also be noted that not only the drive shaft 20 but also the driven shaft 28 are disposed essentially centrally with respect to the longitudinal axis 18 of the gear system to make it possible for media or information to be passed through this gear system 10 both the drive shaft 20 and driven shaft 28 are each embodied as a hollow shaft 30 32 with a respective continuous bore 34 36 or other conduit thus for micro gear systems for the first time the possibility is made available of transporting media information or the like through the center of rotation of the gear so that a laser beam optical fibers shafts supply lines or even media can be carried through the gear system directly on the central axis of rotation it is thus unnecessary for information media or the like to be guided around the gear system which would require major structural expense and a large amount of installation space as can also be seen from fig1 the drive shaft 20 protrudes with a free end portion 38 pointing toward the driven shaft 28 into the bore 36 or conduit in the driven shaft 28 the free end portion 38 of the drive shaft 20 in the exemplary embodiment of fig1 is also received by a bush 40 that is seated in the bore 36 or conduit in the driven shaft 28 between the drive shaft 20 and the driven shaft 28 a sealing system 42 is provided which makes it possible despite the relative motion of the drive shaft.