Parts and assemblies for transmitting, changing, engaging, limiting or braking mechanical drive: gears, gearboxes, gearmotors, shafts, hubs, splines, keys, shaft-hub connections, belt and chain drives, sprockets, pulleys, rope sheaves, couplings, clutches, brakes, backstops and variators. Includes dedicated gearbox housings and drive components. Excludes pipe couplings, complete hydraulic power equipment and linear actuator or positioning assemblies.