JP3479332B2 - Overlock sewing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overlock sewing machine and, more particularly, to an overlock sewing and a sewing other than an overlock sewing (for example, double chain stitching). Overlock sewing machine. An overlock sewing machine that performs double chain stitching using a needle that moves up and down and a lower looper that stops an upper looper and swings back and forth and left and right is conventionally known. When performing this double chain stitch, the needle needs to descend into the triangle formed by the needle thread, the lower looper thread, and the lower looper. As a yarn separating means for this purpose, Japanese Patent Laid-Open No.
As described in No. 12058, it is known to form the above triangle by filtering looper yarns. [0003] An overlock sewing machine capable of performing overlock sewing in addition to double chain stitching has also been conventionally known. [0004] In the case of an overlock sewing machine capable of performing overlock sewing in addition to such double loop sewing, a double loop is used in addition to the upper looper and lower looper for overlock. The provision of the lower looper for sewing complicates the looper mechanism. Therefore, it is desired to perform double chain stitching using the lower looper for overcast. In this case, as shown in FIG. 6A, when the needles 2 and 4 descend, the lower looper 6 moves to the left (in the direction of the arrow). The needles 2 and 4 drop to the left side of the needle thread T, and the needles drop into the triangle formed by the needle thread T, the looper thread R and the lower looper 6. do not do. FIG. 6B shows a state in which an appropriate triangle is formed, and the needles 2 and 4 can descend into the triangle. In order to form such an appropriate triangle, the method of separating the looper thread R as in the above-described prior art is not preferable, and the needle thread T must be separated. Accordingly, the present applicant has filed a Japanese Patent Application No. Hei.
No. 9616 proposes a thread separating apparatus for forming the above triangle with a lower looper for overlock stitching and reliably enabling double chain stitching such as cover stitching. The thread separating apparatus has a thread separating hook. The double thread sewing performs the forward and backward movement and the left and right movement when performing double chain stitching. However, when performing the overlock sewing, the thread separating hook is used. Since it is unnecessary, it is desirable to stop. However, in the case of the yarn separating apparatus disclosed in Japanese Patent Application No. 5-139616, the back and forth movement is stopped but the left and right movement cannot be stopped. For this reason, there is a possibility that the empty ring at the time of the overlock sewing may be entangled with the thread handling hook. Accordingly, an object of the present invention is to provide an overlock sewing machine that can completely stop the thread separating device when performing overcast sewing. According to the present invention, in order to achieve the above object, an overcast mode in which an oscillating upper and lower looper is used, an oscillating motion of an upper looper is stopped, and a lower An overlock sewing machine having a double chain stitching mode for applying forward and backward swinging and left and right swinging movements to a looper, wherein the overlock sewing machine is capable of forward and backward swinging and left and right swinging swinging movement in conjunction with a main shaft of the sewing machine. The needle is dropped into the triangle formed by the lower looper thread, the lower looper, and the needle thread by performing the forward and backward swing motion and the left and right swing motion in the overlock sewing mode. A thread separating hook for holding the needle thread above the lower looper so as to perform the forward and backward swinging motion transmitting means capable of transmitting the forward and backward swinging motion of the lower looper shaft to the thread separating hook; and the lower looper shaft. A left-right oscillating motion transmitting means capable of transmitting a left-right oscillating motion to the thread separating hook; and a front-rear oscillating motion transmitted to the thread separating hook by the front-rear oscillating motion transmitting means and the left-right oscillating motion transmitting means in the double chain stitching mode. And a switching means for transmitting a dynamic motion and a right and left oscillating motion, and stopping transmission to the thread handling hook by the left and right oscillating motion transmitting means in the overcast sewing mode. Is done. In the double chain stitching mode, the lower looper shaft makes a forward and backward swinging movement and a left and right swinging swinging movement, and the movement is transmitted by the forward and backward swinging movement transmitting means and the left and right swinging movement transmitting means. The needle falls into a triangle formed by the lower looper thread, the lower looper, and the needle thread. On the other hand, in the overcast sewing mode, the forward and backward swinging motion of the lower looper shaft is stopped, and the transmission of the left and right swinging motion to the thread separating hook by the left and right swinging motion transmitting means is stopped by the switching means. Therefore, the thread handling hook is completely stopped. An embodiment of an overlock sewing machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of the embodiment, and FIG. 2 is an exploded perspective view of a part of the embodiment. FIG. 3 is a perspective view of a main part of the embodiment, FIG. 4 shows a main part of the embodiment at the time of double chain stitching, (A) is a side view, (B) is a partial top view of (A), FIGS. 5A and 5B show a main portion of the embodiment at the time of overcasting, FIG. 5A is a side view, and FIG. 5B is a partial top view of FIG. In FIG. 1, a support member 10 is rotatably mounted on a hook rotation shaft 8 fixed to a frame of a sewing machine (not shown). The hook rotation shaft 8 extends in the front-rear direction (AB direction in the drawing). This support member 10
The hook swing arm 14 is rotatably attached to the hook swing arm 12 via the auxiliary swing pin 12. The auxiliary swing pin 12 extends in the left-right direction (CD direction in the drawing). The thread swinging arm 14 has a thread handling hook 1
6 is screwed and fixed. The thread handling hook 16
It can rotate in the front-rear direction between the position of the solid line and the position of the two-dot chain line in FIG. At the time of overcasting, the sewing machine stops at the position indicated by the two-dot chain line in the figure as described later. A torsion spring 18 is attached to the hook rotating shaft 8. The torsion spring 18 has one end of its working end abutting on the frame of the sewing machine and the other end thereof abutting on the hook swing arm 14. The hook swing arm 14 is always biased to the right. The lower looper shaft 20 is provided with a frame 22 of the sewing machine.
