7 Power transmissions for agricultural, industrial and commercial machines, consisting of gear boxes, gear drives, power drive lines and power trains; parts of earth augers, namely, power auger drives for excavation; disk mower boxes comprised primarily of gear boxes for power lawn mowers in the nature of disk mowers, and also containing machine parts, namely, gear disk mower cutting heads, and drive shafts; rotary tables; gear boxes, gear drives and gear drive lines for agricultural, industrial and commercial machines, and structural parts therefor, namely, loose gears, drive line shields and driveline couplers; planetary drive gearboxes for agricultural and industrial equipment; mechanically and electrically powered drive lines and drive line safety shields and guards as structural parts of agricultural, industrial and commercial machines not being land vehicles; hydraulic drive systems for agricultural, industrial and commercial machines not being land vehicles