Study of the load on the hand and fingers of mandarin pickers, the 1st report -Investigation of three types of shears and their effect on the workload on the hand and fingers

Mandarins are picked by hand with the use of shears. An average mandarin picker makes at least 20,000 cuts daily. This daily workload on the upper limbs is the cause of occupational cervicobrachial disorders (OCD). In order to improve their working conditions, we devised two types of shears, one with a soft grip wrapped around the handle and another with shock reducing cushions in between the handles. The following two experiments were conducted. First we tested and compared the Borg scale and pinch meter scores of each participant by having them cut sticks as the same radius as those of mandarin stems using both the improved and conventional shears. Next, we placed two pressure sensors on each shear, where the middle finger and thumb contact the handles, to measure and compare the impact pressure within the hand. The results of the first experiment suggested that the improved shears reduces workload to the hand and fingers when comparing results to those of the conventional shears. The second experiment indicates that the shock reducing cushions reduces impact pressure to the hand from the handles when cutting.