Electromagnetic clutches and brakes, not for land vehicles; shaft couplings, rubber and plastic shaft couplings, metal shaft couplings, not for land vehicles; speed change gears for machines, belt speed changer units, power transmission belts and chains for machines; power transmissions and gearing for machines; AC and DC electric motors, not for land vehicles, and parts used therewith; and servo and stepping motors not for land vehicles and parts used therewith