yarns 6 which are pulled into the guide grooves because the stitch base 1 is provided on the inlet and outlet side with a convex curvature in the direction of passage of yarns 6 so that force components are obtained as a result of the tensile load of yarns 6 which force components press against the stitch base 1 said force components which occur in the curvature zone are not sufficient however in order to allow the omission of a stripper 10 which is disposed between the stitch base 1 and the needle board 2 the embodiment according to fig3 differs from the one according to fig1 merely by the arrangement of the stitch base 1 which is continuously curved in a convex manner from the inlet to the outlet side so that force components which are perpendicular to the stitch base 1 are obtained over the entire guide length of the guide grooves 5 which force components press the yarns 6 against the stitch base 1 a stripper 10 is used nevertheless in order to ensure a calmed yarn guidance which is advantageous for the needling process the embodiments according to fig1 and 3 differ not only with respect to the forces acting upon the yarns.