METHOD OF MAKING A HOLLOW CARDBOARD BODY WITH DECREASING MIDDLE DIAMETER, HOLLOW BODY SO OBTAINED AND ITS USE

摘要

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 provided with at least one and preferably at least two slits extending longitudinally along the surface of the hollow body wherein slits begin adjacent each of the ends of the hollow body and are aligned longitudinally with respect to each other so as to remain separated by a portion of the surface of the hollow body which is preferably located closer to one end of the hollow body than the other, and wherein the surface is also provided with an opening having a hinged strip corresponding in size to the opening which pivots into the interior of the hollow body, and wherein the corrugations have an arcuate surface.