Cage Wheel Lugs Research Articles

Effect of circumferential angle, lug spacing and slip on lug wheel forces

This study was conducted to investigate the effect of circumferential angle, lug spacing and wheel slip on forces produced by a cage wheel. Experiments were conducted in a laboratory soil bin having Bangkok Clay soil with 51% (d.b.) soil moisture content. Six ring-type loadcells were used to measure the soil horizontal, vertical and transverse reactions on the cage wheel lugs. The circumferential angle was varied from 0, 15, 30 to 45°. The lug spacing and wheel slip were varied from 20, 30 to 40° and 20, 35 to 50% respectively. All the force measurements were done at a constant 7 cm sinkage. The results showed that increasing circumferntial angle up to 45° can reduce variation in lug wheel forces, at the same time it had little effect on the mean pull and lift values. The side force was affected by the changes of circumferential angle. The 20° lug spacing not only gave the minimum variations but also maximum mean lug forces. The highest lug wheel forces occurred at 35% wheel slip.

Pull and lift forces on multiple cage wheel lugs when operating in wet clay soil

The forces acting on multiple cage wheel lugs were measured when operating in wet clay soil. In a previous study, it was observed that the soil behaviour under the second and subsequent lugs was the same; therefore the forces under these lugs will be the same. Hence only two lugs were used in this study. The effects of soil moisture content, lug sinkage, slip and spacing on lug forces were studied. The lug normal and tangential reactions were measured with the help of strain gauged transducers. These forces were then converted to lug pull and lift forces. It was observed that lug forces on the preceding lug were always higher than those on the succeeding lug. For both the lugs, an increase in soil moisture content caused a decrease in lug forces, but an increase in lug sinkage caused an increase in lug forces. The lug slip did not affect the forces on the preceding lug, but it showed a significant effect on the forces on the succeeding lug. The lug spacing affected the forces on the succedding lug. The comparison of forces predicted by the conventional passive earth pressure theory and measured forces showed that the theory overestimated the lug forces for both lugs. The overestimation was higher for the succeeding lug forces than for the preceding lug forces.

Improvement of the tractive performance of cage wheel lugs by enamel coating

Previous work has shown that enamel coating on cage wheel lugs can significantly reduce soil sticking to the lugs, reducing the possibility of cage wheels blocking with soil. However, the effect of enamel coating on lug forces was unknown. Experiments were conducted, to study the effect of enamel coating on lug forces in a laboratory soil bin as well as in actual field conditions. In both experiments the soil used was a heavy clay soil. The lug surfaces were coated with enamel and their performance was compared with that of uncoated lugs. During the laboratory studies it was observed that at constant sinkage and soil moisture content, the lug forces generated by the enamel coated lug did not differ significantly from those generated by the uncoated lug. An increase in lug sinkage caused an increase in the lug forces while an increase in soil moisture content caused a decrease in lug forces. During the field studies, in different soil conditions, it was observed that the pull of the power tiller's wheels fitted with enamel coated lugs at any level of slip was higher than that of wheels fitted with uncoated lugs. The mean values of pull at 100% slip for enamel coated lugs were about 6% higher than that for the uncoated lugs. The differences between the maximum power transmitted for uncoated and coated cage wheel lugs were not statistically significant. Cage wheel blocking during field trials was never observed in the case of enamel coated lugs but blocking was quite frequent with uncoated cage wheel lugs.

