PROCESS AND DEVICE FOR THE PIECING OF A YARN IN AN OPEN-END SPINNING MACHINE OPERATING WITH A SPINNING ROTOR

摘要

A yarn is fed at a piecing speed to the fiber collection surface of a spinning rotor. It is there combined with the fibers of a fiber ring and is then drawn off from the spinning rotor in the form of a continuous yarn while fibers newly fed into the spinning rotor continue to be incorporated in the yarn. The rotor speed is changed, immediately after piecing, from the piecing speed to a rotational speed which is lower than the piecing speed. The rotor speed is then increased to the production speed. In this manner, optimal conditions are achieved with respect to propagation of twist and draw-off of the piecing joint. To carry out this process, mechanisms are provided for the reduction of the rotor speed from piecing speed to a lower value, for renewed acceleration of the rotor speed after a desired minimum value has been reached after the passage of a predetermined period of time, as well as mechanisms to tie the accelerating rotor speed to the desired production speed.