Position sensing related to a component within a power tool. The component within the power tool is, for example, a hammer of an impact mechanism and can include one or more sensible features that allow a controller of the power tool to precisely determine the position, speed, and acceleration of the component. One or more sensors can be used to determine the rotational position of the hammer and the axial position of the hammer. The rotational position of the hammer can then be used to calculate, for example, rotational speed and acceleration of the hammer. With precise determinations of the rotational and axial position of the hammer, the controller of the power tool is able to precisely time the impact between the hammer and the anvil to optimize the impact between the hammer and the anvil (e.g., to maximize energy transfer between the hammer and the anvil).

Position sensing related to a component within a power tool. The component within the power tool is, for example, a hammer of an impact mechanism and can include one or more sensible features that allow a controller of the power tool to precisely determine the position, speed, and acceleration of the component. One or more sensors can be used to determine the rotational position of the hammer and the axial position of the hammer. The rotational position of the hammer can then be used to calculate, for example, rotational speed and acceleration of the hammer. With precise determinations of the rotational and axial position of the hammer, the controller of the power tool is able to precisely time the impact between the hammer and the anvil to optimize the impact between the hammer and the anvil (e.g., to maximize energy transfer between the hammer and the anvil).

A control unit for a brushless DC motor of a power tool having a rotor and a stator is provided. The control unit detects an initial position of the rotor, commutates the motor beginning at the initial position of the rotor using a low-speed motor commutation scheme until an output speed of the rotor exceeds a speed threshold, and commutates the motor based on a back-electromotive force (back-EMF) voltage of the motor after the output speed of the rotor exceeds the speed threshold. In the low-speed commutation scheme, the control unit applies a first set of voltage pulses to a present sector and a second set of voltage pulses to a next sector, and detects a transition of the rotor from the present sector to the next sector based on motor current measurements associated with the first set of voltage pulses and the second set of voltage pulses.

Rail hammer assemblies suitable for advancing driving a member into or toward or pulling a member from or away from a workpiece, respectively may include an impact mechanism. The impact mechanism may include an elongated slide rail. A first rail impact plate may be carried by the slide rail. A second rail impact plate may be carried by the slide rail in spaced-apart relationship to the first rail impact plate. At least a first permanent magnet may be carried by the slide rail outside the first rail impact plate. At least a second permanent magnet may be carried by the slide rail outside the second rail impact plate. An impact hammer may be slidably carried by the slide rail between the first rail impact plate and the second rail impact plate. The impact hammer may include at least one electromagnet. A control system may include at least one power source. A first button may interface with the at least one power source and the electromagnet to facilitate travel of the impact hammer in a first direction on the slide rail. A second button may interface with the at least one power source and the electromagnet to facilitate travel of the impact hammer in a second direction on the slide rail. Rail hammer methods are also disclosed.

An impact mechanism for an impact tool that includes a housing, a piston slidably disposed in the housing and adapted to transfer impact force to a tool bit, and electromagnetic coils disposed between the piston and the housing. The electromagnetic coils are alternately activated to generate respective magnetic fields to cause the piston to move within the housing.

A power tool includes a motor having a rotatable motor shaft, a first intermediate shaft, and a second intermediate shaft extending in parallel to the first intermediate shaft. An output shaft removably holds a tool accessory and has a driving axis. A motion-converting mechanism converts rotation of the first intermediate shaft only into linear reciprocating motion and thereby hammers the tool accessory along the driving axis. A rotation-transmitting mechanism transmits rotation of the second intermediate shaft to the output shaft and thereby only rotationally drives the output shaft around the driving axis.

A power tool, such as a rotary hammer, includes a housing, an output shaft for mounting a tool accessary and a motor having a motor shaft that generates a rotational output for rotating and linearly hammering the output shaft. The rotational output of the motor shaft is coupled to the output shaft via a driving mechanism that includes a hammer mechanism. An intervening member is axially movable relative to the motor shaft and is operably coupled between the motor shaft and the hammer mechanism. The hammer mechanism and the output shaft are supported by a movable support that is axially movable relative to the housing. Because the output shaft and the driving mechanism are movable relative to the motor and the housing, which preferably includes handle, via the intervening member and the movable support during hammering operations, vibration generated during hammering operations can be dampened before reaching the housing.

A control unit for a brushless DC motor of a power tool having a rotor and a stator is provided. The control unit detects an initial position of the rotor, commutates the motor beginning at the initial position of the rotor using a low-speed motor commutation scheme until an output speed of the rotor exceeds a speed threshold, and commutates the motor based on a back-electromotive force (back-EMF) voltage of the motor after the output speed of the rotor exceeds the speed threshold. In the low-speed commutation scheme, the control unit applies a first set of voltage pulses to a present sector and a second set of voltage pulses to a next sector, and detects a transition of the rotor from the present sector to the next sector based on motor current measurements associated with the first set of voltage pulses and the second set of voltage pulses.

A hand-held power tool, in particular a hammer drill or combination hammer, having a tool fitting for holding a striking and rotating tool on a working axis, an electric motor coupled to a transmission shaft, an impact mechanism, which has a striker that is moved periodically along the working axis, and having a rotary drive, which drives a guide tube carrying the tool fitting in rotation about the working axis, wherein the rotary drive is coupled to the transmission shaft via a rocker lever.

An impact tool includes a housing that includes a motor housing portion, a front housing portion coupled to the motor housing portion, and a D-shaped handle portion extending from the motor housing portion in a direction opposite the front housing portion. The impact tool includes an electric motor supported in the motor housing portion, a battery pack supported by the housing for providing power to the motor, and a drive assembly for converting a continuous torque input from the motor to consecutive rotational impacts upon a workpiece capable of developing at least 1,700 ft-lbs of fastening torque.