Abstract: A force-transmitting arrangement for use in hammer drills and the like includes an internal thread in a chuck of a power tool and an external thread on a portion of the tool element which is to be mounted in the chuck, both threads being of compatible, basically trapezoidal, configurations. The flat flanks of the trapezoidal internal and external threads are offset in the radially outward direction with respect to the mean effective thread diameter. The external thread is rounded at its root with a radius substantially corresponding to the thread height of the external thread, and the internal thread is similarly rounded at its crest with a radius substantially corresponding to the thread height of the external thread, and/or chamfered.

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 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.