A procedure is described in which an open-end rotor spinning machine already in operation can be modernized by means of re-equipping it with new parts. This machine comprises device means for interrupting the spinning process at a spinning station for the purpose of a doffing operation. The machine comprises a doffing arrangement which is movable relative to the spinning stations, which doffing arrangement comprises devices for exchanging a full bobbin for an empty yarn-winding tube. The machine comprises further at least one piecing arrangement movable in relation to the spinning stations, which is designed to restart spinning at the spinning station with a starting winding already connected to the yarn-winding tube. It is an object of the modernization that the piecing arrangement is replaced with a new piecing arrangement, which is designed to restart spinning with a starting yarn which is not connected to the yarn-winding tube, and subsequently to attach a newly spun yarn to the yarn-winding tube. In the case of the new piecing arrangement any piecing point of the yarn after a doffing operation onto the bobbin is omitted. This results in an increase in bobbin quality. The piecing arrangement is also operable to perform piecing operation in case of a yarn break with a partially full bobbin, where yarn from the partially full bobbin is used for piecing.
A method and device for restarting a spinning operation at work stations (2) of an open-end spinning machine (1) after replacement of a cheese (8) with an empty tube by a traveling service unit (16) comprising an auxiliary yarn supply device (21). Each work station comprises a yarn spinning device (3) and a cheese winding device (4) with a creel (9). The auxiliary yarn supply device (21) delivers a starting portion of an auxiliary yarn (24) to a suction nozzle (14), which transfers the auxiliary yarn (24) to a spinning start member (20), after which the suction nozzle (14) pivots to re-take the auxiliary yarn (24) between the supply device (21) and the spinning start member (20) and removes the auxiliary yarn (24) after restarting the spinning operation, whereupon the yarn (7) is brought to the creel (9) of the work station (2).
