Tension control apparatus

Abstract

A yarn tension control device for controlling the tension of yarn being longitudinally advanced having two movable yarn guide members with spaced guide pins alternately engaged by the longitudinally travelling yarn. One of the yarn guide members is pivotally mounted to move its guide pins across the yarn path and has a pin or roller mounted spaced from its pivot and is balanced by a balancing weight. A pivotally mounted control cam has a balancing weight and a laterally extending arm with a biasing weight adjustably positioned on the arm. The control cam has a cam profile in contact with the pin or roller on the first yarn guide member and the biasing weight biases this profile into engagement with the roller or pin to pivot the first yarn guide member in a desired direction. The portion of the arcuate cam profile nearest its pivot is concave, a middle portion thereof is nearly straight, and the portion of the cam profile furthest from the control cam pivot is convex. Thus as the first yarn guide member moves away from the second yarn guide member the biasing is decreased.