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AssigneesKomet Group GmbH, Hartmetall-Werkzeugfabrik Paul Horn GmbH
InventorsUwe Kretzschmann, Rico Schneider, Henry Schuett, Matthias Luik, Matthias Oettle
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The invention relates to a drilling tool with a base, having a central axis of rotation, and a drill bit, detachably connected to the base. The drill bit has a coupling part, which can be coupled with a coupling receptacle on the face of the base and has at least two convexly curved centring portions, which are arranged such that they are distributed over the circumference and engage with an exact fit in complementary concavely curved centring portions of the coupling receptacle. The coupling part has a complementary driver stop, meshing with a rotary driver of the coupling receptacle. It is claimed as novel that the centring portions of the coupling part and/or of the coupling receptacle have clamping surfaces, which run onto each other in the manner of a rotary wedge until the driver stop and the rotary driver come up against each other counter to a predetermined direction of rotation.
A drilling tool with a basic body (32) having a central axis of rotation (24) and with a drill bit (34) connected releasably to the basic body (32), the drill bit (34) having a coupling part (96) which is couplable to an end-face coupling receptacle (94) of the basic body (32) and which has at least two convexly curved centering portions (40) which are arranged so as to be distributed over the circumference and which engage with an exact fit into concavely curved centering portions (42), complementary to said convexly curved centering portions, of the coupling receptacle (94), and the coupling part (96) having at least one complementary driver stop (46) meshing with a rotary driver (44) of the coupling receptacle (94), and the centering portions (40, 42) of the coupling part (96) and/or of the coupling receptacle (94) having, up to the mutual abutment of the driver stop (46) and of the rotary driver (44), tension faces (48, 50) running toward one another in the manner of a rotary wedge opposite to a predetermined working direction of rotation, characterized in that the tension faces (48, 50) of the coupling part (96) form circle segments (40′, 40″) which lie diametrically opposite one another and are eccentric with respect to the axis of rotation (24) and with respect to one another, the concave centering portions (42) of the coupling receptacle (94) form in cross section part circles concentric with respect to the axis of rotation and having a predetermined radius (R1), and the convex centering portions (40) of the coupling part (96) have a part-circular guide portion (40′) concentric with respect to the axis of rotation, with a radius (R1) corresponding to the receptacle-side radius (R1), and a part-circular tension portion (40″) tangentially adjoining said guide portion and eccentric with respect to the axis of rotation, with a radius (R2′, R2″) larger than the receptacle-side radius (R1), the eccentric tension portions (40″) of the coupling part (96) and the part-circular centering portions (42) of the coupling receptacle (94) bearing non-positively one against the other in their tension position.
Dependencies are inferred from the claim text.