Yarn draw-off nozzle for an open-end spinning machine

摘要

An open-end spinning assembly has a curved funnel-shaped contact surface over which a thread is drawn. The surface has a flat end-face (19) translating over a convex (21) surface to a yarn withdrawal passage at 90 degrees to the end-face. The contact surface has linear grooves and ridges which cross the yarn (14) fibres at an acute angle over their entire length. Fibres are always in contact with adjacent grooves and ridges. The angle subtended between the fibres, grooves (23) and ridges is approx. constant. The grooves have a coarse helical pitch. The angle alpha at which the threads intersect the grooves is approx. constant and between 15 and 45. The angle of intersection is against the direction of yarn travel.