US Patent 8141682 Security cone-door for a ladder

A first embodiment of the security apparatus comprises a retaining collar; a plurality of segments forming a generally frusta-conical enclosure, with one or more of the segments having an access opening therein; and a lockable access door covering the opening. The retaining collar is separable into portions that conforms to the shape of the periphery and are coupled together around the structure. The segments have an upper portion that attaches to the collar; and have a bottom portion that extends radically downwardly from the collar at an angle of about 30 degree; with the radial edges interconnected forming the enclosure.