Patent GB-801491-A (GB)
Title: Improved process and apparatus for continuous crimping of synthetic thermoplastic threads or yarns
IPC: D02G1/02
Filed: 1956-02-10
Abstract: 801,491. Crimping yarns; false-twist devices; roller arrangements in textile spinning &c. machines. ONDERZOEKINGSINSTITUUT RESEARCH N. V. Feb. 10, 1956 [March 4, 1955, July 2, 1955, Nov. 18, 1955, Nov. 22. 1955], No. 4220/56. Classes 120(2) and 120(3) In a process for crimping yarns of synthetic thermoplastic material e.g. polyamide or polyester, yarns are continuously supplied by a slip free device via a twist stop, heating device, cooling zone to a false-twisting device comprising a pair of co-operating similar hyperboloids, each having a surface generated by a straight line forming a crossing angle of between 30 and 45 degrees with the axis of revolution and each being connected to a driving means; the hyperboloids are rotatably mounted so as to contact each other along a common line and so that the yarn passing therebetween and to a yarn discharge device follows a straight path which is equi-angular to the axes of the hyperboloids when viewed in a plane parallel to both of said axes. As shown in Fig. 1, a yarn 10 moves 'from a supply device 11, through and in oscillating contact with a fine i.e. less than 0.8 mm. dia., tube 12, heated by passage of electric current therethrough, through an air zone, thence between oppositely rotated hyperboloids 2 and 3, having surfaces of abrasion-resistant rubber, the imparted twist between which and the twist stop at the device 11 being set by the heating effect of the tube 12 followed by cooling in the air zone, around a discharge roller 15 forming a second twist stop. and is collected on a winding device (not shown) optionally with added twist in the same or opposite direction to the said twist produced by the false-twister. As shown in Fig. 2, the hyperboloid 3, the shaft 5 of which is mounted in a forked carrier 17 pivotable on a fixed axis 18 against the damping action of a plate 23 in an oil bath 24, is maintained against the rigidly mounted' hyperboloid 2 under a pressure determined by the position of an adjustable counterweight 20. The yarn may be stretched between the supply and discharge devices by adjustment of the latter and, additionally, prior to heating, as by means of a stretching rod or rods which may co-operate with a pair of intermeshing cog-wheels acting as the twist stop, Fig. 3 (not shown): previously non-stretched yarn may be stretched at this stage as by means of stretching pins. In another modification, Fig. 4 (not shown), the yarn contacts the hyperboloids along a generatrix thereof and a liquid-jacketed cooling tube enclosing the yarn and co-axial with the tube 12 precedes the false-twisting device. The tube 12 may have a straight or helical slit to facilitate thread insertion and is replaceable by a helically wound resistance wire or a curved heating surface. The cooling tube is replaceable by a helically wound tube through which passes a cooling medium or by a metal block comprising bores for the yarn and a cooling medium, or it may be affixed to a tube through which the cooling medium flows and/or it may comprise cooling ribs.