An impact rotary tool includes a hammer and an anvil that transmits rotational impact force from the hammer to a tip tool. The anvil includes a first member and a second member. The first member holds the tip tool thereon. The first member is fitted into the second member. The rotational impact force is applied to the second member. The first member and the second member are arranged to be fitted into each other in a fitting portion. The fitting portion has a tolerating mechanism. The tolerating mechanism tolerates misalignment of a first rotational axis with a second rotational axis. The first rotational axis is a rotational axis of the first member. The second rotational axis is a rotational axis of the second member.

A percussion mechanism device, in particular for an impact wrench, includes a drivable drive shaft that has at least one guide groove, an output shaft, and a percussion unit that includes an anvil coupled with the output shaft in a rotationally fixed manner, a hammer, and at least one ball. The hammer is supported via the at least one ball along the at least one guide groove on the drive shaft and includes an at least regionally concavely curved ball guidance area that has an axial clearance from the at least one ball at a radially innermost point that is greater than a radial clearance between the at least one ball and a radially innermost point of a concave ball guidance area of the at least one guide groove.

An impact tool and a hammer. The impact tool includes a housing, a motor supported within the housing, an anvil extending from the housing, and a drive assembly configured to convert a continuous rotational input from the motor to intermittent applications of torque to the anvil. The drive assembly includes a camshaft driven by the motor and a hammer configured to reciprocate along the camshaft. The hammer includes a core coupled to the camshaft and a sleeve coupled to the core.

A torque transmission mechanism transmits a torque produced by a rotation of a driving shaft to an output shaft. A clutch mechanism is provided between a motor and the torque transmission mechanism. The torque transmission mechanism includes a magnet coupling including a driving magnet member coupled to the driving shaft side and a driven magnet member coupled to the output shaft side. The driving magnet member and the driven magnet member are arranged such that magnetic surfaces on each of which S-pole magnets and N-pole magnets are alternately arranged face other. The clutch mechanism transmits the torque produced by the rotation of the driving shaft to the driving magnet member but does not transmit a torque the driving magnet member receives from the driven magnet member to the driving shaft.

An electric power tool in one aspect of the present disclosure includes a motor, an impact mechanism, and a control circuit. The control circuit executes a motor control process. The motor control process includes limiting an output of the motor in response to establishment of a preset condition. The preset condition is based on a load applied to the motor.

The drill includes a motor, a spindle rotatable with a rotational force transmitted from the motor, a clutch assembly that disables transmission of the rotational force to the spindle in response to a rotational load on the spindle reaching a release value and including an elastic member that adjusts the release value, and a change ring switchable from a clutch mode in which the clutch assembly is operable to a nonclutch mode in which the clutch assembly is inoperable in response to the change ring operated in a forward rotation direction. In the clutch mode, the elastic member elastically deforms to reduce the release value in response to the change ring operated in the forward rotation direction, and to increase the release value in response to the change ring operated in a backward rotation direction.

An anvil for an impact mechanism, where the anvil includes wings that taper at a taper angle of about 5 degrees to about 30 degrees. The anvil may also include a shaft extending from the wings, and a drive end adapted to transfer and apply torque to a work piece. The wings of the anvil also include wing impact surfaces that receive rotational impact forces from a hammer. For example, the hammer contacts and applies torque to the wings of the anvil.

An impact power tool includes a transmission output shaft, a rotary impact assembly with a cam shaft, hammer, and anvil, and a tool output shaft rotatable with the anvil. A coupler removably couples the cam shaft to the transmission output shaft. When torque on the tool output shaft is less than or equal to a first threshold, the transmission output shaft, cam shaft, hammer, and anvil rotate together to transmit torque to the tool output shaft. When torque on the tool output shaft is above the first threshold, the hammer moves along the cam shaft away from the anvil by a first distance and applies rotary impacts to the anvil. When the hammer moves along the cam shaft away from the anvil by a second distance greater than the first distance, the coupler decouples the transmission output shaft from the cam shaft, interrupting torque transmission to the tool output shaft.

A rotary impact tool includes a housing, an electric motor, and a drive assembly for converting a continuous torque input from the motor to consecutive rotational impacts upon a workpiece of at least 900 ft-lbs of fastening torque. An anvil has a bore defining a hexagonal cross-sectional shape and having a nominal width of 7/16 inches. A hammer is rotationally and axially movable relative to the anvil for imparting the consecutive rotational impacts upon the anvil. A spring biases the hammer in an axial direction toward the anvil. A battery pack has a nominal voltage of at least 18 Volts and a nominal capacity of at least 5 Ah. The rotary impact tool has an overall weight including the battery pack that is less than or equal to 7.5 pounds. A ratio of the fastening torque to the overall weight is greater than or equal to 120 ft-lbs per pound.

A method for controlling torque applied during a screw driving operation using a screw driving device. The device includes: an electric motor provided with a rotor; an output member capable of being rotated; and a rebounding impact mechanism rigidly connected to the rotor and to the output member. The method includes power supplying the motor inducing driving the impact mechanism by the rotor and periodically rotating the output member by the impact mechanism; driving the impact mechanism generating a plurality of successive impacts at the end of each of which the rotor rotates in a rebound in the opposite direction to the screw driving operation; determining a maximum rotational frequency reached by the rotor during the rebound following each of the impacts; and stopping the screw driving operation when the maximum rotational frequency reaches a predetermined threshold corresponding to a predetermined torque level.