On the Cleat for Small Tractor in Sand Dune Field
Thrust of the Single Cleat
1980 Volume 42 Issue 1 Pages 37-42
Details
1980 Volume 42 Issue 1 Pages 37-42
I measured and examined the thrust of single cleat to get a constructed data of crawler unit. This unit is used for harvesting of Baker's garlic, by that intended to improve tractive performances of walking tractors on sand dune fields with demountable crawler unit.
1. Having fixed cleat width (b) and cleat length (l) in considering the planting conditions, the grouser height (h), grouser angle (θ) and contact pressure (p), which are another comparatively alterable variables on the cleat factors are examined.
2. Test conditions of these variables used in this study were as follows: grouser height is 3, 6, 9 and 12cm; grouser angle is 45, 60, 75 and 90°; contact pressure is 0.10, 0 15, 0 20, 0.25 and 0.30kg/cm2.
3. For thrusting, effect of these three variables and of interaction p and h is significant at the 1 percent level. Especially, contact pressure was 72 percent as factorial contribution and grouser height was 26 percent. From the above test, it was proved that these two variables have a great influence on thrust.
4. The increase of contact pressure and grouser height makes proportional increase of thrust. Specific thrust, which almost shows a certain value independent of grouser height, varied with the conditions of contact pressure.
5. For grouser angle, thrust reached its maximum value when the angle acting perpendiculerly against the surface of field, was 90.
6. The rate causing thrust by grouser was larger when contact pressure was low, and its maximum value under the condition of the experiment was 52 percent.
7. Still fixing cleat width and soil wet density (γ), an experimental equation which predicts thrust (Ft) together with variables can be written as follow:
Ft=0.315 γ0.254 b 2.056 p 0.746 h 0.198 θ 0.280=38.573 p0.746 h 0.198 θ 0.280
8. Providing various soil wet density (γ) from 1.3 to 1.6g/cm3, it was proved significant for thrust. So showed the change of thrust influenced by soil wet density as ratio of thrust variance, to predict thrust against varied soil wet density in different fields.
