constriction through which the sliver assembly passes a transducer converts excursions of the sensor element into electric pulses a withdrawing roller pair supported downstream of the sliver guiding device pulls the sliver assembly through the sliver guiding device application_number US 54951495 A description fig1 a illustrates a high production drawing frame which may be for example an hs 900 model manufactured by trutzschler gmbh amp co kg monchengladbach germany a plurality of slivers 3 paid out from non illustrated coiler cans enter a sliver guiding device 2 through which they are drawn and further advanced by a pair of cooperating withdrawing rollers 4 and 5 in their travel through the sliver guiding device the slivers 3 move past a measuring member 6 the drawing frame 1 includes an upper inlet roller 7 and a lower inlet roller 8 which are associated with the pre drawing zone 9 delimited at the downstream end by the upper predrawing roller 10 and the lower predrawing roller 11 between the roller pair 10 11 as well as a roller pair formed of the upper main drawing roller 13 and the lower main drawing roller 15 the main drawing zone 12 extends the lower main drawing roller 15 is associated with a second upper main drawing roller 14 such an arrangement is referred to as a four over three drawing system the drafted slivers 3 after passing through the roller pair 14 15 reach the inlet of a sliver guide 16 and are drawn through a sliver trumpet 17 arranged at the downstream end of the sliver guide 16 by cooperating delivery rolls 18 18 39 in the sliver.