Patent GB-570646-A (GB)
Title: Improvements in or relating to the stretching of textile filaments and threads
IPC: G03C1/74
Filed: 1943-07-27
Abstract: <PICT:0570646/IV/1> Filaments or threads, particularly those having a basis of a cellulose acetate or other cellulose ester or ether, or of a synthetic linear polyamide, or other synthetic resin or polymer, are passed in non-slipping contact with a positively-driven feed device, then into an end chamber containing water under pressure and thence directly into a stretching chamber containing moist steam under a lower pressure than that of the water in the end chamber, and the material is withdrawn from the stretching chamber at a rate greater than that at which it is fed into the end chamber and is <PICT:0570646/IV/2> <PICT:0570646/IV/3> chamber and avoids loss of steam through the inlet orifice.  The end chamber and the stretching chamber may be of small cross-section, e.g. in the form of narrow tubes.  The stretched filaments may be led to ring or cap spinning devices or centrifugal pots.  As shown in Figs. 1 and 2, a single end of thread 1 is drawn from a bobbin 2 and passed into a trough 3 containing a washing liquid, e.g. for removing residual solvent. The thread passes from the washing liquid to a drying frame 5 and then through a trough 9 containing water or other conditioning liquid.  It then passes between rollers 14, 15, either or both of which are positively driven, and is fed by them to the stretching apparatus. The thread passes through an end chamber 21, containing water under pressure, and then into a softening and stretching chamber 17 containing steam under pressure.  The pressure in chamber 21 is maintained slightly higher than that of the steam in chamber 17 so that there is a flow of liquid through orifice 24.  The thread is drawn from the steam chamber by a stretching or take-up device 28 and is then passed to a ring 31 and bobbin 33.  The take-up device, shown in plan view in Fig. 3 comprises a conical roll 34, positively driven in timed relation to feed thereby stretched.  The difference of pressure produces a flow of water from the end chamber into the stretching chamber, which assists the passage of the filaments into the stretching rollers 14, 15.  The conical roll has a cylindrical portion 37 adjacent the base.  A pair of guides movable in response to the tension in the thread are provided.  Supporting arm 43 is pivoted at 42, and mounted on it is a member 45 bent to form thread guides 46, 47.  To the arm 43 is attached a tension spring 48 with threaded connecting link 49.  Tension in the spring is adjusted by thumb-screw 54.  A front guide 55 is formed on rod 56 which is pivoted at 57 and extends beyond the pivot to rest against arm 43. A spring 59 holds rod 56 against arm 43.  When starting up, the feed rolls are driven at a speed equal to the peripheral speed of the smallest part of roll 34 and application of steam is started in chamber 17.  As the thread has little stretch at first, the tension of the yarn pulls arm 43 to the narrow end of the cone. As the steam begins to have its softening effect, the thread begins to stretch, allowing the spring 48 to swing the arm 43 toward a larger part of the conical roll.  When the full effect of the steam is imposed upon the yarn, the arm 43 moves so that the path of the thread is round the cylindrical portion 37 of the roll 34.  Specifications 443,773 and 569,669 are referred to.