JPS5835720B2 - Overedge sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overedge sewing machine, and more particularly to a needle with a needle thread and a lower looper with a lower looper thread.

The upper looper is equipped with an upper looper that carries the thread, and a main thread take-up that is linked to the sewing machine mechanism and bends the needle thread between the needle thread tension device and the needle during each intermediate stroke when the needle bar moves up and down. This invention relates to an auxiliary thread take-up which is attached to an over-edge sewing machine that forms an over-edge seam on the edge of a cloth, to ensure thread tightening and to prevent seam defects that occur in addition to the thread-tightening effect of this type of main take-up. It is something.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a cover that covers the outside of the frame 14 of the sewing machine, and a pair of opposing tension plates 2 for applying tension to the needle thread X are provided above the outer front surface of the cover 1. , 3 and a lever 4 for adjusting the pressure of a spring (not shown) that applies pressure to the plate, and a needle thread tensioner 5 with a thread tensioning slit 6 formed below and horizontally in front. A first thread shade 7 is provided that projects from the bottom.

Reference numeral 8 denotes a thread guide whose base is fixed to the cover 1 through an elongated hole 3°4 with a screw 35, and a U-shaped bent portion that encircles the outside of the vertical hole 9 for the thread take-up of the frame 1. 10, and the bent portion 101C forms a threading groove 11 which opens forward and is inclined downward on the opposing side surface.

Reference numeral 12 denotes a second thread hook that projects horizontally forward from the lower surface of the cover 1 and forms a slit 13 therein.

Figure 2 A, B. As shown in Figure 0, 15 is frame 14
The needle bar Vc in the frame 14 is rotatably supported at the upper end of the needle bar link 16.

Reference numeral 17 denotes a fixed shaft fixed within the frame, and the fixed shaft rotatably supports a rocking body 36 in which the connecting arm 19 and the rocking arm 20 are integrally formed. (not shown) is connected to the upper end of a crank arm 18 connected to a crank or the like of a drive shaft that rotates in conjunction with a drive source, and the tip of the swinging arm 20 is connected to the lower end of the needle bar link 16 described above.

Reference numeral 21 denotes a main balance, whose base is fixed to the front end surface of the needle bar link 16, and whose tip protrudes from the hole 9 of the cover 1 into the bent portion 10 of the thread guide 8, and then forms the arcuate portion 22. Then, it is bent downward to form a recess 24 continuous with the slope 23 at the lower end.

Reference numeral 25 denotes a sub-take-up lever formed by bending a single wire as shown in FIG. 1, and its center portion is fitted and fixed to the needle bar 15 below the frame 14, and thread-covering portions 26.25 are provided at both ends.
form 27.

Reference numeral 28 indicates a needle, 29 a lower looper, and 30 an upper looper, and the drive mechanisms 7 for these loopers are omitted as they are not the gist of the present invention.

Y is the lower looper thread, and Z is the upper looper thread.

This invention has the above-mentioned configuration, and as shown in FIG. Bend the thread upward, insert it into the groove 11 of the thread guide 8, bend it further downward, pass it through the slit 13 of the second thread shade 12, and then pass it through the thread shade part 26.27K of the sub thread take-up 25, and then insert it into the thread guide 8 groove 11. Pass it through the needle hole 31.

Upper and lower looper yarns Z and Y are also passed through the twisted upper and lower loopers 30 and 29, respectively.

When the drive shaft (not shown) of the sewing machine is rotated in this state, first, the swinging body 36 swings around the fixed shaft 17 via the crank arm 18, thereby causing the swinging arm 20 and needle bar link 16 to swing. The needle bar 15 reciprocates up and down, and the lower looper 29 swings back and forth on the lower surface of the needle plate by a known appropriate mechanism. The needle moves back and forth between the up and down movement path of the needle, and as a result, the needle thread X and the upper and lower looper threads Z as shown in FIG. 2 A', B', and C' are , Y are used to form an overseam in the cloth 32.

During this seam formation, the main balance 21 and the sub-scale 25 described above operate as follows.

In Figures A and A' of Fig. 2, the needle bar 15 has descended to its lowest position and the needle 28 has reached its lowest dead center, and as shown in Figure A', the lower looper 29 has retreated the most to the left. Seam and lower looper 29
The lower looper thread YH between the y 22 is located further below the lower end of the groove 11 of the thread guide 8 through which the needle thread X passes, and is not in contact with the needle thread It guides the needle thread X.

