Abstract: A series wound commutator motor is disclosed which is particularly suited for an inverse-speed electric tool. A switch is provided for switching between a motor operation mode and a braking operation mode, wherein in motor operation at least one field coil is connected in series with an armature winding in a motor circuit fed with a voltage supply and wherein in braking operation the at least one field coil with the armature winding forms a closed braking circuit separated from the voltage supply. A mains-supplied transformer is provided whose secondary winding is connected in the braking circuit parallel to the at least one field coil. A transistor circuit is provided for controlling the current flowing in the braking circuit through the armature winding and the at least one field coil.

Abstract: A screwdriver is disclosed, comprising a removable depth stop which selectably either, when equipped with the depth stop, allows noiseless shutoff or, with the depth stop removed, allows torque-dependent shutoff, without any chattering occurring when the machine continues to run. To this end, an adjustable torque-dependent release clutch is combined with an entrainment clutch of known type, which is additionally preceded by a disconnect clutch, a locking means being provided in order to hold a throwout ring, which forms one of the two elements of the disconnect clutch, in a predetermined position under load. In this way, noiseless operation is ensured after release, both when working with the depth stop and in the case of torque-dependent shutoff, with the depth stop removed.

Abstract: A power-driven screwdriver with a torque-dependent release clutch having two clutch halves is disclosed. The screwdriver comprises additional entrainment elements provided on the clutch halves for bridging the release clutch. To this end, a motor-driven drive gear is mounted to rotate freely on a tool drive shaft and is secured against axial displacement on the housing side while a cam ring can be adjusted axially, together with the tool drive shaft, via an adjusting device. The clutch elements are formed on the respectively facing sides of the drive gear and the cam ring, and the entrainment element are likewise formed, as separate elements, on the respectively facing sides of the drive gear and the cam ring. As a result of the adjusting device axial displacement of the tool drive shaft results either in a rigid through drive, where the release clutch is nonfunctional, or in the torque-dependent release of the release clutch, where the entrainment elements are nonfunctional.

Abstract: A power-driven hand tool is disclosed, having a housing in which a drive for a tool is received, having at least a first handle which is fastened to a support that is attached at a first end to the housing and with a second end projects laterally out from the housing. The support has at its second end at least a first receptacle for attachment of the first handle in a first position such that the first handle projects with one free end in the direction of the housing. Preferably a second receptacle is also provided, for attaching of the first handle in a second position angled with respect to the first position. In addition, a second handle, which is preferably is configured as a switch handle and is displaceable into various positions about its longitudinal axis, can be arranged preferably at the opposite end of the housing. A particularly ergonomic posture and fatigue-free operation are made possible.

Abstract: A power sander comprising an oscillating drive for oscillatingly driving a sanding tool about an axis fixed with respect to a housing is disclosed. The sanding tool comprises a sanding plate arranged on the sanding tool and having at least two side edges which converge in at least one corner and are arranged symmetrically with respect to a center point. A receptacle for mounting the sanding plate on the drive shaft is arranged on the sanding plate eccentrically with respect to the center point.

Abstract: A power tool, which is preferably configured as a right-angle grinder, has a motor-driven hollow spindle to drive a tool, which is fastened between a clamping flange and a counterflange by means of a quick clamping device via a tension spindle, coaxial with the hollow spindle, that is tensioned in the axial direction by means of elastic elements and is displaceable in the axial direction relative to the hollow spindle, by means of a clamping lever, between a clamped position in which the tool is nonrotatably retained between the flanges, and a released position. The clamping lever is mechanically coupled to the motor switch by means of a link rod in such a way that the clamping lever can be moved into the released position only when the motor is switched off. This rules out improper operation and any potential damage to the power tool.

Abstract: A saw blade possesses a base element onto which boron nitride particles are applied in the cutting region. The boron nitride particles are bonded by means of a metallic bonding layer, which preferably consists of nickel or a nickel alloy with a Vickers hardness of at least 600 HV. The bonding layer is preferably deposited galvanically. The boron nitride particles advantageously possess a particle size of approximately 0.5 to 0.8 mm, preferably approximately 0.6 to 0.7 mm. The saw blade possesses particular advantages for use as a reciprocating saw blade for sawing GGG cast iron pipes with a cement lining and fiber-reinforced cement jacket, resulting in considerably improved cutting performance and service life.

