Gear system for drive of a multi-shaft extruder

Gear system to drive an extruder with several axially parallel shafts, rotating in the same direction, arranged around a circle at equal angles with respect to each other, which are attached in a torque-proof manner to conveyor elements wherewith adjacent shafts engage with each other, wherein the driven shafts of the gear system are attached coaxially and in a torque-proof manner to the shafts, each driven shaft has a pinion, the driven pinions engage with an externally-toothed drive wheel provided on a central drive shaft and with a surrounding internally-toothed hollow gear wheel, axially offset pinions (19, 20) are arranged on adjacent driven shafts (11) and the drive wheels of the central drive shaft and the hollow gear wheels are arranged in similarly offset fashion, characterized in that the hollow gear wheels (24, 25) have an external tooth gearing (51), with which a drive wheel (26 to 29) on an outwardly-located drive shaft (15 to 18) engages, so that each hollow gear wheel (24, 25) is driven with the same torque and half of the torque of each driven pinion (19, 20) is generated via the central drive wheel (21,22) and half via the hollow gear wheel (24, 25).