Abstract: 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.

Abstract: A device on machine tools for transmitting a rotational and/or percussive movement to a tool (22) has two or three rotational drivers (14) which are arranged so as to be symmetrical with respect to rotation. The rotational drivers (14) are stepped and flank parts (16) extending radially to the center axis (15) alternate with guide portions (17) extending along a cylindrical outer surface. Locking members (20) which engage in depressions (28) at the tool (22) are arranged in the region of the rotational drivers (14) for the axial locking of the tools (10). With the tool holder (10) according to the invention, tool shafts having diameters between 8 and 12 mm can be clamped without converting or modifying the tool shafts. Good true running characteristics can be achieved in spite of the stationary rotational drivers (14).

Abstract: A compass saw has a lifting rod for receiving a saw blade which extends downwardly beyond a base plate and supported under the base plate in the region of a saw blade back. A supporting element is formed as a sword extending parallel and in alignment with the saw blade. The saw blade is secured from lateral deviation and bending in that the sword is turnable about an axis located above the base plate and extending substantially parallel to the base plate.

Abstract: The device for transferring torque to a tool member in a hand tool apparatus includes a plurality of catch grooves (23) and at least one elongated locking groove (25) spaced circumferentially from the catch grooves (23) provided in the tool shaft (11) of the tool member (12); a tool holder (10) having a tool receptacle (16) provided with a receptacle cavity (17) for the tool member (12) and having at least two axially extending catch elements (24) projecting inwardly into the receptacle cavity (17) so as to be engageable with the catch grooves (25) and at least one lock element (19) guided in a radial recess (18) provided in the tool receptacle (16) spaced circumferentially from the catch elements (24) so as to be radially movable outwardly against a spring force and engageable in the at least one locking groove (25) so as to limit axial motion of the tool member (12).

Abstract: A device on machine tools for transmitting a rotational and/or percussive movement to a tool (22) has two or three rotational drivers (14) which are arranged so as to be symmetrical with respect to rotation. The rotational drivers (14) are stepped and flank parts (16) extending radially to the center axis (15) alternate with guide portions (17) extending along a cylindrical outer surface. Locking members (20) which engage in depressions (28) at the tool (22) are arranged in the region of the rotational drivers (14) for the axial locking of the tools (10). With the tool holder (10) according to the invention, tool shafts having diameters between 8 and 12 mm can be clamped without converting or modifying the tool shafts. Good true running characteristics can be achieved in spite of the stationary rotational drivers (14).

Abstract: A control unit for a battery-operated device is proposed which via an existing control connection recognizes an overload of the battery and/or of the electric device. The control connection of a temperature-dependent resistor is used, which is thermally connected to the rechargeable battery. This connection, which is typically usable to control a charging unit, now serves during the battery operation of the electric device as a control output for monitoring the battery temperature. Since the temperature gradient is also detected, this signal can also be used to monitor the overload of the electric device, which for instance is an electric motor.