Abstract: A power tool, especially a handheld sander, is described, possessing a motor-driven drive shaft that can be alternatively coupled either by means of an oscillation drive to an oscillatory tool drive shaft, or by means of a rotary drive to a rotary tool receptacle coaxial with the oscillatory tool drive shaft. Switching is provided by a switching element, in a first switch position of which the drive shaft is driven in an oscillating manner about the lengthwise axis of the oscillatory tool drive shaft, with a small pivot angle and at high frequency, by means of the oscillation drive, which can consist for example of an eccentric element on the tool drive shaft and a pivot element guided slidingly thereon and fastened on the tool drive shaft. In the second switch position of the switching element, however, the working engagement of the oscillation drive is abolished, and the tool receptacle is rotationally driven by the drive shaft by means of a bevel gear linkage.

Abstract: A motor-driven machine with variable torque setting feature, especially a screwing machine with a torque-controlled switching-off feature, has a shaft which is driven by a motor via a transmission for driving a tool, and a setting ring for presetting a torque at which the shaft is to be disconnected from the transmission and/or the motor will be switched off. In order to enable approximately identical torque curves to be achieved for hard and for soft screwing applications, a clutch with a variable tripping torque is provided whose tripping torque can be adjusted via an indexing ring, which latter can be adjusted together with the setting ring.

Abstract: The invention proposes a grinder having a rocking shaft adapted to set a grinding tool into an oscillating movement about a rocking axis fixed to the device, the grinding tool having a grinding surface comprising at least one corner area. For the purpose of extracting the grinding dust, there is provided a suction hood, which can be fixed on the device and which communicates with a suction pipe. In order to prevent the risk of surface marks forming during micro-finishing of surfaces, and at the same time to guarantee efficient dust removal, the grinding surface is designed as a continuous, closed surface, without any openings, the suction hood enclosing the grinding tool from above and at least part of the lateral faces of the grinding tool. The suction pipe opens laterally into the suction hood in an area opposite the corner area of the grinding surface. Further, the suction hood comprises a suction chamber extending from the suction pipe to the corner area of the grinding tool.

Abstract: A cutting knife for a cutting tool equipped with an oscillating drive, for cutting off the cement bead of a glass pane cemented in place, in particular in a motor vehicle, comprises at least one cutter element which can be connected, via a mounting element and a mounting opening, to an oscillating drive by which the cutting tool can be set into an oscillating motion about a rocking axis. In order to enable the cutting depth of the cutting tool in the material to be adjusted, the cutter element is provided with a slot extending between the mounting opening and an end of the cutter element opposite the mounting opening, with a roller being held thereon for displacement along the longitudinal axis of the slot.

Abstract: The invention proposes a method for grinding plastics or glass, in particular for grinding acrylic glass, where a mechanically driven grinding tool is moved across a surface to be finished (44). Grinding is effected by a dry process, without any liquid working agent, the grinding tool performing an orbital movement, or oscillating about a fixed rotary axis at high frequencies, while the grinding dust is extracted from the marginal area. The grinding tool comprises a closed abrasive with resiliently embedded abrasive grains, a plurality of the resiliently embedded abrasive grains having, preferably, level front surfaces which are delimited by relatively sharp edges at the transition to their lateral surfaces, the greatest part of the front surfaces being oriented to extend substantially in parallel to the surface to be worked (44). The method enables plastic and glass surfaces to be micro-finished to a particularly high grade (FIG. 1).

Abstract: A portable power tool has, in order to drive a tool (12), a hollow spindle (14) to which the tool (12) can be fastened between two flanges (16, 18). The outer flange (16) is configured at the end of a clamping bolt (22) that is inserted through a central opening (17) of the tool (12) and projects at its other end out of the housing (42). The clamping bolt (22) can be non-rotatably secured at this end by means of a retaining element (20). For actuation, a clamping device (24) is provided, which can be moved, against the force of spring elements (26), between a clamped position in which the retaining element (20) is acted upon axially to clamp the tool (12), and a released position in which the tool is disengaged for manual changing. The spring elements (26) are arranged between an axial fixed stop (28) and an axially displaceable stop (FIG. 1).

