Abstract: A rock drill for hammer drilling machines is proposed, which has a helical shank and a drill head which is connected thereto and on whose end face are arranged a main cutting tip inclined in the shape of a roof and also auxiliary cutting tips disposed transversely thereto. The drill head has two laterally opposite flats for the formation of drilling dust grooves. In plan view the drill head has a very largely rectangular shape in cross section, an acute angle .beta..sub.1 being enclosed between the main cutting tip and the trailing auxiliary cutting tips.

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.

Abstract: A drilling tool which is suitable especially for clearing drill dust from a drillhole in rock-drilling work is provided. For this purpose, the spiral shank has brush elements (6, 17) which are arranged in the groove bottom of a conventional drilling tool or which themselves form spiral feed coils.

Abstract: A drilling tool, in particular for use in axially striking drive machines for drilling in rock, concrete or the like, which drilling tool is designed from both a vibration point of view by varying the abrupt changes in cross-section and from a drilling point of view by optimising the transport of the drilling dust. In order to arrange, from a vibration point of view, the abrupt changes in cross section, caused by the flute webs, in asymmetrically arranged axial positions, the inclination of the conveying flute constantly changes its size within a lead. Furthermore, the radial, tangential and axial force vector which acts on the drilling dust constantly changes its size, the radial force vector also changing its direction. In this way, the drilling dust is subjected to a constantly changing acceleration.

Abstract: A rock drill having a drilling head which, in an asymmetric arrangement relative to the main cutting tip, has at least one additional secondary cutting tip, the angle enclosed between the single cutting edge of the main cutting tip and the secondary cutting tip being formed as an acute angle.

Abstract: A drilling tool is proposed which is preferably suitable for making apertures in concrete work or masonry is fissured rock. To avoid damaging an interchangeable conveying helix (4), the connection between the conveying helix (4) and drilling head (3) is made as a frictional-resistance connection (FIG. 2).

Abstract: A rock drill for rotary and/or percussive stress, in particular for use in percussion or hammer drilling machines, is proposed, which by its geometrical design makes improved efficiency and simplified production possible. For this purpose, the feed spiral 5 is designed alternately with horizontal feed sections 8,8' with a 0.degree. pitch, and adjoining lead sections 9,9', the respective feed sections assuming an angle of rotation of 90.degree. on the drilling tool.

Abstract: A rock drill haivng a drill head with cruciform cutting tips is proposed which has improved chiselling properties in the case of percussive loading in hard rock or the like. For this purpose, the main cutting tip (4) is of a design know per se with secondary cutting tips (7,8) which are arranged transverse thereto and have a roof-shaped cross-section in side elevation. Additional, radially further outward bit points (16) for working the material result from the roof-shaped cross-section of the secondary cutting timps (7,8,) (cf. drawing).

Abstract: A rock drill is provided in which an optimum support of the carbide cutting tip or of a cross cutting edge is achieved by the drill head being made square or rectangular in cross-section. This results in an optimum strengthening of the cross-section against fracture in the slot root for the cutting tips. Moreover, catching of the drill in fissured rock and under extreme loads such as in reinforcement drill holes is avoided.

Abstract: A rock drill for rotary and percussive stressing exhibits equally good or improved transport characteristics of driling dust for a smaller transport groove as compared with prior rock drills. In order to achieve this, a main transport groove having longitudinal profiles is formed, with an interrupted secondary transport groove integrated in the main transport groove, the transport ribs of which exhibit a greater angle of twist than the angle of twist of the main transport groove.

Abstract: The drilling tool proposed serves for making perforations and is equipped with an exchangeable feed helix. To prevent the feed helix from being damaged if the drilling tool becomes tilted or if the feed helix is jammed, the feed helix can execute a specific stroke by means of a supporting spring, in such a way that the drill shank can rotate freely relative to the feed helix.

