHOD FOR GLASS PREFORM FOR OPTICAL FIBER AND STRETCHING DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To make it possible to solve the problem of axis alignment at the time of joining of a preform for stretching and a member for pulling and to enable the immediate start of stretching right after welding of the joint part thereof in an electric furnace stretching stage for the glass preform for an optical fiber. SOLUTION: An aligning mechanism 9 for aligning the preform and the furnace core side free end 2B of the member is disposed between the furnace core tube 4 of the electric furnace and the clamper 5 of the glass preform 1 for stretching and between the furnace core tube 4 and the clamper 6 of the member for pulling. After the free end is aligned by the aligning mechanism, the preform and the clamper side of the member are regularly fixed by both clampers and in succession front ends of both free ends are butted against each other and are fused and joined at the max. temp. part of the electric furnace. Next, the max. temp. part is moved to the stretching part on the glass preform side and the stretching of the glass preform is started.