In the body (1) of the drill chuck, the chuck jaws (3) are arranged in guide bores (5) which converge towards the front in a direction inclined relative to the axis (4) of rotation and emerge at the rear in openings (6) on the circumferential surface of the chuck body (1). An adjusting ring (2), coaxial to the axis of rotation and mounted on the chuck body (1) in such a way as to be rotatable and axially fixed, serves to adjust the chuck jaws (3) and has an adjusting thread (7) which meshes with a tooth row (8) on each chuck jaw (3). A locking ring (17) secures the adjusting ring (2) against undesirable rotation during the drilling operation. This locking ring (17) is arranged axially in front of the adjusting thread (7) of the adjusting ring (2) and is guided on the chuck body (1) in such a way as to be non-rotatable and axially displaceable. The adjusting ring (2) is extended axially to the front beyond the adjusting thread (7) and is provided there with an annular groove (18) which is open towards the chuck body (1) and accommodates the locking ring (17). …<IMAGE>…
