A thread take-up lever switching mechanism can switch the operation of a thread take-up lever which is interlocked with an upper shaft. The thread take-up lever switching mechanism includes: a cylindrical cam provided on the upper shaft, the cylindrical cam having a plurality of cam surfaces; a contact portion provided on the thread take-up lever, the contact portion contacting a first surface of the plurality of cam surfaces; and a switch for switching the contact portion from a first position of contacting the first surface of the plurality of cam surfaces to a second position of contacting a second surface of the plurality of cam surfaces.

An upper decoration mechanism and a sewing machine without requiring an operation of detaching the upper decoration mechanism from the sewing machine without reducing workability even when performing a double chain stitch not using a decoration thread. The upper decoration mechanism provided on a sewing machine includes an expansion retraction mechanism configured to switch a spreader between an expanded state where the spreader cooperates with needles for performing an upper decoration sewing and a retracted state where the spreader is separated from the needles.

An upper decoration mechanism and a sewing machine without requiring an operation of detaching the upper decoration mechanism from the sewing machine without reducing workability even when performing a double chain stitch not using a decoration thread. The upper decoration mechanism provided on a sewing machine includes an expansion retraction mechanism configured to switch a spreader between an expanded state where the spreader cooperates with needles for performing an upper decoration sewing and a retracted state where the spreader is separated from the needles.

A thread positioner provided on a needle plate of a double chain stitch sewing machine for forming a seam by a plurality of needle threads and a looper thread, wherein the thread positioner includes a needle thread holding plate provided below the needle plate 30, the needle thread holding plate extending horizontally from a front to a rear, a rear end portion of the needle thread holding plate includes: a guide portion for guiding the plurality of needle threads; and a thread positioning portion for regulating a movement of the plurality of needle threads in a right-and-left direction, and the thread positioning portion includes: a protrusion linearly protruded rearward from the guide portion; flat portions formed on left and right side surfaces of the protrusion; and an inclined portion formed on a tip of the protrusion, the inclined portion being inclined from a right to a rear left.

A thread positioner provided on a needle plate of a double chain stitch sewing machine for forming a seam by a plurality of needle threads and a looper thread, wherein the thread positioner includes a needle thread holding plate provided below the needle plate 30, the needle thread holding plate extending horizontally from a front to a rear, a rear end portion of the needle thread holding plate includes: a guide portion for guiding the plurality of needle threads; and a thread positioning portion for regulating a movement of the plurality of needle threads in a right-and-left direction, and the thread positioning portion includes: a protrusion linearly protruded rearward from the guide portion; flat portions formed on left and right side surfaces of the protrusion; and an inclined portion formed on a tip of the protrusion, the inclined portion being inclined from a right to a rear left.

A thread finger assembly for a sewing machine has at least one thread finger. The latter can be actuated between a loop engagement position and a loop pull-out position. The loop engagement position serves for the engagement of the thread finger in a thread loop generated by the sewing machine in a stitch forming region. The loop pull-out position is displaced relative to the loop engagement position for pulling out the thread loop with the thread finger, away from the stitch forming area. A thread finger drive serves for actuating the thread finger between the loop engagement position and the loop pull-out position. This results in an assembly of a sewing machine with which an appealing seam pattern is generated in a reproducible manner at a seam beginning.

A thread finger assembly for a sewing machine has at least one thread finger. The latter can be actuated between a loop engagement position and a loop pull-out position. The loop engagement position serves for the engagement of the thread finger in a thread loop generated by the sewing machine in a stitch forming region. The loop pull-out position is displaced relative to the loop engagement position for pulling out the thread loop with the thread finger, away from the stitch forming area. A thread finger drive serves for actuating the thread finger between the loop engagement position and the loop pull-out position. This results in an assembly of a sewing machine with which an appealing seam pattern is generated in a reproducible manner at a seam beginning.

This single chain stitch sewing device is provided with a sewing mechanism provided on a front end arm of a delivery robot. The sewing mechanism comprises a sewing motor for supplying power to sewing needles and loopers. When the sewing motor is energized, power is transmitted to the sewing needles via a first power transmission mechanism, this causing the sewing needles to move reciprocally. At the same time, power is transmitted to the loopers via a second power transmission mechanism to rotate the loopers. Accordingly, sewing is performed. The loopers are provided at an end of a post bed on the side closer to the sewing needles.

A stitch structure has a first surface, a second surface, and includes: a first fabric having a first end section; a second fabric having a second end section; a first stitching that extends in a direction substantially parallel to the direction of extension of the first end section; a second stitching that extends in a direction substantially parallel to the direction of extension of the second end section; a third stitching; and a tape-shaped member. Additionally, a first thread and a second thread is arranged in the first stitching and the second stitching, respectively, to repeatedly return across and penetrate the first fabric and the second fabric, in the thickness direction thereof. A decorative thread is arranged in the third stitching to repeatedly span between at least the first thread and the second thread and the tape-shaped member is binding the first fabric and the second fabric.

A stitch structure has a first surface, a second surface, and includes: a first fabric having a first end section; a second fabric having a second end section; a first stitching that extends in a direction substantially parallel to the direction of extension of the first end section; a second stitching that extends in a direction substantially parallel to the direction of extension of the second end section; a third stitching; and a tape-shaped member. Additionally, a first thread and a second thread is arranged in the first stitching and the second stitching, respectively, to repeatedly return across and penetrate the first fabric and the second fabric, in the thickness direction thereof. A decorative thread is arranged in the third stitching to repeatedly span between at least the first thread and the second thread and the tape-shaped member is binding the first fabric and the second fabric.