Hydraulic pumps and valves therefor; hydraulic power-transmission gear for machines; hydraulic control valves as machine components; hydraulic control valve spools as machine components; lubrication and hydraulic pumps of aluminum; lubrication and hydraulic pumps of cast iron; hydraulic gear pumps; piston pumps; hydraulic control installations for controlling machines consisting primarily of hydraulic pumps, gears, pistons, vane pumps, accumulators, pilot valves, main control valves, supporti...