Percussive tool noise and vibration control.
Proceedings of the symposium on occupational health hazard control technology in the foundry and secondary non-ferrous smelting industries, December 10-12, 1979, Chicago, Illinois. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 81-114, 1981 Aug; :261-271
Methods for controlling vibration and noise produced by chipping hammers were reviewed. Four main sources of noise were identified: workpiece noise, chisel or steel noise, air exhaust noise and case or housing radiated noise. Each of these noise sources has been evaluated according to a test standard by muffling or eliminating the other sources during the taking of measurements. Workpiece noise has been reduced by immersing the casting in a damping medium such as sand or water. Dampers, both internal and external, have been shown to reduce noise from chisels, and mufflers have been used to reduce air exhaust noise. Housing noise has been reduced by addition of a barrier material to outer surfaces of the housing or isolation of the inner barrel from the outer housing. The problems involved with measurement of vibration were discussed. Three processes resulting in vibration were described: resonances in the structure of the chipper, recoil and chisel rebound. Use of the air reservoir technique or isolation of the barrel from the handle have been shown to reduce recoil. The difficulties involved in incorporating vibration isolators into a tool suitable for production were described. Chisel vibration reduction has involved either damping the chisel or insertion of an isolating sleeve between the guiding hand and the chisel. The author concludes that despite use of the measures described chipping hammers still cause greater noise and vibration compared to other metal removal tools, and recommends changes in the casting production allowing the use of quieter tools and automation of the finishing process.
NIOSH-Contract; Hand-tools; Hand-protection; Noise-measurement; Vibration-control; Vibration-monitors; Noise-control
Proceedings of the symposium on occupational health hazard control technology in the foundry and secondary non-ferrous smelting industries, December 10-12, 1979, Chicago, Illinois