Robert Boschgmbh

Michael Habele

Ulrich Single

Joachim Schadow

Cornelius Boeck

Sinisa Andrasic

Martin Schulz

Marcus Schuller

Klaus Dengler

Alfred Odendahl

Gerhard Kraemer

Csaba Kreiter

Josef Enfellner

Jakob Zeyda

The invention relates to a device () for taking a safety precaution in an electrical tool, said electrical tool comprising an electric motor (EM) with at least one field winding and an armature winding. The device () comprises the following features: a sensor unit () which is designed to generate a sensor signal () in accordance with a motor current () passing through the electric motor (EM), an armature voltage () via the armature winding, a voltage () via the field winding and/or a commutation frequency () in the armature winding; a unit () detecting a change of the sensor signal, which is designed to detect a temporal change of the sensor signal () and emit a corresponding modification signal () on the basis of the detected change; and a safety device () which is designed to take a safety precaution () in the electrical tool when a value of the modification signal () is exceeded or not met in relation to a threshold value.

Device and method for taking a safety precaution in an electrical tool

A plug arrangement in a machine tool comprises a primary plug part, which is associated with a drive motor, and a secondary plug part. According to the invention the primary and secondary plug parts are assembled to form a common plug part.

Plug arrangement in a machine tool, in particular a handheld machine tool

The invention relates to a hand-held power tool, particularly an angle grinder having a housing that has a flange neck, having a protective device that can be accommodated on the flange neck and that can be pivoted in the circumferential direction, and having at least one device for blocking at least one pivoting direction of the protective device. The invention proposes that the device for locking includes at least one stop and at least one counter-stop interacting with the stop.

Hand-held power tool

An electric mains-connection device for an electric hand-held power tool equipped with an electric motor (M), in particular for an angle grinder, has mains-connection terminals for a mains-connection cable, and with an anti-interference capacitor; it is designed as a mains-connection module that can be actuated externally, includes mains terminals, houses the anti-interference capacitor, and out of which an electric cable extends, which serves to connect motor electronics and a motor switch in an interface-free manner. An electric device for an electric hand-held power tool equipped with an electric motor, in particular for an angle grinder, includes the electric mains-connection device.

Electric mains-connection device for an electric hand-held power tool

A clamping fixture for detachably fastening a disk-shaped tool on a rotatably driven working spindle with a driven gear includes a fastening element a supporting flange arranged so that the tool is accommodated between the fastening element and the supporting flange and rotatably displaceable relative to the working spindle in the tightening direction and axially in a direction toward the tool. The supporting flange is displaceable relative to the working spindle in a release direction and axially away from the tool when the fastening element is released, and is lockable with the working spindle or a component which is non-rotatably connected with the working spindle in a position which is displaced axially in a direction of the tool, and the supporting flange cannot be displaced axially away from the tool until a lock is released.

Clamping fixture for detachably fastening a disk-shaped tool

A braking device for an electric motor includes a rotor () and a stator, in particular for a direct current series wound motor and a brake element () which is movable between a braking position and an operating position; a brake shoe () that brakes the rotor () in the braking position is mounted on the brake element (). The brake shoe () is mounted on the brake element () on the trailing end relative to the direction of rotation of the rotor ().

Brake device for an electric motor

The invention is based on a braking device for an electric motor with a stator () and a rotor (), in particular for a direct current series-wound motor, with a braking element () that can be moved between an operating position and a braking position depending on a magnetic flux in the stator (), wherein there is an air gap () between the braking element () and the stator (), and with a short-circuit ring () for suppressing mechanical vibrations. The invention proposes that the short-circuit ring () be inclined in relation to the air gap () between the stator () and the braking element ().

The commutator has a cylindrical collector (), disposed on a motor armature shaft, and electrical-contact means (), which during one rotation of the collector () touch at least two each of a plurality of commutator laminations () that are present on the collector () and thereby establish an electrical connection between the applicable commutator laminations and external current connections (). The electrical-contact means becomes especially low-wearing because the electrical-contact means comprise at least two electrically conductive cylinders () disposed in line with one another in the axial direction of the collector (), the longitudinal axes () are parallel to the longitudinal axis () of the collector (); and that the at least two cylinders () are placed relative to the collector () in such a manner and have a diameter such that the collector (), in its rotation, rolls over the inside faces () or the outside faces of the at least two cylinders (), and in the process each of the cylinders () is touched always by only one lamination () of the collector ().

Commutator for electric motors

An electric motor with an electromagnetic brake is disclosed, particularly for use in an angle grinder, which has a stator having at least one pole pair, in which at least one pole has a pole shoe which points to the inside towards the rotor periphery and is surrounded by a stator winding. The pole accommodates the brake means for braking of the rotor of the electric motor. The brake element can be adjusted against the braking force by the magnetic field of the stator winding when the motor is activated. The brake element is constructed of magnetically conductive material as a rocker which is exposed to the braking force off-center of the swivel axis of the brake element. As a result of the off-center application of force the brake element having a disengagement arm can be arranged in the magnetic flux of the stator winding such that a high disengagement moment can be achieved and rapid braking can occur at shutoff.

Electric motor with electromagnetic brake

A screwing device provided with a transmission of measuring signals has improved securing of screwing tool. Its rotary drive shaft is connected to the screwing tool in a rotationally locking manner via a polygonal coupling. The screwing tool is fastened axially by two connecting bodies which are arranged in bores and engage in a positively locking manner into an annular groove arranged in the rotary drive shaft in the region of the polygonal coupling. The connecting bodies are retained in their connection position by a securing element.

Screwing device for ultrasound-controlled tightening of screw connections

Device for signal transmission, especially for a screw driving apparatus

A screwing device provides an ultrasound-controlled tensioning of a screw connection. A measurement of the pre-tensioning force of the screw connection can be performed without complete fitting of a screwing tool on the screw connection. The screwing tool for this purpose is displaceable axially within a certain limit relative to the rotary drive shaft. The screwing tool is pre-tensioned by a spring in direction toward the screw connection, so that a contact pin arranged centrally inside the screwing tool for electrical contacting of a vibration body is arranged always inside the screwing tool to be protected.

Screwing device for measuring arrangement

Disclosed is a device for sorting fasteners, particularly screws, wherein defective fasteners are identified by a series of mechanical and electrical gauging stations arranged one after the other on a rectilinear conveying track and controlling ejection devices for eliminating screws which are not true in size or in quality. The mechanical gauging stations precede the electrical ones operating on the eddy current principle, in order to prevent neutralization of error signals generated by the electrical gauging stations. In this manner a very high accuracy of the entire sorting device is achieved.

Growing community of inventors

Waldenbuch, Germany

Michael Habele