JPH0354598B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a double-stitch overlock sewing machine with an automatic thread cutter and a core cord, and in particular, the present invention relates to a double-stitch overlock sewing machine with an automatic thread cutter and a core cord, and in particular, the core cord and needle thread are inserted in the lateral direction from the lock stitching part of buttonhole overlocking. This invention relates to an automatic thread cutting device for a buttonhole sewing machine that prevents the cord from sticking out.

[Conventional technology]

Conventionally, as a device of this type, there has been known a device for cutting needle thread and cord for a buttonhole sewing machine, as described in Japanese Patent Publication No. 57-41276. but,
In this conventional device, as shown in Fig. 4, the core string and needle thread at the beginning of sewing are swept upward in the sewing direction (right direction in the figure) during buttonholing, and the swept thread is used to sew the workpiece. It is held on the sewing side (to the right in the figure) from the starting position, and the holding position is also not constant. For this reason, during the lock stitching at the end of the second round of double buttonhole stitching, the upper thread and core string that are held above come into contact with the needle and are pulled out, causing some of them to be pulled out. There is a drawback that the needle thread and core string protrude from above the bar-seamed part because they are sewn into the bar-seam.

This state is shown in FIG. That is, the conventional device has a drawback in the holding position and holding force of the needle thread and the core string, and the needle thread and the core string protrude laterally as shown in FIG. Sometimes. 3 in Figure 5 is the upper thread at the end of sewing.
4 indicates the core strings at the end of sewing, and since they extend downward from the bar-sewn portion, they do not spoil the appearance.

[Problems to be Solved by the Invention] The present invention improves this point by moving the core cord and needle thread at the tip of the sewing start during buttonhole stitching to the side opposite to the sewing position from the sewing start position of the workpiece (see Fig. 4). To provide an automatic cord thread cutting device for a buttonhole sewing machine which can be held on the left side) and can hold the core cord and needle thread with a strong holding force.

[Means for solving problems]

The present invention provides an automatic cord cutting device for a buttonhole sewing machine that is equipped with a cord presser spring, an upper thread presser spring, and a moving knife. The holding groove is configured to apply a strong holding force to hold the core string and needle thread in front of the sewing start position of the workpiece (ie, on the opposite side to the sewing side).

[Effect]

Therefore, it is possible to prevent the loosened or misaligned core string and needle thread that have been removed and held, and it is also possible to prevent the retained core string and needle thread from being pulled out by the needle. .

〔Example〕

An embodiment of the present invention will be described based on the drawings.
FIGS. 1 to 3 each show an explanatory view of the operating state of an embodiment of the cord automatic thread cutting device according to the present invention.
In FIGS. 1 to 3, 10 indicates a cord automatic thread cutting device, 11 indicates a fixed cord presser spring, and 1
2 shows a fixed upper thread presser spring. Also, 1
5 indicates a movable knife that rotates around a fixed shaft 13;
16 indicates the core string, 17 indicates the upper thread, and A indicates the sewing start position.

The characteristic operation of an embodiment of the present invention configured as described above will be explained. FIG. 1 shows the state before the start of buttonhole stitching, in which the cord 16 and needle thread 17 are cut by the moving knife 15 and fixed knife (not shown) at the end of sewing the previous workpiece. It is held by a core string presser spring 11 and an upper thread presser spring 12.

Now, when the first round of double overlock stitching is started, the movable knife 15 begins to return while sweeping the core string 16 and needle thread 17 to the left side with the back 20 of the knife part.

As a result, as shown in FIG.
2 and a thread holding groove 21 formed in the movable knife 15 by aligning the rotation locus.
It is held at a position in front of the sewing start position A on the anti-sewing side.

Here, one of the features of the present invention is that the holding position of the core string 16 and needle thread 17 is formed in front of the sewing start position A (ie, on the opposite side to the sewing side).

Further, when the movable knife 15 completely returns to the return position, the thread holding groove 21 overlaps the thread receiving groove 22 as shown in FIG. As a result, the core string 16 and the needle thread 17 are strongly held between the thread holding groove 21 and the thread receiving groove 22, and are held with a strong holding force.

Here, one of the features of the present invention is that the core string and needle thread are held with strong holding force.

As mentioned above, since the core string 16 and needle thread 17 are held with a strong holding force in front of the sewing start position A, they are protected against stretching, shearing, mechanical vibration, etc. of the fabric that occurs during sewing. This prevents possible loosening or displacement of the held cord 16 and needle thread 17. Also, at the start of the second round of sewing or at the end of the second round of sewing, the needle will be positioned to the left of the sewing start position, but at this time the core string 16 and needle thread 17 will be lowered. Since the thread extends in the direction, the needle does not come into contact with the needle and is placed along the core string and needle thread at the end of sewing, improving the appearance of the product.

〔effect〕

As explained above, according to the present invention, the thread receiving groove formed in the needle thread presser spring and the thread holding groove formed in the moving knife hold the core string and needle thread on the side opposite to the sewing position from the sewing start position of the workpiece. The structure is designed to provide a strong holding force and hold it.

Therefore, it is possible to prevent the core string and needle thread that have been removed and held from loosening or slipping, and furthermore, the core string and needle thread held at the beginning of sewing can be prevented from becoming attached to the core string and needle thread at the end of sewing. They can be arranged along the same line, improving the appearance of the product, and when cutting the core cord and needle thread protruding downward with scissors, they can be cut all at once.

[Brief explanation of drawings]

FIGS. 1 to 3 each show an operation explanatory diagram of an embodiment of the present invention. FIG. 4 is an explanatory diagram of a conventional device.
FIG. 5 is an explanatory diagram illustrating the drawbacks of the conventional device. 10... Core string automatic thread cutting device, 11... Core string pressing spring, 12... Needle thread pressing spring, 15... Moving knife, 16
... core string, 17 ... upper thread, 21 ... thread holding groove, 22 ... thread receiving groove, 23 ... hole.

Claims (1)

[Scope of Claims] 1. A movable knife that is rotatably provided to cut the core string and needle thread at the end of sewing the sewing object; a core string holding spring that holds the core string during the cutting; and a core string presser spring that holds the core string during the cutting; A core string automatic thread trimming device for a buttonhole sewing machine equipped with an upper thread presser spring for holding an upper thread, comprising: a thread receiving groove formed at a position on the opposite sewing side from a sewing start position of a workpiece; a back portion formed on the movable knife that sweeps the string and the needle thread in the direction of the thread receiving groove during rotation; and a rotation locus and the thread receiving groove that holds the swept core string and the needle thread. a thread holding groove formed on the moving knife with the thread holding grooves aligned with each other; and means for rotating the moving knife to a position where the thread holding groove overlaps the thread receiving groove. Automatic thread cutting device for the core cord of overlock sewing machines.