Provided is a power tool whereby reduction is made for time-consuming effort and cost required in trouble, inspection and so forth related to a motor. A hammer drill, which is an example of a power tool, includes a plurality of coils, an insulator holding the plurality of coils, a terminal unit that is electrically connected to the plurality of coils and is attached to the insulator, a rotor that is rotatable with respect to the insulator, and a sensor board that detects rotation of the rotor and is attached to the terminal unit. The sensor board is detachable from the terminal unit, while the terminal unit is attached to the insulator.

A protective device at least for protecting a user in the event of an uncontrolled blockage of a portable power tool includes at least one rotationally drivable shaft and at least one wrap-spring-free overload clutch unit which is arranged on the shaft and is configured at least to interrupt transmission of a drive force if a torque limit is exceeded. The protective device further including at least one wrap-spring clutch unit configured to brake the shaft.

A handheld power tool includes a tool holder for holding a tool, an electric motor, a shaft connecting the tool holder and the electric motor, and a protective device for stopping the tool holder in an uncontrolled situation. The protective device includes a sensor for detecting the uncontrolled situation, a switchable current source and a normally closing magnetic brake. The switchable current source outputs a first current not equal to zero in response to signals of the sensor if an uncontrolled situation is not detected; the current source does not output a current or outputs a second current different from the first current if an uncontrolled situation is detected. The normally closing magnetic brake engages on the shaft and does not apply a torque to the shaft when energized by the first current. The normally closing magnetic brake applies a torque counteracting the rotational movement of the shaft when not energized or when energized by the second current.

A machine tool is disclosed. A magneto-pneumatic striking mechanism has a primary actuator arranged around an axis of movement and includes a first magnetic coil and a second magnetic coil. The striking mechanism has, on the axis of movement within the magnetic coils, a striker and a die. Furthermore, the striking mechanism has an air spring acting on the striker in a direction of impact. The air spring may be entirely or partially within the first magnetic coil. The air spring has a ventilation opening that is open to the environment if the striker is less than 10% of its stroke away from the die, and otherwise the ventilation opening is closed. An exchange of air with the environment is therefore only possible when the striker is near the die or is near the impact position.

There is disclosed an orthopaedic impactor, comprising: a strike assembly arranged to impart a force to an object; and a winding arranged to receive a current and thereby generate a magnetic field. The winding is arranged to interact with the strike assembly so that, in use, a magnetic field generated by the winding causes the strike assembly to move so as to impart the force to the object.

There is disclosed an orthopaedic impactor, comprising: a strike assembly arranged to impart a force to an object; and a winding arranged to receive a current and thereby generate a magnetic field. The winding is arranged to interact with the strike assembly so that, in use, a magnetic field generated by the winding causes the strike assembly to move so as to impart the force to the object.

There is disclosed an orthopaedic impactor, comprising: a strike assembly arranged to impart a force to an object; and a winding arranged to receive a current and thereby generate a magnetic field. The winding is arranged to interact with the strike assembly so that, in use, a magnetic field generated by the winding causes the strike assembly to move so as to impart the force to the object.

A rotary hammer adapted to impart axial impacts to a tool bit. The rotary hammer includes a housing, a motor supported by the housing, a spindle coupled to the motor for receiving torque from the motor, causing the spindle to rotate, a reciprocation mechanism operable to create a variable pressure air spring within the spindle, an anvil received within the spindle for reciprocation in response to the pressure of the air spring, the anvil imparting axial impacts to the tool bit, a bit retention assembly for securing the tool bit to the spindle, and an electromagnetic clutch mechanism switchable between a first state, in which the reciprocation mechanism is enabled, such that the anvil imparts axial impacts to the tool bit, and a second state, in which the reciprocation mechanism is disabled, such that the anvil ceases to impart axial impacts to the tool bit.

A power tool (1) is provided, especially a hammer drill and/or a chiseling hammer drill, including a percussive mechanism (12) with a percussive element (13) to generate a percussive pulse onto a tool (1), the element being reversibly movable along a longitudinal axis (R) by a magnetic field in order to generate the percussive pulse, and including at least a first and a second coil device (1, 2) to generate the magnetic field. Each coil device (1, 2) has at least a first coil ring (3) with a first radius (R1) and a second coil ring (4) with a second radius (R2), whereby the first radius (R1) of the first coil ring (3) is greater than the second radius (R2) of the second coil ring (4), so that a space (S) is formed, at least in certain areas, between the at least first and second coil rings (3, 4), whereby a fluid (L), especially an air stream, that serves to cool the coil device (1, 2) can flow through the space.

Percussion unit, especially for a rotary hammer and/or percussion hammer, comprising a control unit which is designed for controlling a pneumatic percussion mechanism. According to the disclosure, the control unit comprises at least one load estimation device.