Means for controlling fiber-drawing apparatus

In a fiber-drawing apparatus comprising a plurality of cascaded roller pairs following one another in a direction of travel of incoming fibers to be combined into an outgoing bundle and drive means for rotating said roller pairs at relative speeds imparting a tensile stress to fibers clamped under compressive stress between the rollers of said pairs, the combination therewith of:

• stress-adjusting means coupled with rollers of said pairs;
• sensing means beyond one of said roller pairs disposed in the path of said outgoing bundle for detecting thickness fluctuations thereof;
• evaluation means connected to said sensing means for determining the extent of said fluctuations;
• and
• control means for setting said stress-adjusting means in a multiplicity of different positions, said control means including a microcomputer with a programmer and a data store, said programmer establishing in an initial phase of a fiber-drawing operation a succession of different settings of said stress-adjusting means for predetermined time periods enabling said evaluation means to supply said data store with a mean value for the fluctuations encountered with each setting, said data store registering the mean values pertaining to said settings and making same available at the end of said initial phase to said evaluation means for enabling same to determine the lowest of said mean values, said control means being responsive to output signals of said evaluation means for re-establishing the setting corresponding to said lowest of said mean values.