Abstract: A quick locking device for producing axial locking forces on a smooth shaft has a housing, a freely supported clamping ring adapted to surround a shaft and located inside the housing with pretensioning by a spring force in a ring-shaped chamber changeable in an axial direction, diametrically opposite pins provided on the clamping ring and contacting surfaces which limit the chamber in contact points, a locking unit and a clamping unit provided with a locking thread and arranged so that axial locking forces are transmitted through the locking unit and the locking thread of the clamping unit and through the pins for form-locking connection between the clamping ring and the shaft in the region of self-locking, and a spring providing tensioning of the clamping ring and vectorially supporting a clamping action through the pins.