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Ever expanding technological growth has led to an increase in the use of tracked excavators for construction, demolition, material handling, rock breaking etc. Excavator operators are exposed to a variety of risk factors that may lead to health problems. A major health hazard among operators is whole-body vibration. Human response to vibration is very complex and nonlinear. Whole Body Vibration in the range of 2 to 30 Hz corresponds to most of the resonant responses of various organs and parts of the human body. The objective of this paper is to assess whole body vibration for the tracked excavator with hydraulic breaker. The job safety analysis conducted through questionnaires for different industrial vehicle operators revealed the presence of a health risk among the operators in rock breaking machinery. To quantify the level of vibration, field tests are performed on four tracked excavators with hydraulic breaker attachments in two different work locations. Accelerometer, a real-time signal conditioning / processing and PULSE data acquisition software are used for vibration measurement. The frequency of vibration exposure is observed to be between 6.8 and 12 Hz. Acceleration levels measured were in the range of 0.87 -2.2 m/s 2 for a tracked excavator operator with breaker. The total vibration exposure calculated was between 0.621 and 1.932 m/s 2 . The vibration dose value recorded was 17.6 -62.72 m/s 1.75 . Whole body vibration exposure of the breaker operator was much higher and lies beyond the upper limit as given in ISO 2631-1. The ranges of vibration parameters measured were concomitant with frequent lower back pain, other muscular-skeletal injuries like leg pain etc which are prevalent among these operators.

Handle vibration from equipment or machines influences musculoskeletal activity as well as comfort in handling the same. New technology can be worse than no technology if it was not developed correctly as ergonomic research has clearly demonstrated the relationship between injury risk and poorly designed hand tools. Clinical and epidemiological studies have shown that operators of handheld power tools are prone to develop various vibration‐induced disorders of the hand and arm, which are collectively referred to as “hand–arm vibration syndrome.'' The vibration direction has a great influence on the transmitted vibration. The present study focuses the effects of low‐frequency vertical vibration on hand to shoulder from handles of different size. The electrodynamic exciter is used for simulating vibration to a vertical handles of four different diameters. PULSE LabShop software is used for evaluating the magnitude of vibration in different frequency bands. The vibration characteristic data were acquired in the yh axis at the wrist, elbow, and shoulder for bent arm and extended arm postures with vibration excitation of 4.5 m/s2. Transmissibility characteristics are computed to determine the influence of handle diameter in yh vibration transmitted to the hand–arm system. The magnitude of vibration transmitted within the hand, elbow, and shoulder was observed to be dependent on the handle size; larger handles cause higher vibration transmissibility. The results also show that the human hand–arm system in an extended arm posture amplifies the vibration transmitted than bent arm in a small difference. © 2011 Wiley Periodicals, Inc.

Industrial vehicle operator's solace and safety have gained significant consideration because of the increment in occupational health issues and accidents. The purpose of this work was to amend the design of the excavator driver cabin through human factor analysis. Thirty operators of excavators who were serving as subjects, were interviewed and identified that their wrist, upper arm and trunk were at a higher risk level while operating. Photograph of the operators was taken and the work environment was simulated. RULA (Rapid Upper Limb Assessment) and REBA (Rapid Entire Body Assessment) scoring was made on different simulated work posture of operators using CATIA V5 and UEAT1.8 softwares. Based on overall RULA and REBA scoring, it was found nearly 46% of the operators were operating at a high hazard level and needed investigation immediately, whereas 35% of operators were at a medium risk level and only 19% of operators were operating safely. The individual RULA and REBA scoring proved prevalence of discomfort in wrist, upper arm and trunk while operating. Identifying the optimized conditions to hold the control levers will help to reduce the operator strain. From the design optimization in excavators, the optimal conditions to hold the control lever is found to be 40cm for popliteal height, 60.51 cm for distance from elbow to ground and 15.07º for reach angle from the seat reference point.

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