Patent ID: 9539708
Date: 2017-01-10
CPC Classifications: B25B,F16D

Claim:
1. A hand-held power tool comprising: a motor; a tool holder; and a percussion mechanism connected in a drive train between the motor and the tool holder, the percussion mechanism including: a first shaft, a second shaft, a hollow wheel connected to the first shaft and whose inside wall is not rotation-symmetrical with respect to an axis of the second shaft, an impeller connected to a second shaft and rotatably situated within the hollow wheel, a magnet situated coaxially to the second shaft, and a magnetorheological fluid filling a cavity between the hollow wheel and the impeller, in a first position, the impeller being spaced apart from the hollow wheel by a first air gap, and in a second position, the impeller being spaced apart from the hollow wheel by a second air gap, the first air gap being smaller than the second air gap, and the impeller and the hollow wheel being made of a magnetically conductive material.