Patent GB-1088046-A (GB)
Title: Yarn treating apparatus
Inventor: TINDALL JOHN RAYMOND
IPC: B65H51/12
Filed: 1963-07-23
Abstract: 1,088,046. Stretching apparatus. COURTAULDS Ltd. July 22, 1964 [July 23, 1963], No. 29057/63. Heading B5B. [Also in Division D1] Yarn is tensioned or stretched by passing the yarn in sequence over first and second rotated pulleys or rollers, the second pulley being rotated at a higher peripheral speed than the first while the first pulley is subjected to a constraining force tending to maintain its peripheral speed at a constant amount below that of the second; when a force is imparted to the first pulley by frictional contact with the yarn greater than the constraining force, its peripheral speed is increased to approach that of the second pulley, to maintain the tension in the yarn substantially constant, or to stretch the yarn to a point where a substantially constant resistance is offered to further tension, whereby inequalities arising from earlier processing stages are removed. When the tension is to be maintained, the pulleys are driven by the yarn; when the yarn is to be stretched, the pulleys are positively rotated. The pulleys may be arranged on the same, or separate shafts. The difference in the peripheral speeds may be brought about by using pulleys of different diameters. The constraining force may be generated by a spring-loaded plate between the pulleys, or when the pulleys are on different shafts, between the first pulley and a fixed collar. When the pulleys are on vertical shafts, they are loosely mounted above collars fixed to the shaft and are loaded by weights placed upon them. In Fig. 2 yarn, which may be drawn from a freely rotatable swift through a gate-tensioner, and be taken up on a driven swift, passes once around a pulley 4 to a guide-roller 5, and then once around a second pulley 7 of a larger diameter. The drive of pulley 7 is transmitted to pulley 4 through a slipping-clutch in the form of two spring-loaded friction plates in contact with the facing surfaces of the pulleys. When the arrangement is used as a constant tension device, the pulleys are rotated by the yarn, which tends to rotate them at constant peripheral speed. But the clutch tends to make pulley 4 rotate at a lower peripheral speed so that it slips to an extent governed by the relative diameters of the pulleys. As the frictional contact between the plates and the pulleys is constant, the tension imparted to the yarn is constant. When the arrangement is used as a stretching device, the pulley 7 is positively rotated at a speed equal to that at which the yarn is taken up; and the yarn is stretched by an amount determined by the ratio of the diameters of the pulleys, which ratio is chosen according to the maximum stretch desired. When a length yarn of a reduced ability to stretch passes through the apparatus, the clutch slips, enabling pulley 4 to rotate at a greater angular speed than pulley 7. In an alternative form of clutch for use in a constant tensioning device, Fig. 4, both pulleys are rotatably mounted on a sleeve prevented from axial movement on a shaft. Between the pulleys is a friction-plate 33, and the two pulleys are urged towards one another by a spring 32 adjustable by a nut 31 on a threaded part of the sleeve.