Research of the Dynamics of a Hydraulic Loader Crane in Case of Conjoint Movement of Sections
Regulations and specifications and maintenance documentation to regulate the work of hydraulic loader cranes, allows to combine im-plementation of movement of several boom sections over time. For that purpose the operator of the loader crane activates several hydrau-lic control valves simultaneously. In comparison with the case of separate movement of sections, conjoint movement of sections leads to the changes in mechanical tension level of supporting iron of a loader crane, as well as the changes overcome by the hydraulic cylinders. Conjoint movement makes it possible to reduce overcoming efforts, with positive effects on capacity and power efficiency of a loader crane. To access the impact of these phenomena on dynamics and loading of loader cranes using the developed mathematical model, there was conducted a computer simulation of dynamics when sections move conjointly. The results of this simulation were confirmed by the experimental research. The method of the experimental research involves video recording of loader crane movements with further processing obtained recordings using the special software, Kinovea. The experimental research made it possible to reveal a random scat-ter of a loader crane speed and acceleration values because of the manual control. It was found that the combination of movements of loader crane sections, which are connected only by hydraulic hinges, allows to reduce the cycle time of 10…40%. In turn, combination of pivot and telescoping section movements over time leads to changing efforts overcome by hydraulic drive of 30…40%. At the same time, efforts in hydraulic drive can both increase and decrease. This is due to both change of inertial load dependent on the current values of section instantaneous velocities and change of inertia moment of a moving boom section relative to the cylinder hinge.