Abstract: A rotary-percussion drill includes a four-start helical shaft (3) having a fourfold rotationally and mirror-symmetrical helix cross-section, with radially projecting convexly formed helical webs (4) extending from a concave groove bottom (5) up to the envelope circle (6) and having an undercut (7) with respect to a web width (S).

Abstract: A solid hard material head for a percussion drilling tool rotatable about a rotational axis (A) in a rotational direction (?), includes at least one main bit and at least one auxiliary bit (5), circumferentially offset relative to the at least one main bit (3) and having an auxiliary cutting edge (6) formed, at least piecewise, as a circular arc section (7) spaced from the rotational axis (A) radially inwardly and inclined in a radial direction, and a straight outer section (8) extending radially outwardly with respect to the circular arc section (7) and inclined in the radial direction.

Abstract: A hard material head (1) for a rotary percussion drill bit (2) having an elongated shaft (15) including at least three cutting edges (4) distributed circumferentially within a circumscribing circle, a bottom surface (6) located opposite the cutting edges (4) and fastened by a material bond to an end (8) of the drill bit shaft (15) of the rotary percussion drill bit (2), concave side surfaces (5) formed circumferentially between adjacent cutting edges (4), and a peripheral pocket (9) opening toward the bottom surface (6) and formed, respectively, in at least two concave side surfaces (5) located opposite one another, and in which a corresponding axial pin (10, 10?) formed on a shaft end (8) is form-locking engageable.

Abstract: A hard material bit for a rotary-percussion tool (2) includes at least one cutting edge (3), a bottom surface (6) located opposite the at least one cutting edge (3), and at least one attachment surface (8) and at least one free surface (10) both extending transverse to the bottom surface (6) and forming, respectively, a piecewise extending first chamfer (9a) and second chamfer (9b), with the second chamfer (9b) having a width greater than a width of the first chamfer (9a).

Abstract: A percussion-rotary drill includes a shaft (2) and a one-piece, hard material head (3, 3?, 3?) having two major cutting bits (4) each having a main cutting edge (5), and two minor cutting bits (6) each having a minor cutting edge (7) axially offset rearwardly along a rotational axis (A) of the drilling head (3, 3?, 3?) relative to an adjacent major cutting edge (5), with the two minor cutting bits (6) each having, in its radially outer region on both sides of the minor cutting edge (7), a tangential edge (8) extending at an angle thereto.

Abstract: A drill bit for a hammer drill for drilling in stone, concrete and the like includes a drill bit head formed as a hard material body with radial legs and having at least three radially extending cutting bits formed on the radial legs, and a centering tip in a center of the hard material body and projecting beyond one of the cutting bits, with the centering tip having concave limiting surfaces stretching between the linearly extending auxiliary cutting edges.

Abstract: A hand-held power tool includes two vibration-damped handles (21), two handle attachment axles (31) for securing the two handles (21) on the tool outer housing (12), respectively, and extending at an angle to respective longitudinal axes (23) of respective handles (21), each handle attachment axle being surrounded, at least in some areas, by the mounting section (24) of the respective handle (21), a damping sleeve (31) formed of an elastic material and provided between the mounting section (24) of the respective handle (21) and the respective handle attachment axle (30), with the damping sleeve (31) forming a first damping element, and a damping body (36) provided on a free end (26) of each handle (21) and forming a second damping element and having an extension (D) in a radial, with respect to the handle longitudinal axis, direction that is greater than a minimal radial extension (T) of the handle (21) at its free, second end.

Abstract: A rotary-percussion drill, includes a hard material bit (2, 2?) having at least one cutting edge (3, 3?), and a shaft having an end (7, 7?) with an axial base surface (6, 6?) provided with a chamfer (8, 8?) at least on its outer radial rim, the bottom surface (4, 4?) of the bit (3, 3?) which lies opposite the cutting edge (3, 3?), being secured to the base surface (6, 6?) of the shaft end (7, 7?) by brazing alloy in a material-locking manner.

