Barrel spring, barrel and their manufacturing processes

Abstract

The invention relates to a barrel spring (4) comprising a blade having two faces connected by two flanks (12a), said blade being wound in turns so as to present two parallel principal faces (14a) formed respectively by the flanks (12a) of the turns.The sides (12a) of all or part of the coils that form at least one of the principal faces (14a) of the cylinder spring (4) intended to be visible to a user and / or at least one of the faces of all or part of the coils comprise respectively at least one modified appearance area (20) treated to present a modified surface appearance compared to the initial surface appearance of the blade, and whose location has been defined so that, when the cylinder spring (4) is at least in one of its armed, unarmed or intermediate states between its armed and unarmed states, the modified appearance areas (20) of the sides (12a) of said at least one principal face (14a) and / or of said at least one of the faces of all or part of the coils are arranged to display at least one predetermined decorative element on said at least one principal face (14a) and / or on said at least one of the faces of the blade which is visible.