PREFORM ROD-DRAWING APPARATUS

摘要

PURPOSE: To clear the boundary part between a constant-diameter part and a tapered-diameter part joining to both ends thereof and prevent a proper part of a preform from excessively cutting by including a specific mechanism in an apparatus for drawing a preform rod having the constant-diameter part and the tapered-diameter part. CONSTITUTION: This preform rod-drawing apparatus 10 is equipped with a fixed table 14 for holding one end of a preform rod 20, a movable table 18 for holding other end and moving to the direction separated from the fixed table 14 and a heating means 28 moving from either one of the movable table 18 to other one. Each boundary 56 from a constant-diameter part 20A of the preform rod 20 having both end supported by the fixed table 14 and the movable table 18 to each tapered-diameter part 20B is set in previously indicated state and an indication mechanism 34 equipped with the first and second indicating means 40 and 42 capable of integrally moving together with the boundary 56 so as to continue to indicate the boundary 56 when the boundary 56 is moved by partially successively drawing a preform rod 20 is provided in the apparatus 10.