Patent ID: 7399150

Claim:
A screw element for engagement with a component having a concavely curved inner surface defining a longitudinal axis extending therethrough and also defining a radius of a single center of a curvature comprising: a force application area for a turning tool; and a contact surface which points in the direction in which the screw element is screwed in, and which contact surface is configured as a convexly curved outer surface configured for making contact with the concavely curved inner surface of the component, where the convexly curved outer surface of the screw element and the concavely curved inner surface of the component are coaxial with respect to the longitudinal axis which extends through the component and the screw element, wherein the contact surface defines when viewed in axial cross section of the screw element circular sections having centers of curvatures which are spaced from the longitudinal axis such that the convexly curved outer surface of the screw element and the concavely curved inner surface of the component are configured so as when fastened to each other they are in contact with each other between ends of the circular sections, the circular sections of the convexly curved outer surface define centers of curvature that are spaced apart from each other in a direction extending perpendicular to the longitudinal axis, and where the radius belonging to the center of curvature of the concavely curved inner surface is longer than the radii of the centers of curvature circular sections of the convexly curved outer surface.