Service device and method for applying an air blast to a broken yarn end in a ring spinning machine

摘要

A service device in a ring spinning machine is moved after a yarn break to the appropriate spinning position to separate the broken yarn end from the winding by generating an air blast that acts on the yarn end. If the winding build-up is in a stage in which the initial winding cone has not yet been completed, the air blast is set at a high value so that a relatively strong separating force acts on the broken yarn end. If, on the other hand, the build-up of the winding cone has been completed, the separating force acting on the yarn end is less. The stage of the winding build-up is determined with the aid of a switch, which is connected to a stop member that contacts and rests on the ring rail of the spinning position. The setting of the two air blasts is performed by a switchable trottle. Taking into consideration the stage of the winding build-up when setting the air blast that acts on the yarn end assures that the broken yarn end is separated in every instance from the winding, yet prevents loops from being separated at the same time.