Machine coupling and transmission components except for land vehicles; parts of machines and machine tools, namely, driving belts and conveyor belts, in particular toothed belts, tracked toothed belts [ and toothed lock washers ] ; conveyor belts and belts for conveyers, [ cam belts, cams; tension rollers for bands and belts, connecting elements, clamping joints and clamping plates for toothed belts included in this class ]