fibers hereinafter simply referred to as a fiber stream 54 which is no longer spun in this fiber stream 54 is eliminated by means of the suction nozzle 12 of the yarn suction device or system 12a in a manner conventional in this particular art now at this spinning position some good fiber material is of course guided into the yarn suction device or system 12a but there does not exist any danger of damaging the working elements of the machine i e there is not required any immediate intervention on the part of the operating personnel in fig2 c there is shown what happens following the arrival of the travelling control device 24 at a spinning position where there prevail the operating conditions described above with reference to fig2 b the light receiver 30 due to the absence of any reflection of the emitted light beam does not receive any reflected light beam 31 now in this case an appropriate signal indicative of this condition is transmitted by the electrical circuit line or conductor 32 to the control device 32 39 fig1 this signal activates the flow of compressed air by means of the valve 41 into the pneumatic cylinder 38 thus the fiber stream deflecting device 33 is brought into its working position i e the suction tube 35 is moved into its extended position shown in phantom lines in fig1 in this position the suction nozzle 36 as best seen by referring to fig2 c is placed between the nip of the delivery roll 6 and 7 of the drafting arrangement 3 and the suction nozzle 12 of the.