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Cloueuses portatives - Développement de méthodes de diagnostic vibratoire et acoustique
Le fonctionnement des cloueuses portatives étant basé sur un processus d'impact visant à enfoncer un clou, l'utilisation de ces outils expose les travailleurs à des bruits et à des vibrations à caractère impulsionnel, en générant des niveaux très élevés pendant un très court laps de temps. Par ailleurs, l'exposition aux bruits et aux vibrations impulsionnels engendre un risque de développer des maladies professionnelles. Des échanges avec l'Association paritaire pour la santé...
Occupational biomechanical risk factors for surgically treated ulnar nerve entrapment in a prospective study of male construction workers
Evidence was provided for forceful hand-grip work, with and without vibration, as a risk factor for ulnar nerve entrapment (UNE) surgery in a large cohort of Swedish construction workers. Several individual biomechanical factors comprising such work were associated with increased risk of UNE, including: increased grip force, upper extremity load, frequency of hand-held tool use, and hand arm vibration. Source: Jackson, J. A., Olsson, D., Punnett, L., Burdorf, A., Järvholm, B. et Wahlström, J. (2018). Scandinavian journal of work, environment & health . http://dx.doi.org/10.5271/sjweh...
Caractérisation du syndrome du marteau hypothénarien chez les travailleurs utilisant des outils manuels et exposés aux vibrations main-bras
Les travailleurs utilisant des outils portatifs vibrants et/ou des outils manuels (sans vibrations) sont à risque de développer le syndrome du marteau hypothénarien (SMH) et s'exposent ainsi à de lourdes conséquences pour la santé, dont l'amputation des doigts. En effet, l'artère cubitale de la paume de la main est située en superficie et n'est pas suffisamment protégée par des tissus (par exemple, des muscles). Elle est ainsi particulièrement vulnérable aux coups et vibrations ainsi qu'aux traumatismes...
Calculette vibration ensemble du corps
Cette calculette au format Excel permet d'évaluer l'exposition quotidienne aux vibrations transmises à l'ensemble du corps par les engins mobiles. A partir des données vibratoires connues au préalables (mesures ou bases de données, suivant les 3 directions ou l'axe dominant), elle permet de calculer rapidement et facilement l'exposition vibratoire journalière A(8) d'un conducteur, et ceci même si ce dernier utilise plusieurs engins dans sa journée. Les résultats donnés par la calculette permettent de situer...
Caractérisation du syndrome du marteau hypothénarien chez les travailleurs utilisant des outils manuels
Les travailleurs utilisant des outils portatifs vibrants et/ou des outils manuels (sans vibrations) sont à risque de développer le syndrome du marteau hypothénarien (SMH) et s'exposent ainsi à de lourdes conséquences pour la santé, dont l'amputation des doigts (Thompson et House, 2006; Honma et collab., 2000; Kaji et collab., 1993). En effet, l'artère cubitale de la paume de la main est située en superficie et n'est pas suffisamment protégée par des tissus (par exemple, des muscles). Elle est ainsi particulièrement...
Outils vibrants
Paramètres biomécaniques et sensorimoteurs affectant la réponse biodynamique du système main-bras L'exposition aux vibrations est une préoccupation importante au regard de la prévention des troubles musculo-squelettiques aux membres supérieurs. Les vibrations main-bras sont spécifiquement reconnues pour être la cause du syndrome des vibrations, une maladie atteignant les doigts et la main en matière vasculaire, musculo-squelettique et neurosensoriel. De longues durées et de fortes intensités de vibration peuvent...
Retrofit anti-vibration devices
A study of their effectiveness and influence on hand-arm vibration exposure This project set out to try to determine what benefits, if any, could be gained in terms of reducing vibration exposure by retrofitting different types of anti-vibration device to different hand-held machines. Four types of device were selected for laboratory investigation: anti-vibration handles, spring balances/tensioners, a vibration reducing flange and chisel sleeves. The results from all the different devices used in this project, with the exception of the chisel sleeves, demonstrated that an end user cannot be confident...
Calculette vibration mains bras
Cette calculette au format Excel permet d'évaluer l'exposition quotidienne aux vibrations transmises aux membres supérieurs. Sans avoir besoin de réaliser des mesures complexes, elle permet d'estimer rapidement l'exposition vibratoire journalière transmise par les machines portatives ou guidées à la main, et ceci même si l'opérateur utilise plusieurs équipements dans une même journée. Les résultats donnés par la calculette permettent de situer les niveaux d'exposition d'un opérateur...
