Design a new cutter-bar mechanism with flexible blades and its evaluation on harvesting of lentil

Abstract

One of the challenging problems of the cutter-bars is the damaging effect of stones on their blades. This problem is much bigger while harvesting short plants. One of the valuable but short height crops is lentil, which can grow well in stony fields. Lentil in most countries especially in West Asia and North Africa (WANA) is harvested by hand.In order to overcome the problem of blades damaging, a new mechanism was designed and fabricated. Each blade has its own safety mechanism and so can show flexion independently. The harvester was tested in lentil farms which were rein-fed and manually distributing planted. Forward speed, knife speed and carousel speed were the independent variables that their impacts on both product losses and cutting height were evaluated. The obtained data was analyzed by Design Expert software and two quadratic stepwise models with the R2 of 0.9505 and 0.9046 were obtained for losses and cutting-height respectively. The results showed that forward speed has the greatest impact on both of losses and cutting height.On the other hand, the new cutter-bar and a conventional one with almost equal blades, working widths and cutting height were tested in lentil farm. The conventional cutter-bar had lost half of its blades after a while but there was not any damaged blade of the new cutter-bar.Finally, forward speed of 2 kmh−1, carousel speed of 34.83 rpm and knife speed of 476 rpm was recognized as the best working set-up for the testing region.