JPH0214782Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application This invention relates to a throat plate used in a safety stitch sewing machine that simultaneously forms an edge stitch and a parallel double chain stitch.

Prior Art When the sewing machine is driven even when the workpiece is not inserted, such as with a sewing machine that forms edge stitches or double chain stitches, the workpiece that has been sewn is completely sewn on a sewing machine that forms an empty ring. When sewing is performed continuously with the next new workpiece connected with an empty ring,
There are cases where a known loop cutting device cuts the loop connected to the end of the workpiece after it has been sewn when it comes out of the presser foot, but in any case, the loop is always formed in a stable state. It is necessary to Particularly in double chain stitching, if an empty ring is no longer formed during the formation of an empty ring, skipped stitches will occur when the next sewing is performed in this state. This is because when an empty ring no longer occurs and the thread becomes slack, the necessary triangle that should be formed by the looper thread and the needle thread loop hanging on the looper is no longer formed, and the needle no longer passes through the area of the triangle. Therefore, conventionally, the empty ring that comes out from the needle hole for double chainstitching to the top of the throat plate is sandwiched between the presser foot and the throat plate.
Furthermore, the empty ring is sandwiched between the feed dog that protrudes and retracts from the slot for the feed dog in the throat plate and the presser foot, and is sent out behind the presser foot to ensure that the empty ring for double chainstitching is formed.

Problems that the invention aims to solve: The throat plate used in safety stitch sewing machines has a needle hole for double chainstitch adjacent to the needle hole for edge stitching, but the needle hole for double chainstitch is The hollow ring protruding from the upper surface of the throat plate did not necessarily extend toward the action area of the feed dog, and it sometimes came off the feed dog and could no longer be fed.

Solution: A guide groove is provided on the throat plate of the safety stitch sewing machine from the needle hole for double chain stitching toward the front of the feed dog, thereby guiding the empty ring to ensure that it reaches the action area of the feed dog.

Embodiment FIG. 2 shows a needle 1 for stitching an edge, and a lower looper 2 and an upper looper 3 working together to form an edge stitch at the edge of the material to be sewn, and on the inside of the stitch. In parallel with this, a safety stitch sewing machine is shown in which a double chain stitch is formed using a double chain stitch needle 5 and a double chain looper. A needle hole 8 for the double chain stitch and a needle hole 9 for the double chain stitch are provided, and a guide groove 12 is formed that reaches from the needle hole 9 for the double chain stitch to just before the elongated hole 11 for the feed dog. This guide groove 12 has a needle drop 13 for edge stitching.
If the width of the double chainstitch needle drop 14 is narrower than the distance between the hem stitch needle drop 13 and the center of the action area of the feed dog 10, move it to the left (Fig. 3); if it is wider, move it to the left. It is inclined to the right (FIG. 4) and is formed so as to always extend toward the center of the action area of the feed dog 10. If the distance between both needle drops is narrower than the distance between the needle drop 13 and the center of the action area of the feed dog 10, it is recommended to further bend the double chainstitch needle hole 9 from behind the needle drop 14 to the left. desirable. It is also desirable that the guide groove 12 is inclined from the lower surface of the throat plate of the double chainstitch needle hole 9 to the upper surface of the throat plate as shown in the drawing. As a result, the double chain stitch formed by the needle 5 and the double chain looper 6 is smoothly inserted into the guide groove when the needle thread loop N that has been hung on the double chain looper 6 comes out of the double chain looper 6. It will be guided to reach the upper surface of the throat plate. The distance M between the exit of the guide groove and the end of the feed dog elongated hole is preferably about 1 to 2 stitches of the empty ring.
Here, the empty ring that has come out of the guide groove 12 is held between the presser foot 15 and the empty ring is pulled back to the needle drop side and does not loosen even when the feed dog 10 descends from the upper surface of the throat plate.

Effects According to the present invention, the empty ring is guided through the guide groove and reliably reaches the action area of the feed dog, so that when the feed dog rises above the throat plate, it is caught between the presser foot and fed. As a result, a stable double chainstitch loop is always created, and skipped stitches do not occur at the beginning of sewing.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of the throat plate according to the present invention, Fig. 2 is a perspective view of a safety stitch sewing machine equipped with the throat plate, and Figs. 3 and 4 are enlarged plan views of the main parts of the throat plate. It is a diagram. 7... Throat plate, 8... Needle hole for edge stitching, 9...
...Needle hole for double chain stitch, 10...Feed dog, 11...
Long hole for feed dog, 12... Guide groove, 13... Needle drop for edge stitching, 14... Needle drop for double chain stitch,
15...Presser foot.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A needle hole 8 for edge stitching, a needle hole 9 for double chain stitch, and a needle hole 9 formed at the rear of the needle hole 9 for double chain stitch in the feeding direction. In the throat plate of a safety stitch sewing machine in which a long hole 11 for the feed dog in which the tooth 10 appears and retracts is formed, the empty ring of the double chainstitch that is formed is inserted into the feed dog 10.
A throat plate in which a guide groove 12 is formed on the throat plate from the needle hole 9 for double chainstitch toward the long hole 11 for the feed dog, terminating at a position in front of the long hole 11. . (2) The needle plate according to claim 1, wherein the guide groove 12 extends toward the center of the action area of the feed dog 10. (3) The throat plate according to claim 1, wherein the guide groove 12 is inclined from the lower surface of the throat plate toward the upper surface of the throat plate of the needle hole 9 for double chainstitch.