Fingers vibration transmission performance of vibration reducing gloves

Abstract

Vibration attenuation performance of vibration reducing (VR) gloves is, invariably, measured at the palm using the method described in ISO 10819 (2013). The standardized method, however, does not address the glove performance in terms of fingers vibration, which is substantially different from that of the palm. An investigation was conducted to enhance the understanding of fingers vibration transmission properties of 4 different types of VR gloves (air, gel, hybrid and leather) using 4 male subjects in the laboratory. Three different finger adapters, each containing a miniature three-axis accelerometer, were designed and assessed for measurements of vibration responses at the fingers of the gloved hand. Vibration responses of the VR gloves were measured at the middle phalanges of the index and middle fingers using two Velcro finger adapters under the standardized vibration spectra and the spectra of 3 different hand tools, namely a road breaker, a nutrunner and an orbital sander. Vibration transmissibility of the gloves was also measured at the palm using the standardized palm adapter. The frequency response functions (FRF) obtained for the fingers of the gloved hand were used to estimate vibration transmission performances of the gloves at the index and middle fingers. The results show that only the air and hybrid VR gloves provide some attenuation of vibration transmitted to the index finger compared to the bare hand, while nearly all the gloves amplify vibration of the middle finger. The vibration attenuation was evident at the palm for the air and hybrid gloves above 40 Hz. The gel and leather gloves revealed nearly unity transmissibility in most of the frequency range. Only the hybrid glove passed the criteria of ISO 10819 (2013) to be designated as an anti-vibration (AV) glove, although it amplified vibration transmitted to the middle finger, particularly in the H-frequency range (200–1250 Hz). Fairly good agreements (−11%–13%) were obtained between the measured and estimated fingers vibration responses for all the gloves using the FRF method under the vibration spectra of the selected tools.Relevance to industry:Vibration is transmitted to the hand-arm system of operators using power tools and occupational exposure to hand transmitted vibration (HTV) arising from hand-held power tools has been related to an array of disorders. Vibration reducing (VR) gloves are viewed as one of the simple methods to protect workers from hand-arm vibration syndrome (HAVS). The international standard on the assessment of VR gloves addresses only the transmission of vibration to the palm, even though the vibration responses of fingers are substantially different. This study explored both the palm and fingers vibration transmissibility characteristics of VR gloves and proposed a method for assessing the vibration reduction performance of the glove under vibration spectra of different tools. The results of the study are thus considered to provide guidance towards enhanced screening criteria for AV gloves, and for selection of gloves for different tools.