Patent ID: 8099835

Claim:
A method of drawing a fiber structure to a yarn for a spinning machine having a roller drafting apparatus that defines a drafting field for fibers having a known average staple length, the roller drafting apparatus having a middle pressure roller that is looped around by a drafting apron that is guided and tensioned by an apron cage, the roller drafting apparatus having a pressure roller and opposed lower cylinder at the output of the drafting field, the pressure roller having an inner layer fastened around a core of the pressure roller, wherein an endless cover apron travels in a running path over the pressure roller and a deflection rail, the cover apron formed as an outer layer that loosely surrounds the inner layer of the pressure roller, the method comprising: selecting a deflection rail with a cross-sectional circumference that is greater than the known average staple length of the fibers drawn on the roller drafting apparatus; tensioning the endless apron covering only slightly such that the intrinsic tension of the cover apron would result in a circular form of the cover apron in the free non-tensioned state; rapidly running the pressure roller at high running speeds many times greater than the speed of the middle pressure roller; and producing yarn at the output of the drafting field.