Abstract: The invention relates to a protective device formed by a hollow body with a first end, a second end and a surface wherein at least a section of a surface is provided with a series of corrugations extending longitudinally from the first end and essentially to the second end, wherein a portion of the hollow body has a cylindrical shape and a portion has a frustoconical shape and wherein the corrugations converge towards a point on the longitudinal axis of the hollow body with their depth increasing in the direction of their convergence so that the average diameter of the body decreased in a substantially progressive manner along the longitudinal axis beginning adjacent the first end of the body, preferably wherein an annular element having an exterior diameter corresponding essentially to the exterior diameter of the first end is attached thereto and wherein the second end of the hollow body is opened with its surface folding in towards the interior of the hollow body as a lip and wherein the hollow body is pro