As the oscillating body 36 oscillates clockwise from the state shown in FIGS. 2A and 2A', the needle bar 15 gradually begins to rise, and the lower looper 29 begins to oscillate to the right, and the upper looper 30 begins to move upward.

This allows the lower looper 29 to
captures the needle thread loop of the needle thread Coupled with the slight clockwise rotation about the center, the arcuate portion 22 pushes the central part of the needle thread X passing between the grooves 11 of the thread guide 8 outward and bends it, as shown in Figure B'. Thread threading is carried out by pulling the loosened lower looper thread on the lower surface of the cloth in the needle through hole one stitch before, and the thread shadowing part 26 of the sub thread take-up 25 allows the main thread take-up 21 to pick up the needle thread. B rises by 7
As shown in the figure, the needle thread X between the stitch and the second thread guide 12 is bent to take up excess needle thread X from the needle thread supply source.

As the oscillating body 36 further oscillates clockwise from the state shown in FIG. It passes through the edge of the cloth 32 and rises to the upper surface of the cloth.

As a result, as shown in Figure 2c and c', the upper looper 3
0 catches and locks the lower looper thread Y of the lower looper 29, and its tip moves beyond the needle vertical movement path on the upper surface of the fabric.
The main thread take-up 21 is slightly rotated counterclockwise about the upper part of the needle bar link 16 and the shape of the slope 23 and recess 24 is changed to adjust the degree of bending of the needle thread X inside the thread guide 8. decrease.

The sub-take-up lever 25 &iC lifts up as shown in Figure 2, bends the needle thread X between the stitch and the second thread shade 12, and picks up the needle thread. , and the needle bar reaches top dead center.

As the rocking direction of the rocking body 36 is reversed from the state shown in FIG. The upper looper 30 also begins to move downward in the opposite direction, and the twisted cloth is fed one pitch while the needle 28 is in the upper right position.

Then, the needle 28 plunges into the upper looper thread Z that connects the seam and the tip of the upper looper 30 and pierces the cloth 32, and the upper looper 30 descends from the upper surface of the cloth through the edge of the cloth and locks the lower Release looper thread Y.

When the needle bar 15 is lowered, the main thread take-up 21 moves in the opposite direction to that when the needle bar is raised, bending the needle thread X in the thread guide 8 in the same way as shown in FIG. At the same time, the auxiliary thread take-up 25 also descends and lets out the needle thread X between the stitch and the second thread cover 12 picked up by the auxiliary thread take-up 25, as shown in FIG. 2C. The needle thread X between the two does not stretch.

Repeat the above steps to form a three-thread overlock stitch on the edge of the fabric.

When the main thread take-up 21 is raised, the needle bar 15 is lifted [i-During the intermediate process, when the lower looper thread Y is relaxed, the lower looper thread Y is relaxed.
, B', the needle thread is picked up and the thread is tightened, but the main thread take-up 21 is pressed when the needle bar 15 is lowered and thread tightening is not necessary, but the thread is still in the intermediate process. Similarly, the needle thread X is bent, and therefore, the following disadvantages occur when the sub-take-up lever 25 is not provided.

That is, in the case where there is no secondary balance 25, when the needle bar 15 starts descending after reaching the top dead center as shown in Fig. 2 c and c',
The needle thread X between the second thread shade 12 and the stitch shown by the two-dot chain line is bent by the main thread take-up 21 as shown in FIG. 2B, and its tension is increased.

As a result, the needle 28 descends with the needle thread X having increased tension as shown in FIG. Z
When the upper looper thread 2 crosses the thread hole 31 of the needle 28, it is strongly pinched by the needle thread X with strong tension, and when the needle 28 further descends from this state, the upper looper thread
is pulled into the needle hole 31 of the needle 28 as shown in FIGS. 3C and 4 by the clamping force of the needle thread X at the above-mentioned portion.

