GB1323724A - Method and apparatus for winding yarn - Google Patents

Abstract

1323724 Automatic removal of yarn defects KANEBO Ltd 16 July 1970 [25 July 1969 (2)] 34504/70 Heading D1J The invention relates to a method for automatically removing yarn defects in a yarn winding system wherein the take-up package is driven by a drive from an A.C. reversible driving motor. When a slub passes a detector 4, Fig. 1, the detector 4 causes an inverse phase of the A.C. to be applied to the driving motor so that it slows down and then reverses the direction of rotation of the package driving drum 3. The motor is eventually stopped by applying D.C. to it. The reverse rotation causes the yarn 11 to become slack and it is then sucked into a U- shaped tube 6 that has upper and lower slits 9 and 10. Externally positioned guides 8c, 8d ensure that as the yarn 11 is drawn around the U-bend of the tube 6 the upper part of the yarn extends out of the slot 9 and the lower part of the yarn extends out of the slot 10. The effect, as shown in Fig. 1, is to position two yarn lengths across a knotting mechanism 7, the amount of reverse rotation of the drum 3 being controlled such that the detected slub is within the U-tube. The knotting mechanism 7 then operates to cut off the yarn lengths extending into the tube 6 and knot the cut ends together. The U-tube removes the slub and normal drive by the motor recommences. In Fig. 4, when a slub is detected, the threepole switch 17 responds to an output signal from the slub detector and moves from a setting in which the motor 15 is connected across a 3-phase supply 22 to the setting shown in which the motor 15 is connected across a 3-phase bank of resistances 16 to cause the speed of the motor to rapidly reduce. A time delay circuit 19 then causes switches 17 and 18 to change from the setting shown and so reverse the phase supply to the motor 15. This first stops the motor 15 and then reverses its direction to cause the package to unwind and so feed the slub to the slub removing means. After a predetermined number of unwinding rotations, or after the inverse phase A.C. has been supplied to the motor for a certain time, the contacts of switch 20 are changed to the D.C. power source 21 to stop the motor 15. Introducing a fresh supply bobbin Fig. 8 shows how the apparatus is used to introduce a fresh supply bobbin 35 as the old one 1 nears exhaustion. A lower detector 41, on sensing fluorescent paint on the exhausted cop spindle, stops the drive to the drum 3 and causes the yarn extending from the spindle 1 to be sucked into the U-tube 6 and thence into the slot 9 so as to extend across the knotter 7. The turret 34 rotates to bring the new cop 35 opposite the detector 41, a jet nozzle 38 rotates the cop in its unwinding direction, and a further jet 40 blows the unwound end up into the suction tube 6 and into the slot 10 so as to extend across the knotter 7. The yarn ends are then joined by the knotter, excess material is cut off and removed by the U-tube 6, and winding is restarted. Presser member In Fig. 7 a belt 31 has one end connected to the cradle arm 30 carrying the package 2. The other end of the belt 31 is wound round a pulley 32 of a torque motor 33. During normal operation the torque motor creates a predetermined constant torque against which the arm 30 is forced to rise and the package 2 increases in diameter. However, when a yarn defect is detected the torque motor 33 receives an electrical signal causing the motor to produce an increased torque so that the contact pressure between the package 2 and the drum 3 is increased during the reverse rotation of the drum 3.