RESEARCH OF DYNAMIC LOADS IN THE LIFTING MECHANISM OF THE « SOKOL» PORTAL CRANES

Abstract

 Portal grappling cranes are widely used for transshipment of bulk cargo in sea and river ports. The economic state of the country over the past 25 years has led to the fact that more than 90% of portal cranes that are currently operated in ports have fulfilled the standard period. Their further operation is due to the fact that new equipment arrives at ports in small Volumes.   

As practical experience shows, a considerable number of mechanism failures and accidents are associated with lifting equipment that has served its time and continues to be intensively operated in a cyclic mode. Today, an extremely important scientific and applied task is to determine the level of dynamic loads in the lifting mechanisms of Grab cranes.

The analysis of works showed that the dynamic loads in the lifting drive of a portal grab crane, which were soldered for more than 40 years, have not been sufficiently studied. It should be noted that each crane requires a separate study, since the dynamic characteristics of mechanisms depend on the operating conditions, geometric, physical and mechanical parameters of its

 The object of research is used for transshipment of bulk materials to a ship in a seaport.  The elktrotensometric method was used to determine dynamic forces. The maximum measured load values in the rope branches were observed at the moment of separation of the Grab with the load from the base. Changes in loads over time are fluctuating, which is consistent with known studies. Based on the obtained data, the dynamism coefficients are calculated. Analysis of the results showed that when working with loads weighing from 10 tons to 15 tons, the dynamism coefficient varies from 1.35 to 1.95, and the dependence on the weight of the load is nonlinear. The calculated values of the dynamism coefficients exceed the standard values, which indicates an overload of the lifting drive, and also leads to periodic replacement of its components.