For the purpose of carrying out the butt-end joining of two lengths (35, 36) of a rubberized fabric, in particular, reinforced with cords disposed parallelly at the edge to be jointed, there is foreseen a stitching device (1) which comprises two superimposed pairs of frusto-conical rollers (26,27; 20,21) having their lateral surfaces tangent to the very same horizontal plane, and opposing pairs of rollers (26,21; 27,20) in the vertical plane, with their axes of rotation being symmetrically inclined, with respect to the tern of planes comprised by a first horizontal plane (h-h), or the resting plane for the lengths to be jointed, by a second vertical plane (m-m) that contains the seam-line of said lengths, and by a third vertical plane, orthogonal to both the two above-said planes.
Owing to the inclination of the axes, the pairs of the vertically opposite rollers grasp each border (E, U) of the lengths to be jointed, on both the surfaces, in correspondence of a narrow transversal portion of said fabric. Thereupon, they take said narrow transversal portion of the border, and press it against the facing border, with shifting said narrow portion progressively and with continuity, along the entire length of the seam-line.