JPH0732829B2 - Lower looper thread hooking device for overlock sewing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lower looper thread hooking device for an overlock sewing machine.

[Conventional technology]

FIG. 5 shows a lower looper thread hooking device in a conventional overlock sewing machine, 1 is a substantially horizontal lower looper, 1a is a lower looper thread hole formed at one end of the lower looper 1, and 1b.
Is a looper threading notch formed at the other end of the lower looper 1 and 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 1b. The lower looper 1 has a swing arm having an upper portion thereof, 33 is a lower looper swing arm shaft for swinging the swing arm 2, 4 is a lower looper balance provided on the lower looper swing arm shaft 3, and 7 is Looper thread, 8 is a frame, 9 is a looper thread hook provided along the swing arm 2, 9a and 9b are looper thread hooks and lower looper thread balances formed on the upper and middle portions of the looper thread hook 9, respectively. Reference numeral 100 denotes a plate-shaped looper thread hooking base fixed to the swing arm 2, 10 'denotes a slide groove formed on the looper thread hooking base 10 and includes a slanting portion 10a extending obliquely downward and a hanging portion 10b extending therefrom. Fits into the slide groove 10 ' A slide shaft provided in the lower portion of the looper thread hook 9 has a link 13 rotatably supported at one end to the lower end of the looper thread hook 9 via a connecting pin 12, and 14 has the other end of the link 13. A pivot pin for pivotally supporting the looper thread hanging base 10 on the
Reference numeral 15 is an operating spring having its ends connected between the lower end of the link 13 and the lower end of the swing arm 2, and 16 is a rotating arm of the looper thread hook 9 connected to the link 13, and the operating spring 15
In the state shown in Fig. 5, the straight line connecting both ends is a link.
Since the link 13 passes above the pivot pin 14, it acts to prevent the link 13 from rotating in the clockwise direction.

In the lower looper thread hooking device in such an overlock sewing machine, after turning a knob (not shown) of the sewing machine, the swing arm 2 is rotated clockwise about the lower looper swing arm shaft 3 in FIG. , Push down the rotating arm 16 and slide shaft
When 11 is moved downward along the slanted portion 10a of the slide groove 10 ', the tip end of the looper thread hook 9 resists the actuating spring 15 with the pivot pin 14 as a fulcrum and moves downward in the right direction in FIG. Slide shaft 11 to the hanging portion 11 of slide groove 10 '.
When it reaches 0b, the straight line connecting both ends of the actuating spring 15 is the pivot pin.
14 so that the actuating spring 15 moves beyond the dead center of its actuation, so that the actuating spring 15 acts to assist its drooping and the tip of the looper thread hook 9 further extends to the frame 8. Of the lower looper balance
9b is also moved to the right, and the state shown in FIG. 6 is reached.

In this state, the tip end of the looper thread hook 9 is largely moved out of the frame 8 so that the thread hooking operation on the looper thread hooking portion 9a and the lower looper thread hole 1a can be performed easily and quickly, and the lower looper can still be operated. Since there is no need to bother with moving the tool left and right and hanging the looper thread using a tool, the work rate is greatly improved.

When the looper thread 7 has been hung up, the rotary arm 16 is pushed up to move the slide shaft 11 upward along the slide groove 10 'against the actuating spring 15 so that the slide shaft 11 is slanted portion 10a.
Is reached, the actuating spring 15 crosses the dead point again and the slide shaft
It operates to assist the movement of 11 and returns to the original state. At this time, the tip of the looper thread hook 9 is located on the upper surface of the left end of the lower looper 1, and the thread exit of the looped thread hook 9a Since the lower looper thread groove 1c and the lower looper thread groove 1c coincide with each other, the looper thread 7 can be guided along the lower looper thread groove 1c.

[Problems to be Solved by the Invention]

However, in the lower looper thread hooking device in the conventional overlock sewing machine as described above, the user manually sets the looper thread hook to the thread hooking position and returns it to the original (sewn state) position. Therefore, if you forget to return the looper thread hook to the original (sewn) position after setting the thread and start the sewing machine in this state, thread breakage or thread entanglement (tangle) may occur, and Even if it is not, the thread is not in the regular thread setting state (thread tension state), so that the thread tension (dialing position) according to the manual cannot be sewn neatly and the sewing feeling is bad, or a problem such as skipping occurs.

In addition, the user has to remember to return the looper thread to the original (sewn) position by hand even in normal operation, which is very troublesome.

The present invention eliminates the above drawbacks.

