Abstract: The invention relates to an instrument for making openings in bone in form of a bone lid. The object of invention is that several cutting pins are carried along a hypotrochoid and in this way the instrument by utilizing a rotating drive mechanism produces the opening and the bone lid in a shape resembling a equilateral polygon with rounded edges.

Abstract: The invention relates to a lamp device which is worn on or directly in front of the forehead, respectively, or above or beside the eyes, respectively, and which ensures that the wearer's freedom of movement is neither restricted nor hindered by cables or other connections. The present invention is special in that several non-thermal, light-emitting elements are provided for the generation of light and that the individual light-emitting elements emit the light in a defined direction of radiation and are located in such a way that the light which is generated is directional. The light-emitting elements are located in such a way that each of them forms a particular angle with the visual axis of the wearer so that all light sources have a common intersection point just at the wearer's monitoring or working distance, respectively. Moreover, all individual light-emitting elements have the same distance to that intersection point.

Abstract: The invention relates to a lamp device which is worn on or directly in front of the forehead, respectively, or above or beside the eyes, respectively, and which ensures that the wearer's freedom of movement is neither restricted nor hindered by cables or other connections. The present invention is special in that several non-thermal, light-emitting elements are provided for the generation of light and that the individual light-emitting elements emit the light in a defined direction of radiation and are located in such a way that the light which is generated is directional. Those light-emitting elements (1) are located in such a way that each of them forms a particular angle with the visual axis of the wearer so that all light sources (1) have a common intersection point just at the wearer's monitoring or working distance, respectively. Moreover, all individual light-emitting elements (1) have the same distance to that intersection point.