Stitch forming method and device

Abstract

The invention provides a method and device for forming stitches of a sewing machine. According to an object of the invention, in thick skin of a vehicular sheet or furniture, when top sides of two sheets of sewing materials are aligned, ends thereof are sewn together and thereafter, the sewing materials are split to open by putting a sewing portion thereof on an inner side, the sewing materials are sewn together such that stitch thread does not appear at the top sides of the sewing materials. A stitch is continuously formed in cloth by repeating operation of forming a plurality of stitches by feeding the cloth in one direction by (n+1) stitches to a sewing machine for forming lock stitch by a cloth feed apparatus and thereafter feeding the cloth by n stitches in a direction reverse to the one direction by the same feed amount.

Description

technical field [0001] The present invention relates to a stitch forming method and device of a sewing machine, especially in sewing thick leather objects such as car seats and furniture, after the ends of two pieces of sewing material are joined together and the ends are stitched together, the seam Stitch forming method and device for sewing materials used when the sewing material is unfolded and the seaming part is placed inside. Background technique [0002] Conventionally, in the case of using a sewing machine to perform the above-mentioned sewing, for example Figure 7 As shown, firstly, the surfaces of the upper cloth W1 and the lower cloth W2 are overlapped, and then through the cooperation of the needle and the hook, the upper and lower cloths are formed on the side ends as shown in Fig. Figure 8 The shown lockstitch stitch consisting of upper thread NS and lower thread US accomplishes the seaming of the side end. Then, if Figure 9 As shown, it is used in a state...

AI Technical Summary

Problems solved by technology

[0007] However, in the lockstitch sewing machine, although the knotted portion is formed in the center of the upper and lower fabrics by balancing the tensions of the upper and lower threads NS and US, since tension is applied to the lower thread US set on the bobbin case, The mechanism is composed of a thin spring plate, so this structure can only apply a certain limit of tension to the lower thread US. Therefore, as a result, it cannot apply a large tension to the upper thread NS and the lower thread US, so that the connecting force of the upper thread NS and the lower thread US increase is limited

[0008] Moreover, even if the tension is increased as mentioned above to suture, when the expanded part of the suture is impacted, it will form Figure 9 The upper thread NS and the lower thread US shown, or the knotted points of both, are exposed on the surface of the upper cloth W1 and the lower cloth W2, thereby resulting in a decrease in the value of the product.

[0009] In addition, even if the binding force is improved by loop stitches composed of a combination of multiple threads like double chain stitching or flat stitching, when some of the loop stitches are cut, they will come apart from there, Therefore, there is a problem of poor durability

[0010] In addition, although it is also conceivable to increase the strength of the connection force by overlapping the stitches at the stitches that have been stitched once and stitching again to improve the strength of the connecting force, but after the first stitching, it is necessary to return to the sewing start position to align the upper cloth. Sew again with the lower fabric, so not only the work efficiency is low, but also it is difficult to make the needle pierce the same part of the last sewing stitch, so there is no way to prevent the knotting of the upper thread NS and the lower thread US Problems such as point deformation

[0011] In addition, although it is also possible to consider Figure 10 As shown, two threads HS1 and HS2 are used to sew the upper cloth W1 and the lower cloth W2 by hand, but it takes a lot of working time to form the stitches, so the sewing work efficiency is low, and due to the limitation of the length of the thread, it cannot be formed Problems such as long stitches

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