And extends in the front-rear direction. Reference numeral 22 is located inside a looper cover of a sewing machine (not shown), and the apparatus shown in FIG. 1 is positioned so that an operator can inspect the looper cover in a state where the looper cover is opened toward the operator (toward the operator). When the main shaft (not shown) rotates, the lower looper shaft 20
The main shaft is used as a drive source to cause a left-right swing motion via a looper cam, a looper rod, etc., not shown, and to move back and forth via a double ring cam, a front-rear swing shaft, etc., not shown. In addition, when performing the overlock sewing, the lower looper shaft 20 is prevented from moving back and forth by a back and forth movement stopping device (not shown) (see Japanese Patent Application No. 3-79670). A lower looper support arm 24 for supporting the lower looper 6 and a longitudinal swing transmission arm 26 having a bifurcated portion 26a at the top as shown in FIG. A hook swing cam 28 provided with a cam portion 28b is slidably fitted. Hook swing cam 2
A spring 29 is provided between the lower looper support arm 8 and the lower looper support arm 24. The lower looper 6 and the thread handling hook 16
Is located below the needle plate 30 of the sewing machine. A fitting pin 32 is fixed to the forward and backward swing transmission arm 26, and the fitting pin 32 is connected to the hook swing cam 28.
Can be fitted into a fitting hole 28a (see FIG. 4). The hook swing arm 14 has a front and rear swing pin 31.
And one end of the left / right swing transmission pin 33 are fixed and movable in the direction of the arrow, respectively. As shown in FIG. 2, the other end of the front-rear swing pin 31 is fitted into the fork 26 a of the front-rear swing transmission arm 26, and the left-right swing transmission pin 33 can abut on the cam portion 28 b of the hook swing cam 28. It is. As shown in FIG. 3, a support member 34 is fixed to the frame 22, and a switching lever 38 is rotatably attached to the support member 34 via a step screw 36.
A knob 3 is provided on one end side (operator side) of the switching lever 38.
8a, and a long hole 38b is formed on the other end side.
A sewing specification switching pin 40 is connected to 8b via a screw. The sewing specification switching pin 40 passes through the frame 22. When performing double chain stitching (during double chain stitching mode), the switching lever 38 is positioned at the position indicated by the solid line in FIG. As a result, as shown in FIG. 3, the tip of the sewing specification switching pin 40 moves rearward, and the hook swing cam 28 is also pressed by the spring 29 and retreats from the position shown by the two-dot chain line to the position shown by the solid line. The hook swing cam 28 is held between the fitting pin 32 and the spring 29 at the retracted position. The lower looper support arm 24 is always fixed to the lower looper shaft 20. Therefore, as shown in FIG. 4B, the other end of the left / right swing transmission pin 33 is connected to the cam portion 28 of the hook swing cam 28.
b, the left and right swing of the lower looper shaft 20 is transmitted to the hook swing arm 14 via the hook swing cam 28 and the left and right swing transmission pin 33. As a result, the hook swing arm 14 swings left and right about the hook rotation shaft 8. Torsion spring 18
Due to the urging force, the left / right swing transmission pin 33 is in contact with the cam portion 28b of the hook swing cam 28, so that the hook swing arm 14 makes a left / right swing motion along the shape of the cam portion 28b. At this time, the lower looper shaft 20 also moves back and forth. Therefore, the forward / backward swing transmission arm 26 also moves back and forth together with the lower looper shaft 20, but this movement is performed by the hook swing via the forward / backward swing pin 31 inserted into the fork 26a of the forward / backward swing transmission arm 26. It is transmitted to the arm 14. As a result, the hook swing arm 14 moves back and forth around the auxiliary swing pin 12. The front-rear oscillating motion transmitting means is provided by the front-rear oscillating pin 31, the front-rear oscillating transmission arm 26, and the like.
