MODERNIZATION OF THE MOVEMENT MECHANISM OF THE SUSPENSION CRANE WITH A LIFTING CAPACITY OF 5 TONS (DEVELOPMENT AND INSTALLATION OF A FLOATING UNIT)

The relevance of the research topic consists in optimizing the operation of transport equipment in order to increase its reliability and reduce  operating costs.

Object of study: overhead suspension crane with a lifting capacity of 5 tons.

The purpose of the work is to increase reliability and minimize operating costs for maintenance and maintenance. 

Tasks: justification and selection of the most optimal structural arrangement of the crane. 

The theoretical basis for the study was the research and production experience of Kran-Service LLC. 

The practical significance of the work lies in the possibility of implementing  the proposed measures in production conditions. 

In the course of the analysis of the production experience in maintenance and technical maintenance, Kran-Service LLC systematized and classified the defects that occur in the metal structures of the PTM during operation, as well as the causes of their occurrence. 

The main goals and objectives of the modernization, namely:

- Calculate the span and end beams;

- Determine the loads and optimal design options for these beams;

- design a floating node;

- develop installation technology to ensure safe work methods;

- Conduct a feasibility study of the decisions made. 

In the course of fulfilling the tasks, the main units of the crane's metal structure were calculated and designed, namely the bridge and support beams with a movement mechanism.

The analysis of a number of studies made it possible to establish that the rigid connection of the overhead and support beams of the crane, although it provides rigidity of the cross-sectional contour of the superstructure, practically does not help in ensuring its rigidity and strength under the influence of dynamic loads.

When the span beams deviate from the vertical during their installation and during long-term operation of the crane, there is a significant abrasion of the flanges of the running wheels, twisting and uneven wear of the crane runways, which in turn leads to a decrease in the overhaul cycle, replacement of the crane runway, and, as a result, a decrease in the reliability of the crane metal structure and the formation of increased stresses in the joints of welded joints.

Also, among others, vertical loads resulting from the operation of the lifting mechanism have an impact. The amplitude of the deformation of the crane bridge at the initial moment of lifting the load depends on the speed of lifting the load and the ratio of the stiffness of the crane bridge and the ropes of the pulley. Reducing the amplitude of vibrations is possible by reducing the lifting speed and stiffness of the ropes or increasing the rigidity of the bridge, but this can adversely affect the characteristics, dimensions and weight of the crane, not to mention the efficiency of the work performed.

In case of long-term operation of the crane with distortions and deviations from the vertical of the crane superstructures, there is a significant abrasion of the flanges of the running wheels, twisting and uneven wear of the crane runways, which in turn leads to a decrease in the overhaul cycle, replacement of the crane runway, and, as a result, a decrease in the reliability of the crane metal structure and the formation of increased stresses in the joints of welded joints.

To minimize these loads and increase operational reliability, the use of a floating unit - a sliding support - is proposed in this design.

The main issues of operation and repair of this unit and the crane as a whole in compliance with safety requirements are considered.

The technical and economic calculation showed the effectiveness of the decisions made, the reduction of operating costs for the standard service life amounted to 723.95 thousand rubles, while for each subsequent year of operation this amount will increase by an average of 48.263 thousand rubles. Thus, these measures can be considered effective.

CONTENT

INTRODUCTION..........................................................................

1 DESIGN, ANALYSIS AND PROBLEM STATEMENT..............

1.1 Composition and arrangement of the overhead crane.....................................

1.2 Crane Steel Structure..................................................

1.3 Setting and justifying the goal and objectives..................................

2 DESIGN SECTION..............................

2.1 Input..............................................................

2.2 Selection of the main geometrical parameters of the structure..........

2.3   Determination of design loads on structural steel units and forces in them.........................................................................

2.4 Design of welds..........................................................

2.5 Coupling of span beams to end beams.............................

2.5.1 Determination of the smallest cross-section of the roller shaft and axis..............

2.5.2 Bearing selection........................................................

3 INSTALLATION, COMMISSIONING. MAINTENANCE & REPAIR...........................................................................

3.1 Installation...........................................................................

3.1.1 Organization of installation works...........................................

3.1.2 General installation instructions..............................................

3.1.3 Complete assembly............................................

3.1.4 Element-by-element installation of the crane.............................................

3.1.5 Installation of electrical equipment............................................

3.2 Maintenance..................................................

4 FEASIBILITY STUDY.......................

CONCLUSION.......................................................................

LIST OF ABBREVIATIONS......................................................

REFERENCES.....................

The graphic part consists of a general view of the crane, metal structures, a movement mechanism, and an assembly drawing of the floating unit.