A rotary tool or machine includes: an output shaft; a motor that rotates the output shaft; an operation part for commanding driving/stopping of the motor; and a control unit that controls the driving/stopping of the motor in accordance with commands from the operation part. The control unit is configured to generate a braking force in the motor or on the output shaft when the motor is to be stopped in proportion to a tightening force (torque) applied to the tool accessory when the motor is started up, such that the greater the tightening force (torque), the greater the braking force.

An electric work machine (1) includes a motor (1), a manipulatable part (9), a control part (20) configured to perform a first braking control and a second braking control that differ from each other, and a kickback-detection part (20, S30) that detects whether kickback has occurred. The control part energizes the motor in response to detection of user-manipulation of the manipulatable part. In response to detection of kickback, the control part performs the first braking control and thereby causes the motor to generate a first braking force. In response to detection of a state change of the manipulatable part to an unmanipulated or OFF state, the control part performs the second braking control and thereby causes the motor to generate a second braking force, which is weaker than the first braking force.

An electric work machine (1) includes a motor (1), a manipulatable part (9), a control part (20) configured to perform a first braking control and a second braking control that differ from each other, and a kickback-detection part (20, S30) that detects whether kickback has occurred. The control part energizes the motor in response to detection of user-manipulation of the manipulatable part. In response to detection of kickback, the control part performs the first braking control and thereby causes the motor to generate a first braking force. In response to detection of a state change of the manipulatable part to an unmanipulated or OFF state, the control part performs the second braking control and thereby causes the motor to generate a second braking force, which is weaker than the first braking force.

A power tool that includes a housing, a motor, an end effector, an electrostatic clutch assembly, and a control circuit is provided. In a first mode of operation, the control circuit causes a first voltage to be applied to a first electrode and a different second voltage to be applied to a second electrode, generating a first attractive force between the first and second electrodes, which causes an output member to rotate together with an input member when a torque on the output member is less than or equal to a first threshold value and which causes the output member to rotationally slip relative to the input member when the torque on the output member exceeds the first threshold value, interrupting torque transmission from the input member to the output member.

A sawing apparatus can have a drive shaft that is rotatable about a central axis for rotationally driving a saw blade. The apparatus includes an electrical rotary feedthrough for the electrically conductive connection of the drive shaft to a connection assembly. The electrical rotary feedthrough includes a first component having a contact section that tapers in the direction of a second component and the shell surface of said contact section forms a first contact surface. The second component has a receiving channel that extends along the central axis and the side surface of the receiving channel forms a second contact surface. The first contact surface lies against the second contact surface in sections. The receiving channel and the tapering contact section has a clearance for ruling out a purely axial abutment of the components. In addition, an electrical rotary feedthrough for a sawing apparatus, is described.

A sawing apparatus can have a drive shaft that is rotatable about a central axis for rotationally driving a saw blade. The apparatus includes an electrical rotary feedthrough for the electrically conductive connection of the drive shaft to a connection assembly. The electrical rotary feedthrough includes a first component having a contact section that tapers in the direction of a second component and the shell surface of said contact section forms a first contact surface. The second component has a receiving channel that extends along the central axis and the side surface of the receiving channel forms a second contact surface. The first contact surface lies against the second contact surface in sections. The receiving channel and the tapering contact section has a clearance for ruling out a purely axial abutment of the components. In addition, an electrical rotary feedthrough for a sawing apparatus, is described.

Systems and methods for braking a power tool using a stamped brake resistor. The power tool includes a motor, a trigger configured to be actuated, and a brake switch coupled to the motor. A brake resistor assembly is selectively coupled to the motor via the brake switch and includes a stamped brake resistor. The stamped brake resistor includes a terminal portion and a resistive portion. The resistive portion includes a planar serpentine path. A controller including an electronic processor and a memory is coupled to the trigger, the motor, and the brake switch, and is configured to control power delivered to the motor based on a position of the trigger, determine to brake the motor during operation of the motor, and activate, in response to determining to brake the motor, the brake switch to connect the stamped brake resistor to the motor.

Systems and methods for braking a power tool using a stamped brake resistor. The power tool includes a motor, a trigger configured to be actuated, and a brake switch coupled to the motor. A brake resistor assembly is selectively coupled to the motor via the brake switch and includes a stamped brake resistor. The stamped brake resistor includes a terminal portion and a resistive portion. The resistive portion includes a planar serpentine path. A controller including an electronic processor and a memory is coupled to the trigger, the motor, and the brake switch, and is configured to control power delivered to the motor based on a position of the trigger, determine to brake the motor during operation of the motor, and activate, in response to determining to brake the motor, the brake switch to connect the stamped brake resistor to the motor.

A work apparatus has a drive motor and a work tool driven in a rotating manner by the drive motor. The work tool is at least partially covered by a protective hood which is mounted pivotably about the rotational axis of the work tool. A control unit is provided for controlling at least one component of the work apparatus. The work apparatus has a detection unit for detecting at least one position of the protective hood. The control unit is configured for controlling the at least one component of the work apparatus depending on the detected position of the protective hood. In a method for operating a work apparatus, the detection unit detects at least one position of the protective hood and supplies the information to the control unit. The control unit activates the at least one component depending on the detected position of the protective hood.

A work apparatus has a drive motor and a work tool driven in a rotating manner by the drive motor. The work tool is at least partially covered by a protective hood which is mounted pivotably about the rotational axis of the work tool. A control unit is provided for controlling at least one component of the work apparatus. The work apparatus has a detection unit for detecting at least one position of the protective hood. The control unit is configured for controlling the at least one component of the work apparatus depending on the detected position of the protective hood. In a method for operating a work apparatus, the detection unit detects at least one position of the protective hood and supplies the information to the control unit. The control unit activates the at least one component depending on the detected position of the protective hood.