Ergonomic Evaluation of Hand Chaff Cutter for Dry Maize Fodder

摘要

Hand chaff cutters is one of the common agricultural machinery used in rural areas, but is involved in a significant proportion of limb injuries. Safety standards are somewhere difficult to enforce because manufacturing of hand chaff cutters are done at widely dispersed local workshops. To ease the fodder cutting operations a commercially available hand chaff cutter was evaluated for dry maize crop with 12 male workers to assess its suitability for workers of western region of India. The parameters used for the ergonomical evaluation include machine operation at different speed, heart rate and discomfort ratings. The mean value of heart rate of the subjects ranged from 103.74 to 123.48 beats/min for 25 to 45 rpm speed of operation of chaff cutter. The energy expenditure rate of the subject ranged from 15.78 to 23.82 kJ/min. The value of EER at 35 rpm was 18.59 kJ/min. The overall discomfort rating (ODR) ranged from 7.50 to 8.5 and the body parts discomfort score (BPDS) ranged from 46 to 67. The majority of discomfort was experienced in neck, clavicle left, clavicle right, left shoulder, right shoulder, left elbow and right elbow. The output capacity of hand chaff cutter was minimum at 25 rpm, i.e.14.1 kg/h and maximum 18.5 kg/h at 45 rpm. Modification in existing hand chaff cutter was required due to high discomfort felt by operators, for that reduction of 50 mm in stand height of hand chaff cutter was suggested. After modification of hand chaff cutter mean working heart rate and mean △HR of subjects decreased 1.25 percent and 4.75 per cent respectively. The decrease in ODR and BPDS were found 5.09 and 13.3 per cent.