Abstract: An annular bit (1) having an attachable center drill (6) is proposed, in which annular bit (1), on the one hand, reliable holding of the center drill (6) in the annular bit (1) is ensured and, in particular, distributions of the cutting segments (3) on the annular bit (1) differing from the 90.degree. symmetry are made possible. This is achieved according to the invention in that the center-drill holder (4) has at least one push-in pin (11) and the wall of the annular bit (1) has at least one recess (14, 15, 16) for accommodating the push-in pin (11), which pin and recess are formed in such a way that the push-in pin (11) is retained in the recess (14, 15, 16) in the axial direction relative to the annular-bit axis in the locked state of the center-drill holder (4).

Abstract: A drill bit is proposed, in particular for the rotary-percussive drilling of preferably rock, concrete or the like, which includes a thin-walled cylindrical drilling body (106) open to the drilling side and a drill-bit base (20) extending essentially radially and having an axially arranged drill-bit shank (101) for fastening the drill bit. The drill-bit base (20) has an outer contour in the radial direction, which outer contour follows a curve shape which has at least one inflection point. Furthermore, a drill bit is proposed whose drill-bit base (20) has an outer contour which passes through a minimum in the radial direction, the drill-bit base being connected in the rising radially outer curve section of its outer contour to the cylindrical drilling body.

Abstract: A drilling tool for rotary percussion drilling including: a drilling body defining: a longitudinal centerline axis extending in a drilling direction; a bore extending in a direction of the centerline axis and having a bore bottom; and a recess extending in a direction transverse to the centerline axis and eccentrically with respect thereto. A centering drill is adapted to move in the drilling direction and has a centering drill end, a centering drill shank and a chucking portion having a flattened clearance on one side thereof, the centering drill shank having an end side cylinder section for limiting an axial path of the centering drill during its movement in the drilling direction, the centering drill extending in the bore of the drilling body and the bore bottom being effective as an exclusive stop for the centering drill end when the centering drill is being subjected to percussion stress.

Abstract: A drill bit includes a one-piece cylindrical drill bit tube having a longitudinal axis and defining cylindrical surfaces including an inner cylindrical surface and an outer cylindrical surface. At least one of the cylindrical surfaces is configured to include deformations comprising at least one of embossments and recesses, all of the deformations appear over an entire length of the tube. At least some of the deformations are finite over the at least one of the cylindrical surfaces, the deformations further being adapted to stiffen the tube in the longitudinal direction without additional material reinforcements being disposed on the tube. The drill bit further includes hard-metal cutting elements disposed on a front face of the tube.

Abstract: The device for transferring torque to a tool member in a hand tool apparatus includes a plurality of catch grooves (23) and at least one elongated locking groove (25) spaced circumferentially from the catch grooves (23) provided in the tool shaft (11) of the tool member (12); a tool holder (10) having a tool receptacle (16) provided with a receptacle cavity (17) for the tool member (12) and having at least two axially extending catch elements (24) projecting inwardly into the receptacle cavity (17) so as to be engageable with the catch grooves (25) and at least one lock element (19) guided in a radial recess (18) provided in the tool receptacle (16) spaced circumferentially from the catch elements (24) so as to be radially movable outwardly against a spring force and engageable in the at least one locking groove (25) so as to limit axial motion of the tool member (12).

Abstract: A device on power tools for driving impact and/or drilling tools has a tool having a tool shaft provided with at least two drive grooves open toward a shaft end and at least one locking trough closed toward the shaft end, in which correspondingly a driver and a locking body of a tool receptacle engage. For increasing the driving, at least one axial formation is provided on a projection of the thicker portion of the tool shaft to a thinner insertion end of the tool at the end side for an additional driving, which axial formation cooperates with an axial formation, for example a tooth, of a driven part, for example an auxiliary strip, at the end side of the tool holder.

Abstract: A device for driving impact and/or drilling tools on a hand power tool has a tool with a tool shaft having at least two drive grooves which are open toward the shaft end and at least one locking trough which is closed toward the shaft end. A driver for a radially displaceable locking body of a tool receptacle engage correspondingly in each drive groove and locking trough. For strengthening the driving, the locking body is provided with an axially extending, strip-shaped radial projection which engages in a correspondingly formed depression of the locking trough of the tool shaft for forming an additional drive flank.

Abstract: A drilling tool and, in particular, a rock drill for the creation of breaches in concrete or masonry for the use of drill hammers is proposed, which is configured as a cross drill bit having four cutting fins. In order to optimize drilling capacity, the drilling tool is provided with a cross drilling head which merges in one piece into a conveyor spiral matched to the drill head. A purpose-specific cutting element facing serves to optimize the drilling capacity.