Abstract: A hammer drill has a chuck forming a tool receptacle defining a chuck axis and provided with a tool-holding element radially displaceable into a position protruding into the tool receptacle. The tool has a shank defining a tool axis receivable axially in the receptacle. This shank is formed with a radially outwardly open recess closed at both of its axial ends and shaped to receive the tool-holding element, and with an axially extending groove separate from the recess and open axially at a free end of the shank. At least a section of the shank has a conical shape decreasing in a direction towards the free end of the shank. The shank may be provided with at least one cylindrical guiding section located adjacent to the above conical section.

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 hammer drill has a chuck forming a tool receptacle defining a chuck axis and provided with a tool-holding element radially displaceable into a position protruding into the tool receptacle. The tool has a shank defining a tool axis receivable axially in the receptacle. This shank is formed with a radially outwardly opening recess closed at both axial ends and shaped to receive the tool-holding element, and with an axially extending groove separate from the recess and opening axially at the end of the shank. This groove has at least one flank extending substantially radially of the tool axis. A rotary-entrainment formation in the receptacle is formed with at least one side flatly engageable with the flank for maximum force transmission and minimum wear.

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 portable power tool wherein the housing contains a pump, a tank for a supply of oil for the pump, an electric motor for the pump and one or more hydraulic motors which receive pressurized oil from the pump and impart movements to a rotary and/or reciprocable tool, such as a rock drill or chisel. The motor which imparts reciprocatory movements to the tool is a cylinder and piston unit whose piston is rigid with a piston rod serving to strike against the tool whenever the piston performs a forward stroke. A valve assembly having a motor-driven rotary spool controls the flow of pressurized fluid to and the outflow of spent fluid from the cylinder. A spring brakes the rearward movements of the piston, and a bladder type accumulator is connected with the outlet of the pump. The tank is cooled by currents of air which are induced by a blower on the output shaft of the electric motor and which cool the electric motor before they reach cooling fins provided at the outer side of the tank.

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 housing has a tool mounted therein so that a portion of the tool can slide for reciprocatory movement deeper into and farther out of the housing. A prestressed biasing spring or a cushion of gas is interposed between and acts upon the housing and the aforementioned portion of the tool, being prestressed to an extent which is less than the minimum force with which the tool can engage a workpiece when the tool is pushed against the workpiece by the weight of the hammer, and which biasing means has a flat spring characteristic.

Abstract: A portable torque and impulse transmitting machine comprises an elongated housing having a median plane of symmetry which extends in direction of the elongation of the housing, and a tool holder which is mounted on the housing for holding a material-penetrating tool. A drive motor is mounted in the housing and has a rotary output shaft which is mounted in the housing so as to lie in and substantially bisect the median plane. An impeller assembly is also mounted in the housing and includes an impeller mounted for reciprocting movement therein and operative for transmitting impulses to the tool. A first power train is mounted in the housing and arranged to effect reciprocatory movement of the impeller in response to rotation of the rotary shaft of the drive motor. The first power train comprises a crank gear having an axis of rotation which is substantially parallel to the rotary shaft and which is also offset from the median plane.

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 torque-transmitting system, particularly a hammer drill, has a housing provided with a tool holder section, and a driven output shaft which is journalled in the housing and has a free end portion at the tool holder section. A tool has a shaft provided with an end portion of profiled cross-section, the profiling of the cross-section being inclined circumferentially of the end portion. A receiver for the end portion is formed in the tool holder and configurated for matingly receiving the profiled end portion, so that the tool is held in the tool holder section in motion-transmitting relationship with the free end portion of the shaft.

Abstract: A portable power tool wherein the housing contains a pump, a tank for a supply of oil for the pump, an electric motor for the pump and one or more hydraulic motors which receive pressurized oil from the pump and impart movements to a rotary and/or reciprocable tool, such as a rock drill or chisel. The motor which imparts reciprocatory movements to the tool is a cylinder and piston unit whose piston is rigid with a piston rod serving to strike against the tool whenever the piston performs a forward stroke. A valve assembly having a motor-driven rotary spool controls the flow of pressurized fluid to and the outflow of spent fluid from the cylinder. A spring brakes the rearward movements of the piston, and a bladder type accumulator is connected with the outlet of the pump. The tank is cooled by currents of air which are induced by a blower on the output shaft of the electric motor and which cool the electric motor before they reach cooling fins provided at the outer side of the tank.

Abstract: A rotary spindle of a drill mount has a free end provided with a thread whose angle of rise is so selected that its tangent is at least equal to the coefficient of static friction of steel on steel.

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.