Abstract: A hand-held motor-driven percussion tool comprises a piston driven over an air cushion and acting over an axially movable anvil on the inner end of a tool axially movable in a tool receiver provided at one end of a tool housing. The anvil has an annular collar located in the cavity of an impact body which is movable in the direction of the impact of the piston against a cushioning ring. The impact body has an abutment face adapted to be engaged by a collar of the anvil when the latter is driven by the piston. A face of the impact body facing away from the cushioning ring is directed toward a part fixedly connected with the tool housing. The mass of the impact body is for instance 10% greater than that of the anvil. If the tool during operation is withdrawn from a workpiece, then the flange of the anvil impinges upon the abutment face of the impact body and accelerates the latter towards the cushioning ring.

Abstract: A hammer drill has a housing provided with a tool chuck in which a tool is to be mounted. A drive is provided which is capable of rotating and/or axially impacting the tool chuck. This drive includes a piston reciprocable in axial direction of the tool chuck, a drum rotating on a shaft extending parallel to the direction of reciprocation of the piston and provided with a circumferentially extending cam track, and a transmitting arrangement which travels in part in engagement with the cam track and which has another part connected with the piston to reciprocate the same.

Abstract: A power driven hammer drill has a tool impacting mechanism, a wobble unit for reciprocating the tool striking mechanism and having a drum member which can be releasably coupled with an intermediate shaft driven by a motor, wherein a switching device is provided outside of a hammer drill housing and arranged so as to disengage a coupling element of the intermediate shaft out of a coupling element of the drum member of the wobble unit against the action of a spring.

Abstract: A hand-held power tool with an electric drive motor, by means of which a rotary sleeve impacting upon a tool retainer holding a tool can be rotatably driven by a transmission, and by means of which an impacting mechanism can furthermore be driven. The power tool includes an axially oscillating drive piston, an impactor impinged by the drive piston over an air cushion which will transmit its impact energy onto the tool. A translation drive acts upon the drive piston with a rotatably driven drive member with a curved guide. At least one actuator follows the curve guide and acts upon the drive piston to effect its axial displacement. The drive member consists of a drive sleeve coaxial with and concentrically enclosing the drive piston and the impactor. The drive sleeve has a guide surface closed in itself in the circumferential direction and has an essentially steadily rising or falling incline with curve maxima and curve minima.

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 electrically driven linear vibrator has swing drive for vibrating troughs, jarring tables or the like comprises a stator with an exciter winding, an armature guided for linear movement in a direction transverse to the field produced by the stator and a pair of oppositely acting return springs forming together a swing drive, the vibration of which may be used to drive a device connected to the vibrator. The return springs may be constituted by metal springs, gas springs or a combination of both. The swing drive may be constructed as single-acting or double-acting drives. A diode may be connected with the electrical conductors leading to exciter winding so that at a line frequency of 50 Hz, an oscillation frequency of 100 Hz, 50 Hz or 25 Hz may be obtained. The vibrator may also be provided with a piston blower for cooling the windings of the stator.

Abstract: A handle-connecting assemby for hand-held machine tools comprises a wire element having a loop engaging a tool-supporting projection of the tool and a hollow member adapted to receive the ends of the wire element. The ends of the wire element are rigidly connected to a head of a bolt, the end threaded portion of which is threaded into a handle. The wire element connecting the tool-supporting projection to the handle provides for sufficient flexibility of such connection thereby the handle may positioned at an acute angle to the axis of elongation of the projection.

Abstract: A hand-held power tool, particularly a chipping tool has an impact-damping arrangement for damping axial impacts of a striking member against a working tool. The arrangement includes a shaped member which is firmly and axially movably held on an outwardly extending portion of the tool and constituted by an elastic material. The shaped member has a substantially radial abutment face which abuts against a face of a tool holder in striking and noise-damping manner and radially overlaps an opening of a receiving recess of the tool holder so as to serve simultaneously for protection from dust.

