An impact power tool includes a housing, a motor, a controller, an output member configured to be rotated when the motor is energized, and an impact mechanism configured to rotationally drive the output member. The impact mechanism is configured to selectively apply rotational impacts to the output member when a torque on the output member exceeds a torque threshold. The controller is configured to control the motor during a first phase of operation with open loop control and a baseline conduction band and advance angle setting when a sensed tool operation parameter is one of above or below a threshold value. The controller is configured to control the motor during a second phase of operation with closed speed loop control and an increased conduction band and advance angle setting when the sensed tool operation parameter is the other of above or below the threshold value.

Torque produced in an oil unit is leveled irrespective of the temperature variation to maintain intended operation efficiency. An impact driver includes a brushless motor, and an oil unit rotatable by the brushless motor. The oil unit includes a case including a projection inside, a spindle protruding from the case, a coil spring held at the spindle in the case, and a blade held at the spindle in the case and urged outward in a radial direction of the case by the coil spring. The blade comes in contact with the projection in a rotation direction of the case.

An improved impact structure comprising a transmission shaft, an impact disc, a driving disc, an output shaft and an impact spring, wherein the driving disc is cylindrical, a lower surface of the driving disc is provided with two V-shaped first inclined surfaces arranged symmetrically. Two V-shaped second inclined surfaces matched with the first inclined surfaces are symmetrically arranged in the middle hole of the impact disc. An output end of the transmission shaft penetrates through the impact disc and is movably connected to the output shaft. One end of the output shaft and an upper end surface of the impact disc are circumferentially provided with a first and a second impact block. One end of the impact spring extends into the inner cavity of the impact disc. Through adopting the present disclosure, the transmission shaft without V-shaped grooves has a higher strength, and qualification rate is significantly improved.

Rotation of a spindle relative to a first cam is reduced. A power tool includes a spindle to receive a tip tool and rotatable about a rotation axis, and a vibration mechanism that vibrates the spindle in an axial direction. The spindle has an outer surface including, in a cross section orthogonal to the rotation axis, a first portion at a first distance from the rotation axis, and a second portion at a second distance from the rotation axis. The vibration mechanism includes a first cam surrounding the spindle, and a second cam located behind and in contact with the first cam.

An angled impact wrench includes a housing mounting a motor having an output shaft rotatable about a first axis, and an impact drive unit mounted in the housing for rotation about a second axis that is nonparallel to the first axis. The impact drive unit is configured to repeatedly cycle between an energy storing and energy release conditions in response to a drive torque supplied by the motor. The impact drive unit has a through passage extending along the second axis to allow a workpiece to extend completely through the impact wrench while the drive unit torques a threaded fastener onto the workpiece.

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.

A method for estimating a clamp force obtained at tightening of a screw joint via a torque pulse sequence includes applying a primary torque pulse to rotate the screw joint in a tightening direction, measuring a torque level obtained by the primary torque pulse, applying a secondary torque pulse to move the screw joint in a loosening direction, measuring a torque level obtained by the secondary torque pulse, and calculating a difference between the torque level obtained by the primary torque pulse and the torque level obtained by the secondary torque pulse. The obtained clamp force is estimated from the difference between the obtained torque levels.

An anvil for use with an impact wrench includes a first end, a second end opposite the first end, a shank adjacent the first end, and a head adjacent the second end. The shank includes a diameter and an outer cylindrical surface that defines a longitudinal axis that extends centrally through the anvil between the first end and the second end. The head includes a plurality of planar faces and an outer cylindrical surface. The outer cylindrical surface defines a diameter of the head. A ratio between the diameter of the shank and the diameter of the head is between approximately 1:1 and approximately 1.35:1.

A twin hammer impact tool includes a hammer spindle, an inner ring hammer sleeved on the hammer spindle, an outer ring hammer disposed around the inner ring hammer, and rolling beads. The inner ring hammer has bead grooves each having a ball half-shape, and angularly spaced-apart hammer projections. The inner ring hammer is reciprocally movable relative to the hammer spindle while rotating together with the hammer spindle. The outer ring hammer has guiding grooves. The bead grooves respectively face and open toward the guiding grooves. Each rolling bead is received within one of the bead grooves and one of the guiding grooves. An output hammer has angularly spaced engagement projections to engage the hammer projections.

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.