US Patent 9272400 Torque-limited impact tool

Illustrative embodiments of torque-limited impact tools are disclosed. An impact tool may include a shaft adapted to rotate about an axis, a hammer having a hammer jaw with an obtuse impact surface, and an anvil having an anvil jaw with an acute impact surface. The shaft may include a first helical groove, and the hammer may include a second helical groove. The impact tool may further include a ball received in the first and second helical grooves, wherein the ball rotationally couples the hammer to the shaft and permits axial travel of the hammer relative to the shaft. The obtuse impact surface of the hammer jaw may be adapted to impact the acute impact surface of the anvil jaw when the shaft rotates in a first direction.