Means of attachment M series TYPE “A” COUPLING FORM A milling operation is carried out on the roller shaft in order to obtain the key for the insertion of the various supports. TYPE “B” COUPLING FORM A drilling and internal threading operation is carried out on the roller shaft for fixing it to the structure. TYPE “C” COUPLING FORM A turning and external threading operation is carried out on the roller shaft for fixing it to the structure. TYPE “D” COUPLING FORM A projection is left on the roller shaft in such a way as to allow it to be fixed to the structure. TYPE “E” COUPLING FORM A retractable shaft to permit fixing to the structure.