Coupling forces exerted on chain saws by inexperienced tree fellers
Prolonged, intensive exposure to vibrations produced by vibrating tools could cause non-specific disorders in upper extremities of the operator, referred to as hand-arm vibration syndrome (HAVS). The severity of HAVS is affected by the magnitude of coupling forces exerted on the tool handle. The aim of the study was to measure the coupling forces exerted by inexperienced tree fellers on chain saws. Forces exerted by inexperienced tree fellers were compared to those of professional lumberjacks to investigate the relationship between the coupling forces and the experience of the chain saw operator...
Comparative analysis of exposure limit values of vibrating hand-held tools
In the European Union, one of every four workers claims to be exposed to vibration for up to 2 h of his/her working day. The use of vibrating hand-held tools is the most common cause of vibration-related injury in workers. Of all sectors of professional activity, the construction industry has the highest number of workers affected by vibration. European Directive 2002/44/EC on the minimum health and safety requirements regarding worker exposure to risks from physical agents (e.g. vibration) limits exposure to vibration. This study analysed the exposure level of construction workers to hand-arm...
Nodal control of grass trimmer handle vibration
Imposing node technique is applied to the grass trimmer shaft in order to achieve very low vibration (node) at the handle location. The optimum tuning frequencies of the two tuned vibration absorbers (TVAs) attached at 0.74L and 0.85L along the shaft of the grass trimmer are determined using the imposing node technique. Transverse deflection, experimental modal analysis and operating deflection shape analysis of the grass trimmer were carried out, and the results indicated that nearly zero deflection (node) was induced at the position very close the loop handle location. Moreover, the vibration...
The effectiveness of BS EN ISO 28927-9:2009 concerning the vibration emission of scaling hammers and needle scalers
The work in this report provides HSE with information regarding: the likelihood that use of a tool's vibration emission value will result in minimised vibration exposures for the end user; and the limitations of the declared vibration emission value measured according to the standard test code, for use in a vibration exposure assessment. Source : http://www.hse.gov.uk/research/rrpdf/rr967.pdf
An investigation into the effects of potential changes in concrete properties when aged and weathered on hand arm vibration emission magnitudes
During vibration emission measurements of hammers according to EN60745-2-6 (work published as RR868), variations in results were found which appeared to be related to the condition or age of the concrete test blocks following a 12-month period of outside storage. In one case, the emission value was reduced by 36%. For two of the three tools identified in RR868, the variation in vibration emission resulted in a change from the manufacturers' data not being verified to being verified in accordance with EN12096. This work aimed to replicate the situation that gave rise to the results detailed...
Comparative analysis of exposure limit values of vibrating hand-held tools
In the European Union, one of every four workers claims to be exposed to vibration for up to 2 h of his/her working day. The use of vibrating hand-held tools is the most common cause of vibration-related injury in workers. Of all sectors of professional activity, the construction industry has the highest number of workers affected by vibration. European Directive 2002/44/EC on the minimum health and safety requirements regarding worker exposure to risks from physical agents (e.g. vibration) limits exposure to vibration.This study analysed the exposure level of construction workers to hand-arm vibration...
Mise à jour du répertoire des silencieux, soufflettes et pistolets aspirateurs
Souvent bruyants, les appareils alimentés à l'air comprimé peuvent cependant être munis de silencieux, cependant l'efficacité de ces derniers varie beaucoup. C'est aussi le cas, d'ailleurs, des soufflettes et des pistolets à air comprimé. Ce document présente les résultats de mesures obtenues sur des appareils déjà testés en 1995 et encore offerts sur le marché ainsi que ceux obtenus sur 91 nouvelles soufflettes, 22 nouveaux silencieux et 6 pistolets aspirateurs. Le rapport contient un guide...
Optimal suspension characteristics for the reduction of the vibrations transmitted by a small pneumatic hammer.
This paper describes a systematic approach for optimizing suspension systems to reduce the vibrations transmitted to workers by hand-held power tools. The optimization is based on modeling tool-operator interactions using a mobility scheme. The tool is modeled as a vibration generator, and its internal impedance is included. A hand–arm impedance matrix is used to model the operator upper limbs. The mobility model is used to identify the optimal suspension characteristics, which in our study were the set of parameters that minimizes the frequency-weighted acceleration at the hand–tool...