3. The hook swing cam 28 forms a left and right swing motion transmitting means. As described above, the hook swing arm 14 is composed of the forward and backward movement by the forward and backward swing movement transmitting means and the left and right swing movement by the left and right swing movement transmitting means, so that the thread separating hook 16 is suitable for the yarn handling. Draw a special motion trajectory close to a D-shape. As a result of this motion trajectory, as shown in FIG.
A triangle formed by the needle thread T, the lower looper thread R and the lower looper 6 can be forcibly formed below the needles 2 and 4. When performing the overlock stitch (in the overlock stitch mode), the switching lever 38 is positioned at the position indicated by the two-dot chain line in FIG. As a result, the sewing specification switching pin 40 moves forward (to the left in the drawing), and the hook swing cam 28 also moves forward while being fitted with the fitting pin 32 as shown in FIG. For this reason, as shown in FIG. 5B, the left and right swing transmission pins 33 do not come into contact with the cam portion 28b of the hook swing cam 28, and always come into contact with the outer periphery of the hook swing cam 28. Hook swing arm 14
That is, the yarn separating hook 16 does not move left and right. Further, as described above, the lower looper shaft 20 is prevented from moving back and forth by the back-and-forth movement stopping device (not shown), so that the hook swing arm 14 does not move back and forth, and
Pause completely at the position indicated by the two-dot chain line. At this time, the hook swing cam 2 urged rearward by the spring 29
The position 8 is regulated by the sewing specification switching pin 40. Although the overlock sewing machine according to the present invention has been described based on one embodiment shown in the drawings, the present invention is not limited to this embodiment and can be variously modified.
For example, in the double chain stitching mode, the front and rear rocking motion transmitting means and the right and left rocking motion transmitting means transmit the front and rear rocking motion and the right and left rocking motion to the thread separating hook. The switching means may be configured to have no effect and to stop the transmission to the yarn handling hook by the left and right swinging movement means. More specifically, a movement transmitting member (not shown), which is made to operate / inactivate by switching the switching lever 38, is connected to the vicinity of the elongated hole 38b of the switching lever 38 in FIG. . According to the overlock sewing machine of the present invention, the thread separating device can be completely stopped when performing the overlock sewing. Therefore, there is no possibility that the empty ring at the time of the overlock sewing is entangled with the thread handling hook.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a main part of an embodiment of an overlock sewing machine according to the present invention. FIG. 2 is an exploded perspective view of a part of the embodiment. FIG. 3 is a perspective view of a main part of the embodiment. 4 (A) is a side view, and FIG. 4 (B) is a partial top view of FIG. 5 (A) is a side view, and FIG. 5 (B) is a partial top view of FIG. FIGS. 6A and 6B are schematic diagrams showing a positional relationship between a needle thread, a looper thread and a lower looper when the needle descends, wherein FIG. 6A shows an incorrect positional relationship and FIG. 6B shows an appropriate positional relationship. DESCRIPTION OF SYMBOLS 2, 4 needles 6 Lower looper 8 Hook rotation shaft 12 Auxiliary swing pin 14 Hook swing arm 16 Thread separating hook 20 Lower looper shaft 22 Frame 24 Lower looper support arm 26, 31 Forward / backward swing motion transmission means 28, 33 Right and left swing motion transmitting means 30 Needle plate 32 Fitting pin 34 Support member 38 Switching lever (switching means) 40 Sewing specification switching pin

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Claims (1)

(1) An overlock sewing mode using an upper and lower looper capable of oscillating motion, and a swaying motion of an upper looper and a forward and backward swing and a left and right swing by a lower looper. An overlock sewing machine having a double chain stitching mode for applying a motion, wherein the front and rear swinging motion and the right and left swinging motion can be performed in conjunction with a main shaft of the sewing machine, and the front and rear swinging motion stops in the overcast sewing mode. The lower looper shaft, and the needle thread is moved above the lower looper so that the needle falls into a triangle formed by the lower looper thread, the lower looper, and the needle thread by performing a back-and-forth swinging motion and a left-right swinging motion. A thread separating hook held by: a forward / backward swinging motion transmitting means capable of transmitting the forward / backward swinging motion of the lower looper shaft to the thread handling hook; and transmitting the left / right swinging motion of the lower looper shaft to the thread handling hook. Possible A left-right oscillating motion transmitting means; and a front-rear oscillating motion and a right-left oscillating motion transmitted to the thread separating hook by the front-rear oscillating motion transmitting means and the left-right oscillating motion transmitting means in the double chain stitching mode. A switching means for stopping transmission of the right and left swinging motion transmitting means to the thread separating hook in the overlock sewing mode.