Abstract: A friction false twist device is of the type comprising three parallel shafts located at the corners of an equilateral triangle, and carrying rotationally symmetric friction elements. At least one of the shafts can be shifted in relation to the other shaft or shafts so as to open the device for threading. An additional shaft is arranged in relation to the three shafts carrying the friction elements so that, if connected by a line, the centers of the four shafts preferably would lie at the corners of a generally kite-shaped quadrilateral. Each of the four shafts carrys a whorl, the four whorls being drivingly interconnected by an endless belt of relatively minimum elasticity. At least one other shaft is coupled with said shiftable shaft for conjoint movement such that changes in the circumferential length of the quadrilateral caused by movement of the shiftably mounted shaft are substantially compensated by conjoint movement of the coupled shaft.

Abstract: Devices are described for determining the helix angle of twisted threads during false-twist texturing. The thread passes over a convex spherical surface at the top of a two-armed lever pivoted between the arms and having a vertical zero position. Magnetic means act on the lower arm to bias the lever to the zero position. In one device the lever is pivoted about a diameter of a vertical cylindrical tube rotatable on a second vertical tube, a scale being provided to indicate the position of the tube about its axis which, in turn, depends on the helix angle of the thread traversing the spherical surface, which has a radius of curvature equivalent to the length of the upper lever arm. In another device the two-armed lever is carried by a ball in a spherical bearing and has a pointer at the lower end that indicates the position of the lever with respect to polar co-ordinates on a flat surface.

Abstract: A friction drive for a twist-tube for false-twist texturing of textile yarns is described wherein a continuously running belt rotates a pair of driving rolls, maintained at a constant pressure against the belt, to which rollers for rotating the twist tube are co-axially fixed. The driving rolls are carried at the end of a rod, mounted to slide through a fixed holder and subjected to an axial force by a weight hanging on a cord passing over a pulley having a fixed axis to a pin on the rod. The rolls are so mounted on the rod that they can be arranged to engage either face of the belt. Therefore, the force necessary to press the driving rolls against the belt is reversible. This is achieved by providing the rod with two pins, either of which can be chosen for attachment of the cord and from which the cord will hang in opposite directions over the pulley. This gravity mechanism can be replaced by fluid or electromagnetic means for exerting the force on the rod.

Abstract: A twist tube for a false-twisting device for texturing textile yarns has an enlarged end in which the bore has an oblong cross-section with both the major and minor axes substantially longer than the bore of the main portion of the tube. The thread guide pin extends in the direction of the minor axis between flat sides of the bore which are joined at each end by arcuate sides. Two circular, coaxial openings extend from outside the enlarged end to the arcuate sides. The oblong shape and these openings assist the threading of the twist tube. The thread guide pin is displaced laterally with respect to the longitudinal axis of the main portion of the tube by a fraction of the pin diameter. The axis of the openings, which is perpendicular to the pin axis, is displaced from the pin axis by a similar fraction, towards the main portion of the tube.

Abstract: Friction discs for use in driving of guide rollers for twist tubes in false twist devices for texturing synthetic filaments are described in which the disc comprises a support disc of non-resilient material surrounded by a friction ring of synthetic resilient material that is tapered radially outward to the circumferential surface making contact with the twist tube. This enables the friction discs to be spaced more closely together in the roller and shorter twist tubes to be used. Centrifugal force on the friction ring is also reduced. Higher rotation speed are, therefore, achieved. The ratio of the width of the inner circumferential surface of the friction ring to the width of its surface engaging the twist tube is between 1.5:1 and 3:1. The support disc may be of metal alloy or consist of an inner disc of synthetic plastics material with an outer ring of metal alloy. In each case the metal alloy should have a modulus of elasticity of at least 6500 kp/mm.sup.2 and a tensile strength of at least 25 kp/mm.sup.

Abstract: Devices for false-twist texturing textile filaments are described wherein a twist tube is rotated while magnetically held in a wedge shaped gap between a driven roller and a supporting roller which is rotated by power transmitted thereto predominantly by a rotary driving member in frictional contact with the two rollers. This driving member may be a cylindrical pin in the wedge shaped gap opposite that containing the twist tube and held in the gap by magnetic attraction or repulsion. Alternatively the driving member may be a roller mounted freely to rotate about its axis in frictional contact with roller surfaces on shafts carrying the driving and supporting rollers.

Abstract: A twist-tube for false-twist devices for texturing textile yarns is described in which the tube is provided with an enlargement, which may be at one end, formed with opposed grooves. A sapphire thread guide extends across the enlargement with its ends extending into and peripherally fitting in opposed terminal ends of the grooves. This enables a comparatively short pin to be used which is positively prevented from escaping laterally from the tube so that harmful effects of centrifugal force are avoided. The grooves may either locate the pin with its axis intersecting the tube axis or with its curved surface displaced by a fraction of the yarn thickness beyond the tube axis.

Abstract: A friction disc is described for very quietly driving twist tubes at several hundred thousand revolutions per minute in a false-twist device for texturing synthetic filaments. The disc has a titanium alloy support flange having a specific electrical resistance of between 1 and 2 .OMEGA./mm.sup.2 /m, a modulus of elasticity of at least 6500 kg/mm.sup.2 and an ultimate tensile strength of at least 25 kg/mm.sup.2. The support flange has a circular cylindrical circumferential surface which fits and is rigidly fixed to the internal surface of a polyurethane friction ring, the external cylindrical surface of which frictionally drives the twist tube. A twist tube driving roller has two such discs spaced apart on a steel driving shaft.

Abstract: A false-twist device comprises two axially parallel rollers rotatable about their axis for supporting a twist tube in the cuneal throat formed thereby, driving means for simultaneously driving the rollers, at least one yarn deviating element for feeding a yarn end to, or removing it from, the twist tube at a predetermined angle relatively to the tube axis, and means for holding the tube in place when no yarn is present in the tube.