Patent ID: 9688564
Date: 2017-06-27
CPC Classifications: C03B

Claim:
1. A method comprising: hanging a substantially cylindrical glass base material from a feeder; heating the glass base material with a heating furnace arranged below the feeder; producing a glass rod having a smaller diameter than the glass base material in a downward direction from the heating furnace; as the glass rod is produced in the downward direction from the heating furnace, guiding the glass rod with three or more sets of rollers including a first set of rollers that are all at a first distance from the heating furnace in the downward direction, a second set of rollers that are all at a second distance from the heating furnace in the downward direction, and a third set of rollers that are all at a third distance from the heating furnace in the downward direction, each of the three or more sets of rollers capable of switching between a grasping state in which the set of rollers grasps the glass rod and a releasing state in which the set of rollers does not grasp the glass rod, each of the three or more sets of rollers being in the grasping state for at least a portion of said guiding, said guiding including guiding at least one fusion-bonded joint of the glass rod through each set of rollers; detecting a horizontal plane position of the glass base material; controlling the horizontal plane position of the glass base material to match a target position; before the fusion-bonded joint reaches each set of rollers, switching the reached set of rollers to the releasing state; after the fusion-bonded joint has passed each set of rollers, switching the passed set of rollers to the grasping state; and after the fusion-bonded joint has passed the third set of rollers and the third set of rollers has switched to the grasping state, switching the second set of rollers to the releasing state, wherein the first distance is less than the second distance and the second distance is less than the third distance, and one set of the three or more sets of rollers does not have the ability to drive, but only guides the glass rod.