Adjustable quick-release buckle, particularly for diving masks or similar

A combination of an adjustable quick-release buckle and a strap which has a set of equally spaced teeth, arranged on at least one end portion of said strap, particularly for masks, which combination comprises:

• a) a buckle body;
• b) a return roller rotatably mounted on the buckle body and around which passes the strap;
• c) a ratchet strap retaining means mounted in a displaceable way on the buckle body and urged by elastic means in a direction of an active position, in which said ratchet means prevent the strap to slide in a loosening direction allow it to slide in opposite tightening direction;
• d) means for manually displacing the ratchet means against the action of the elastic means in an inactive position, in which said ratchet means allow the strap to slide freely in both the loosening direction and the tightening direction;
• characterized in that
• e) the buckle body has an arched wall, which extends coaxial to the roller through a certain angular width, a distance between the arched wall and the roller substantially corresponding to or being slightly greater than a thickness of a strap, but smaller than the total thickness of the strap including a projection of the teeth of the strap;
• f) the return roller has longitudinal external teeth and a strap is passed between the roller and the arched wall of the buckle body so as to engage the teeth of the strap between the teeth of the roller;
• g) the return roller is rotatably mounted on a central pin, the pin bears at one of its ends at least one axial locking tooth, the tooth cooperates with a crown of axial teeth on a facing end side of the roller, the teeth have a guide slanted side facing a strap tightening direction of rotation, and a substantially axial steep front on the side facing a strap loosening direction of rotation, wherein the pin is mounted in such a way as to be unable to rotate but to be able to slide axially to move the locking tooth from the crown of axial teeth on an facing end side of the roller, while opposing the action of elastic means which stably push said pin towards engagement of the locking tooth with the teeth of the end side of the roller, said pin projecting out of a transverse wall of the buckle with a button head.