Abstract: A hand-held power tool has a tool holder, a tool axially reciprocable in the tool holder, and a striking mechanism including a drive piston and a striker having a disc-shaped plate with a small axial dimension and a striker shaft having a cross sectional dimension corresponding to that of a tool shaft. The striker shaft transmits impact energy directly to a rear end face of the tool shaft without an intermediate member.

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 portable machine tool, especially a hammer drill, mainly comprises a housing in which a guide tube is arranged. A piston and a beater are guided in the guide tube reciprocatable in axial direction, the piston and the beater having facing axially spaced ends forming therebetween in the guide tube an air pillow through which the impact energy of the piston is transmitted to the beater. A turning sleeve coaxially surrounds the guide tube and is provided at its front end with a holding bushing formed with a coaxial bore therethrough in which a shaft of a tool, for instance a drill, is mounted for rotation therewith and for limited axial movement relative thereto. The beater is provided at the front end with a beater bolt having an outer diameter slightly smaller than the inner diameter of the bore so that the beater bolt, which transmits its impact energy directly to the free end of said tool shaft, may enter into the bore to be guided therein during reciprocation of the beater.

Abstract: A hammer drill has a housing provided with a tool chuck in which a tool is to be mounted. A drive is provided which is capable of rotating and/or axially impacting the tool chuck. This drive includes a piston reciprocable in axial direction of the tool chuck, a drum rotating on a shaft extending parallel to the direction of reciprocation of the piston and provided with a circumferentially extending cam track, and a transmitting arrangement which travels in part in engagement with the cam track and which has another part connected with the piston to reciprocate the same.

Abstract: A hand-held power tool has a tool holder for holding a tool, a striking mechanism including a cylindrical sleeve, a drive piston reciprocable in the sleeve, and a striker actuated by the latter, and a drive motor located axially parallel with and laterally adjacent to the cylindrical sleeve. The drive motor transmits the movement to the striking mechanism through a crank drive which is a one-stage crank drive and has a drive train extending transversely to a longitudinal axis of the cylindrical sleeve. The crank drive includes a rotatable shaft, a bevel gear fixedly mounted on one end portion of the drive shaft and meshing with a drive pinion of the motor, and a crank lever mounted on the other end portion of the drive shaft and connected with the drive piston of the striking mechanism. A fan is mounted on the motor shaft and operative for aspirating air, so that air flows through the motor, then flows around the cylindrical sleeve of the striking mechanism and then discharges toward the tool holder.

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 shaft seal for a rotatable shaft which is surrounded by a substantially rigid structural element, has a ring-shaped body portion adapted to be supported by the structural element and having an axis and two axially spaced end faces, a radially displaceable ring-shaped inner portion located radially inwardly of the body portion, extending in an axial direction, and together with the body portion forming an axially extending gap, at least one sealing lip provided in the inner portion and subjected to radial vibrations during rotation of the shaft which vibrations are transmitted to the radially displaceable inner portion and displace the latter, and elements for damping radial vibrations of the sealing lip.

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 tool for introducing self-tapping dowels in a structure by a drilling process which is accompanied by the generation of large-size drillings, has a shaft connectable with a drive, a dowel holder connectable with the shaft and having a receiving bore which includes a first section adapted to receive a dowel shank and a second section adapted to receive the large-size drillings, and a suction arrangement movable relative to the dowel holder to and from an operative position in which it communicates with the second portion of the dowel holder and draws air therethrough to thereby suck the large-size drillings into the second section of the dowel holder bore wherein they are retained during the drilling process.

Abstract: A hammer drill has a movable tool and a driving element substantially coaxial with the tool. The driving element directly transmits axial impact from the same to the tool without transmission of torque. A tool holder surrounds proximal end portions of the driving element and the tool and transmits torque from the former to the latter without transmission of axial impact. Drive means are provided for selectively imparting torque and/or axial impact to the driving element. The tool holder comprises a sleeve which surrounds the proximal end portions. The sleeve is axially movable relative to the driving element and the tool and, at the same time, are connected with them for joint rotation therewith. An additional sleeve is provided surrounding the sleeve and enabling an operator to hold and to guide the hammer drill.

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.