Abstract: A hand drill, in particular a hammer drill has a combination tool holder provided with a first tool receptacle with clamping jaws displaceable relative to a base body and adjustable by a rotatable adjusting ring to different diameters of tool shafts, and a second separate tool receptacle for tools with a groove shaft and provided with means for at least one driving and locking as well as with a central receiving opening for the groove shaft tool, and an arresting device having a blocking slider which is arranged displaceably in the base body and non-rotatably connected with the base body in a circumferential direction, the blocking slider being movable between a first end position in which a radially inwardly directed end of the blocking slider engages in the central receiving opening and is provided with teeth such that when a groove shaft tool is inserted in the receiving opening the teeth in another end position of the blocking slider non-rotatably engage with counter teeth connected with the adjusting rin

Abstract: A chuck for use in a percussion drill or the like has a unit for securing the chuck jaws against unintentional loosening during operation. The securing unit moves from an unlocked position in which a tool can be received by the chuck jaws to a locked position automatically for drilling operations without the use of a key. The securing unit includes a first surface (22) upon which a sliding member (21) is slidable to be received in a recess (26) during the shaking caused by drilling, so that coupling members (15, 19) between a securing sleeve (17) and a clamping sleeve (13) engage with one another.

Abstract: To apply hard cutting particles, for example of tungsten carbide, on the surface of the cutting edge of a cutting tool, such as a saw blade, a drill, or the like, the cutting edge is partially melted by an energy beam, for example a laser beam, or an electron beam. A laser beam is preferred since, then, the process can be carried out in air, or in a protective gas atmosphere, rather than in a vacuum. The beam partially melts the cutting edge and the granules of the hard metal particles, preferably in a random grain size of between 0.3 to 1.5 mm is permitted to run down, over the partially melted surface, excess being collected for reuse; alternatively, the partially melted surface can be dipped into the granules, and permitted to solidify.

Abstract: A drilling tool has a drilling shaft member, a crown drilling member with an annular wall provided with a plurality of cutting edges and detachably mounted on the shaft member, a center drilling member detachably mounted on the shaft member inside the crown drilling member and having a further cutting edge, and elements for limiting a drilling depth of the tool when the center drilling member is mounted on the shaft member. Thereby, the operator of the drilling tool, after drilling a guiding groove in a rock, is forced to remove the center drilling member from the drilling tool and drill further without the center drilling member, which increases the drilling efficiency.

Abstract: An arrangement for producing grooves in walls, ceilings and the like with the use of a hand-held processing machine, has a rotatable material-removing tool driven in rotation by the machine, and a housing surrounding the tool. The housing has a guiding piece through which the tool extends. The guiding piece has a guiding surface which is adapted to lie on the surface of the wall, ceiling and the like, and is inclined at an acute angle relative to the axis of the tool. The guiding piece is detachably mounted on the processing machine.

Abstract: A dust-intercepting member is so mounted on a hand-held power tool as to contact a structure being acted upon around the tool element of the power tool, by a mounting arrangement which includes two hollow elongated mounting members one of which is received within the other for telescoping relative thereto while being retained against rotation with respect to the other mounting member about the common axis of the mounting members, and a helical compression spring the ends of which are respectively received in the interiors of the mounting members and urge the latter in opposite directions. The other mounting member is attached to an auxiliary hand grip which, in turn, is mounted on a cylindrical extension of the housing by a quick-release clamping arrangement. A setting ring on the inner one of the mounting members determines the depth of penetration of the tool element into the structure. A depth-determining profiled rod is displaceably and arrestably mounted on the auxiliary hand grip.

Abstract: A dust-intercepting member is so mounted on a hand-held power tool as to contact a structure being acted upon around the tool element of the power tool, by a mounting arrangement which includes two hollow elongated mounting members one of which is received within the other for telescoping relative thereto while being retained against rotation with respect to the other mounting member about the common axis of the mounting members, and a helical compression spring the ends of which are respectively received in the interiors of the mounting members and urge the latter in opposite directions. The other mounting member is attached to an auxiliary hand grip which, in turn, is mounted on a cylindrical extension of the housing by a quick-release clamping arrangement. A setting ring on the inner one of the mounting members determines the depth of penetration of the tool element into the structure. A depth-determining profiled rod is displaceably and arrestably mounted on the auxiliary hand grip.

