Abstract: The invention relates to a method of and a system for controlling the operation of open-end spinning machines comprising a plurality of spinning units, which method is based upon a permanent cyclic communication of a central unit of the system with the individual spinning units. According to the invention, at a given instant, a single spinning unit only is connected to the central unit of the control system, said central unit being supplied with information data about the condition of the spinning unit connected thereto while said central unit simultaneously transmits instructions for said spinning unit, the other spinning units operating automatically on the basis of the stored instruction the validity of which lasts for the time of one control cycle.

Abstract: Method of and apparatus for operating an open end spinning machine having a plurality of spinning units each including a sliver feeding device, a fiber separating device, a twist forming element, a yarn taking-off device, yarn winding device and a reversing mechanism for returning the yarn end back into the twist forming element. The twist forming element and the fiber separating device are set in operation; thereafter the fiber feeding is started simultaneously with the yarn end reverse travel to return same into the twist forming element in which a fibrous ribbon is formed of the fibers supplied. After spinning-in said yarn end with said fibrous ribbon the yarn is again set into a forward operative travel.

Abstract: A method of and an apparatus for piecing yarn in open end rotor spinning units. The returning of the yarn end into the spinning rotor for piecing is performed in two stages, in the first of which the yarn is stopped immediately upon breakage within the sucking range of the spinning rotor, and is brought immediately thereafter into a withdrawal chamber in which the yarn end is retained. In the second stage the yarn end is separated and deposited in said withdrawal chamber, and the new yarn end is introduced by further reverse motion into the spinning rotor. The apparatus has a withdrawal chamber interposed between the inlet of the withdrawing channel and a cutting mechanism. In one embodiment said chamber is connected to the withdrawing channel, opposite which there is mounted a nozzle connected to a controlled pressure air source. In another embodiment there is provided a nozzle communicating with the withdrawal chamber, said nozzle being connected to a controlled source of underpressure.

Abstract: An improved technique for stopping the advance of spun yarn through the draw-off rollers and distributing cylinder of an open-end spinning machine in response to a detected yarn breakage condition is described. A reversible clutch is selectively interposed between first and second oppositely rotating drive shafts and the cylinder, which in turn is coupled to the draw-off rollers. The clutch is operated from a normal forward advance condition to an operated reverse condition for a duration corresponding to a variable-duration control pulse generated in response to a yarn breakage condition upstream of the discharge end of the machine withdrawal tube. The duration of the control pulse is adjusted to dynamically brake the forward motion of the advancing yarn to a stop. The control pulse is removed soon enough to prevent reverse movement of the yarn.