GB893350A - Improvements in or relating to the feeding of threads, yarns, and the like - Google Patents

Abstract

893,350. Feeding yarns. BRITISH NYLON SPINNERS Ltd. June 1, 1960 [June 20, 1959], No. 21239/59. Class 120(2) [Also in Group VIII] Yarn positively forwarded to apparatus in which it is to be utilized at a rate equivalent to and variable with the rate of utilization, is sustained in a free loop immediately prior to such utilization, the location of the bottom of the free loop is sensed and the rate of forwarding is varied automatically in accordance with said location. Low denier yarn 1, withdrawn from a bobbin 3 by a pair of nip rolls 5, of which the lower one is driven by a motor, and passing over a guide 11 immediately to a circular knitting machine, is sustained in a free loop 9 by a stream of air 15 from a nozzle 17; and its position is sensed by dielectric or photoelectric means 25 which is activated if the bottom of the loop rises or falls and which energizes one or other of two controlling circuits, to increase or decrease the motor speed. The loop is protected from extraneous draughts by a casing 13 and may be formed and sustained in or near to the horizontal plane. Conical nip rolls driven at constant speed may be used, the forwarding rate of the yarn being varied by varying the position of the yarn along the nip. Instead of two signal points, only one may be used, the closed end of the loop "hunting" across it. Photo-electric sensing and control means may comprise a constant voltage lamp positioned on one side of the bottom of the loop and a co-acting photo-electric cell on the other.