ES344020A1 - Apparatus for returning a yarn end into an open end spinning machine - Google Patents

Abstract

In an open end spinning machine wherein a yarn reserve is created to be fed back to the spinning chamber 32 in the event of the yarn becoming detached from the spinning chamber surface or on starting up spinning, the reserve is created by increasing the length of yarn path between the spinning chamber 32 and take up means 40 while spinning is in progress and at such a rate that the yarn count is not changed substantially. As shown in Fig. 3 the yarn is delivered through a tube 37 pivoted to the chamber delivery tube 36 and biassed away from the vertical by a spring 41. Normally the tension in yarn 38 balances the force of spring 41 and maintains tube 37 in the position shown in full lines. When the yarn tension drops tube 37 is drawn against a stop 42 and a switch 43 is closed. In consequence a solenoid 46 is operated to move an armature 47 which is linked to tube 37 and slides in a cylinder 48. Thus tube 37 is drawn into an upright position and the reserve yarn length created is sucked back into the collecting chamber by the suction applied to casing 31'. The motion of tube 37 to the vertical and its subsequent return to its normal position is controlled by a valve 50, a throttle 51 and an opening 49 in cylinder 48. In another embodiment (Fig. 2 not shown), the lengthened yarn path is obtained by passing the yarn about a pin displaced from the straight line path of the yarn the pin being retractable on yarn slackening. In Figs. 4 and 5 not shown the yarn passes along a series of tubes two of which are telescoped together on yarn slackening to produce a shorter path. In the embodiment of Fig. 5 the collecting chamber is stationary while a yarn gripping device associated with the delivery tube rotates. In Fig. 6 not shown, the yarn path is defined by an elastic tube which is normally stretched to provide a long yarn path but is released on yarn slackening to form a shortened path. In Fig. 7 not shown the path lengthening device consisting of a pivoted lever which deflects the yarn, is mounted between the doffing rollers and the spooling device and a further solenoid is provided to separate the doffing rollers on yarn slackening to allow the excess length of yarn to be drawn into the spinning chamber. An electrostatic spinning arrangement is shown in Fig. 8, the collecting chamber 84 being regatively charged with respect to the positively charged sliver feeding rollers 83. In addition to the solenoids operating the yarn path shortening lever 91 and opening doffing rollers 89 a further solenoid is operated on yarn breakage to pivot a suction tube 96 under chamber 84 so as to draw back the slack end of the yarn. A detailed description of the solenoid means for pivoting lever 91 is given.