Stitch structure of double chain loop seam

Abstract

A method for preventing seam ravel of multi-thread chain stitches is provided. After normal sewing is terminated with a looper set in a forward movement state, a state in which a needle thread loop caught by the looper is subjected to position-holding at a position closer to a forward movement end of the looper than a descent position of a needle is maintained until the needle descends through the needle thread loop caught by the looper. Thereafter, the position-holding of the needle thread loop is released to permit a sewing action for at least one stitch, thereby allowing the needle thread loop to be self-looped with a needle thread held by the needle. This surely strongly prevents the seam ravel of multi-thread chain stitches formed by the single needle, irrespective of the dimension of tension applied to the needle thread and the looper thread.

Description

[0001] The patent application of the present invention is the application number 201210338785.4, the application date is September 13, 2012, and the name is "the method for the stitch opening of anti-double chain ring sewing, the anti-stitch opening device of double chain ring sewing machine and the double chain ring sewing machine." The divisional application of the invention patent application of "stitch structure of seam". technical field [0002] The present invention relates to a stitch structure of a double-chain loop seam. The stitch structure of the double-chain loop stitch uses a double-chain loop sewing machine mainly represented by a horizontal cylinder type, and the thread of the double-chain loop stitch is formed by suture thread and a looper thread stitches, and can prevent the stitches of the double-chain loop seam at the end of sewing part to produce open thread. Background technique [0003] A general double-chain sewing machine such as a horizontal cylinder...

AI Technical Summary

Problems solved by technology

[0004] There are following problems in the structure of the stitches M of the general double-chain loop stitching formed by the double-chain loop sewing machine: Figure 27 As shown, the end of the looper thread 10 that is cut off at the end of sewing is Figure 27 When stretched in the direction indicated by the middle arrow, the looper thread 10 will be pulled out from the final suture loops 20a, 20b formed by the sutures 20, 20. There will be open lines on the whole of the stitch M

[0010] However, in the currently proposed anti-opening method, there are the following problems: Figure 28 and Figure 29 The y-direction of the looper thread 10 is easy to pull out from the final suture loops 20a, 20b when the tensile force is applied in the y direction. The whole stitch will produce open lines

[0011] For example, in the case of a thinner or softer fabric to be sewn, since the sewing is performed under a state where the applied tension of the suture and the looper thread is small, a good sewing effect can be obtained. Therefore, the suture ring 20a , 20b are insufficient to fasten the looper thread 10, as a result, the above-mentioned open thread is more likely to occur

[0012] Particularly, in the case of the stitches of the double chain loop stitching formed by one needle, the looper thread 10 is only interwoven with the last stitch loop 20a of the stitching thread 20 in the state of being intertwined, therefore, Pull-out occurs only by applying a slight tensile force, so the effect of preventing thread opening is very low

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