designated as final product by 81 from the installation in the needle loom installation 6 two double needle looms 9 may be combined in one common machine frame to form a twin unit which has common upper and lower stitching supports not shown for the web to be processed all upper needle bars i e the upper needle bar groups of the twin arrangement may be driven commonly and the same applies to all lower needle bars since the horizontal drives 11 for the needle bars 10 require a certain space the gaps z between adjoining twin units where the horizontal drives are accommodated are each bridged by endlessly revolving transport belts 14 which support the processed fiber fleece web 8 from below so that it does not sag by its own weight and be thereby possibly stretched in an undesired manner as an alternative smooth support plates of a small surface friction can be taken into consideration over which the fiber fleece web can easily slip since the web 8 is needled from both sides and the invention therefore uses double needle looms in which in a needling zone two needle units needling against one another oppose and whose needles alternatingly stitch into the fiber fleece web the stitching supports on both sides of the fiber fleece web against which the latter is pressed by the needle movement are lamella grates with longitudinally extending lots or slotted plates whose slots enable the horizontal movement of the needles for the transport of the fiber fleece web 8 in the state stitched into same details are not shown but reference may be made in this respect to the documents mentioned above again by example the use of lamella grates is known per.