Hammer drill, English: Hammerdrill structure principle: Hammer drill has a hammer tube rotatably supported in the housing. The hammer tube can be driven in rotation by a transmission gear placed on the hammer tube by a transmission device. An impact mechanism arranged in the hammer tube, the impact mechanism has a piston that can be driven into a reciprocating stroke, and has a work type switch for the work types "percussion drilling" and "chiselling". The work The type conversion switch has a manually operated conversion knob and a conversion mechanism connected with the conversion knob.
The conversion mechanism couples the hammer tube with the transmission gear in the setting position "impact drilling" of the conversion knob and in the setting position. The hammer tube is fixed in the housing in a non-rotatable manner in the "chiselling", which is characterized in that the switching mechanism has a switch ring that can be fixed on the hammer tube without relative rotation and axially movably, and the switch ring faces away from the hammer. There is at least one radially protruding locking projection on the outside of the tube, which is configured to: on the one hand, be inserted into at least one axial groove fixed to the transmission gear in a form-locking manner in the circumferential direction, and on the other hand On the one hand, it is inserted into the axial tooth part fixed to the housing in a form-fitting manner in the circumferential direction.