Patent ID: 7806358
Filing Date: 2010-10-05
Classification: B65H

Abstract:
1. A yarn tension control device for controlling tension in a running yarn, said tension control device comprising: a housing having a yarn guiding inlet for receiving running yarn at an unwinding tension from a yarn supply source, and a yarn guiding outlet for guiding the running yarn exiting said housing at a delivery tension; first and second opposing yarn engaging surfaces disposed between said inlet and said outlet, and adapted to frictionally engage opposite sides of the running yarn along a path of yarn travel through said housing; said first and second yarn engaging surfaces defining a respective plurality of sequentially spaced friction rolls downstream of said yarn guiding inlet; a pivoted rocker block carried by said housing, and wherein said first yarn engaging surface is defined by an inside surface of said rocker block, and wherein said rocker block comprises a single pivot point, and said pivot point being located upstream of a leading one of said friction rolls; and means for resiliently urging said first and second yarn engaging surfaces together, wherein said opposing friction rolls cooperate to form a plurality of sequentially spaced nip points adapted to adjust yarn delivery tension in response to stress variations in running yarn entering said housing, such that greater frictional resistance is applied at said nip points to running yarn entering said housing at a relatively low degree of unwinding tension, and lesser frictional resistance is applied at said nip points to running yarn entering said housing at a relatively high degree of unwinding tension.