JPH0649114B2 - Sewing machine threading device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a threading device for a sewing machine having a plurality of needles.

[Prior Art] Threading a thread through a sewing needle is a difficult task even for an operator with good visual acuity, and especially a two-needle overlock sewing machine or a two-needle overlock sewing machine
In a sewing machine having a plurality of needles such as the main needle interlock sewing machine, a knife for cutting cloth is provided in the vicinity of the needles, and threading work is difficult.

Conventionally, various types of devices using threading needles have been proposed as threading devices (Japanese Utility Model Publication No. 53-35061 and Japanese Utility Model Publication No. 61-35188). However, such a threading device was developed for a normal single-needle, lockstitch sewing machine, and is not suitable for an overlock sewing machine equipped with a looper, a knife for cutting cloth, and the like. Not applicable to sewing machines.

On the other hand, as a threading device for a sewing machine having a plurality of needles, a threading device pivotally attached to a needle stop portion of a needle bar has been proposed (Japanese Patent Publication No. 39-1782).

[Problems to be Solved by the Invention] However, this threader is configured to be detachably attached to the cylindrical screw shaft portion of the needle stopper main body at the lower portion of the needle bar. The needle bar has a different structure, and cannot be used in a sewing machine equipped with a looper, a knife or the like as described above. In addition, such a conventional threading device has a problem in operability such that it lacks stability of operation and also has to be removed because it prevents feeding of the cloth at the time of sewing. Further, in the conventional threading device for a single needle, it is necessary to position the needle for penetrating the thread hooking member into the hole of the needle at a predetermined position, for example, top dead center. Therefore, separately from the threading device. Equipped with a needle positioner.

However, the needle positioner is expensive and has a drawback that the mechanism is complicated.

[Object of the Invention] The present invention solves the problems of such a conventional threading device and provides a threading device for a two-needle overlock sewing machine which has stable operability, high reliability, and a simple mechanism. The purpose is to provide.

Further, another object of the present invention is to provide a threading device that has a positioning mechanism in the threading mechanism itself and does not malfunction.

[Means for Solving the Problems] A threading device for a sewing machine of the present invention that achieves such an object is provided with a rotary shaft that intersects with the feed direction of a cloth, and a fixing member on the rotary shaft. A threading member that is fixed and swings by rotation of the rotary shaft, and a threading needle that is fixed to the threading member are provided, and the fixing member swings the threading member on two or more different swinging surfaces. As described above, a switching means for switching the position of the threading member is provided.

[Operation] When the rotary shaft is rotated, the threading member fixed to the rotary shaft swings on the first swing surface, and the thread hooking needle moves backward in the needle hole of the first needle in the swing surface. Penetrate from. After threading on the threading needle that has penetrated, when the rotation axis is reversed, the threading member retracts to the rear of the needle, and at the same time the threading needle escapes from the hole of the needle and is hooked on the threading needle. The thread is passed through the needle hole.

Next, the threading member is switched to the second swing position by sliding the threading member by the switching means provided on the fixed member or rotating the threading member with respect to the rotation shaft. Then, when the rotary shaft is rotated, the threading member swings on the second swing surface, whereby the threading needle penetrates from the rear into the needle hole of the second needle in the second swing surface. To do. Hereafter, the threading operation can be performed in the same manner as the above-mentioned operation.

[Example] Hereinafter, a threading device of the present invention will be described based on an example shown in the drawings.

FIG. 1 is a diagram showing the entire overlock sewing machine to which the present invention is applied. The needle bar 1 moves up and down by the rotation of a main shaft (not shown), and an arc shape is formed below the needle plate 2 by the rotation of the main shaft. A lower looper 3 (Fig. 2) that reciprocates, and an upper looper 4 (the same diagram) that reciprocates curvedly by passing the side surface of the needle plate 2, and the needle bar 1 has a right needle 5 and a left needle. 6 is fixed via a needle stopper. In such an overlock sewing machine, as shown in FIG. 2, the loci of the right needle 5 and the left needle 6 cross the loci of the lower looper 3 and the upper looper 4, respectively, and the threads are scooped up to sew the overlock sewing machine. Is formed, for example, the lower looper 3 is the left needle 6
Since the needle bar 1 moves upward while moving to the right needle 5 after crossing with the right needle 5, the lower looper 3 also crosses the right needle 5 and thus the right needle 5 and the left needle 6 move up and down. There is a slight deviation in the direction. A scalpel (not shown) for cutting the end of the cloth is provided on the side of the needle plate 2.

