Improvements in or relating to the twisting and crimping of textile filaments

797,051. Spinning and crimping yarns; twist tubes. BRITISH NYLON SPINNERS Ltd. June 22, 1956 [July 19, 1955], No 20802/55..Classes 120(2) and 120(3) A device for imparting a plurality of turns of false-twist to a monofilament multifilament, or staple fibre yarn for each revolution of a rotatable part thereof, as may be required in crimping the yarn, comprises at least one rotatable member, e.g. a driven twist-tube. The member has a continuous bore, of circular crosssection and coaxial with the axis of rotation of the member, the surface of which comprises, at least at or around one endportion thereof, a non-abrasive material e.g. rubber with carbon black filler, having a high coefficient of friction with the yarn to be twisted by contact therewith on the path through the device: the least diameter of any bore exceeds the diameter of the largest yarn to be twisted and the shape and location of the material is such that the yarn is in contact therewith when the path of the yarn between entering and leaving the device is turned through an angle of at least 90 degrees. The tube shown in Fig. 1 comprises an annular portion 3 mounted on bearings 5, 7, within a fixed annular portion 1, rotated by a band 9 and carrying a rubber bush or insert 11 the full length of the inner surface and curved end portions of which engage a yarn 13. In a process for crimping yarn (or rendering it twist-lively) the yarn of thermoplastic material, e.g. synthetic linear polymeric amides or esters such as nylon or polyethylene terephthalate, cellulose acetate and triacetate, or non-thermoplastic filaments which have been treated with a thermosetting agent, passes around the drum of a magnetic hysteresis tensioner 19 which imposes a constant output tension on the yarn, through an infra-red heating device 21 comprising a glass tube 23 having electric resistance coils 25 wound thereon, through an air path constituting a cooling zone, through a twist tube 27 so mounted that the yarn makes contact with one side 29 of the rubber bush therewithin, over a pulley-wheel 31, and through feed rolls 33, 35, which forward the yarn at a slightly greater speed than that at which it is wound on a package 39. Heating of the yarn may be effected electrically by contact or radiation, by steam under pressure or by contact with heated solid particles, such as glass, in "fluidized" condition produced by passage of air therethrough. False twist of differing senses may be imparted to filaments, i.e. one or som