JPH0446720Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a throat plate for a zigzag sewing machine, and particularly to a throat plate for a zigzag sewing machine that is provided with a horizontal rotary hook that rotates about a vertical axis at the lower front side of the throat plate.

(Prior Art) Figures 1 to 4 show the needle 2 and the horizontal rotary hook of a zigzag sewing machine, in which the horizontal rotary hook 1 is disposed in front of and below the needle 2, which reciprocates in the vertical direction and swings in the horizontal direction. This figure shows the relationship with the bobbin thread 5 pulled out from inside 1. When performing straight stitches on such a zigzag sewing machine, especially straight stitches at the left needle drop reference position, the regular perfect stitch as shown in Figure 5 is shown. In some cases, stitches 3 include hit stitches 4 which have poor thread arrangement and are undesirable in terms of appearance. That is, when the needle 2 falls to the right side of the bobbin thread 5 as shown in FIGS. 1 and 2 when viewed from the front when the falling needle 2 intersects with the bobbin thread 5 being pulled out,
Form stitch 3 of the perfect stitch,
When the bobbin thread 5 falls on the left side as shown in FIGS. 3 and 4, a hit stitch 4 is formed. Therefore, when performing straight stitches, in order to always form only the perfect stitch stitch 3, when the needle 2 intersects with the bobbin thread 5, the needle 2 should always be positioned as shown in Figures 1 and 2 when viewed from the front. It is necessary for the bobbin thread 5 to fall to the right side as shown in Figs. 2 and 4.
As shown in the figure, since the distance S between the needle 2 and the pull-out opening of the bobbin thread 5 at the left needle drop reference position is small, the bobbin thread 5 often wraps around to the right side of the needle 2 as shown in the fourth figure.
In other words, the needle 2 often falls to the left side of the bobbin thread 5, resulting in the stitch 4 of the hit stitch.

(Purpose) This invention was devised in order to eliminate the above-mentioned drawbacks of the conventional technology. This is intended to prevent hit-stitch stitches that tend to occur when performing straight stitches at the left needle drop reference position in a zigzag sewing machine equipped with a horizontal rotary hook that rotates as a horizontal rotary hook.

(Embodiment) The structure of an embodiment of the present invention will be described below with reference to FIGS. 6 and 7. The horizontal rotary hook 1 includes an outer hook 11 that rotates fully in the direction of arrow C around a vertical shaft 10 supported on a sewing machine frame (not shown) at a position below the falling position of the needle 2, and an inner portion of the outer hook. The inner pot 12 is housed in the inner pot 12. The bobbin 13 is connected to the inner pot 1.
The bobbin thread 5 wound on the bobbin is housed inside the bobbin 2, and the bobbin thread 5 is attached to the cut end 14 of the adjustment spring 14 fixed to the inner hook 12 provided at a position to the left of the left needle drop part.
a, and is adapted to be let out by the vertical movement of the bobbin thread payout lever 15, etc.

Next, the guiding action of the bobbin thread 5 will be explained.

The throat plate 19 is formed as shown in FIGS. 7 to 12, and the left end of the needle hole 17, which is formed into an elongated hole for the needle 2 that oscillates in a zigzag pattern, is formed on the back side of the throat plate. A sloped surface 16 is formed that is wide across the front and rear of the needle droplet and deepens toward the feed dog groove located further to the left of the left end needle droplet, and further extends from the needle hole 17 with the sloped surface 16. Groove deeper than 16 1
8 is formed. Therefore, the throat plate 19 first guides the bobbin thread pulled out from the drawer opening of the bobbin 13 to the left side of the needle hole 17 by means of the inclined surface 16 provided at the left needle drop corresponding part of the zigzag width, and then guides the lower thread to the left side of the needle hole 17. The extending groove 18 acts to move the needle to the left side of the needle hole 17, thereby enhancing the guiding effect of the bobbin thread.

According to the experimental results, the effect of providing the groove 18 is significantly higher than the effect of forming the slope 16 alone, so the effect of providing the groove 18 is particularly emphasized (effect). The present invention has the above-mentioned structure and operation, and is intended to prevent the occurrence of hits and stitches during straight stitching at the left needle drop position in a sewing machine equipped with a throat plate having a zigzag needle hole. This has a great practical effect in that beautiful seam tension can be obtained.

[Brief explanation of the drawing]

Figures 1 to 4 are illustrations of the relationship between the horizontal hook, needle, and bobbin thread, Figure 5 is an illustration of the perfect stitch, and Figure 6 is an explanation of the action of pulling out the bobbin thread from the horizontal hook. 7 to 12 relate to embodiments of the present invention, in which FIG. 7 is a perspective view of the back of the throat plate, and FIG.
The figure is a top view of the throat plate, Figure 9 is a front view, Figure 10 is a bottom view, Figure 11 is an enlarged view of the needle drop in the bottom view,
FIG. 12 is a cross-sectional view of FIG. 11, where 16 is an inclined surface, 17 is a needle hole, 18 is a groove, and 19
is the needle plate.

Claims (1)

[Scope of utility model registration request] A horizontal rotary hook that rotates around a vertical axis is provided below the front of the throat plate, an inner hook is supported within the horizontal rotary hook, a bobbin on which bobbin thread is wound is stored in the inner hook, and the bobbin is mounted on the throat plate. In the needle plate of a sewing machine, which is provided with a needle hole for guiding the bobbin thread pulled out from the needle hole 17,
is formed into an elongated hole that can be zigzag, and a wide sloped surface 16 is provided in front and behind the left needle drop side end of the needle hole 17 on the back side of the needle plate, and a wide sloped surface 16 is provided on the extension of the needle hole and is deeper than the sloped surface. A throat plate for a zigzag sewing machine characterized by being provided with a groove portion 18.