US 4408376 A abstract a plurality of yarns are drawn from supply sources onto feed rolls and over a set of draw rolls in adjacent relationship the yarns are urged into a desired contiguous relationship on the draw rolls by a concave guide surface in the course of passing from the yarn feed rolls to the draw rolls application_number US 90094178 A description referring now to fig1 of the drawing three yarn source rolls 10 12 and 14 which may have wound thereon yarns r w and b of three different colors are disposed above feed rolls 16u and 16l after engaging guides 15 the yarns are wound about the feed rolls prior to passing to the draw rolls 18u and 18l the latter rolls are driven at a desired increased rate of speed relative to the speed of the feed rolls so as to effect the desired stretching of the yarns r w and b wound thereabout in accordance with this invention the yarns r w and b are maintained in desired untwisted side by side relationship on the draw rolls by engaging a concave guide surface such as roller 20 having an annularly relieved concave outer periphery as is most clearly seen from fig4 and 5 the roller 20 may be rotatably mounted on pin 22 roller 20 is preferably formed of ceramic or other wear resistant material or composition the roller 20 upon engaging the yarns r w and b slightly displaces the same from the vertical plane defined by the normal straight line yarn passage from the feed rolls to the draw rolls toward the axes of said rolls as is clearly seen from fig2 the linear.