Design and Development of a Lifting Mechanism Using Karakuri Principles to Reduce Workload and Improve Productivity in Clay Pot Crab Production

Abstract

Clay pot crab is a well-known product of the Khlong Nam Khem Tanjai community enterprise. Currently, increasing consumer demand has continuously increased production volume. A study of the clay pot crab production process, consisting of eight stages involving manual labor in every stage, revealed that the transportation of fried and seasoned crabs to the drying area for moisture reduction required the greatest working distance and processing time. This process significantly affected production efficiency and operator workload in manual material handling tasks. Therefore, this research aimed to design and develop a lifting mechanism by applying Karakuri principles, which are characterized by simple mechanical systems, ease of maintenance, and no requirement for external energy. The developed lifting mechanism has dimensions of 490 mm in width, 600 mm in length, and 750 mm in height. The mechanism operates using gravity to transmit force through gears, sprockets, and chains, and returns to its initial position through spring force. Experimental results compared with the conventional production method showed that the average transportation time was reduced from 20.47 s to 14.73 s, representing a reduction of 28.04%. In addition, the average lifting and transportation distance of crabs was reduced from 14.8 m to 7.4 m, corresponding to a reduction of 50%. Transportation distance and operation time were used as indicators for evaluating operator workload in manual material handling. The results demonstrate that the developed lifting mechanism can improve work efficiency, reduce manual material handling workload, and effectively enhance the production capability of the community enterprise.