Abstract: A locking element or latch is embodied from a metal plate and comprises a first pair of articulation tabs, a second pair of tabs to receive strains, these tabs being received in corresponding openings formed in the flanges of the base. The retaining member of the latch is guided in displacement in an L-shaped cutout and is associated with a floating contact with a rocker articulated on an ejector. A push button comprises engagement surfaces cooperating selectively with the locking member and ejector and ramps to assist the lifting of the latch. A single spring serves to actuate, and place under tension, all of the moving parts of the buckle.