Abstract: A solid hard material head for a percussion drilling tool rotatable about a rotational axis (A) in a rotational direction (?), includes at least one main bit and at least one auxiliary bit (5), circumferentially offset relative to the at least one main bit (3) and having an auxiliary cutting edge (6) formed, at least piecewise, as a circular arc section (7) spaced from the rotational axis (A) radially inwardly and inclined in a radial direction, and a straight outer section (8) extending radially outwardly with respect to the circular arc section (7) and inclined in the radial direction.

Abstract: A one-piece drilling head (4) which is to be secured, in a material-locking manner, at an end of a helical shaft of a drill, is formed of hard material and includes four radially extending, in a cross-shaped manner, legs (5) forming, respectively, two diametrically opposite main cutting edges (6) and two auxiliary cutting edges (7), with the main cutting edges (6) and the auxiliary cutting edges (7) extending proceeding from a drilling head drilling head tip (8), monotonously and strictly axially up to a radially outer edge, and with an envelope surface (9?) of the auxiliary cutting edges (7) lying completely within an envelope surface (9) of the main cutting edges (6) and contacts the same only at the drilling head tip (8).

Abstract: A hard material insert (1) for a drill (2, 2?) includes an axially central reinforcement (3) provided in the insert, and two diametrically opposite, radial arms (4) each having a cross-section tapering radially outwardly, opposite free side (8) and connection side (7), with the free and connection sides (8, 7) of one of the radial arms (4) being arranged alternatively to the free and connection sides of another of the radial arms (4), and a concave recess (6) provided on the connection side (7).

Abstract: A hard material head (1) for a rotary percussion drill bit (2) having an elongated shaft (15) including at least three cutting edges (4) distributed circumferentially within a circumscribing circle, a bottom surface (6) located opposite the cutting edges (4) and fastened by a material bond to an end (8) of the drill bit shaft (15) of the rotary percussion drill bit (2), concave side surfaces (5) formed circumferentially between adjacent cutting edges (4), and a peripheral pocket (9) opening toward the bottom surface (6) and formed, respectively, in at least two concave side surfaces (5) located opposite one another, and in which a corresponding axial pin (10, 10?) formed on a shaft end (8) is form-locking engageable.

Abstract: A rotary-percussion drill includes a four-start helical shaft (3) having a fourfold rotationally and mirror-symmetrical helix cross-section, with radially projecting convexly formed helical webs (4) extending from a concave groove bottom (5) up to the envelope circle (6) and having an undercut (7) with respect to a web width (S).

Abstract: A hard material bit for a rotary-percussion tool (2) includes at least one cutting edge (3), a bottom surface (6) located opposite the at least one cutting edge (3), and at least one attachment surface (8) and at least one free surface (10) both extending transverse to the bottom surface (6) and forming, respectively, a piecewise extending first chamfer (9a) and second chamfer (9b), with the second chamfer (9b) having a width greater than a width of the first chamfer (9a).

Abstract: A drill, which is used in a hammer drill for drilling holes in stone, concrete and the like, includes a drilling head (10, 20, 30) formed of a hard material and provided, at its first end (5) with at least one main bit (3) having a tip (4), and at a second end (6) located opposite the first end (5), with a bottom surface (7) for the mounting the drilling head (10; 20; 30) on the drill stem (8), and having a plurality of axially extending through-grooves (11; 21; 31) for removing drillings produced during a drilling process and having a cross-section which increases, at least regionwise, in a direction toward the bottom surface (7) of the drilling head (10; 20; 30).

Abstract: A drill in particular for a hammer drill for drilling in stone, concrete and the like includes a drilling head (2) formed as a hard material body with radial legs (18,19) and having at least three radially extending cutting bits (5) formed on the radial legs (18,19), and a centering tip (11;21) provided in a center of the hard material body and projecting beyond one of the cutting bits (16,17), with the centering tip (11;21) having concave limiting surfaces (12;22) stretching between the linearly extending auxiliary cutting edges (13;24,24).