Studies on the Cultivating Characteristics of the Knife Edge Curve of Rotary Blade (Part II) : Effects of Edge Curve on Soil Cutting Resistance

The edge curve angle of a vertical rotary blade has a considerable influence on the cultivating resistance, the reactions or penetrating actions of the soil, and the entwining phenomenon of grass or straw. In this paper, the experimental results of the effects of the edge curve on the maximum cultivating torque and the cultivating work were reported with regard to the cases of the fixed rotation (circle) and the traveling rotation (trocoid curve). The theoretical operational rotating angle θop which has been already obtained in the previous report were used for the calculation of the cultivating work W. The minimum values of the maximum cultivating torque and work were reached at an edge curve angle of 55” to 60’ under all conditions. Since it is generally recognized that this value of the edge curve angle is in the permission limit of the entwining phenomenon of grass or straw, it may be considered that this range of edge curve angle of a rotary blade is the most reasonable one