Device for mechanical attachment to the end of a tube

An attachment device obtained by joining three components, at the end of a tube, comprising:

• a conical insert in the form of a truncated cone, the diameter of which narrows in the direction of the end of said tube, the conical insert having a receiving element for receiving a gripping or attachment member;
• an internal ring provided with a recess in the form of a truncated cone, the diameter of which narrows in the direction of the center of the tube and the angle of which is equal to or less than the angle of the truncated cone of the conical insert, the external wall of said internal ring being cylindrical with a diameter substantially equal to the internal diameter of the tube, said insert being located in the recess of said internal ring;
• and
• an external ring comprising a cylindrical portion, the internal diameter of which is substantially equal to the external diameter of said tube, the internal wall of said cylindrical portion of said external ring being intended to come into contact with the cylindrical external wall of the tube, said external ring comprising a shoulder which partially closes an end of said external ring and which has a circular opening, said shoulder comprising an annular internal face intended to abut the end face of the tube and against the transverse end face of the internal ring located on the side of the end of said tube,
• characterized in that the conical insert and the external ring are sized so that in their assembled position with the internal ring and the tube:
• either a smallest-diameter transverse end face of the conical insert abuts the internal face of the external ring, the circular opening having a sufficient diameter to allow free access to the receiving element and less than the diameter of the smallest-diameter transverse end face, or
• the smallest-diameter transverse end face of the conical insert is in the same plane as the external face of the external ring.