Method for automatically starting and stopping an open-end spinning machine

Claim 1

In a method for the automatic starting and stopping of an open-end spinning machine system containing a plurality of spinning units, the components of each unit including a spinning turbine having a fiber collection trough, a breakup roller, a feed roller, a yarn extraction device and a yarn winding apparatus, wherein, during stopping of the system, the rates of rotation of the turbine, the feed roller, the yarn extraction device and the yarn winding apparatus of each unit are simultaneously reduced to below the normal spinning speed before being completely stopped, and the end of each yarn being spun remains in its spinning turbine and during restarting of the system each yarn extraction device and winding apparatus are caused to move opposite to their direction of normal movement for a limited time to feed the yarn end back into the spinning turbine, and the spinning turbine, the feed roller, the yarn extraction device and the yarn winding apparatus are brought to a rated speed below the normal spinning speed in order to start the spinning process, the improvement wherein: a. the stopping of the system, from an operating state, comprises the steps of: i. effecting such simultaneous reduction in the rates of rotation of the turbine, feed roller, yarn extraction device and yarn winding apparatus of each unit by permitting the rates of rotation thereof to decrease in unison in a free run-down manner while remaining within the range permitting yarn spinning to continue, and ii. positively and rapidly braking such components only when their rates of rotation reach the lower limit of such range; and b. the restarting of the system comprises effecting such movement of the yarn extraction device and the winding apparatus of each unit opposite to their normal direction of movement by initially driving the yarn extraction device and the yarn winding apparatus of each unit through a selected, fixed, distance in the direction opposite to their normal operating direction, which distance is independent of the existing speed of the system, for feeding a fixed, predetermined, length of yarn back into the fiber collection trough of the associated spinning turbine.