Determination of Loads Arising During Movement of Traveling Wheels of Bridge Cranes

Different working conditions and design features of individual lifting machines and crane paths cause a wide variety of mechanisms for moving cranes and crane trolleys. The movement resistance of the crane or trolley is formed when the wheels roll on the rails and in the wheel bearings. During the operation of the crane, the running wheels are under the influence of various loads - the weight of the cargo, the crane's own weight, air pressure, the force of inertia and loads that occur when the cranes are skewed on the under-crane paths, when there are defects in the under-crane paths and the crane's undercarriage. The dimensions of the rails must correspond to the loads and dimensions of the running wheels and are ensured by calculating them for bending and for local compression under the wheel. During the operation of the crane, the load on the running wheels sometimes varies widely. Its durability, reliability, ease of manufacture and maintenance largely depends on the structural form of the beam. The design of the closed profile gives the maximum increase in torsional stiffness. Tilting of a moving crane is the result of such reasons as slipping or slipping of the crane's drive wheels on the rails, differences in the diameters of the drive wheels, incorrect installation of the wheels, and defects in the crane paths. Impact loads that occur during the movement of the running wheels occur in two cases: when the cranes hit the end stops and when passing the joints of the rail path and local irregularities. In order to reduce shock loads, modern cranes and cargo trolleys have buffers when they approach the end stops, which allow to extend the working stroke of the crane Impact loads that occur during the movement of the running wheels occur in two cases: when the cranes hit the end stops and when passing the joints of the rail path and local irregularities. In order to reduce shock loads, modern cranes and cargo trolleys have buffers when they approach the end stops, which allow to extend the working stroke of the crane and increase the reliability and safety of crane operation. The choice of the type of running rail is related to the amount of load on the running wheels and the design features of the movement mechanism - conical running wheels can move only on a convex rail, cylindrical wheels - on both convex and flat rails. The wear and tear of the elements of the under-crane path leads to the failure of the metal structures of the under-crane beams, which causes significant economic losses. The transition in crane structures from riveted under-crane beams, which had discrete belt connections with defined mobility to welded beams with a rigid system of belt connections without structural compensation of mobility, led to a significant decrease in the durability of welded beams. The local stress state of the wall in the welded crane girders, which determines the fatigue strength in this zone, can only be adjusted using the crane rail. But the operation of the under-crane path has not been properly investigated until now. Possible deformations of both the running wheels themselves and the rail tracks depend to a large extent on the height and nature of the rail joint, the shape of the rail and the speed of the running wheels. In the article, a more precise definition of the loads that occur in the under-rail beams was carried out, some assumptions were rejected and new calculation formulas were obtained. In addition, an analysis of the influence of the method of installing rails on the value of force factors was carried out.