US Patent 7258349 Hand power tool

A hand power tool selected from the group consisting of a drill hammer and an impact hammer has an exchangeable tool holder, a guide pipe which receives the tool holder at its free end, a locking device arranged on the guide pipe and operative manually for fixing the tool holder on the guide pipe in a defined locking position assumed by the tool holder on the guide pipe, so that the locking position is arranged before a mounting position in a displacement direction of the tool holder, in which mounting position the tool holder is held unlocked on the guide pipe, the locking device being provided with means activatable by a release of the locking device and providing a displacement of the tool holder to the mounting position.