JPH048392A - Lower looper thread guard device in overlock sewing machine - Google Patents

Abstract

PURPOSE:To automatically reset a looper thread guard to a position of sewing condition by the first lower looper, even in the case of starting a sewing machine by forgetting the looper thread guard to be returned, by providing a guide member, having a supporting surface, and a sliding surface provided in a link. CONSTITUTION:Even in the case of starting by mistake a sewing machine left as placed in a condition that a point end part of a thread guard 9 is large protruded rightward from a frame by pressing down a turn arm 16 from a condition that the looper thread guard 9 is placed in a sewing position, a swivel arm 2 is started to turn by the starting with the thread guard 9 in the counterclockwise direction with a lower looper swivel arm shaft 3 serving as the center, and a straight line, connecting both end parts of an operation spring 15, agrees with a pivotal supporting pin 14 of a link 13 by sliding a sliding surface 17 of the link 13 left as brought into contact with a supporting surface 18 of a guide lever plate 19. When the swivel arm 2 is turned to the counterclockwise direction further from this position, the link 13 exceeds the dead point of its action, and the looper thread guard 9 is reset to the sowing position by turning the thread guard 9 to the counterclockwise direction relatively to the swivel arm 2 by action of the operation spring 15 to place the thread guard in a condition of dotted line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lower looper threading device for an overlo and sewing machine.

[Conventional technology]

FIG. 5 shows a lower looper threading device in a conventional overlock sewing machine, where 1 is a substantially horizontal lower looper, 1a is a lower looper thread hole formed at one end of this lower looper 1,
1b is a looper threading notch formed at the other end of the lower looper 1; 1c is a lower looper thread groove formed along the lower looper 1 so as to extend from the lower looper thread hole 1a to the looper threading notch Itlb; 2 is a swinging arm having the lower looper 1 on its upper part; 3 is a lower looper swinging arm shaft for swinging this swinging arm 2; 4 is a lower looper balance provided on this lower looper swinging arm shaft 3; , 7 is the looper, 8 is the frame, 9
is a looper thread hook provided along the swinging arm 2, 9a;
Reference numeral 9b indicates a looper thread hook portion and a lower looper balance formed at the upper and middle portions of the looper thread hook 9, respectively; 10 indicates a plate-shaped looper thread hook fixed to the swinging arm 2;
' is a slide groove formed in the base 10 for this looper thread hook, and is made up of an oblique part 10a extending diagonally downward and a hanging part 10b extending from this, and 11 is a lower part of the looper thread hook 9 so as to fit into the slide groove 10'. A slide shaft 13 provided in the section is a link 1 whose one end is rotatably pivoted to the lower end of the looper thread hook 9 via a connecting pin 12.
4 connects the other end of this link 13 to the looper threading stand 10
15 is an operating spring whose ends are connected between the lower end of the link 13 and the lower end of the swing arm 2, and 16 is a looper connected to the link 13. The rotating arm of the thread hook 9 is shown, and when the operating spring 15 is in the state shown in FIG.
Since it passes above the pivot pin 14 of the link 13, it acts to prevent the link 13 from rotating clockwise.

To thread the lower looper in such an overlock sewing machine, the device rotates a knob (not shown) on the sewing machine to rotate the swinging arm 2 six times clockwise around the lower looper swinging shaft 3 as shown in Fig. 5. After that, if the rotating arm 16 is pushed down and the slide shaft 11 is moved downward along the diagonal portion 10a of the slide groove 10', the tip of the looper thread hook 9 will be attached to the operating spring with the pivot pin 14 as a fulcrum. 15 and moves downward to the right in FIG. It became like this,
That is, the operating spring 15 exceeds its dead point of operation, and therefore the operating spring 15 operates to help it hang down, and the tip of the looper thread hook 9 further protrudes to the right side of the frame 8, and at the same time, the lower looper thread take-up 9b is also moved to the right and becomes the state shown in FIG.

In this state, the tip of the looper thread hook 9 is largely moved outside the frame 8, and the looper thread hooking section 9a and the lower looper thread hole 1a can be easily and quickly operated, and the lower Since there is no need to move the looper from side to side and use tools to hang the looper thread, work efficiency is greatly improved.

When the looper thread 7 has been threaded, push up the rotating arm 16 and move the slide shaft 11 upward along the slide groove 10' against the operating spring 15 until the slide shaft 11 reaches the oblique portion 10a. After that, the operating spring 15 operates to help move the slide shaft 11 beyond the dead center again, returning to the original state, and at this time, the tip of the looper thread hook 9 is placed on the upper surface of the left end of the lower looper 1. The looper thread hook that has been positioned and threaded is in a state where the thread outlet of the section 9a and the lower looper thread groove 1c are aligned, so the looper thread 7 is placed in the lower looper thread groove I.
We can guide you along C.

