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.

Power tools described herein include a housing, a brushless direct current (DC) motor, a non-conductive terminal mount, and a plurality of terminals. The housing has a motor housing portion, a handle portion, and a battery pack interface. The brushless DC motor is located within the motor housing portion and has a rotor and a stator. The non-conductive terminal mount is located on an outer peripheral surface of the stator and includes an angled surface. The angled surface is not substantially parallel to a longitudinal axis of the motor. The plurality of terminals is mounted on the angled surface of the terminal mount. Each of the terminals is angled in a first direction such that the terminals are not substantially parallel to the longitudinal axis of the motor.

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 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 power tool is provided including a brushless motor having a stator defining a plurality of phases and a rotor. A power unit is provided including power switches and a control unit outputs a drive signal to the motor switches to drive the phases of the motor using a trapezoidal control scheme over a series of sectors. The control unit sets a conduction band within which each phase is commutated to a baseline value that is greater than 120 degrees, sets at least one commutation transition point as a function of the set conduction band, and within each sector, monitors an open-phase voltage of the motor to detect a back electromotive force (back-EMF) voltage of the motor and control commutation of at least one phase based on the open-phase voltage of the motor in relation to the at least one commutation transition point.

A linear electric machine includes a mover and a stator. The mover includes permanent magnets, and the stator includes a ferromagnetic core-structure and windings for conducting electric currents. The linear electric machine includes support structures on both sides of the ferromagnetic core-structure and supporting the mover to be linearly movable with respect to the stator in the longitudinal direction of the linear electric machine. At least one of the support structures includes a support element arranged to keep the mover a distance away from solid metal constituting a frame-portion of the support structure. The support element includes material whose electrical conductivity is less than that of the solid metal. As the mover is kept the distance away from the solid metal, eddy currents induced by the moving permanent magnets to the solid metal are reduced.

A power tool is provided including a brushless motor having a stator defining a plurality of phases and a rotor. A power unit is provided including power switches operable to deliver power to the motor. A primary controller is interfaced with the power unit to output drive signals to drive the phases of the motor over a series of sectors of the rotor rotation. The primary controller measures a back-electromotive force voltage of the motor and transitions motor commutation from the present sector to the next sector based in relation to the back-EMF voltage. A second controller is provided to receive at least one of the drive signals, calculate a speed and/or direction of rotation of the motor from the drive signals, and take corrective action to cut off supply of power to the motor if it detects an overspeed condition or incorrect direction of rotation.

A hand-held power tool includes a tool holder, a motor for rotational and/or percussive driving of the tool holder, and a magnetic field sensor disposed in a vicinity of the motor, where a magnetic field of the motor that is created by driving the tool holder by the motor is detectable by the magnetic field sensor. The hand-held power tool further includes a control device where the control device determines a load state of the motor in dependence on a detected magnetic field of the motor and differentiates between an idle mode of the hand-held power tool and a load mode of the hand-held power tool based on the determined load state of the motor.

A percussion tool comprises a housing, an electric motor positioned within the housing, a percussion mechanism driven by the motor and including a striker supported for reciprocation in the housing along a first axis, and a pair of handles coupled to the housing. The handles define a second axis. The percussion tool further comprises a battery pack removably coupled to the housing for providing power to the motor when coupled to the housing. The first and second axes are contained within first and second planes, respectively, that are parallel to each other.