Verifying the Lifting and Slewing Dynamics of a Harvester Crane with Possible Levelling When Operating on Sloping Grounds

Václav Mergl,Jaroslav Kašpárek

doi:10.3390/f13020357

Abstract

This paper focuses on the force and torque load of a harvester hydraulic crane employed on sloping grounds, both levelled and not levelled. Field research was conducted for this purpose and the results were compared with a dynamic analysis of the crane in MSC Adams. It was found that levelling the slewing platform of the crane is necessary for use on sloping grounds, primarily because the effect on the force and lifting torques is reduced. The research showed that when the slope of the slewing gear is up to −12°, the lifting torque reaches a higher maximum lifting force than when the slewing gear is in a horizontal position (0°). As part of the theoretical verification by a dynamic analysis of the crane and the AH6 machine, a different pressure was detected in the lifting cylinder of the crane compared to the field research. The total deviation between the simulation and the field research was 9.82%. The slewing torque of the hydraulic crane without the slewing bearing being levelled can be characterized 97.38% by a parabola whose vertex is located in front of the front part of the machine and falls as the crane moves left or right. Overall, it can be determined that when the crane rotates up a slope, whether it is from left or right, the slewing torque reaches the lowest values, and its value increases as the crane gets closer to the front of the machine (along the longitudinal axis of the machine). This change in the slewing torque is then characterized by a parabola. Furthermore, an effect was observed of the slewing gear slope on the lifting torque, which reached higher values in a tilted position than on a flat surface.

Highlights

The CTL (Cut to length) technology is employed increasingly often on previously inaccessible sloping grounds, as evidenced by many studies [1,2,3,4]
Even from these data, that the slope affects the lifting torque in favour of the slewing gear not levelled. This statement has been verified by statistical analyses showing that the tilt of the slewing gear affects the lifting torque of the hydraulic crane since all the values shown in Table 2 were lower than the specified level of significance (0.05)
It can be stated that levelling the slewing gear of a crane is necessary on a sloping ground, especially since the effect on the lifting and slewing torques is reduced

Summary

Introduction

The CTL (Cut to length) technology is employed increasingly often on previously inaccessible sloping grounds, as evidenced by many studies [1,2,3,4]. Their use improves work safety and reduces financial expenses [5,6,7]. The harvesters and forwarders used are equipped with the option of levelling the hydraulic crane and the cabin, which makes its operation more ergonomic, and better stability of the machine is ensured [1,10]. For example: How different will the slewing and lifting torques be of a levelled crane and a not levelled crane? Is there a relationship between the slope and the lifting torque? Can the slope of the crane affect the hydraulic pressure in the cylinder?

Methods

Results

Discussion

Conclusion