ANALYSIS FLAT MECHANISM OF THE FOURTH CLASS WITH A MOVING CLOSED LOOP AND THREE COMPLEX LINKS

Abstract

The study of complex structural groups of links of flat mechanisms allows to improve the existing technological equipment and design new machines. Such mechanisms, based on structural groups of the fourth and higher classes, can ensure the implementation of innovative technological processes of production. Kinematic studies of complex flat mechanisms of the fourth class and higher are certainly relevant, if we take into account the individual approach to their research. The use of such mechanisms is increasingly observed in modern equipment that ensures the execution of technological processes at enterprises of the fashion industry. The work developed a sequence of actions for finding the velocity vectors of the points of the fourth-class mechanism with a moving closed loop, which is formed by four links, three of which have the form of complex links, is developed. The linear vectors of the velocities of the points coinciding with the geometric centers of the kinematic pairs of the structural group of links of the fourth class of the third order were determined. We conditionally changed the input mechanism to another structurally possible in a flat mechanism. The research was carried out using the graph-analytical method. In order to carry out a kinematic analysis of the mechanism, it is proposed to take into account the presence of complex links in its structure, namely the structural feature of the formation of a sequential connection of three links in a kinematic chain of the type “rocker arm – connecting rod – rocker arm”. This made it possible to determine the position of the instantaneous center of velocity of the link, which has plane-parallel motion. Conditional rotation of another conditionally leading link around such an instantaneous center of rotation made it possible to simplify the graphic constructions of the study. The application of the graph-analytical method made it possible to perform vector graphic constructions in an arbitrarily chosen scale for the entire mechanism, and after their completion, to perform detailed calculations of the scale of a certain vector construction.