ABSTRACT
Keywords: Hand-transmitted vibration, repetitive measurements, electric hand-held tools, adaptability of operators
Hand-transmitted vibration occurs at work with electric, pneumatic and hydraulic tools, i.e. hand-held drills, grinders, saws, cutters, planes, spanner wrenches, rammers, hammer drills, hammers, and other similar tools. In professional practice, electric hand-held tools are widely used. Vibration is transmitted to the hands of the operator from the grasped handle of a hand-held tool and from the hand-held material being machined or from another grip on the tool being used. Depending
upon the type of tool, the working position of the operator, and the location of the workplace, vibration may enter only one arm or both arms simultaneously and may be transmitted by the hand and the arm to the shoulder. Hand-transmitted vibration is a source of discomfort and possible decrease in labour efficiency. The long-term use of vibrating mechanized tools is connected with the occurrence of symptoms of diseases affecting blood vessels, nerves, bones, tendons, joints, muscles and fibrous tissues of hand and forearm. The level of exposure of the person who is subject to hand-transmitted vibration is determined by the intensity of vibration, which is defined as the total weighted level of vibration acceleration and the duration of exposure. Other factors influencing the effects of exposure of operator's hands to vibration are working methods and operator's skill, quality of made temporal analysis of work, working posture of hand and arm, type, condition and weight of hand-held tool being used, properties of material being machined, microclimatic conditions and thermal situation in the working place, noise, health condition and use of medicines and/or habit forming substances influencing the human circulatory system. In view of the above-mentioned factors, the total weighted level of hand-transmitted vibration acceleration declared by the manufacturer usually differs from a resultant value (in accordance with relevant international standards) measured during a specific activity under real conditions.
