Yarn tensioning apparatus

Filament tensioning apparatus for tensioning a plurality of filaments comprising,

• a plurality of filament tensioning devices, each said filament tensioning device including,
• means for guiding the movement of a filament in a discrete filament path,
• tensioning means for placing the filament under tension, said tensioning means including a solenoid for exerting tension on the filament,
• a control circuit for controlling the duration of the duty cycle of said solenoid based upon the tension exerted on said filament, said circuit comprising:
• a power supply;
• means for generating a reference current signal corresponding to a given tension upon said filament;
• means for measuring the tension exerted on said filament;
• means for generating a measured tension current signal based on the measured tension exerted on said filament;
• means for generating an error signal corresponding to the difference between said reference current signal and said measured tension current signal;
• and
• means for incrementing or decrementing the duty cycle of said solenoid based upon said error signal.

A method for tensioning a plurality of filaments comprising:

• moving a plurality of filaments in respective discrete filament paths;
• activating a plurality of solenoids to exert force on a plurality of respective tensioning means which in turn apply tension to a respective one of said plurality of filaments;
• measuring the tension on each of said plurality of filaments;
• comparing the measured tension on each of said filaments with a reference tension;
• and
• incrementing or decrementing the duty cycle of each of said solenoids based upon the difference between the measured tension on a respective filament and the reference tension to thereby adjust the tension exerted on each of said filaments.