Abstract: A device is disclosed for producing surface channels of at least approximately rectangular cross-section in sheeting consisting of a soft material, in particular mineral-fiber insulating mats or sheeting consisting of a styrene polymer. The device makes use of a motor-operated cutting tool with an oscillating cutter. The cutter comprises sections which are bent off relative to each other and which are provided with a cutting edge, at least in part. The cutting edge extends over at least three of two sections which form together a U or L, respectively. The cutter is passed through the sheeting approximately along a straight line.

Abstract: The invention concerns a retaining device for an angled head (10, 11) that is driven by a drive (1) especially a drilling gun, in which the drive unit (1) has a receiving connector (2) to receive the angled head (10, 11). To allow adjustment of the angular position of the angled head with respect to the drive unit, a socket (31) that can be screwed onto threads (33) of the receiving connector (2) is provided to receive the angled head (10, 11). Pins (21) which can be displaced axially in order to retain or release balls (25) are provided in the socket (31). The receiving connector (2) has on its outer surface a plurality of lengthwise grooves (29) in which the balls are held (25). When the pins (21) are displaced axially the balls (25) are released, so that the socket (31) can rotate relative to the receiving connector (2) until the balls (25) engage in corresponding lengthwise grooves ( 29) and are retained by the pins.

Abstract: A compact device for clamping a disc-shaped tool on a tool spindle of a portable machine tool with a clamping anchor arranged in the tool spindle, with a clamping flange attachable to the free end of the clamping anchor, with an abutment arranged at the tool end of the tool spindle and with a manual actuating mechanism for releasably pressing the clamping flange against the abutment, thereby clamping the tool between the clamping anchor and the tool spindle. The manual actuating mechanism includes a first pressure cylinder having a first cavity and a second pressure cylinder having a second cavity, and a connecting channel between the cavities. The second pressure cylinder includes a piston delimiting the second cavity. The piston is adjustable and fixable by the manual actuating mechanism from the tool end of the tool spindle for releasably clamping the tool on the tool spindle.

Abstract: A motor-operated tool is provided for tool sockets revolving about an axis, in particular for drills or spanners. The tool comprises a tool head containing a drive spindle. The drive spindle comprises a driving opening for a drive shank of the tool socket and a plurality of ball elements for engaging a part of the drive shank to lock it in the driving opening. The ball elements preferably are adapted to lock the drive shank in the driving opening automatically and to be released by a suitable mechanism. The tool socket is designed as a drill chuck and is provided with key elements for actuating the mechanism.

Abstract: A portable grinder (10) has a motor-driven drive shaft (15) and a quick-acting chucking device for a grinding tool (43), which comprises a spindle (20), coaxial with the drive shaft (15), which is braced against the drive shaft (15) by a spring (24) in the axial direction and can be displaced in the axial direction relative to the drive shaft (15) by means of a clamping lever (32). One external free end of the spindle (20) retains the grinding tool (43), which in a released position--with the free end of the spindle (20) extended and the spring (24) tensioned--can be removed from the free end, and in a tightened position--with the free end of the spindle (20) retracted and the spring (24) partly relaxed--is non-rotatably joined to the drive shaft. The free end is configured as a bayonet end (40) which extends though the grinding tool (43). An attachment collet (41) with a bayonet opening can be placed from outside onto the bayonet end (40).

Abstract: Grinding with known grinders such as corner, belt or vibratory grinders poses insoluble problems, such as the grinding of inner edges set at an angle to each other for example in retainer strips of window and door glasses. A portable grinder has thus been developed in which the grinding or sanding tool (3, 20, 30) effects an oscillatory movement which, unlike in the state of the art, is effected around a fixed axis of the apparatus (29) with a minimum pivoting angle, preferably between 0.5.degree. and with a high pivoting frequency of between ten thousand and twenty five thousand vibrations per minute. This different oscillation movement makes it possible to provide the grinding or sending tool with almost any shape. Furthermore, grinding does not inevitably have to be made with the transverse surface of the tool (3), in particular the perpendicular surface, in relation to the diametrical axis (29) but it is also possible to use a surface which is almost parallel to the first or is even arched.