JPH0452158B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention reciprocates the front side of sewing machine needles arranged in parallel in the horizontal direction, hooks decorative thread extending from a seam forming area, and lets it out in a direction crossing the sewing direction. This invention relates to a top cover thread looper for a top cover stitch sewing machine which sews a top cover stitch on the upper surface of a cloth with a needle thread to form interlock stitches.

PRIOR ART This type of top thread looper is usually composed of an arc-shaped piece that makes a reciprocating circular arc movement from side to side in front of the sewing machine needle, centered on a vertical axis supported parallel to the needle bar.
The middle part is equipped with a hook, and when the looper moves back and forth when the sewing machine is driven, the decorative thread that extends diagonally upward to the right from the seam forming area is caught on the hook and pulled to the left until it reaches the left end. In the case of a two-needle sewing machine, the left needle moves down inside the loop of the decorative thread that has been hooked to the hook and is bent, and the right needle moves down in front of the loop, and when the looper moves back and forth, the decorative thread is released from the hook. The released decorative thread is pushed down by the right needle thread so that it can be sewn onto the fabric. As mentioned above, the looper for decorative threads needs to have the function of hooking and pulling the decorative threads, as well as allowing the hooked decorative threads to be released smoothly when necessary. The seed looper is equipped with a hook as described above, but if the decorative thread is thick or loose due to loose thread, it may not engage the hook properly and fail to hook, or the presser foot may fail. When the thread or needle bar rises and the decorative thread moves backward or becomes loose, it comes off the hook, causing skipped stitches and the problem of not being able to obtain beautiful decorative stitches. In order to solve this problem, the Special Publication No. 54-9112
No. 1 proposes a hook in which the hook projects from the inside of the arc, that is, toward the needle side, and a cut groove is provided in the horizontal direction between the hook and the looper body. It was not sufficient to solve the problem.

Problems to be Solved by the Invention It is an object of the present invention to solve the above-mentioned problems and to provide a looper for a decorative thread of a decorative stitch sewing machine that can produce beautiful decorative stitches without skipped stitches.

Means for Solving the Problems In other words, the present invention reciprocates the front side of the sewing machine needle to hook the decorative thread extending from the seam forming area and feed it out in a direction crossing the sewing direction, and sews it onto the upper surface of the fabric with the needle thread. In a looper for the top cover thread of a decorative stitch sewing machine that is attached to form interlock stitches, a folded piece is provided at an appropriate position on the upper surface of the looper body and extends toward the base end of the looper with an appropriate gap from the main body, so that the folded piece is free. The looper is characterized in that a hook is formed at the end and is folded back downward and toward the tip of the looper body.

Here, the folded piece is bent into an inverted L shape, for example, and is formed to stand up from a proper position of the looper body and extend parallel to the body, or is formed to extend at an angle from the looper body, or is formed in an arch shape.

Further, the direction in which the hook faces does not necessarily have to be aligned with the tip of the looper body, but may be directed slightly toward the needle bar side, for example.

A two- to four-needle interlock stitch sewing machine is usually used as a decorative stitch sewing machine.

Embodiment The figure shows an example in which the top cover thread looper according to the present invention is installed in a two-needle interlock stitch sewing machine. The thread passes through the thread hole 3 of the thread guide 2 which is firmly fixed and moves up and down with the needle bar 1, and reaches the bottom of the presser foot 6 through the elongated hole 5 of the decorative thread guide 4 supported by the sewing machine arm. The top cover thread looper 7 is attached to a holder 9 fixed to the vertical shaft 8, and its lower part is bent in the horizontal direction so that the front side of the needle bar is curved in an arc shape toward the needle bar side, and the upper and lower ends of the needle bar 1 The hands 10, 1 move in conjunction with the movement.
It is designed to make a reciprocating circular arc movement on the near side of 1. A folding piece 12, which is formed by bending a wire, is protrudingly provided at a suitable location on the upper surface (the figure shows an example where it is provided near the tip, but it may be provided at a position away from the tip). As shown in FIG. 1, the piece 12 has a portion a rising up from the looper body.
, an intermediate portion b extending rearward with an appropriate distance from the looper body, and a hook portion c bent downward at the free end toward the tip of the looper body, and surrounded by these. The decorative thread T can freely enter and exit the approximately C-shaped space through the gap between the tip of the hook and the looper body, and the decorative thread T introduced into the space is inserted into the middle part b or the hook. Part c prevents it from coming off upward.

