character 16a and which roller can be driven with variable peripheral speed by means of a not particularly illustrated but conventional infinite gearing or drive the yarn or thread 2 is placed about the entire periphery of the roller 16 and is thus positively entrained thereby with the exemplary embodiment depicted in fig8 again an endless transport belt 4 travels over the rollers 5 and 6 of which one for instance similar to the embodiment of fig1 and 2 can be driven by an infinitely variable gearing or drive generally indicated by reference character 100 in fig8 in order to be able to change the speed of rotation of the transport belt 4 the thread or yarn 2 in this case is pressed by means of a roller 17 against the belt 4 the roller 17 is mounted at an arm 18 of an angle lever arrangement or angle lever means 18 19 at the other arm 19 there acts an eccentric cam 20 through the rotation of which the lever arrangement 18 19 is rocked or piveted and thus the roller 17 is pressed against or lifted away from the belt 4 consequently in this instance the yarn or thread 2 can be optionally brought into and out of engagement with the belt 4 and entrained thereby the exemplary embodiment of fig9 differs from that of fig8 only insofar as here instead of the roller 17 there is provided a yarn press shoe 21 at a double arm lever arrangement 22 23 at which a.