Limitations of passive earth pressure theory for cage wheel lug and tine force prediction : Salokhe, V M; Rajaram, G; Gee-Clough, D Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7–11 December 1987V1, P5.171–5.184. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Limitations of passive earth pressure theory for cage wheel lug and tine force prediction : Salokhe, V M; Rajaram, G; Gee-Clough, D Proc Ninth Southeast Asian Geotechnical Conference, Bangkok, 7–11 December 1987V1, P5.171–5.184. Publ Bangkok: Southeast Asian Geotechnical Society, 1987

Improvement of the tractive performance of cage wheel lugs by enamel coating

Previous work has shown that enamel coating on cage wheel lugs can significantly reduce soil sticking to the lugs, reducing the possibility of cage wheels blocking with soil. However, the effect of enamel coating on lug forces was unknown. Experiments were conducted, to study the effect of enamel coating on lug forces in a laboratory soil bin as well as in actual field conditions. In both experiments the soil used was a heavy clay soil. The lug surfaces were coated with enamel and their performance was compared with that of uncoated lugs. During the laboratory studies it was observed that at constant sinkage and soil moisture content, the lug forces generated by the enamel coated lug did not differ significantly from those generated by the uncoated lug. An increase in lug sinkage caused an increase in the lug forces while an increase in soil moisture content caused a decrease in lug forces. During the field studies, in different soil conditions, it was observed that the pull of the power tiller's wheels fitted with enamel coated lugs at any level of slip was higher than that of wheels fitted with uncoated lugs. The mean values of pull at 100% slip for enamel coated lugs were about 6% higher than that for the uncoated lugs. The differences between the maximum power transmitted for uncoated and coated cage wheel lugs were not statistically significant. Cage wheel blocking during field trials was never observed in the case of enamel coated lugs but blocking was quite frequent with uncoated cage wheel lugs.

Studies on effect of surface coating on forces produced by cage wheel lugs in wet clay soil

Experiments were conducted to study the effect of surface coating on lug forces in a laboratory soil bin with the help of model cage wheel lugs in quasi-static condition. The lug surfaces were coated with Teflon tape, ceramic tile and enamel and their performance was compared with an uncoated mild steel lug. An ‘L’ shaped force transducer was designed to measure normal and tangential soil reactions. These forces were then converted into pull and lift forces. At constant sinkage, slip and soil moisture content, lug forces generated by the coated lugs did not differ significantly from those generated by the uncoated lug. Increase in lug sinkage caused increase in lug forces. However, at any constant sinkage lug forces produced by the various lugs were almost the same. Increasing lug slip beyond 35% slip did not affect the lug forces significantly. Increase in soil moisture content caused a decrease in lug forces. However, lug forces generated by the various lugs at any moisture did not differ significantly from each other. In general it was observed that coating of lug surfaces with the above mentioned non-wettable materials did not affect the lug forces.

Pull and lift forces acting on single cage wheel lugs

The lug forces, normal and tangential, on a single model cage wheel lug were measured in a wet clay soil. These normal and tangential forces were converted into lug pull and lift forces. The effect of lug sinkage, slip and soil moisture content on lug forces was investigated. Lug normal and pull forces increased up to a certain degree of lug rotation and then after attaining a peak value decreased. The lug tangential and lift force also increased up to a certain angle of lug rotation, then dropped continuously, attained a negative peak value and finally rose again to become zero at lug exit. Increase in lug sinkage showed an almost proportionate increase in lug forces while increase in soil moisture content caused a decrease in lug forces. The effect of lug slip on lug forces at constant sinkage was found to be statistically nonsignificant as lug slip was always high. Using the passive pressure soil failure theory the lug forces were predicted and compared with the measured values. It was found that the theory did not predict the lug forces accurately.

TRACTIVE PERFORMANCE OF A POWER TILLER WITH ENAMEL-COATED CAGE WHEEL LUGS

ABSTRACT Field studies were conducted to compare the tractive performance of a power tiller fitted with enamel-coated and uncoated cage wheel lugs in different soil conditions. The drawbar pull of the power tiller wheels fitted with enamel-coated lugs at any level of slip and depth of hard pan was higher than that of wheels fitted with uncoated lugs for moist soil conditions (close to the lower plastic limit of the soil and higher). The mean values of drawbar pull at 100% slip for enamel-coated lugs were higher by 6.03% on an average than that for the uncoated lugs. Cage wheel blocking was never observed with the enamel coated lugs whereas the uncoated lugs resulted in blocking even in trials of very short duration.

