Patent ID: 7494437

Claim:
An impact power tool comprising: a motor having a drive gear shaft; a first planetary gear set including a first planet carrier, and a plurality of first planet gears pivotally connected with the first planet carrier and engaged with the drive gear shaft; a second planetary gear set including a second planet carrier having an internal gear, a plurality of second planet gears pivotally connected with the second planet carrier, and a clutch having a sun gear; wherein the second planet gears engage with the sun gear, and the clutch connects with the first planet carrier; a transmission shaft comprising a round shaft at one end, a polygonal shaft at the other end, and a small gear disposed between the round shaft and the polygonal shaft; wherein the round shaft passes through a central hole of the sun gear of the clutch; an intermediate shaft having an axial polygonal hole; wherein the polygonal shaft of the transmission shaft is fitted into the polygonal hole of the intermediate shaft; an impact seat including a plurality of hammer blocks on an end surface; wherein the intermediate shaft is fitted into and drives the impact seat to rotate; and an output shaft comprising a polygonal hole at one end corresponding to the polygonal shaft of the transmission shaft, and a plurality of projections to be struck by the hammer blocks.