The invention relates to a device (1) for covering a surface (3), comprising: (a) a cover (10), each longitudinal edge of which is provided with a roll (12) formed by a core (12c) contained in a tubular sheath (12t) provided with a strip (12b) along the length thereof, said strip being attached to at least one surface of the cover； (b) a rotatably mounted drum (2) that can wind or unwind the cover (10), said drum (2) being mounted on a longitudinal translation mechanism comprising rails (6) arranged either side of said surface (3)； and (c) a system for continuously locking the roll (12) of the longitudinal edges of the cover (10) in the rails (5), and unlocking said roll from same, during the translation of the drum, characterized in that the core (12c) of the roll is attached to the tubular sheath (12t) in such a way as to prevent it from sliding along the sheath.
