7 Machines for working in concrete, masonry, rock and earth, namely, paving breakers, jackhammers, backfill tampers, rammers, chipping hammers, rivet busters, trenching machines, rock drills, pusher legs, roto-hammers, chisels and drill rods for machines, needle and chisel scalers and scabblers; machines for pumping water, namely, diaphragm, sump and barrel pumps; machines for compressing air, gas and fluids, namely, air compressors, gas compressors and pumps; machines for material handling, namely, air, electric, spring and fluid operated hoists, balancers, winches and tuggers; machines for suppression, removal and disposal of dust, namely, vacuum and mist spray machines, centrifugal separators, cyclonic separators