RECHNERGESTÜTZTE ANALYSE DER FADENBEANSPRUCHUNGEN BEIM WEBEN

The load of warp threads on the weaving machine is determined by the force arising during the shed formation and the weft beat up. The author describes, using computer aided modelling, the course of warp stress during these processes. The results of the modelling process and those of practical measurements match qualitatively well. Using the modelling process also circumstances of the loosening of the upper shed side at open shed can be shown. The author's research work proves that the loosening of upper shed side can be eliminated only if the basic yarn stress increases proportionally with the shed distortion. The computer aided method of modelling, introduced in this article, neglects, in first approach, the dynamic effects, the elasticity of the fabric and, for example, the effect of the sprung back test roller. If these effects and also the parameters of weft beat up are taken into consideration, the method can be improved and can be available for the quantitative analysis of warp thread stress, too

OPTIMIERUNG DER FADENBEANSPRUCHUNGEN BEI DER FACHBILDUNG

The character and size of yarn stress during the shed formation are determined by its technological dimensions: the height and other measurements of the shed, the breaking angle of the basis level and the course of shed formation. On shuttle weaving machines the shed must be clear, i.e., each warp thread must be in the same plane in the front part of the shed. In clear shed the elongation of yarns depends on which heddles are threaded in with the yarn. Further variations of elongation come from various shed lengths that depend on the row of lamella and on the order of threading in. On shuttleless weaving machines clear shed is not necessary. It is useful to prescribe the order of threading in the lamella in that way that yarns drawn in the healds No. 1 to 2 should be threaded in row No. 1 of lamella, etc. and elliptic shed form should be set up determined by the various shed lengths and equal yarn elongations

ZUSAMMENHÄNGE ZWISCHEN DEN GARNEIGENSCHAFTEN, DER GEWEBE-DICHTEPARAMETERN UND DER EINSTELLUNGSPARAMETERN DER MASCHINEN

The author has compared the parameters describing fabric density and weaveability. These parameters can be calculated from the cover factor, the density index (this takes also the yarn crossings into consideration) and the yarn stress in the weaving process. The analysis has proved that the structural co-efficient refiects the most sensitively the reldations of weaveability, and the author demonstrates in this article the connection of the structural co-efficient with the multiple density index. Practical measurements prove that yarn stress during the weaving process follows the theoretical relationships with the structural co-efficient and the elasticity co-efficient. This latter one expresses the elasticity of the warp threads and the woven fabrie, resp. Also the relation of the structural co-efficient and the machine setting has been analysed. The results of measurements have proved that the machine setting parameters, i.e., the basic load, the pre-closing of the shed and the breaking angle of the basis level form characteristically the relation of the structural co-efficient and the density index