Abstract: The instant invention relates to a process and device for piecing on an open-end spinning device. Before the beginning of the piecing process the desired run-up curve for the fiber stream which is to be fed to the fiber collection surface and the acceleration curve of the fiber feeding device corresponding to this run-up curve are defined. During piecing the fiber feeding device is switched on and is driven in accordance with the defined acceleration curve. The fiber stream produced thereby is deflected and removed on its way between the fiber feeding device and a fiber collection surface. In this process the current actual values are calculated from the acceleration curve of the fiber feeding device and the fiber stream is again fed to the fiber collection surface when a predetermined desired value has been reached, before the fiber stream which is started by switching on the fiber feeding device has reached its full strength.

Abstract: For piecing a thread in an open-end spinning apparatus having a fibre collection surface, a sliver is supplied to the clothing of an opening cylinder and opened thereby into fibres and is supplied in this form to the fibre collection surface. There, the fibres are incorporated into the end of a returned thread which is then drawn off continuously. During this, the leading end of the sliver, forming a tuft, is supplied for piecing to the opening cylinder, at a penetration depth which is greater than the penetration depth after piecing, whereas piecing is carried out in a manner conventional per se, matched to a reduction in the penetration depth. This reduction in the penetration depth is carried out suddenly in order to counter thick points in the joint. To carry out the process, a penetration depth alteration apparatus is provided which is in controlled connection with a control apparatus.

Abstract: A process for cleaning an open-end spinning rotor which has a fiber collection channel and an open edge, which is covered by a rotor cover. A first compressed-air stream is directed towards the fiber collection channel in a first cleaning phase. Then, in a second cleaning phase, the spacing between the open edge of the spinning rotor and the rotor cover is increased. In addition, a suction air flow leaving the spinning rotor over its open edge is produced. To carry out this process, there is associated with the rotor cover an opening apparatus which is connected, together with at least one blower channel to a common control apparatus.

Abstract: A yarn piecing device and process for an open-end spinning machine wherein opened fiber is fed to a fiber collection surface in a pneumatic stream. The stream of fibers is shifted from the fiber collection surface when a broken or missing yarn is detected and the fiber feed to an opening device is interrupted. After the yarn is back-fed to the collection surface, the fiber feed to the opening device is restarted and the pneumatic stream of fibers is shifted back to the fiber collection surface before the fiber density in the pneumatic stream attains its production strength density.