Abstract: A power tool, particularly a hammer drill, is equipped with a blower which is mounted on the output shaft of the motor which drives the tool element which is clamped in the chuck of the power tool. The particulate material which is removed by the tool element from a structure is entrained in a stream of air generated by the blower and conveyed toward the latter. Before the particulate material enters the blower, at least most of it impacts an impact member which extends across an inlet section of the conduit through which the stream of air passes, so that the impact member deprives the entrained particulate material at least of the greater part of the kinetic energy possessed thereby, before the particulate material reaches the blower and damages the same due to its high kinetic energy.

Abstract: A rock drill comprises a shaft having a leading and a trailing end, a shank connected to the trailing end, and a drill head connected to the leading end of the shaft. Means for transporting drilling from the leading end toward the trailing end of the shaft are provided which include at least one channel extending parallel to the shaft from the drill head toward the shank. A shell coaxially surrounds the shaft and bounds the channel, which shell has an open front end adjacent the drill head, a closed rear end facing the shank and at least one transverse bore adjacent the rear end of the shaft and open at the outer surface of the shell.

Abstract: A hole saw for use in a hand drill has a cup centered on a rotation axis and having a rim centered on this axis and provided with a plurality of teeth. This cup has a shaft extending backwardly along the axis and adapted to be received in a drill chuck so that when the shaft and cup are rotated about the axis the teeth can sink into a workpiece and cut a large-diameter hole therein. The cup is formed at its base with a bore lying on the axis and opening into the cup and with a passage extending non-axially from the bore to the outer surface of the shaft. A pilot bit has a shank non-rotatably received in this bore and a tip extending axially beyond the rim of the cup so that this pilot bit serves to center the drill accessory during the start of a hole-making operation. A collar is fitted to the outside of the drill shank over the passage and is connected to aspirating means so as to aspirate particles from inside the cup.

Abstract: A hammer drill is provided with an accessory that is rotatably supported on the chuck of the drill and has a handle fixed to the support rotatable on the drill chuck. Structure is provided forming a throughgoing passage extending from the tool through the handle to the outer end of the handle and a flexible conduit is connected to this handle at the outer end thereof for drawing gas and particles from the tool through the passage. The structure may surround an intermediate portion of the tool at the radial opening of an axial bore through the tool so that particles and the like can be aspirated directly through the tool. Alternately a telescoping tube is provided connected at its rear end to the passage at the support and at its front end to a cup through whose base the drill passes, so that this cup is pressed against the workpiece during the drilling operation.

Abstract: A hand-guided power tool comprises a housing and a base plate mounted below the housing. The base plate is adapted to be juxtaposed with an object which has material to be removed therefrom. A tool element such as a reciprocable cutting blade extends through a slot formed in the base plate and is operative for removing material from the object with concomitant production of undesirable particulate material in the circumambient region of the element. A channel member is also mounted below the housing but at a distance from the base plate to thereby form a suction channel which is in communication with the circumambient region of the tool element and which is operative for removing and guiding the particulate material from the tool element.

Abstract: A self drilling anchoring dowel for drilling a hole into a hard support structure and anchoring in this hole to be available as a fixture by means of which an object may be attached to the support structure. The dowel is formed as an elongated dowel body having a front end and a rear end. At the front end, a drilling head is formed and, spacedly from the rear end, a circumferential weakened zone is provided in the wall of the dowel body in which zone the thickness of this wall is diminished. Thus, at the rear end of the dowel body, a rear terminal section is delimited which may be broken off therefrom after the dowel has been driven to a desired depth into the structure, so that a front end is provided on the dowel body which end is substantially flush with the structure surface. A longitudinal bore inside the dowel body extends therethrough and is available for removing from the drilled hole waste chips and dust produced by drilling.

Abstract: A vacuum sweeper, particularly for collecting borings, has an upright cylindrical receptacle with a tangential inlet for admission of an air stream which carries borings and/or other solids and an open top which is overlapped by a platelike air filter disposed below a cover which is separably connected with the receptacle and has downwardly extending projections to prevent upward flexing of the filter. A side channel vacuum pump is installed in the cover and has an inlet which draws air from the receptacle via filter and a passage of the cover, and an outlet which communicates with a sound deadening annular channel provided in the cover and concentrically surrounding the rotor of the pump. The open end of the channel extends upwardly and contains a spherical float which rises therein to a level indicating the rate of air flow from the channel.