[Means for Solving the Problems]

A lower looper thread hooking device in an overlock sewing machine of the present invention comprises a looper thread hook extending along a swing arm having a lower looper on the upper portion, a looper thread hooking portion formed on the upper portion of the looper thread hook, and the swing arm. Looper thread hanging base fixed to the lower part of the loop, a link whose one end is rotatably supported on this looper thread hanging base, and a connection for rotatably connecting the other end of this link and the lower part of the looper thread hook. A pin, a means for moving the looper thread hook relative to the swing arm, an operation spring for restraining the link from rotating in opposite directions before and after the dead center position of the rotation of the link, and a support A guide member having a surface, and a sliding surface provided on the link so as to slide on the support surface when the swing arm rotates so as to rotate the link beyond its dead center position. Special To.

[Action]

In the lower looper thread hooking device of the overlock sewing machine of the present invention, the looper thread hook is automatically returned to the sewing position by swinging of the lower looper.

〔Example〕

 Embodiments of the present invention will be described 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 having a supporting surface 18 that is in contact with the sliding surface 17 is provided on the frame 8. When the swing arm 2 is fixedly provided, the tip end of the looper thread hook 9 is projected from the frame 8 to the right side as shown in FIG. As shown in FIGS. 3 and 4, the link 13 is rotated beyond the position beyond the dead point.

Since the lower looper thread hooking device in the overlock sewing machine of the present invention has the above-described structure, the looper thread hooker is rotated from the state in which 9 is in the sewing position as shown in FIG.
Even if the sewing machine is accidentally started up by pushing down 16 so that the tip of the looper thread hook 9 projects largely to the right of the frame 8 as shown in FIG. Starts rotating counterclockwise around 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 comes into contact with the supporting surface 18 of the guide lever plate 19. As shown in FIG. 3, the straight line connecting both ends of the actuating spring 15 is moved to move the pivot pin 14 of the link 13.
Will match.

If the swing arm 2 further rotates counterclockwise from this position, the link 13 will exceed the dead point of its operation, and therefore the looper thread hook 9 will be actuated by the actuating spring 15 to cause the swing arm 2 to move.
4 is rotated counterclockwise relative to the state shown by the dotted line in FIG. 4, and in this state, the looper thread hook 9 is returned to the sewing position.

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

〔The invention's effect〕

Since the lower looper thread hooking device in the overlock sewing machine of the present invention has the above-described structure, the looper thread hooking 9
Even if you forget to return the sewing machine and start the sewing machine, there is a great advantage that the looper thread hook can be automatically returned to the sewing position by the first movement of the lower looper.

Of course, the present invention can be applied not only to the lock sewing machine but also to all other sewing machines having a looper mechanism.

[Brief description of drawings]

1 to 4 are front views showing the operating state of the lower looper thread hooking device in the overlock sewing machine of the present invention, and FIG.
FIG. 6 is a front view of a lower looper thread hooking device in a conventional overlock sewing machine, and FIG. 6 is a front view showing its operating state. 1 ... Lower looper, 1a ... Lower looper thread hole, 1b ... Looper threading notch, 1c ... Lower looper thread groove, 2 ... Swing arm, 3 ... Lower looper swing arm shaft, 4 ... … Lower looper balance, 7 …… looper thread, 8 …… frame, 9 …… looper thread hook, 9a …… looper thread hooking part, 9b …… lower looper thread balance, 10 …… looper thread hook, 10 ′ …… Sliding groove, 10a: skewed portion, 10b: hanging portion, 11: slide shaft, 12: connecting pin, 13: link, 14: pivot pin, 15: operating spring, 16: rotation Moving arm, 17 …… Sliding surface, 18
…… Supporting surface, 19 …… Guide lever plate.

Claims (1)

[Claims] 1. A looper thread hook extending along a swing arm having a lower looper on an upper portion, a looper thread hook portion formed on an upper portion of the looper thread hook, and a looper thread hook fixed on a lower portion of the swing arm. The base, a link whose one end is rotatably supported by the looper thread hooking base, a connecting pin which rotatably connects the other end of the link and the lower portion of the looper thread hook, and the looper thread hook A means for moving the link relatively to the swing arm, an actuating spring for restraining the link to rotate in opposite directions before and after the dead center position of the rotation of the link, a guide member having a supporting surface, and An overlock sewing machine comprising: a sliding surface provided on the link so that the link, which has slid on the supporting surface when the swing arm rotates, can be rotated beyond its dead center position. Lower looper Over apparatus.