US Patent 10471573 Impact tool

An impact tool includes a housing, a motor supported in the housing, and a drive assembly for converting a continuous torque input from the motor to consecutive rotational impacts upon a workpiece. The drive assembly includes an anvil, a hammer that is both rotationally and axially movable relative to the anvil, and a spring for biasing the hammer in an axial direction toward the anvil. The spring is rotationally unitized to the hammer for co-rotation therewith at all times during operation of the impact tool.