Abstract: A drilling tool is proposed which is provided with an interchangeable conveying spiral and an axial supporting device of the conveying spiral. To achieve a cost-effective and simply constructed, but at the same time reliable axial support of the conveying spiral (14), an elastic sleeve (15) is held in a recessed groove (19) in the drill shank (11) against axial slipping by a support ring (17).

Abstract: A rock drill in which the depth of the recessed groove for accommodating the cutting body is made greater than the axial brazing-in depth of the cutting body whereby a largely stress-free seating of the cutting body results. In particular, for rock drills for making break-throughs, this recessed groove extended in the radial direction into lobes of a drill head can be used for locating cutting bodies in the lobes.

Abstract: An interchangeable conveying spiral which can be removably, slidably mounted on a drill shaft for conveying drillings away from a drill head mounted on the end of the spiral. The spiral includes an elongated strip having at least first and second substantially orthogonal webs. The first web has a free, squared-off end. The strip is wound in a spiral with the free, squared-off end of one turn abuting the free, squared-off end of an adjoining turn of the spiral so that the first web forms a closed jacket tube which can be removably, slidably mounted on a drill shaft, and the second web serves exclusively as a transporting shoulder for conveying drillings.

Abstract: A drilling tool for percussion drilling machines is proposed which has an increased endurance strength or fatigue strength when used in percussion drilling machines having a high striking speed. For this purpose, the carbide cutting tip (11) is arranged transversely to the flute runout (12, 13) so that the effective moment of resistance area in the area of the groove root (22) of the recessed groove (14) is not weakened by flute runout surfaces.

Abstract: A drill bit, hvaing heavy-duty cutting elements, is proposed which is intended for rotary, air-cooled application. So that the drill bit can be operated with a relatively low thrust pressure, PCD cutting elements (14) are provided which only slightly overlap the thin-walled cylinder (11, 12) to produce an air gap for cooling and for conveying the drilling dust.

Abstract: A boring tool for producing undercuts in preformed holes. The boring tool has a cutting element which is provided at one end of a driving shaft. In order to produce the undercut, the driving shaft can be deflected at right angles to the axis thereof via a deflection mechanism. The deflection mechanism is accommodated in the boring tool, and is provided with a longitudinally displaceable deflection rod for positively deflecting the driving shaft. In the deflected position, the driving shaft is driven by a rotary drive which is separate from the turning drive. As a result, the undercuts can be very precisely produced.

Abstract: A drilling bit having two helical withdrawal grooves which extend from the drilling head in the direction toward the insertion or chucking end. The withdrawal grooves have least slope in the vicinity of the drilling head. In the other regions, the withdrawal grooves have a different slope. As a result, no cross-sectional jumps disposed at uniform intervals are provided on the drilling bit, so that transverse oscillations cannot be reinforced by partially constantly or continuously reflected pulses. A considerable reduction in noise is achieved. Furthermore, the central portion of the drilling bit, which is critical during drilling, receives great rigidity.

Abstract: A boring tool for radial widening or enlargement of a cylindrical bottom, foundation, or anchor bore. The boring tool comprises a tubular tool body having a tool shank provided for clamping in a driving machine or prime mover, and an enlarging spindle guided in the tool body and adapted to be supported on the bottom of the bore. When entering into the tool body, the enlarging spindle radially adjusts the cutting parts or elements provided for carrying out the enlargement. The tool body is formed of radially resilient segments which extend in the axial direction and delimit longitudinal slots which are open toward the front end of the tool. Cutting parts or elements are arranged on the free ends of the segments, with each part having an axial working which extends in the circumferential direction of the tool body, with those working surfaces which are adjacent one another in the circumferential direction forming the front end face of the tool body.

Abstract: A rock drill, particularly for reinforced concrete, for rotary blow drilling, having one or several helical removal grooves for the removal of drill dust and a drill head furnished with a hard metal cutting ring is disclosed. In a preferred embodiment, the drill shaft is provided with a removal channel communicating the cutting ring head and a removal groove in the drill shaft surface.