Patent DE-10062937-A1 (DE)
Title: To operate a disconnected bobbin at an open-end spinner, on a yarn break, an auxiliary drive roller is pressed against the bobbin surface at an adjustable and controlled pressure to preserve the wound yarn structure
Inventor: WALK JOHANN
IPC: B65H63/036
Filed: 2000-12-16
Abstract: To rotate a disconnected bobbin (162) at an open-end spinning station (10), the bobbin is lifted from a bobbin shaft (160) against an auxiliary drive roller (211), which presses against the outer circumference of the bobbin with a variable pressure according to the actual operating conditions.  To drive a bobbin, at an open-end spinning station, the actual operating conditions include the selected acceleration of the auxiliary drive roller and/or the bobbin parameters. On splicing a broken yarn, the roller pressure is selected according to the yarn characteristics. On an increasing bobbin acceleration, the roller pressure is raised. A lower roller pressure is applied when the yarn end is to be located at the bobbin. On splicing, the roller pressure is strengthened with an increasing bobbin diameter. The roller pressure is selected according to the auxiliary roller shape and also the tension of the yarn being wound around the bobbin, and especially at a low roller pressure when the bobbin is to be dyed. The open-end spinner has a control unit (20) which sets the pressure applied by the auxiliary drive roller against the bobbin, according to the spinner operating data and the bobbin data. An Independent claim is included for an open-end spinner where the bobbin is lifted from the bobbin shaft against an auxiliary drive roller, with its pressure against the bobbin surface set by a control unit according to the operating conditions in force. Preferred Features: A force unit (210) acts on the swing lever (21) which supports the auxiliary drive roller, to give an adjustable pressure by the roller against the bobbin surface, using an adjustable pull/push action on the swing lever. The auxiliary drive roller can be mounted to a robot (2), as a mobile maintenance unit which travels along the line of spinning stations. A further Independent claim is included for an auxiliary drive roller, with a profiled surface of recesses and/or projections to give a friction grip against the bobbin. Preferred Features: The auxiliary drive roller has a cambered outer shape with a radius in the longitudinal direction of 30-200 mm and preferably 40-100 mm. The profile of the roller surface is formed by one or more axial or spiral recesses and/or projections along its length. The recess has a width of at least 5 mm. The recesses and/or projections have a cross section shape which is rectangular, triangular or rounded. The gap between the recesses and/or projections is at least 2 mm at the roller surface. When the bobbin brought out of action, the structured surface of the auxiliary drive roller exerts a force component on the bobbin surface at its nearest side. The auxiliary drive roller can be formed by a mantle drawn over a core, with spacers between them as axial webs at intervals of at least 3 mm. The difference between the maximum and minimum outer radii of the outer circumference of the auxiliary drive roller is at least 0.5 mm and preferably at least 1.5 mm.