An angle grinder includes a motor including a rotor and windings, a power supply for supplying power to the motor, a main switch for turning on/off an electrical connection between the windings of the motor and the power supply, an output shaft driven by the rotor to rotate, a rotor brake circuit for slowing down the rotor of the motor when the windings are short circuited or reverse connected, an output shaft brake circuit for producing a magnetic field to slow down the output shaft and a controller for detecting whether the rotor brake circuit short circuits or reverse connects with the windings. When the windings are short circuited or reverse connected for a time which reaches a preset value, the output shaft brake circuit produces the magnetic field to slow down the output shaft.

An output member is configured to transfer rotation and torque from a motor of a power tool to a working element of the power tool. The working element is configured to contact a workpiece. The output member includes a hub, an outer shell, and an isolator. The hub is configured to be driven rotationally about an axis of rotation by the motor of the power tool. The outer shell is configured to be coupled to the working element of the power tool. The isolator is interposed between the hub and the outer shell and is configured to electrically isolate the hub from the outer shell.

A machine tool includes a rotary table to which a workpiece is mounted, a brake, a displays, a memory configured to store a table in which values of a first coefficient correspond to different sizes of a disturbance torque, and values of a second coefficient correspond to different sizes of inertia of the workpiece. The controller is configured to calculate a size of the disturbance torque, find a first coefficient corresponding to the calculated size of the disturbance torque and the table, find a second coefficient corresponding to the size of the inertia of the workpiece and the table, accumulate the found values of the first and second coefficients, and cause the display to generate an indicator of necessity of a replacement of the brake in response to that the accumulated values of the first and second coefficients reaches a predetermined value.

The control method for a hammer drill (1) provides the following steps. During basic operation, the motor (5) rotates at an operating speed for the drilling operation with chiseling action in order to rotationally drive the tool holder (2) and to drive the hammer mechanism (6) with a nominal striking power. The torque coupling (21) is monitored with the aid of a sensor (26). If a disengagement of the torque coupling (21) occurs, the striking power of the hammer mechanism (6) is reduced to below 10% of the nominal striking power during a disengagement of the torque coupling (21), and the torque coupling (21) is driven. When the disengagement of the torque coupling (21) ends, the striking power of the hammer mechanism (6) is increased to the nominal striking power and the torque coupling (21) is driven at the operating speed for the drilling operation with chiseling action.

An emergency stop system for suppressing the possibility that an emergency stop state of a machine is released due to the shock of the falling of an emergency stop switch that stops an operation of the machine in an emergency is provided. The emergency stop system includes: a fall detection unit that detects falling of an emergency stop switch on the basis of a detection value obtained by an acceleration sensor; a shock detection unit that detects shock after the falling of the emergency stop switch on the basis of the detection value of the acceleration sensor; a switch state detection unit that detects an ON-OFF state of the emergency stop switch; and a signal output unit that outputs an emergency stop signal to the machine regardless of the ON-OFF state of the emergency stop switch when the switch state detection unit has detected switching of the ON-OFF state of the emergency stop switch within a predetermined period after the fall detection unit detected the falling and the shock detection unit detected the shock.

A protective apparatus and a machine tool are provided. The machine tool includes an operational element, a driving element, and the protective apparatus. The operational element and the driving element are disposed on machine table. The protective apparatus includes an insulating unit, conducting unit, capacitance sensor, and control unit. The insulating unit is disposed between the operational element and the driving element. The driving element drives the operational element by the insulating unit. The conducting unit contacts the operational element. The capacitance sensor electrically connects the conducting unit for sensing capacitance of the conducting unit. The control unit electrically connects the capacitance sensor and the driving element and determines whether a user approaches the operational element based on the capacitance. When the control unit detects that the distance between the user and the operational element is too close, the control unit stops the operation of the operational element.

A high-precision, low false alarm rate detection apparatus, system, and method for rapid reaction to sudden kinetic impulses caused by abnormal motion, such as kickback, of a power tool. The apparatus, system and method includes local measurement of sensing modalities with local real-time processing and advanced digital signal processing to measure the total kinematic motion of any power tool. A machine learning model pre-trained for the power tool to predict an occurrence of an abnormal motion such as a kickback event of the power tool, the machine learning model using data received from sensing modalities to predict an occurrence of the kickback event, and a reactive device of the power tool is activated upon prediction of the kickback event.

An electric working machine comprises a motor, a switch, a drive device, a brake device, and a failure determiner. The switch is configured for operation by a user, has an on-state and an off-state. The drive device is configured to drive the motor in response to the switch being placed in the on-state. The brake device is configured to control deceleration of the motor to a stopped state in response to the switch being placed in the off-state. The failure determiner is configured to monitor deceleration of the motor during controlled deceleration and to determine whether the brake device has failed based on the monitored deceleration.

A machining system comprises: a machining device that machines a workpiece; a set-up station with which pallet workpiece attachment/detachment is carried out; and a pallet conveyance device that conveys the pallet between the machining device and the set-up station. A partially cylindrical operator door, which can rotate around a set-up table on which the pallet is mounted, includes a partially cylindrical outer door and a partially cylindrical inner door which rotate following coaxial circular trajectories of different radii. The set-up station is provided with an interlocking mechanism that causes the outer door and the inner door to rotate in an interlocked manner so that a shielded state is constantly maintained between the operator side and the pallet conveyance device side.

The disclosure is based on a sensor device, in particular a hand-held power-tool sensor device, for identifying an uncontrolled occurrence of jamming in the case of a hand-held power tool, having at least one sensor unit, which is provided to sense at least one motion characteristic value of the hand-held power tool, and having a protective unit, which is provided to control the hand-held power tool in dependence on at least one triggering threshold value and the at least one motion characteristic value. It is proposed that the protective unit be provided to set the at least one triggering threshold value in a variable manner and/or to define at least one further triggering threshold value.