A device according to the present invention comprises: a tubular body (2) and a first attachment means (6), a piston (30) provided with a rod (12) connected to a second attachment means (10), the piston (30) sliding inside the tubular body (2) and defining inside said body a working chamber filled with hydraulic fluid, an accumulator comprising a rigid shell (20) inside of which a separation means (40) is located, defining a compensation chamber (42) that is filled with hydraulic fluid and is in communication with the working chamber, and a chamber (47) filled with pressurized gas, the rigid shell (20) being a metal shell produced by means of welded assembly and the accumulator being made such as to obtain an entirely welded enclosure (47) containing the gas.