Synthesis of the heddle drive mechanism

Abstract

Introduction. Domestic enterprises in various industries use a variety of process equipment, including weaving machines. Modern weaving machines have several unique features, including a close relationship between technical condition, productivity, and product quality. Weaving machines are widely used in the textile industry in Russia and other countries. To produce cotton, silk, wool, linen, and other types of fabrics, appropriate machines are designed, including shuttle, shuttleless, pneumatic, and hydraulic machines. One of the most crucial parts of the machine is the heddle lifting mechanism, which determines the weave pattern and the quality of the fabric produced. The purpose of the work is to reduce the dimensions of the loom by changing the design parameters of the heddle lifting mechanism. The research methods are based on the theory of machines and mechanisms. They enable the development of a method for synthesizing the heddle lifting mechanism and designing a device with reduced dimensions. The paper presents the synthesis and analysis of the Assur group algorithm, which can determine the kinematic characteristics of the mechanism. Results and discussion. Following the proposed methodology, the mechanism design was modified by removing the fixing device from the lever mechanism operating area. This allowed for a reduction in interaxial distances and a change in the kinematic scheme. As a result of the new position of the fixed axes, some levers, the connecting rod, and the angle of the double-arm lever were also altered. The synthesis of the mechanism is proposed to begin with the last Assur group, setting it a specific value for the G-point motion equal to 75 mm. (motion of the fourth heddle shaft). As a limitation, the equality of arcs (chords) E´E = F´F ` was accepted. By assigning these values to the input element for the second-class first-type Assur group and bearing in mind the accepted conditions, the motions for point D were obtained. Thus, the value of the swing angle  of the roller shaft equal to 22.46° was obtained, which is 27.44 mm along the chord. Applying the interpolation principle, we found the initial motion value of 28 mm. Since the loom is planned to produce interlacing fabric patterns using 10 heddles, the design provides for a variable parameter that allows changing the motion of the heddles depending on their location in the depth of the machine. This role was assigned to the lever B03D. A cam pair synthesis was performed after determining the maximum and minimum values of the center of the roller motion. In total, 5 types of laws of motion were considered: straight-line, harmonic, double harmonic, power-law, cycloidal ones. For the center of the roller, the cycloidal law of motion was selected since it better corresponds to the specified conditions. The synthesis's accuracy was confirmed by the constructed cam profile and conducted kinematic studies for the Assur groups.