In such an overlock sewing machine, the threading device is provided with a shaft 11 which is a rotary shaft that is pivotally supported by the sewing machine main body so as to intersect the cloth feeding direction, and a shaft that is fixed to one end of the shaft 11 and is outside the sewing machine main body. Knob 12 for rotating 11
And a fixing member 13 fixed to the other end of the shaft 11, and a threading member 14 whose locking position with respect to the fixing member 13 can be switched.

The shaft 11 is axially supported by the body frame 10 via bearings so as to intersect with the cloth feeding direction, and is rotated by a positioning member 17 and a knob 12 for determining the timing of rotation thereof.
A return spring 18 and a stopper 19 for automatically reversing 1 are provided, and their functions will be described later.

The fixing member 13 is fixed to the shaft 11 by a set screw 30, and has a switching means for switching the position of the threading member 14.

3 (a), (b) and FIG. 4 show the first embodiment of the fixing member 13, and in this embodiment, the fixing member 1
3 has an inclined surface 32 for slidingly guiding the threading member 14. The threading member 14 is fixed to the fixing member 1 by the presser 31.
3 and the threading member 14 is attached to the inclined surface 32.
A long groove 33 is formed in the presser 31 so as to slide over.

The threading member 14 can be selectively positioned by the ball 34 fitted into the hole of the presser 31 by the leaf spring member 35 and the two recesses 36a and 36b formed in the threading member 14.

On the other hand, the threading member 14 has a thread guide 15 and a thread hooking needle 16 fixed to the tip thereof, and the other end serves as an operating portion 14a for slidingly operating the threading member 14. Therefore, the inclined surface 32 of the fixing member 13, the presser foot 31 and the long groove 33 of the presser foot 31 serve as a sliding means for sliding the threading member 14 within the plane including the axis of the shaft 11, and the thread protruding from the presser foot 33. The operation unit 1 which is a part of the through member 14
4a is moved in the direction of the arrow in the drawing to move the threading member 14
Can be slid along the inclined surface 32 in the groove 31 to switch between a first position and a second position determined by the ball 34 and the two recesses 36a, 36b. That is, the threading member 14 can swing on two swinging surfaces corresponding to these two positions.

By the way, as described above, in the two-needle overlock sewing machine, although the heights of the right needle 5 and the left needle 6 are different, the fixing member 13
The inclined surface 32 is formed such that its inclination is equal to the inclination of the line connecting the needle hole of the right needle 5 and the needle hole of the left needle 6. This means that the threading needle 16 of the threading member 14 is in a position to be inserted into the right needle 5 in the first position thereof, and the threading member 14 is slid in the groove 31 along the inclined surface 32. The position 2 means that the left needle 6 is inserted. That is, the threading member 14 is swung on two different swinging surfaces by the rotation of the shaft 11, whereby the threading needle 16 is inserted from the rear of the needle bar 1 into either the right needle 5 or the left needle 6. Will be done.

In this embodiment, two recesses are shown as the recesses into which the balls 34 are fitted, but the number of recesses is increased depending on the number of needles or the model, so that the rocking surface is 3 or more. It goes without saying that you can do it.