Then, the 11 needles 28 in the state shown in FIGS. 3C and 4 are attached to the cloth 32.
When the upper looper thread 2 passes through the fabric and leaves a loop on the bottom surface of the fabric as shown in Figure 5, an exposed seam defect occurs, and the loop is exposed to other threads. Since it is not intertwined with the upper looper thread Z of that part
When it is pulled on the upper surface of the cloth, it protrudes from the upper surface of the cloth as shown by the dotted chain line in Figure 5, which has the disadvantage of reducing the commercial value of the product.

As described above, this invention has a needle with a needle thread, a lower looper with a lower louver thread, an upper looper with an upper looper thread, and a lower looper thread between the lower looper and the seam that is linked to the sewing machine mechanism. A main balance is provided which bends and picks up the needle thread between the needle thread tension device and the needle by pressing a button at each intermediate step when the needle bar moves up and down so as to pick up the needle thread when it is loosened.
Press the button on the sewing machine that forms overlock stitches on the edge of the fabric using three threads, adjust the sewing machine mechanism, and adjust the needle thread between the needle thread tension device and the needle to the upward stroke of the needle bar [i- and the main thread take-up]. In addition to picking up more needle thread than the amount of needle thread picked up by the main thread take-up, the main thread take-up is allowed to be taken up by the main thread take-up.In the lowering process, a sub-take thread is provided which functions to let out the picked up needle thread, so the following procedure is performed. It has a great effect.

1. The needle thread tension required to pull up the loosened lower looper thread when the needle thread is tightened is small, which allows for stitches with a good texture, as well as stitches like denim fabric.
Even when sewing thick fabrics, the needle thread can be picked up reliably, ensuring that there is no thread left behind, which improves the quality of sewn products. Even when using a needle that does not have a thread groove into which threads can enter, the thread can be tightened reliably, and it is also highly adaptable to many types of needles.

In this invention, even if the main thread take-up attempts to tension the needle thread when the needle descends, the needle thread picked up by the sub-take thread is fed out and the needle thread is not tensioned before the needle pierces the fabric, as shown in Figure 5. It is possible to always form reliable seams without causing seam defects such as the upper looper thread protruding to the lower surface of the cloth, and there are effects such as obtaining products with high commercial value.

In the above embodiment, the main balance 21 is the needle bar link 1.
6 shows an example in which the sub-take-up is provided on the needle bar, but in other embodiments, the main and sub-take take-up may be provided on the needle bar 15 and the swing shaft 17.
．． Alternatively, the same effect as in the above embodiment can be obtained by installing the main balance 21 at the tip of an arm or the like whose base is fixed to the swing shaft. Even if it is provided, the same effect as in the above embodiment can be obtained.

[Brief explanation of drawings]

FIG. 1 is a needle perspective view of the sewing machine with some parts omitted, and FIG. 2 is an explanatory view showing the operation of the thread take-up and stitches in sequence, A, A'
B and B' are the states in which the needle bar has reached the bottom dead center, B and B' are the states in which the needle bar is rising and the needle thread is tightened, and c and c' are the states in which the needle bar has reached the top dead center. . FIG. 3 is an explanatory diagram illustrating the process of occurrence of seam defects that occur when a main balance is provided but no sub-scale take-up, and FIGS. 4 and 5 are explanatory diagrams illustrating seam defects. 1 is a frame, 5 is a needle thread tension device, 12 is a thread guard, 15 is a needle bar, 21 is a main thread take-up, 25 is a sub thread take-up, 28 is a needle, 30 is an upper looper, X is a needle thread, - system. Z is Lupa

Claims (1)

[Scope of Claims] 1. A needle with needle thread, an upper looper with looper thread, and intermediate strokes of the vertical movement of the needle bar linked to the sewing machine mechanism [i-] between the needle thread tension regulator and the needle. In an overlock stitch sewing machine equipped with a main thread take-up that bends and picks up the needle thread of the needle bar and lets out the picked up needle thread near the top and bottom dead center of the needle bar, It consists of a thread hook fixed to the frame and a thread shade fixed to the needle bar, which bends the needle thread during the upward stroke of the needle bar, and allows the needle thread to be picked up more than the amount taken up by the main balance near the top dead center of the needle bar. This overlock stitch sewing machine is equipped with a sub-take-up lever which pays out the needle thread picked-up during the downward stroke of the needle bar and prevents the needle thread from being tensioned by the main take-up of the needle thread.