The following are two screen captures of a CAD drawings that outline my patented gearing inside of a fishing reel assembly, one of many application my gearing can be used for.
Picture on the left
The exploded view represents all 3 gears. First, the input drive worm gear which is a standard worm gear with a square center powered by the crank handle of the fishing reel. Second, the round gear, the larger gear has 2 sets of teeth. One set of teeth are subsurface and they are meshing with and driven by the input drive worm gear, the 2nd set of teeth are on the outside surface edge of the worm wheel and drive the output gear. The output gear is hollow in the center and has the output shaft going up and down inside of it and the output gear rotates around driving the spool cup driving by this and the spool.
Picture on the Right
The fishing reel has three gears in it. The bottom gear is a standard worm gear that powers the gearing as the fisherman turn the crank handle of the fishing reel. The round intermediate large gear is a worm wheel that is both driving and driven. It is driven by the teeth that are the subsurface of the output drive of the gear. The second set of teeth is on the outside surface of the worm wheel and these teeth drive the output gear. The output gear is held in place with a nut that is threading it and keeps it in place. The output gear is hollow and has the output shaft traveling through its center and going up and down. The up and down motion creates level wind effect so the line does not bunch up on the spool. The spool is not shown, but on the final assembly the spool connects both to the output gear action and up and down motion.