DE 10 2004 050 798 A1 describes a hand-held power tool which includes a tool shaft which may be driven in an oscillating manner, and on which a tool is installed; the oscillating drive results in a rotational pendulum motion of the tool which may be used for grinding or cutting. The tool shaft with the tool installed thereon is actuated by an eccentric coupling device which is driven by an electric motor. The motor shaft of the electric motor drives an eccentric disk in which an arm which is non-rotatably connected to the tool shaft engages. A rotational motion of the eccentric disk therefore results in an oscillating motion of the arm and, therefore, the tool shaft.
In drives of this type, it must be ensured that, when motion is transferred between the motor shaft and the tool shaft, impermissibly high forces do not occur in one of the shafts or the coupling device used to transfer motion. The amount of play in all of the components which are involved in the transfer of motion must be relatively small to prevent wear which may increase rapidly between the motion-transferring components if the amount of play increases due to impacts and hammering. However, if the amount of play is too small, which may occur, e.g. when preload is greater, there is a risk that the dynamically highly-loaded roller bearings may become overheated due to friction.