Patent ID: 8381831

Claim:
A rotary impact tool comprising: a motor for producing rotational power; an output shaft for receiving the rotational power; an impact mechanism including a hammer and an anvil; a changeover unit for changing over an impact mode in which the impact mechanism is operated and a drill driver mode in which the rotational power produced by the motor is transferred to the output shaft without operating the impact mechanism; and a multi-stage speed reduction mechanism for transferring the rotational power produced by the motor to the output shaft at variable speeds in at least three speed modes including a low speed mode, a middle speed mode and a high speed mode, wherein the multi-stage speed reduction mechanism includes at least two planetary speed changer units shiftable between a reduction state and a non-reduction state and at least one speed reducer unit operable in a reduction state at all times, at least one of the three speed modes being used as the impact mode, at least two of the three speed modes being used as the drill driver mode, each of the three speed modes being established through a speed reduction operation of at least two stages in which the speed reducer unit and at least one of the speed changer units are kept in the reduction state such that the impact mode is established through a speed reduction operation of at least two stages.