Variable frequency drives for motors, other than for land vehicles; Ball transfer units; Machine coupling and belting except for land vehicles; Roller bearings for machines; Transmissions for machines; Linear motors; Machine coupling and transmission components, except for land vehicles, and parts therefor; Sliding bearings for machines; Numerically controlled machines and machine tools used for machining parts; Self-lubricating mechanical friction parts, especially of composite materials, namely, wear rings, washers, bushings, spherical bearings, bearing pads, sliding blocks and machine transmission gears all for load bearing machines, conveyors, handling trucks and machines, lifting machines, agricultural machinery, construction equipment machines and hydraulic turbines