Analysis of an appliance of pantographs for automatic technological packing lines
Students Name: Hamula Maksym Bohdanovych
Qualification Level: magister
Speciality: Machines and Packaging Technologies
Institute: Institute of Mechanical Engineering and Transport
Mode of Study: full
Academic Year: 2023-2024 н.р.
Language of Defence: ukrainian
Abstract: In the master’s qualification work, the areas of use and the main technical characteristics of scissor lifts are considered. The analysis of the use of pantographs in production technological lines, in particular in the packaging industry, was performed. In addition to the basic capabilities of pantographs, in particular as a lift, for loading and unloading equipment and vehicles, it is possible to combine its capabilities with traditional means of transporting products, in particular conveyors. Such a complex execution of scissor lifts allows you to flexibly integrate them into the composition of high-performance packaging lines as a flow separator. The purpose of the work is the calculation of the scissor lift and modeling of the stress-strain state of the responsible elements. To achieve the goal, you need to solve the following tasks: - choose a scheme and a specific constructive variant of the scissor lift; - drawing up the calculation scheme and determining the main loads; - analysis of the strength of the studied elements; - optimization of basic solutions. The object of development and research is the optimization of the scissor lift. The subject of calculation and research is the characteristics of the stress-strain state. In the second section, a structural diagram of a scissor pantograph with an internal lever drive from a hydraulic cylinder is selected. The main geometric ratios and values of design parameters are given. The effort required to raise the elevator was determined, and the nature of its change was determined. The maximum value of the force in the lower position of the pantograph is 10.23 kN with a platform load capacity of 1 kN. The height of pantograph lifting and lowering can be adjustable and variable due to the execution of the lower frame from two parts, the distance between which is determined by the stroke of a special hydraulic cylinder. The main and most responsible elements of the lift are the system of external and internal levers, which are hingedly connected by the central axis of rotation. In the third section, the stress-strain state of the levers loaded in the lower position by the weight of the platform and the lifting force is simulated. Hinged fastenings are selected in the places of installation of the levers and relative to the axis of their joint rotation. The equivalent stresses and coefficient values of 1.4-1.5 were determined, which is within the permissible values for welded structures with static and low shock loads. Based on the value of the reactions in the hinges of two separate levers, the resulting radial force acting on their central axis is determined. This made it possible to check the axis for the cut and make sure that its strength is ensured. However, the stress distribution graphs have significant unevenness, which made it possible to identify significantly underloaded areas of the levers. By removing part of the material inside the side plates, it was possible to significantly reduce the weight of the inner and outer levers by 22% and 24%, respectively. At the same time, the value of the safety factor decreased slightly, in particular to 1.4. Thus, the most fundamental tasks of calculation and modeling of the stress-strain state of the scissor lift and its optimization have been solved. In the section of the economic assessment, the technical and economic justification of the proposed scissor lift solution with adjustable lowering and lifting height, compared to the standard vertical lift, is performed, the advantages of the proposed implementation and its industrial utility are given. Key words: scissor lift, lever, equivalent stresses, safety factor, calculation.