Patent ID: 8590718

Claim:
A coupling unit for the semi-permanent connection of two freight cars of a rail vehicle, comprising: a first housing, which has an opening region, for fastening to a first railroad freight car; a second housing coupled pivotably and rotatably to the first housing and fastenable to a second railroad freight car; a bearing outer ring having a hollow spherical inner bearing surface fastened to the second housing; a bearing inner ring having a spherical outer surface and an inner bore, the bearing outer ring guided in a sliding manner on the bearing inner ring; a shaft fastened to the first housing, the shaft extending through the inner bore of the inner ring, the shaft having a first end with one or two first flattened portions running in an axial direction of the shaft and a second end having one or two second flattened portions running in the axial direction of the shaft; and at least one clamping piece bearing against one of the flattened portions and positioned in the opening region in the first housing, thereby securing the shaft against rotation, wherein the clamping piece is arranged so that the clamping piece only rotatively fixes the shaft relative to the first housing, and is outside of a force flux for transmitting operating loads between the shaft and the first housing.