US Patent 11554457 Planetary concrete grinder

A concrete grinder has a rotating planetary gearbox with counter rotating tooling plates attached. The planetary gearbox is powered directly from a trowel gearbox output shaft, which is connected to a center bore of the planetary gearbox. As the planetary gearbox rotates, tooling shafts are forced to counter rotate because the input shaft of the planetary gearbox is connected to a fixed pulley or sprocket. The planetary gearbox is sealed to keep water, dust or slurry from entering.