PROCEDIMENTO E DISPOSITIVO PER STACCARE L'ESTREMITA' DEL FILATO NELL'ATTACCO DEL FILATO IN UN'UNITA' DI FILATURA OPENEND

The invention relates to a method and a device for severing the yarn end during piecing on an open-end spinning unit. The quality of the yarns produced by the open-end spinning process depends to a great extent on the quality of the connecting or attachment points of the yarn. The invention indicates a method for achieving improvement in quality in this respect, and it also indicates a device for carrying out the method. The method according to the invention proceeds from a method for severing the yarn end during piecing on an open-end spinning unit, in which the yarn located in the draw-off tube of the spinning rotor is opened in a specific region by opening means, the severed yarn end is removed and the fresh yarn end is guided back into the spinning rotor for piecing. Provision is made, according to the invention, for the yarn end, secured by local clamping and opened, to be severed from the remaining yarn as a result of the effect of a brief increase in the axial yarn tension between the clamping point and the draw-off rollers of the spinning unit. The invention relates, furthermore, to a device for carrying out the method on an open-end spinning unit, which has a piecing device with a reversing means for guiding the yarn end back into the spinning rotor, means for the local opening of the yarn and for the removal of the severed yarn end through a removal channel connected to the draw-off tube of the spinning rotor, and means for a brief increase in the axial yarn tension. Provision is made, according to the invention, for there to be present in the removal channel a clamping means for clamping the yarn end, which is coupled to the means for the brief increase in the yarn tension between the clamping point of the yarn by the clamping means and the draw-off rollers of the spinning unit.