Next, the positioning member 17 for determining the timing of rotating the shaft 11 cooperates with the timing disc 20 (hereinafter referred to as disc) to determine the timing so that the threading operation is performed at a predetermined position of the needle. The disk 20 is fixed to the main shaft by contacting the pulley 8 that rotates integrally with the main shaft, and the notch 20 for engaging the tip 17a of the positioning member 17 with the pulley 20.
It has a and rotates integrally with the main shaft. Therefore, the movement is interlocked with the operation of the needle bar 1, and when the main shaft is at a predetermined position, that is, when the needle is at a predetermined position above the needle plate, for example, at top dead center, the notch 20a has its notch 20a at the tip of the positioning member 17. It becomes a position which engages with 17a. When the shaft 11 is rotated by the knob 12 at this position, the positioning member 17 can be further rotated by the depth of the notch 20a. By this rotation, the thread hooking needle 16 can penetrate into the needle hole of the needle. At any other timing, even if the positioning member 17 is rotated, the tip 17a of the positioning member 17 contacts the outer periphery of the disk 20 other than the notch and does not rotate any more. That is, the thread hook needle 16
Is locked at a position close to the needle and does not collide with the needle below the top dead center.

Further, the return spring 1 is provided between the pin 21 implanted in the body frame 10 and the pin 22a implanted in the return ring 22.
8 is suspended and is rotated by a knob 12.
1 is automatically reversed to retract the threading member 14.

The reverse rotation is stopped by the pin 23a implanted in the stop ring 23 coming into contact with the stopper 19 implanted in the body frame 10. As a result, the retracted position of the threading member 14 is determined.

Next, the threading operation will be described.

First, when threading the right needle 5, the operating portion 14a of the threading member 14 is pulled to the right (R) and the threading member 14 is moved to the first position.
After switching to the position of, the pulley 8 is rotated so that the right needle 5 comes to the top dead center. After that, the knob 1 with one hand
When turning 2, the tip 17a of the positioning member 17 engages with the notch 20a of the disk 20 and rotates, whereby the threading member 14 rotates on the first swinging surface and the threading needle 16 moves to the right needle. Penetrate into needle hole 5. Here, the thread that has already been pulled out along the thread guide, the thread tension disc, the balance, etc. is guided with the other hand 1
Pull it as if hooking on 5, and release knob 12. At this time, even if the thread is not hooked on the thread hooking needle 16, the thread guide 15
It is very easy to operate because it only needs to be scratched. When the knob 12 is released, the shaft 11 is rotated in the reverse direction by the return spring 18, and the thread hooking needle 16 escapes from the needle hole while retracting the thread at the fishing-like tip, and moves backward, and comes into contact with the stopper 19 to stop. Next, the thread passed through the needle hole in a loop shape is pulled, and the tip of the thread is pulled out to complete the threading operation.

Next, when threading the left needle 6, the operating portion 14a of the threading member 14 is pushed to the left (L) and the threading member 14 is switched to the second position, and thereafter the knob is operated in exactly the same manner as described above. 1
2 is operated to perform the threading operation. As described above, by sliding the threading member 14 and switching the swinging surface thereof, it is possible to easily thread the needle holes of the two needles. In this case, since the threading member 14 does not rotate so as to penetrate into the needle hole at a predetermined position of the needle, that is, at the top dead center in the present embodiment, there is no risk of damage to the needle and the thread hooking needle due to malfunction.

Further, since the threading member 14 is normally in a position where it is largely retracted by the return spring 18, it does not interfere with sewing or the like.

In this embodiment, the case where the positions of the left needle and the right needle are vertically displaced has been described, but when the heights of both needles are the same, the inclined surface 32 of the fixing member 13 is horizontal and the threading is performed. It goes without saying that the member 14 may be slid horizontally.

Further, the mechanism that determines the rotation of the shaft 11 is not limited to the positioning member 17 and the disk 20, and any mechanism that allows the shaft 11 to rotate at a predetermined rotation position of the main shaft may be used.

Further, the structure for stopping and returning the shaft 11 is not limited to this embodiment, and it is possible to freely change it by directly implanting a stop pin, a returning pin or the like on the shaft 11 or the arm. it can.

Next, FIGS. 5 and 6 show other embodiments of the threading device according to the present invention. In the embodiment of FIG. 5, the threading member 14 'is attached to the shaft 11 and the fixing member 13'. It is configured so that the position is switched by rotating it with respect to.