[Problem to be solved by the invention]

However, in the conventional overlock sewing machine as mentioned above, the lower looper threading device requires the user to manually set the looper threader to the center position and return it to the original (sewing state) position. ing. Therefore, if you forget to return the thread to its original (sewing state) position and start the sewing machine in this state, thread breakage or thread tangles may occur. Even if you can sew, the thread is not properly set (thread tension), so if you use the thread tension (dial position) as per the manual, you will not be able to sew neatly, resulting in problems such as poor stitching or skipped stitches.

In addition, there is a problem in that the user does not forget to return the looper threader to the original (sewing state) position by hand each time the looper is threaded, which is very troublesome even during normal operation.

The present invention seeks to eliminate the above-mentioned drawbacks.

[Means to solve the problem]

The lower lubar thread hook in the overlock sewing machine of the present invention includes a looper thread hook extending along a swinging arm having a lower looper on the upper part, a looper thread hook portion formed at the upper part of the looper thread hook, and the above-mentioned swinger. The looper thread hook fixed to the lower part of the movable arm has a stand, this looper thread hook has a link with one end rotatably supported on the stand, and the other end of this link and the lower part of the looper thread hook are rotatably connected to the stand. a connecting pin connected to the looper thread hook, means for moving the looper threader relative to the swinging arm, and an operation for restraining the link from rotating in opposite directions before and after the dead center position of the rotation of the link. a spring, a guide member having a support surface, and a sliding surface provided on the link so as to slide on the support surface when the swing arm rotates, causing the link to rotate past its dead center position. It is characterized by consisting of.

[For production]

In the overlock sewing machine of the present invention, the lower looper threader is automatically returned to the sewing position by the swinging of the lower looper.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

In the present invention, as shown in FIG. 1, a sliding surface 17 is formed on the lower surface of the link 13, and a guide lever plate 19 has a support surface 18 that is in contact with the sliding surface 17.
is fixed to the frame 8, and when the swing arm 2 rotates counterclockwise, the tip of the looper thread hook 9 protrudes to the right from the frame 8 as shown in FIG. From the rotational position, the link 13 is rotated beyond the dead center as shown in FIGS. 3 and 4.

Since the lower looper threader in the overlock sewing machine of the present invention has the above-mentioned configuration, as shown in FIG.
6 so that the tip of the looper thread hook 9 protrudes far to the right from the frame 8 as shown in FIG. begins to rotate counterclockwise about the lower looper swing arm shaft 3 together with the looper thread hook 9, and in this case, the sliding surface 17 of the link 13 contacts the support surface 18 of the guide lever plate 19. As shown in FIG.
-i with the pivot pin 14 of.

If the swinging arm 2 rotates further counterclockwise from this position, the link 13 will pass its dead center of operation, and the looper thread hook 9 will move relative to the swinging arm 2 due to the action of the operating spring 15. 4, and the looper thread hook 9 is returned to the sewing position.

Thereafter, the swinging arm returns to the position shown by the solid line in FIG. 4 together with the looper thread hook 9, and the sewing operation is then performed by swinging between the solid line position and the dotted line position.

〔Effect of the invention〕

The lower looper threader in the overlock sewing machine of the present invention has the above-described configuration, so the lower looper threader 9
Even if you forget to return the looper and start the sewing machine, there is a great advantage that the first movement of the lower looper will automatically return the looper threader to the sewing position.

It goes without saying that the present invention can be applied not only to lock sewing machines but also to all other sewing machines having a looper mechanism.

[Brief explanation of the drawing]

Figures 1 to 4 are front views showing the operating state of the lower looper threading device in the overlock sewing machine of the present invention;
The figure shows a front view of a lower looper threading device in a conventional overlock sewing machine, and FIG. 6 shows a front view showing its operating state. 1...Lower looper, la...Lower looper thread hole, 1
b... Looper threading notch, lc... Lower looper thread groove, 2... Swinging arm, 3... Lower looper swinging arm shaft,
4... Lower looper take-up, 7... Looper thread, 8...
・Frame, 9・Looper thread hook, 9a...Looper thread hook is part, 9b...Lower thread take-up, 1o...Looper thread hook is stand 1.10' Slide groove, 10a・
- Oblique part, 10b... Drooping part, 11... Slide shaft, 12... Connecting pin, 13... Link, 14...
Pivot pin, 15... Operating spring, 16... Rotating arm, 1
7...Sliding surface, 18...Supporting surface, 19...Guide lever plate. Oh Zukatsu! silk hard

Claims (1)

[Claims] (1) A looper thread hook extending along a swing arm having a lower looper at the top, a looper thread hook portion formed at the top of the looper thread hook, and a looper thread hook fixed to the bottom of the swing arm. , a link having one end rotatably supported on the looper threader, a connecting pin rotatably connecting the other end of the link to the lower part of the looper threader, and a connecting pin that rotatably connects the other end of the link to the lower part of the looper threader; means for causing the link to move relative to the arm; an actuating spring that restrains the link from rotating in opposite directions before and after the dead center position of the link; a guide member having a support surface; A lower looper in an overlock sewing machine, comprising a sliding surface provided on the link so that when the arm rotates, the link slides on the support surface and rotates the link past its dead center position. Threading device.