Bio-mechanical Parameters While Operating Hand Operated Maize Dehusker-sheller

Mathematical equations were developed for assessing bio-mechanical parameter to establish relationship between human and machine system. For development of mathematical equations, the human body was assumed to be made up of five major links (1^st link - Fore arm, 2^nd link - Upper arm, 3^rd link – Head & trunk, 4^th link – Upper leg and 5^th link – Lower leg) joined together to form a kinematics link. While developing the equations forces acting on fore arm, upper arm, head & trunk, upper leg and lower leg were resolved in vertical and horizontal planes. For the condition of static equilibrium the sum of all the horizontal forces, all the vertical forces as well as the sum of moments were separately taken as zero. The force required in moving the handle when attached to the main (cylinder) shaft of dehuskersheller with chain and sprocket was measured at four positions of handle from ground i.e., top (0°), front (90°), bottom (180°) and back side (270°). It was observed that in operating the maize dehusker-sheller the force exerted by the subject (farm women) on upper leg from trunk when handle had to move from top to front side was 73.08 N, front to bottom side 83.2 N and bottom to back side 73.28 N. During operation of handle from back side to top, the force of 89.47 N was observed on trunk from upper leg for movement of handle from back side to top position of handle which might be due to anti-gravity action of hand.