Design and development of lever operated maize cob sheller for marginal and small farmers

In the present study, a low cost lever operated maize cob sheller was designed, developed and evaluated for its performance and techno-economic feasibility in comparison to two existing maize shelling methods (tubular maize shelling and beating method). It consists of different components viz. frame, handle, handle support, depressor and push rod assembly, shelling unit. The main working principle of developed prototype is based on the application of compressive force on the maize cob along its length. The maize cobs are fed manually to the shelling unit between the depressor plate and the top end of shelling unit. By pressing the lever, the depressor and push rod comes down vertically and due to the downward stroke, a compressive force applies on the maize cob and grains are detached from the cob. The developed prototype was evaluated under two levels of cob moisture content (16–20% and 12–16%) and three levels of cob diameter size (< 30 mm, 30–40 mm, and > 40 mm). The effect of different performance parameters like labour requirement, energy requirement and cost of shelling were discussed. Both moisture content and cob size significantly affected labour requirement and energy requirement. The labour requirement and energy involved for maize shelling increased directly with increase in cob moisture content and decrease in cob size. The mean shelling capacity for developed prototype (30.50 kg/h) was 2.92 and 1.73 times higher than tubular maize sheller (10.43 kg/h) and beating method (17.56 kg/h), respectively. The average grain damage was 5.33% for the developed prototype which was slightly higher (1.28%) than tubular maize sheller (4.05). The shelling efficiency for the developed prototype was observed 1.46% and 18.37% higher than tubular maize sheller and beating method, respectively. The cost of operation of lever operated maize shelling was Rs1398/t which were about two times less than beating method and three times less than tubular maize shelling. So, the lever operated maize cob sheller is very useful and innovative shelling equipment for marginal and small farmers of the hilly regions.