the working direction a on the upper face of the plate 42 a a support element 20 is secured which holds a small displacement measuring member 19 for example a piezoelectric element which functions as a force take up device opposite the supporting element 20 the measuring element 19 cooperates with a frame like pressing element 18 composed of a supporting element 43 contacting the measuring member 19 and a rotary deflecting roller 46 secured to the upper region of the supporting element 43 the length portions 7 u2032 u2033 of the slivers 7 a 7 f emerging from the transporting rolls 15 16 are deflected as they run underneath a deflecting roller 44 from a horizontal position to proceed upwardly at an oblique angle to the deflecting roller 46 and then running above the deflecting roller 46 the slivers are deflected at an angle to proceed downwardly to a deflecting roller 45 and are as they run underneath the deflecting roller 45 reoriented into a horizontal direction the slivers exert via the deflecting roller 46 and the supporting element 43 a pressing force on the measuring element 19 in operation first the frame 42 is set on the draw frame cover 41 so that the length portions 7 u2032 u2033 of the slivers 7 a 7 f remain unaffected thereafter the frame like supporting element 43 is passed within the frame 42 under the length portions 7 u2032 u2033 and above the force take up device 19 and is positioned and immobilized on the frame 42 the measuring process may be activated when the intended delivery speed is reached to eliminate the.