Device for the transmission of a rotation motion with a flexible shaft in a sheath comprising shoulder-forming areas and an inner tube

A device for the transmission of a rotation motion comprising a flexible shaft and a sheath inside which the shaft is accommodated, said sheath comprising a core constituted of a cylinder, the core comprising at least one shoulder-forming area which is obtained by a plastic deformation, said area comprising at least three portions, two external portions and a central portion, said portions having axes substantially parallel to that of the core and having diameters substantially equal to that of the core, the external portions being substantially coaxial and having their axes shifted with respect to the axis of the central portion and of the core, an inner tube positioned inside the core and the external diameter of which is substantially equal to the internal diameter of the core and the internal diameter of which is so arranged as to allow the rotation of said shaft inside said tube, the tube being deformed in a similar way as the core in the shoulder-forming area.