JPH0231999B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention involves forming an empty ring of a predetermined length after completing the formation of an overlock seam on a fabric, cutting this empty ring on the fabric side, This invention relates to an empty chain sewing device for a two-needle overlock sewing machine, which holds the side leading to the needle and sews it into a newly formed overlock seam during the next sewing.

[Prior art]

The overlock stitch by the overlock sewing machine is formed using needle thread, upper looper thread, and lower looper system, and following the completion of forming the overlock stitch in the fabric, an empty ring is formed to a predetermined length, and then
Change the direction of the fabric along with the empty ring to the operator side, stretch the empty ring, cut and clamp the fabric side end with an empty ring holding/cutting device, etc., and cut the side of the empty ring that reaches the needle to the throat plate surface. The empty ring held in this state is then sewn into a newly formed overlock seam during the next sewing process.

By the way, this type of sewing machine is usually equipped with two loopers as a means of providing the thread that makes up the stitches on the fabric, and when performing overlock stitches, one looper (lower looper) is attached to the bottom of the fabric. , move from the needle to the edge of the fabric in a direction perpendicular to the seam line, and then
The book loopers (upper loopers) move over the fabric from the edge to cross the needle, and the action of these loopers causes the thread to pass over the edge to form an overlock stitch.

A two-needle overlock sewing machine has two sewing needles as shown in FIG. 1, and each needle has an inner claw and an outer claw on one side of the needle drop. In other words, both inner and outer claws are often provided in parallel on both sides of the needle drop portion of the outer sewing needle. In the figure, 1 is a throat plate, 2 is an outer claw, 3 is an inner claw having needle drop portions (sewing needles) N ₁ and N ₂ on both sides thereof, and 4 is an empty ring holding/cutting device.

After the sewing work of the fabric is completed, the operator carries the fabric and the empty ring connected to it (turnback) and cuts and clamps the empty ring with the empty ring holding/cutting device 4, resulting in the state shown in Fig. 2. The empty ring is held on the needle plate 1.

In the figure, A indicates an empty ring.

[Problem that the invention seeks to solve]

However, since the empty ring A is held in the above state, when the needle descends at the beginning of sewing,
Since the empty ring A is drawn toward the needle by the needle thread, it is easily sewn in by the outer sewing thread _N2 , and in this case, subsequent sewing is not performed and most of the empty ring is at the sewing start point. There was a problem in which it remained in a protruding state beyond the tip. In addition, as mentioned above, in overlock stitching, the upper looper forms a loop with the looper thread on the upper surface of the fabric edge, and the sewing thread of the sewing needle engages with this loop to perform sewing. As a result, loop formation by the upper looper is inhibited.

To explain this with reference to Fig. 3, the thread triangle (loop) B formed by the upper looper 5 is pulled by the empty ring A as shown in the figure, and is placed opposite the sewing needles N ₁ and N ₂ with the upper looper 5 in between. The problem arises that stitch skipping occurs because the stitches are placed closer to the side (below the upper looper 5 in the figure).

[Means for solving problems]

The present invention attempts to solve the above-mentioned problems by providing an engaging portion for locking the empty ring at the end of the throat plate or the outer pawl of the presser foot.

〔Example〕

An embodiment of the present invention will be described based on the drawings from FIG. 4 onwards. Note that the same parts in the conventional example are given the same reference numerals, and duplicate explanations will be omitted.

FIG. 4 is an enlarged view of the main parts of this embodiment. In the figure, 2a is a notch formed at the end of the outer claw 2 as an engagement part of a hollow ring. In this embodiment, the notch 2a is a semicircular recess, but it goes without saying that its shape and structure are not limited as long as it allows the empty ring to enter and exit smoothly.

Next, the operation will be explained with reference to FIGS. 5 and 6.

When the sewing of the fabric is completed, the empty ring connected to the fabric is locked in the empty ring engaging part 2a at the end of the outer claw 2, and brought to the operator side, and the end on the fabric side is held in the empty ring holding/cutting device 4. Cut and clamp. And the next fabric C
When sewing is started, the loop A is held at a proper position by the engaging portion 2a without being affected by the outer needle _N2 , so that the loop A is smoothly sewn into the overlock stitch D. (See Figure 5) Also, as shown in Figure 6, the empty ring A is locked to the engaging portion 2a of the outer claw 2, and is pulled from this point as a starting point and clamped to the empty ring holding and cutting device. Therefore, unnecessary force is not applied to the loop formation of the upper looper 5, so that the loop can be formed at an appropriate position. ₁ and N ₂ exactly complement this. Furthermore, FIGS. 7 to 9 are diagrams showing other embodiments of the present invention. In FIG. 7, a notch is provided at the left end of the throat plate outer claw 2 to form an engaging portion 2a, which locks the empty ring A by cooperation with the outer claw 6a of the presser foot 6. It's summery. In FIG. 8, the engaging portion 2a is composed of the left end of the throat plate outer claw 2 and the right end of the presser foot outer claw 6a. That is, the engagement portion 2a is formed by the gap formed between the right end of the straight presser foot outer claw 6a and the left end of the throat plate outer claw 2 which is shaped to expand downward.

In FIG. 9, an engaging portion 2a is formed by a recess provided at the tip of the outer claw 6a of the presser foot. In these embodiments the operation does not differ from that described above.

〔Effect of the invention〕

As explained above, this invention has a structure in which an engaging portion for locking the empty ring is formed on the outer claw of the throat plate, so that the relative position of the empty ring and the sewing needle is accurately regulated, and the overlapping of the empty ring When sewing into a lock seam, the sewing needle does not sew an empty ring, so the work of sewing the empty ring at the starting edge of the fabric is smooth.
done accurately. Furthermore, since the loops of the upper looper are formed accurately, it is possible to reliably prevent skipped stitches from forming overlock seams.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main parts of the device in the conventional example, Fig. 2 is an explanatory diagram showing the holding state of the empty ring in the conventional example, and Fig. 3 is a diagram showing the relationship between the loop formation by the upper looper and the empty ring in the conventional example. FIG. 4 is an enlarged view of the main part of an embodiment of the present invention, FIG. 5 is a diagram showing the sewing state of the hollow ring in the embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing the relationship between loop formation by the upper looper and empty rings, and FIGS. 7 to 9 are diagrams showing other embodiments. 2...(outer) claw, 2a...engaging portion, 4...empty ring holding/cutting device, _N1 , _N2 ...needle drop portion, A...empty ring.

Claims (1)

[Claims] 1. An empty ring holding and cutting device is provided in front of the needle drop section. 2.
In this needle overlock sewing machine, the tip of the outer claw of the throat plate or presser foot, or the outer claw of the throat plate and the outer claw of the presser foot, forms an engaging portion 2a, and after sewing the fabric, the fabric is moved toward the operator side. Empty ring sewing of a two-needle overlock sewing machine, characterized in that when an empty ring connected to a carried cloth is held by an empty ring holding/cutting device, the empty ring thread is locked in an engaging part 2a. Device.