Electrical machine tools for grinding, blast cleaning, milling, napping, plaining, polishing, routing, roughening, descaling and grooving and also for mechanical removal of floor coverings, markings, thermoplastics, paints and rust, and parts and fittings therefor; electrical vacuum cleaners for construction purposes, and parts and accessories for vacuum cleaners in the nature of fume hoods, hoses, sacks and bags for collecting dust and other dirt, and filter cartridges