Device for fast connection of a tube to a rigid element with anti-extraction ring and safety seal

A quick-coupling device for coupling a tube to a rigid element (50) having a bore, the device comprising a tubular insert (1) having means (7) enabling it to be anchored in the bore of the rigid element (50), declutchable tube retaining means (11), and a slide (13) mounted to move in translation in the tubular insert (1) to declutch the retaining means (11) when it is pushed into the tubular insert (1), said slide (13) possessing a rear portion which projects outside the tubular insert (1) and which presents a shoulder surface (23) situated facing an end surface (24) of the tubular insert (1) and co-operating with said end surface to define a groove in which a removable intermediate ring (25) is received to oppose pushing in of the declutching slide (13), said ring being closed and having a mechanically weak portion (27) forming a break starter which, once broken, divides said ring into two elastic branches and enables said ring to be removed.