An impact device is adapted to be mounted to an electric nail gun that includes a flywheel, and includes a swing arm unit, a track unit and an impact unit. The swing arm unit is adapted to be pivoted toward or away from the flywheel. The track unit includes a guiding track movably connected to the swing arm unit. The impact unit is connected to the guiding track, and is movable relative to the guiding track in a striking direction and a return direction that are opposite to each other. The guiding track is movable resiliently relative to the swing arm unit between a front position, where the impact unit is adapted to contact the flywheel, and a rear position, where the impact unit is adapted to be spaced apart from the flywheel.

A power tool is provided including a brushless motor having a stator defining a plurality of phases, a rotor rotatable relative to the stator, and power terminals electrically connected to the phases of the motor. A power unit is provided including power switches. A control unit is interfaced with the power unit to output a drive signal to one or more of the motor switches to drive the phases of the motor over a series of sectors of the rotor rotation. The control unit is configured detect incorrect rotation of the rotor by applying a first series of voltage pulses to a present sector and a second series of voltage pulses to a previous sector, measuring motor currents associated with the first and second series of voltage pulses, and comparing corresponding motor current measurements to detect a transition from the present sector to the previous sector.

A rotary-to-linear lifter for fastener driving tools is provided that has independently movable lifter pins that lift a driver with driver protrusions during a lift stroke. The lifter includes a central lifter shaft that rotates during a lift stroke, a solenoid that actuates, a plurality of lifter pins, and a lifter base. When the solenoid actuates, the lifter pins protrude from the top of the lifter base, and when not actuated, the lifter pins retract inside the lifter base. Each lifter pin has a set of forward and rearward springs that allow for longitudinal pin movements along the lifter's axis of rotation. If there is interference during a lift stroke, individual lifter pin(s) become blocked, and mostly remain inside the lifter base, until the lifter rotates the affected pin away from the interference. Then that lifter pin will again protrude from the lifter base, ready to engage the driver protrusions.

A rotary-to-linear lifter for fastener driving tools is provided that has independently movable lifter pins that lift a driver with driver protrusions during a lift stroke. The lifter includes a central lifter shaft that rotates during a lift stroke, a solenoid that actuates, a plurality of lifter pins, and a lifter base. When the solenoid actuates, the lifter pins protrude from the top of the lifter base, and when not actuated, the lifter pins retract inside the lifter base. Each lifter pin has a set of forward and rearward springs that allow for longitudinal pin movements along the lifter's axis of rotation. If there is interference during a lift stroke, individual lifter pin(s) become blocked, and mostly remain inside the lifter base, until the lifter rotates the affected pin away from the interference. Then that lifter pin will again protrude from the lifter base, ready to engage the driver protrusions.

A hammer drill having an impact mechanism and a rotary drive, wherein the hammer drill is designed to rotate a tool at a speed n about a longitudinal axis of the tool and to drive it with an output impact power PS along the longitudinal axis with a striking movement is disclosed. At a working point, at least one condition is met: 1. The ratio of the output impact power PS to the speed n is at least 3.5 W/rpm; 2. Depending on the output impact power PS, the speed n is at most (PSAN−300)2/2000+150) rpm; 3. In the event of an infinitesimal change in the output impact power PS, the speed n changes by at most 0.1 rpm/W.

A hammer drill having an impact mechanism and a rotary drive, wherein the hammer drill is designed to rotate a tool at a speed n about a longitudinal axis of the tool and to drive it with an output impact power PS along the longitudinal axis with a striking movement is disclosed. At a working point, at least one condition is met: 1. The ratio of the output impact power PS to the speed n is at least 3.5 W/rpm; 2. Depending on the output impact power PS, the speed n is at most (PSAN−300)2/2000+150) rpm; 3. In the event of an infinitesimal change in the output impact power PS, the speed n changes by at most 0.1 rpm/W.

To prevent, for example, a tube in a case from blocking an oil port, an oil unit includes a case that contains oil, a blade inside the case, an output shaft holding the blade and protruding from the case, at least one oil port formed on the case, a hollow tube adjacent to an inner surface in which the at least one oil port is open in the case, and a flow channel definer positioning the tube adjacent to an opening of the at least one oil port in the inner surface at a predetermined position and defining a flow channel of oil to flow into the case through the opening.

A hand-held power tool includes a tool fitting, an impact mechanism, and a rotary drive. The hand-held power tool is configured to rotate a tool held in the tool fitting with a rotational speed about a longitudinal axis of the tool and to drive the tool with an impact movement along the longitudinal axis at an impact frequency f. A ratio of the rotational speed to the impact frequency f at least at a working point of the hand-held power tool is at most 5.0 rpm/Hz or at least at the working point of the hand-held power tool the rotational speed is at most (0.2*(f/Hz-22){circumflex over ( )}2+80) rpm for impact frequencies f in a range from 20 to 60 Hz.

A hand-held power tool includes a tool fitting, an impact mechanism, and a rotary drive. The hand-held power tool is configured to rotate a tool held in the tool fitting with a rotational speed about a longitudinal axis of the tool and to drive the tool with an impact movement along the longitudinal axis at an impact frequency f. A ratio of the rotational speed to the impact frequency f at least at a working point of the hand-held power tool is at most 5.0 rpm/Hz or at least at the working point of the hand-held power tool the rotational speed is at most (0.2*(f/Hz-22){circumflex over ( )}2+80) rpm for impact frequencies f in a range from 20 to 60 Hz.

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.