Abstract
The writer made analytical studies on the load and harrowing characteristics of both the spur-lugged and the spiral-lugged rotors as puddling mechanism in order that their modal characteristics may be made clear and that their working conditions, together with the technical data for the development of new designs, may be defined.
(1) The power consumption in paddling per unit working width and per section increases as the slippage rate and the velocity rise. This increase is expressed by a logarithmic equation, y=axb. In the case of a heavier small-type tractor, effective puddling should be accompanied by an appropriate increase in slippage.
(2) The puddling resistance decreases in logarithmical proportion as the slippage rate increases. The puddling resistance of spur-lugged rotors is less than that of spiral-lugged ones. The harrowing effect of both types, however, is not satisfactory because their slippage is not large enough.
(3) The power consumption and the harrowing index of spur-lugged rotors are greater than those of spiral-lugged ones. At the lower speeds, wide difference in the harrowing effect was observed between the upper and the lower profiles.
(4) The curve of the hardness-depth of tilth is almost a straight line, showing that the effect of harrowing is becoming less in a lower profile.
