Abstract: A planetary gear arrangement includes a gear housing, a first shaft and a second shaft located coaxially opposite each other, an internal geared wheel, a sun wheel torsionally fixedly connected to the first shaft, a planet carrier that forms a rotatably supported constructional unit together with the second shaft, and several step planets that are rotatably supported in the planet carrier. Each step planet includes two connected planet wheels with different effective diameters, whereby the larger planet wheels intermesh with the sun wheel, and the smaller planet wheels intermesh with the internal geared wheel. Each planet wheel is arranged as a separate unit and is rotatably supported on both sides in the planet carrier respectively via at least one roller bearing, with high stability under load. The two planet wheels of each step planet are coupled to each other in a torsionally fixed manner via an additional shaft that engages each planet wheel in a positive-locking manner in the circumferential direction.

Abstract: The present shaft coupling is intended for releasably linking two or more vices to each other in a torque transmitting manner. The devices may, for example, be turbines each of which has a shaft. Two bearing mounts are provided for one of the shafts, but only one bearing mount is provided for the other shaft at its end remote from the coupling. The coupling between the two shafts is formed by inserting a non-circular end portion of one shaft in a corresponding non-circular aperture in the end of the other shaft. An axially extending bolt firmly clamps the two shafts together in the axial direction. One or both of the shafts may be hollow. The non-circular profiles of the shafts may be splined, or have a polygonal profile, and the polygonal profile may be tapered. A polygonal profile as used herein may be one with only three sides.