Device and process for the handling and control of the yarn in a crosswinding head of a crosswinding machine in bobbin doffing operations

A process for the handling and control of the yarn (1) in a crosswinding head of a crosswinding machine in bobbin (2) doffing operations, said crosswinding machine being equipped with a series of crosswinding heads and with at least one service trolley (13), each of said crosswinding heads comprising a pirn, from which a yarn (1) is unravelled and is wound to form a bobbin (2), around a winding tube, two mouths for the suction of the yarn (1) ends possibly formed, by breakage or cutting, on the side of the pirn or on the side of the bobbin (2) respectively, and for the delivery of these ends to a joining device (7), situated along the run of the yarn (1) from the pirn to the bobbin (2), to re-establish the yarn continuity, said service trolley (13) being capable of running along the whole crosswinding machine, in order to position itself in correspondence with each crosswinding head and comprising a manipulation device (12) of the yarn (1) characterized in that it comprises the following phases:

• moving of the yarn (1) run in a defined position, near the terminal portion of its course from the pirn to the bobbin (2),
• seizure and cutting of the yarn (1), in correspondence with said defined position on the part of a manipulation device (12) of the service trolley (13), which withholds the end coming from the pirn,
• distancing of the bobbin (2), arrangement on a new winding tube of the yarn (1) coming from the pirn and start of the formation of a new bobbin.