thread 4 a instead of on the preceding thread 4 in this manner the part 1 a of the machine 1 can continue the yarn processing without any interruption in the meantime the operator in charge of the machine has all the time necessary to note the abnormality and to change the now empty bobbin 6 or repair the thread 4 which was interrupted in either case the thread 4 is again connected in known manner to the device 5 and the thread 4 again associated with the change over device 10 to enable this latter to again effect a change over when the thread 4 a runs out or breaks each time a change over is signalled a request can be fed to the operator to intervene and a signal be fed to the textile machine indicating that thread change over has taken place in order if necessary to mark the yarn bobbins produced if this production is to be classified as second choice if a double indication of thread change over takes place originating from both the devices 5 and 5 a and fed to the unit 11 an alarm signal can be generated to halt the process on the textile machine t as production is impossible without both the threads 4 and 4 a this solution evidently enables potentially perpetual production to take place in spite of any breakages or run outs of the threads 4 or 4 a from the bobbins 6.