The measurement of forces on a cage wheel lug when operating in wet clay soil

The forces acting on a single model cage wheel lug were measured when operating in a wet clay soil. After initial lug entry into the soil, the normal and tangential forces acting on the lug increased up to a certain peak value and then dropped as lug rotation increased further. The tangential force later attained a negative peak value. The pull force showed the same trend as lug normal force. The lift force showed the same trend as tangential force, however, the positive peak value of lift force was much higher than the positive peak value of tangential component. The lift force was higher than the pull force. Increase in lug sinkage showed almost proportionate increase in lug forces while increase in soil moisture showed decrease in lug forces. The effect of lug slip on lug forces at constant sinkage was found to be statistically non-significant.

Technology showcase applications of enamel coating in agriculture

Recently various experiments were conducted at the Asian Institute of Technology, Bangkok, to study the effect of enamel coating on the performance of some agricultural equipment. In order to reduce soil adhesion on cage wheel lugs, nine different coating materials were tried and enamel coating was found to be the best among these materials. It reduced soil adhesion on cage wheel lugs considerably to avoid cage wheel blocking. To investigate effect of coating on lug forces detailed lab studies were undertaken to measure the lug forces. The effects of lug slip, soil moisture content and sinkage were investigated. It was observed that enamel coating did not affect the lug forces. The pull and lift forces generated by the enamel coated and uncoated lugs were almost the same. When enamel coated bolt-on plates were mounted on the power tiller cage wheel lugs and trials were conducted in actual field conditions, it was observed that in actual field conditions enamel coated bolt-on plates on cage wheel lugs improved the performance of a power tiller. Studies about coating effects on the drag force required to pull floats on soil surface were also conducted. It was observed that enamel coating on floats reduced the drag force significantly. It also greatly improved the scouring of a mouldboard plough used in a wet, sticky clay soil.

Limitations of passive earth pressure theory for cage wheel lug and tine force predictions

Experiments in wet clay soil with cage wheel lug showed that the failure pattern in front of a lug was totally different from that assumed in passive soil pressure theory. Based on the failure pattern, the area of deformation zone and surcharge buildup in front of the lug, it was observed that the existing passive soil pressure theory could not be used to describe the soil movement caused by the action of the cage wheel lug. While working with a tine, four types of soil failure patterns were observed. It was found that these types of soil failures in front of a rigid tine were a strong function of soil moisture content. Passive pressure theory does not accurately predict the forces measured.

Wet clay soil behaviour under multiple cage wheel lugs

This paper presents the results of studies on the deformation of wet clay soil under the action of multiple lugs. The effect of trench spacing (the distance between trenches cut by successive lugs), lug slip and lug spacing on the soil deformation under cage wheel lugs was studies. Wedge formation under a succeeding lug has also been studied. It was observed that the soil behaviour under multiple cage wheel lugs was significantly affected by lug spacing and slip. The soil wedge formation as well as soil adhering to the succeeding lug was a strong function of lug slip and spacing. In all cases the soil deformation pattern was quite different from that caused by a single lug.

Modes of wet clay soil behaviour under a single cage wheel lug

Abstract This paper presents the results of studies on the effect of sinkage and slip of a single cage wheel lug on the deformation of wet clay soil. It was observed that the deformation pattern was strongly influenced by lug sinkage and slip. Soil wedge formation on the lug was also found to be a function of sinkage and slip. Four different deformation patterns were identified during this investigation. It seems unlikely that these can be predicted without a more exact knowledge of stress-strain relationships in soils.

Behaviour of wet clay soil under single cage wheel lugs

This paper presents the results of studies on the deformation of wet clay soil under the action of a single lug. The effect of lug angle on the soil deformation has been investigated. The experimental results are critically compared with the conventional theories of soil failure. It was observed that the existing passive soil pressure theory could not be used to describe soil movement caused by the action of the cage wheel lug. Speculation about the soil failure prediction due to a rigid tine or soil cutting blade has raised doubts about the wisdom of applying this theory to other soil cutting tools.