Noise control of hand-held power tools.
NOISE-CON 2003: Proceedings of the 2003 National Conference on Noise Control Engineering, Cleveland, Ohio, June 23-25, 2003. Holger DK, Maling Jr. GC, eds., Ames, IA: Institute of Noise Control Engineering of the USA, 2003 Jun; :1-9
The noise control solutions for commonly used hand-held tools were identified and implemented. The implementation of the torsional vibration damper yielded a considerable reduction in vibrations at 30 Hz with an impact wrench. However, no significant reduction in the overall sound power level occurred, due to the fact that large changes in level at low frequencies do not translate to large changes in overall sound power level when using the A weighted scale. To achieve an overall reduction in sound power levels, it is recommended that a frequency in the range of 1 kHz - 2 kHz be targeted for the torsional vibration damper. This design would be more likely to reduce noise in bands which contribute most to loudness as perceived by the human ear, which was the primary goal of this study. A higher tuned resonance frequency could be achieved by decreasing the outer radius of the steel ring, decreasing the thickness of the spring, decreasing the density of the steel, or selecting a spring material with a higher shear modulus. Noise control solution utilizing acoustic foam for the jigsaw resulted in the decrease of overall sound pressure level by a 1.5 dB in an idle condition and 2.4 dB when cutting. An attenuation of 1.9 and 2.5 dB of sound power were achieved, respectively. The goal of attenuating the noise under 6kHz was achieved. With further work on the solution design and more professional tools, this solution has the ability to produced greater attenuation of the noise.
Hearing-loss; Noise; Noise-exposure; Noise-induced-hearing-loss; Noise-levels; Engineering-controls; Control-technology; Noise-measurement; Noise-transmission; Vibration-control; Vibration-effects; Vibration-exposure; Vibration-suppressors
NIOSH, Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Holger-DK; Maling-GC Jr.
NOISE-CON 2003: Proceedings of the 2003 National Conference on Noise Control Engineering, Cleveland, Ohio, June 23-25, 2003