Function Next, the process of feeding out the top thread by this looper will be explained based on FIGS. 2 to 5.

When the looper 7 moves back to the right, the outside of the hook portion C of the folding piece 12 engages with the top thread T extending diagonally between the bottom of the presser foot 6 and the front position of the elongated hole 5 near the right dead center. and push it in the same direction, and while it reaches the right dead center, the top thread T is pushed down on the outside of the hook (Fig. 2),
After reaching the tip, it comes off from there and enters the upper side of the space surrounded by the folding piece 12 and the looper body (FIG. 3). When reciprocating to the left, the top thread T introduced into the upper part of the space as described above is caught by the hook c and pulled to the left, the folded piece 12 passes over the left needle 10, and then When the looper 7 reaches the left dead center, the top thread T extends from below the presser foot.
forms a loop bent into a dogleg shape at the hook c. At this time, the thread path 2 is located above together with the needle bar, and the top thread T is returned to the rear side of the elongated hole 5. Therefore, among the needles 10 and 11 that descend from the top dead center, the left needle 10
is inside the loop, and the right needle 11 is lowered to the outside of the loop on the near side (Fig. 4). The top thread T, which loosens as the looper 7 moves back to the right, is pushed down by the right needle thread _N1 as the right needle 11 further descends, and is removed downward from the hook c (Fig. 5). . It is then sewn onto the fabric under the presser foot using needle thread. Prior to this, the thread guide 2 that descends together with the needles 10 and 11 pushes the top thread toward the front, and the slack in the loop is absorbed while passing through the left needle 10. Thereafter, the above-described operation is repeated.

As described above, in this looper 7, the top thread T enters the upper part of the space, so it is reliably caught on the hook part during the return movement, and even if the top thread T is slightly slack or the path is misaligned, it will not fail to hook. There is no possibility of the thread coming off. In addition, even if the top thread T moves toward the rear of the elongated hole and away from the looper by raising the presser foot 6 while the top thread T has entered the space, it will not turn back. It is restricted by the middle part b and hook part c of the piece 12, and will not come off upwards.

Also, when the looper 7 moves back to the right from the state shown in Fig. 4 and the top thread T is pushed down by the right needle thread _N1 ,
Since the hook part c is opened toward the lower left, the top thread T can be smoothly removed from the looper without being hindered by the hook part c.

Effects of the Invention As described above, according to the top thread looper of the present invention, the top thread can be reliably hooked by the hook portion of the folded piece during forward movement, and moreover, it is caught on the hook portion and attached to the hook portion. Until the engaged top thread is pushed down by the needle thread, it will not come off even if the thread loosens or the thread moves upward, making it possible to obtain beautiful decorative stitches without skipped stitches. can.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially cutaway front view showing the function of its main parts, and FIGS. 2 to 5 are perspective views similarly showing the function. 1... Needle bar, 2... Thread guide, 4... Decorative thread guide,
6... Presser foot, 7... Looper for top thread, 8...
Vertical axis, 10, 11...needle, 12...folding piece, a...
...Rising part, b...middle part, c...hook part, T
... Decorative thread, N ₁ , N ₂ ... Needle thread.

Claims (1)

[Claims] 1 A decorative stitch sewing machine that reciprocates the front of the sewing machine's needle to hook decorative thread extending from the seam forming area, feeds it out in a direction intersecting the sewing direction, and sews this onto the top surface of the fabric using needle thread to form interlock stitches. In the looper for top thread, a folded piece 12 is provided at a suitable position on the upper surface of the looper body 7 and extends toward the base end of the looper with an appropriate gap between the folded piece 12 and the looper body. A looper for top thread that has a hook c that is folded back toward the tip of the main body.