Screwing element

A screwing element for holding and for forcibly turning a fastener (6), comprising a plurality of jaws (3, 4), which are disposed in succession in circumferential direction for seizing the fastener (6), wherein the jaws (3, 4) engage in a tubular holder (2) and, in combination with this holder (2), in a first end position are extended beyond the holder (2) and forced radially apart for the purpose of receiving the fastener head, and in a second end position are retracted and radially squeezed together inside the holder (2), characterized in that incisions (15, 16) or recesses are formed on the free and region of the jaws (3, 4) for mechanical and/or frictional accommodation of the fastener head (5), in that gripper-like parts (17, 18) jutting outwardly toward the central axis (24) or directed away therefrom are formed on the free end of the jaws (3, 4) adjoining the incisions (15, 16) or recesses, for the purpose of additional mechanical and/or frictional seizing of portions of the fastener head (5), in that an axially reciprocal means is provided for alternately extending said jaws and forcing them radially apart or retracting them and radially squeezing them together, and in that an axially reciprocable means is provided responsive to axial pressure by a received fastener head to retract the jaws (3, 4) from the first to the second end position.