A percussion tool is used for performing a chiseling operation on a workpiece with a chisel. The percussion tool comprises a housing including a cylinder portion, a tool holder coupled to the cylinder portion for holding the chisel, and a percussion mechanism including a striker supported for reciprocation in the cylinder portion. The percussion mechanism is configured to impart repeated axial impacts to the chisel with the striker. The percussion tool further comprises a flange between the cylinder portion and the tool holder. Movement of the chisel within the tool holder toward the percussion mechanism is stopped by the flange.

An impact tool includes a motor, a driving mechanism, a tool body, an elastically-connected part elastically connected to the tool body to be movable at least in a front-rear direction relative to the tool body, a detecting mechanism configured to detect pressing of a tool accessory against a workpiece, and a control part configured to control driving of the motor based on a detection result of the detecting mechanism. The detecting mechanism includes a movable member that is provided in one of the tool body and the elastically-connected part and configured to be moved by relative movement of the other of the tool body and the elastically-connected part in the front-rear direction, and a detector that is provided in the one of the tool body and the elastically-connected part and configured to detect rearward pressing of the tool accessory by detecting movement of the movable member.

An impact tool includes a motor, a driving mechanism, a tool body, an elastically-connected part elastically connected to the tool body to be movable at least in a front-rear direction relative to the tool body, a detecting mechanism configured to detect pressing of a tool accessory against a workpiece, and a control part configured to control driving of the motor based on a detection result of the detecting mechanism. The detecting mechanism includes a movable member that is provided in one of the tool body and the elastically-connected part and configured to be moved by relative movement of the other of the tool body and the elastically-connected part in the front-rear direction, and a detector that is provided in the one of the tool body and the elastically-connected part and configured to detect rearward pressing of the tool accessory by detecting movement of the movable member.

Vibrations resulting from a reciprocating piston and vibrations resulting from a rotating crank shaft are reduced effectively. A housing for a hammer drill accommodates, at a position at which a cap closes a supply port, a counterweight movable in cooperation with a crank mechanism to reduce vibrations in a striking axis direction resulting from a reciprocating piston, and a second counterweight rotatable in cooperation with the crank mechanism to reduce vibrations in a rotational direction resulting from a crank shaft.

A rotor has reduced weight. A hammer drill includes a motor including a stator and a rotor rotatable relative to the stator. The rotor includes a rotor core having a first space, and a permanent magnet fixed on the rotor core.

A rotor has reduced weight. A hammer drill includes a motor including a stator and a rotor rotatable relative to the stator. The rotor includes a rotor core having a first space, and a permanent magnet fixed on the rotor core.

An electric power tool includes a drive device for providing a driving force, a rotation wheel that has a central axis and is driven by the drive device to rotate around the central axis, a spindle that supports a tool holder configured to hold a tool of the electric power tool, a first intermediate member, a second intermediate member, and a counterweight device. The first intermediate member is offset from the central axis of the rotation wheel, and revolves around the central axis when driven by the rotating rotation wheel, while driving the spindle to reciprocate in a first direction. The second intermediate member is driven by the first intermediate member to rotate around the central axis and is disposed to be offset from the central axis of the rotation wheel on the side opposite the first intermediate member. The counterweight device is driven by the second intermediate member.

An electric power tool includes a drive device for providing a driving force, a rotation wheel that has a central axis and is driven by the drive device to rotate around the central axis, a spindle that supports a tool holder configured to hold a tool of the electric power tool, a first intermediate member, a second intermediate member, and a counterweight device. The first intermediate member is offset from the central axis of the rotation wheel, and revolves around the central axis when driven by the rotating rotation wheel, while driving the spindle to reciprocate in a first direction. The second intermediate member is driven by the first intermediate member to rotate around the central axis and is disposed to be offset from the central axis of the rotation wheel on the side opposite the first intermediate member. The counterweight device is driven by the second intermediate member.

A method for reducing vibrations in a percussion tool includes activating, using an electronic controller of the percussion tool, the motor of the percussion tool, determining, using the electronic controller, that the percussion tool is in a loaded condition, and operating, using the electronic controller, the motor in accordance with a predetermined profile in response to determining that the percussion tool is in the loaded condition. The method also includes determining, using the electronic controller, that the percussion tool is in a no-load condition and operating, using the electronic controller, the motor with reduced speed in response to determining that the percussion tool is in the no-load condition.

A percussion mechanism contains a guide tube, an exciter piston, a hammer, a pneumatic chamber for coupling the hammer to the motion of the exciter piston, a striker, and a seat for the striker. The hammer has a striking point, defined by a striking surface of the striker when the striker lies against the seat. A check valve has an outlet opening and a closing mechanism for closing the check valve against an air flow from the interior of the guide tube. The outlet opening is arranged in such a way that the outlet opening is closed by the hammer during striking operation and otherwise is open.