Abstract: A sliding base is guided for vertical movement on an upright of the traverse mechanism. It bears a camera having its lens directed along a horizontal axis toward a vertical bank of lights. A drum supported by uprights and driven rotatingly by a motor can move back and forth on rails, while the traversing carriage bearing vertical rolls guiding a cable can likewise move parallel to the axis of the drum in order to check and, if neccessary, modify the approach angle formed by the incoming cable about to be laid on the winding. The silhouette of the zone of the winding where the turns are laid down is formed on a receiving surface within the camera, this surface taking the form of a photodiode grid, the periodic scanning of which yields signals sensing the conditions under which the cable is being wound.