Quick clamping unit, quick clamping system, machine or tool part and pre- or forming tool

Quick clamping unit (14, 15), particularly for locking of tool parts (10, 12) of pre- or forming tools or of origin or forming tools on respective origin or forming, wherein the quick release unit (14, 15) corresponding with the quick-clamping unit (14, 15) holding part (16) can be locked, wherein the quick release unit (14, 15) for axially engaging the holding part (16) provided sleeve member (30) engaging an axially into the sleeve member (30) or the sleeve element (30) by cross-, opposite the sleeve element (30) between a locking position and a Entrieglungsstellung axially movable piston member (32) and the sleeve element (30) in the radial direction at least partially through cross locking members (42) such that the locking elements (42) in the locking position by the piston member (32) are acted upon radially outward by the holding part lock (16) to engage behind, and for releasing the holding member (16) in the unlocked position radially are shiftable inside, characterized in that between the piston member (32) and the sleeve element (30) (a first spring element (46) for acting upon the piston member 32) in the locking position, and between the sleeve element (30) and a em the quick release unit (14, 15) receiving the component (18, 20) are provided a second spring element (50) for axial actuation of the sleeve member (30) in direction towards the retaining part (16) in such a way and matched to one another that (upon moving of quick-action clamping unit 14) and holding member (16) in the locked state of the quick-action clamping unit (14) said sleeve member (30) against the spring force of the two spring elements (46) is moved so far in the axial direction 50 until the locking elements (42) radially inward dive, and that then the sleeve member (30) and piston member (32) in the other, the direction of movement of the holding part (16) opposite direction due to the spring force of the second spring element (50) is moved so far until the locking elements (42) (the holding member 16 ) engaging behind displace radially outward, in which case the piston element (32) from the first spring element (46) is urged in the locking position.