US Patent 11872680 Impact power tool

An impact power tool includes a transmission output shaft, a rotary impact assembly with a cam shaft, hammer, and anvil, and a tool output shaft rotatable with the anvil. A coupler removably couples the cam shaft to the transmission output shaft. When torque on the tool output shaft is less than or equal to a first threshold, the transmission output shaft, cam shaft, hammer, and anvil rotate together to transmit torque to the tool output shaft. When torque on the tool output shaft is above the first threshold, the hammer moves along the cam shaft away from the anvil by a first distance and applies rotary impacts to the anvil. When the hammer moves along the cam shaft away from the anvil by a second distance greater than the first distance, the coupler decouples the transmission output shaft from the cam shaft, interrupting torque transmission to the tool output shaft.