Use of vibratory tools increases more than five times the risk of developing CTS
A conservative definition of CTS employed to include nerve conduction abnormality with symptoms and/or signs showed that risk factors significantly associated with an increased risk of CTS among exposed workers were: vibration [odds ratio (OR) 5.40; 95% CI 3.14, 9.31], hand force (OR 4.23; 95% CI 1.53, 11.68) and repetition (OR 2.26; 95% CI 1.73, 2.94). Using National Institute for Occupational Health and Safety criteria for case definition, a significant positive association between CTS and hand force, repetition, use of vibratory tools and wrist posture was observed with approximate doubling...
A bit isolator and a chuck isolator reduce the noise radiated by the drill steel and chuck
Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response to this problem, the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the most significant contributor to a roof bolting machine operator’s noise exposure. NIOSH OMSHR has determined that the drill steel and chuck are the dominant sources...
A tuned vibration absorber reduces the risk of hand-arm vibration syndrome for a grass trimmer
Prolonged use of electric grass trimmer exposes the user to the risk of hand-arm vibration syndrome. A simple approach for the suppression of hand-arm vibration in electric grass trimmer is presented. The proposed system is a tuned vibration absorber (TVA). The results indicated that minimum vibration level was related to the position of the TVA on the shaft of electric grass trimmer. The tuned vibration absorber when installed to the electric grass trimmer attenuated the vibration total value by 67%. This significantly reduces the risk of hand-arm vibration syndrome. Source : Tuned vibration absorber...
Employees affected by the vibrations of air chisels : The UK vehicule manufacturer was prosecuted.
Two employees in the weld destruct section where air chisels were used to undo welds on cars to test the strength of them developped Hand Arm Vibration Syndrome (HAVS) in December 2006. The subsequent investigation by HSE found that vibrating hand tools were being used across the plant with a lack of assessment and management of risk and when a health surveillance regime was then made effective, other cases came to light. There was no system in place to measure how long was being spent using the tools by each employee or the levels of vibration. The recommended amount of time for one of the tools...
Models of the substructures of the hand-arm system can be used to help design and analyze palm and orbital sanders
Prolonged, intensive exposure to vibrations from palm and orbital sanders could cause finger disorders. They are associated with the biodynamic responses of the fingers. This study confirmed that the distributed hand responses generally varied with locations on each finger, vibration frequencies, and applied hand force. This study enhanced the understanding of the biodynamic responses of the fingers and hand exposed to vibrations on a contact surface with a large effective radius such as that found on palm and orbital sanders. These results are useful for developing hand and finger models required...
Handle types on the commonly used grass trimmer reaches the exposure limit value for daily vibration exposure.
The portable petrol driven grass trimmer is identified as a type of machine whose operator can be subjected to large magnitude of hand-arm vibration. The vibration total level on the handle of grass trimmer of 11.30 m/s 2 was measured, and it has reached the exposure limit value of 5.0 m/s 2 for daily vibration exposure A(8). Operators were not fully aware of the level of vibration. Different prototype handles were tested; one that is made of heavier material results in the lowest hand-arm vibration. The new handle has significantly reduced the vibration total value by 76% compare with the existing...
Pneumatic nail guns produce loud “impulse” noise peaks in a range from 109 to 136 dBA.
Pneumatic nail guns produce short (less than a tenth of a second in du­ration) but loud “impulse” noise peaks: one from driving the nail and one from exhausting the air. Most nail gun manufacturers recommend that users wear hearing protection when operating a nailer. Available information indicates that nail gun noise can vary depending on the gun, the work piece, air pressure, and the work setting. The type of trigger system does not appear to affect the noise level. Peak noise emission levels for several nailers ranged from 109 to 136 dBA. These loud short bursts can contribute...
Manufacturers’ data can seriously underestimate the risks associated with use of electric hammers.
The HSL interpretation of the application of the test code has resulted in emission values that better indicate the vibration risk . Comparing the HSL measured emission data with the vibration magnitudes measured at HSL during typical use showed a reasonable level of agreement. The HSL interpretation of the application of the test code has resulted in emission values that reach or exceed the upper quartile of HSL field magnitudes in most cases. However, the large differences between HSL measured emission values and those determined by manufacturers have not been explained and suggest differences...
Effects of vibration at workplaces
Characteristic values of hand-arm and whole-body vibration The effects of vibration when working with handheld and hand-guided devices (Hand-Arm Vibration – HAV) and when driving mobile work machines and vehicles (Whole-Body Vibrations – WBV) can endanger the health and safety of employees. Damage to bones and joints and circulatory problems in the hand and arm systems as well as disc damage to the spine as a result of the effects of vibrations are recognised occupational diseases. Since the entry into force of the EC Vibration Protection Directive 2002/44/ EC in 2002 there has been...
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