The threading member 14 'is pivotally supported at a point A with respect to a fixing member 13' fixed to one end of the shaft 11, and the spring 41
And, it is locked to the fixing member 13 ′ via the ball 42.
On the other hand, the fixing member 13 ′ has two recesses 43 a and 43 b that engage with the ball 41, and the spring 41 and the ball 4
A rotation means for switching the threading member 14 'to two positions together with 2 is constituted. That is, the threading member 14 '
When the threading member 14 'is rotated by operating the operating portion 14'a at the tip of the
a and 43b to engage the threading member 14 '
Can be switched to one position. The threading member 14 'can swing on two swinging surfaces corresponding to these two positions.

When this position is switched, the threading member 14 'rotates about the point A, but the point A is separated from the needle hole of the right needle 5 and the needle hole of the left needle 6 as shown in FIG. The positions are set so that the distance is equal to the distance.

Therefore, when the threading member 14 'is in the first position, the threading needle 16 is in a position corresponding to the needle hole of the right needle 5, and when the shaft 11 is rotated, the threading member 14' is swung to the first position. The yarn hooking needle 16 is inserted in the needle hole of the right needle 5 from the rear by rotating in the plane. or,
When the threading member 14 'is switched to the second position by the operating portion 14'a, the threading needle 16 is at a position corresponding to the needle hole of the left needle 6, and the shaft 11 is rotated to rotate the threading member. When 14 'is rotated on the second swing surface, it penetrates into the needle hole of the left needle 6.

The mechanism for determining the rotation timing of the shaft 11 and the threading operation are the same as those in the first embodiment, and will not be described.

[Effects of the Invention] As is apparent from the above embodiments, according to the threading device of the present invention, a rotary shaft is provided in a gap of another power transmission mechanism or the like so as to intersect with the cloth feeding direction. On the other hand, since the threading member whose swinging surface is switchable is attached, it is not necessary to remove the threading member one by one, and the threading can be easily performed on the two needles by a simple switching operation. Further, since it is at the retracted position behind the knife during sewing, it does not get in the way and the operability is good.

Further, since the threading device of the present invention has a mechanism for determining the rotation timing of the rotary shaft and is configured to always operate at the top dead center of the needle, an expensive device such as a knee positioner is unnecessary and malfunctions occur. There is no.

Furthermore, since only two operations of turning the knob and hooking the thread are necessary, any operator can perform the operation very easily.

[Brief description of drawings]

FIG. 1 is an overall view of an overlock sewing machine to which the present invention is applied, FIG. 2 is a view showing a relationship between a needle and a looper, and FIGS. 3 (a) and 3 (b) are views of a threading device according to the present invention. 1 is a side view of the first embodiment, FIG. 4 is a perspective view of a main part thereof, FIG. 5 is a view showing another embodiment of the threading device according to the present invention, and FIG. 6 is an exploded perspective view of the main part. . 1 ... Needle bar 2 ... Needle plate 5 ... Right needle 6 ... Left needle 11 ... Rotating shaft 13, 13 '... Fixing member 14, 14' ... Threading member 14a ... Operating part (switching means ) 17 Positioning member 20 Disc 20a Notch 31 Presser (slide means) 32 Inclined surface (slide means) 33 Long groove (slide means) 34, 41 ...... Ball 42 ...... Spring 36 , 43a, 43b ... Recesses

Claims (3)

[Claims] 1. A rotary shaft provided so as to intersect with a cloth feeding direction, a threading member fixed to the rotary shaft via a fixing member and swingable by rotation of the rotary shaft, and the threading member. A sewing machine having a fixed threading needle, wherein the fixing member has a switching means for switching the position of the threading member so that the threading member swings on two or more different swinging surfaces. Threading device. 2. The threading device for a sewing machine according to claim 1, wherein the switching means is a sliding means for sliding the threading member in a plane including the axis of the rotary shaft. 3. The threading device for a sewing machine according to claim 1, wherein the switching means is a rotating means for rotating the threading member with respect to the rotary shaft.