Electric motor impact tool

摘要

An electric impact tool (210) in which a rotating mass rotates in a forward direction (201) to impact upon and transfer torque to an anvil (135), and rotates in a reverse direction opposite the forward direction (202) in response to such impact. A direction sensor (355,360) monitors the direction of rotation of the rotating mass, and a controller (370) turns an electric motor (255) on and off during respective forward and reverse rotation of the rotating mass. An energy storing mechanism (275,280) may be used to absorb energy from reverse rotation of the rotating mass and release the absorbed energy to rotate the rotating mass in the forward direction. A controller (370) may be used to store the angular position of the rotating mass upon each impact and turn off the motor (255) prior to the following impact to avoid energizing the motor during stall.