So you've been hearing about the benefits of impact drivers, impact wrenches, drill drivers, with or without hammer mechanism, GSB 120-LI versus GSR 120-LI, but ever wondered how does an impact driver actually go about loosening or tightening a bolt or a nut?

In this video, the impact adaptor cutaway shows a basic cam-action hammer and anvil - which also forms the output shaft. By powering the input shaft (via the electric drill), the hammer is accelerated and impacts the anvil - sending all the stored energy in the accelerating hammer to the anvil.

In this cam-action hammer and anvil mechanism, the impact energy produces a rotational force which is then transferred through the output shaft as torque.