Yarn tensioning method and device for textile weaving machines

DETAILED DESCRIPTION It is a primary object of the present invention to provide yarn tensioning method and device which facilitate the production of three-dimensional fabrics with a large yarn orientation angle as mentioned above, imparting a higher tension to the feed yarn in a yarn draw-out phase of a weaving operation and a lower tension to the feed yarn in a yarn draw-back phase with a large yarn draw-back capacity.
It is another object of the present invention to provide yarn tensioning method and device suitable for use on a textile weaving machine which is arranged to produce a three-dimensional fabric by interweaving a large number of yarns on yarn carriers which are driven by a carrier drive mechanism to shift their positions along predetermined loci of movements within a common carrier shifting plane, the yarn tensioning method and apparatus including means for producing beating effects in a favorable manner to increase the yarn orientation angle of the fabric.
It is still another object of the present invention to provide yarn tensioning method and device which, in addition to the beating effect which permits to increase the yarn orientation angle of fabrics, are capable of suppressing the degree of yarn fluffing, which would take place at the time of yarn draw-back through a large bending angle, by lowering the tension in the feed yarn in the yarn draw-back phases.
It is a further object of the present invention to provide yarn tensioning method and device, which employ a high tensioning mechanism and a low tensioning mechanism on a yarn carrier, applying a high tension to the yarn by the high tensioning mechanism in a yarn draw-out phase of a weaving operation and applying a low tension to the yarn by the low tensioning mechanism in a yarn draw-back phase past a limit point of yarn draw-back by the high tensioning mechanism.
It is a further object of the invention to provide a yarn tensioning device having a support member for the high tensioning mechanism easily detachably mounted on an upper end portion of a bobbin support shaft erected at the center of a carrier, or having the bobbin support shaft easily detachably planted on the carrier, thereby facilitating the replacement of the bobbin while ensuring stabilized weaving operations