Shock absorber

A telescopic system for an adjustable hydropneumatic shock absorber, said telescopic system comprising an outer sliding tube having a closed end and an open end, wherein said closed end is equipped with attachments for fastening to a wheel axis, and wherein said open end provides for telescopically mounting an inner sliding tube, wherein said inner sliding tube has at one end a first plug assembly, and wherein said inner sliding tube includes elastic means to stress in the expansion of said telescopic system whose internal chambers are partially occupied by air and partially by liquid, said chambers being arranged in such a way that, in the expansion phase of said telescopic system, said liquid flows through a valve means to adequately slow the expansion stroke of said telescopic system, and a closed end of a barrel is internally and coaxially fastened at a closed end of said telescopic system, said barrel having a length proportional to the stroke of said telescopic system and said barrel being closed by a second plug assembly axially traversed by a support tube integral with said first plug assembly, said support tube attached to a piston which delimits upper and lower opposite pressure chambers in said barrel both containing said liquid, and said barrel having a lower chamber in permanent communication with a chamber of the telescopic system containing said liquid through at least one lower hole, wherein said piston comprises first and second valve means which control the passage of said liquid between said upper and lower chambers of said barrel, wherein said first valve means is open in the compression phase and closed in the expansion phase of said telescopic system, and wherein said second valve means is open both in the compression and expansion phases and is adjustable by means of an adjustment screw positioned axially within said support tube and which protrudes with lateral seal from said first plug assembly.