JPH074459B2 - Lock sewing machine thread tension device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Industrial field of application] The present invention relates to a thread tension device for a three-thread lock sewing machine.

[Prior Art] As shown in FIG. 5, a known three-thread lock sewing machine A includes three thread tension regulators including a needle thread tension regulator 1, an upper looper thread tension regulator 2, and a lower looper thread tension regulator 3. Is provided, it is necessary to separately adjust the three thread tension devices depending on the type of cloth, the thickness of the thread used, and the type in order to perform good sewing.

The stitches of the lock sewing machine are as shown in FIG. 6 for single-needle, three-thread overlock stitch (normal lock stitch) and for single-needle, three-thread overedge stitch (variable winding lock stitch) in FIG. , The needle thread 1a, the upper looper thread 2a, and the lower looper thread 3a are intricately intertwined with each other with respect to the cloth B to be sewn to form a seam, so that it is necessary to properly adjust the three thread tension devices. Adjusting the tone generator is a complicated task.

[Problems to be Solved by the Invention] By the way, in recent years, lock sewing machines have come to be used in general households, and there is a demand for the appearance of a lock sewing machine capable of easily forming a good stitch even by a person who cannot handle it. There is.

The present invention intends to provide a lock sewing machine capable of easily forming a good stitch by anyone.

(B) Structure of the Invention [Means for Solving Problems] In the present invention, the thread tension values of the upper looper thread tensioner and the lower looper thread tensioner are each fixed to a constant value, and only the needle thread tensioner is thin. , It is possible to easily perform normal lock sewing by arranging the adjustment set position corresponding to the cloth thickness of normal cloth, thick cloth, etc., and further, the lower looper thread tension device has two locks, normal lock and winding lock. In addition to providing the adjusting set position, the needle thread tension adjuster is also provided with a winding lock setting position so that winding lock sewing can be performed by switching the setting position.

That is, according to the present invention, the adjustment of each thread tension device can be performed simply by switching the pointer so that good stitches can be always formed in the ordinary lock sewing and the winding lock sewing even in the case of thin cloth, plain cloth and thick cloth. It is a thing.

In the case of ordinary lock sewing, only the needle thread tension adjuster 1 is thin,
Three or two switching set positions of normal ground and thick ground are provided, and the other upper looper thread tensioner and lower looper thread tensioner are each intended to be fixed in advance to a constant tension value. Since the adjustment for lock sewing is different from that for normal lock sewing, the lower looper thread tension regulator should have two switching set positions for normal lock and winding lock, and the needle thread tension regulator should also have a winding lock set position. Is to solve this.

[Operation] As described above, in the present invention, in the case of only the ordinary lock sewing, only the adjustment set position of the needle thread tension adjuster is switched, and in the case of the winding lock sewing, the needle thread tension adjuster and the lower looper are used. By simply switching the thread tension regulator to the winding lock set position, it is possible to obtain a good stitch without requiring any other adjustment.

[Examples] The present invention will be described below with reference to the examples shown in the drawings.

FIG. 1 shows a lock sewing machine according to the present invention having the same structure as that of the conventional lock sewing machine shown in FIG. 5, in which the sewing mechanism is omitted and the front lower part is shown in order to show the route of the looper thread. The cover 4 is shown in an open state.

In the present invention, as shown in FIG. 2 (a), among the three thread tension regulators provided on the face plate 5 on the front surface of the lock sewing machine main body, the needle thread tension regulator 1 has three types of thin cloth, plain cloth and thick cloth. An adjustment set position is provided, and the upper looper thread tension regulator 2 is set and fixed at a constant tension position, and the lower looper thread tension regulator 3 is fixed at a constant tension position when it is dedicated to a normal lock mechanism, but is normally locked. When both sewing and winding lock sewing are performed, as shown in FIG. 2, two setting positions, that is, a normal lock setting position and a winding lock setting position are provided. In the case of ordinary locking sewing, the lower looper thread tension adjuster 3 is set. The pointer is adjusted to the normal lock, and then the needle of the needle thread tension adjuster 1 is sewn according to the thin cloth, the normal cloth, and the thick cloth according to the cloth thickness. Further, when switching to the winding lock sewing, the pointers of the lower looper thread tension adjuster 3 and the needle thread tension adjuster 1 may simply be adjusted to the winding lock.

Next, the reason why it becomes possible to adjust the three thread tension devices as in the present invention will be described.

Fig. 3 shows the sewing experiment data in the case of the ordinary lock stitch sewing machine. Since the type of sewing thread is roughly determined according to the fabric, Tetoron # 80 and cotton broad (ordinary fabric) for Georgette (thin fabric) The upper looper thread tension scale 3 (tension span # 60 13g, Tetoron # 80 15g) lower looper thread tension (span # 60) 20g for # 60, 2 for Tetoron # 80
7 g), the needle thread tension scale 2 (tension 26 g), plain cloth 5 (65 g) thick cloth 5 (65 g) thick cloth 6 (95 g) were used for good sewing under the conditions shown in the figure ( Thick needle thread tension scales of both 5 and 6 are good).

Therefore, in view of such data, FIG. 2 (a)
As shown in Fig. 2, it is preferable to set the normal ground and the thick ground as separate adjustment set positions, but as shown in Fig. 2 (b), the normal ground and the thick ground adjustment set positions of the needle thread tension indicator pointer are the same position. However, good sewing is possible with almost no difference.

Further, as shown in FIG. 4, in the winding lock sewing, when the needle thread Tetron # 80, the upper looper thread Woolley, and the lower looper thread Tetron # 80 are used, the lower looper thread tension is changed to 100 g. , As in the case of ordinary lock sewing, set the needle thread tension scale to 4 (tension
In the case of (95), it was possible to sew sufficiently well on both thin and plain fabrics. (Normally, thick lock winding is not performed.) As described above, according to the sewing experiment, in normal lock sewing, the tension of the upper looper and the lower looper thread tension device is fixed to a constant value, and the needle If only the thread tension regulator is switched and set according to the sewing cloth thickness, good sewing can always be performed.Also, in winding lock stitching, the upper looper thread tension regulator is set to the same tension as in normal lock stitching. , If the lower looper thread tension device is set to switch so that the tension is high, and the needle thread tension device is also set to the winding lock position (corresponding to the needle thread tension scale 4), good winding is possible on both thin and plain ground. Lock sewing can be performed.

It should be noted that as the sewn fabric, a display portion of medium-thickness fabric or extra-thickness fabric may be provided. Further, in the case of the two-thread sewing, since there is simply no upper looper thread, the same sewing is possible.

(C) Effect of the Invention According to the present invention, in ordinary lock stitching, by simply setting the needle thread tension adjuster at the position indicated by the index according to the cloth thickness, it is possible to always perform good sewing. When using both lock and roll lock stitches, just by setting the lower looper thread tension regulator and needle thread tension regulator to the winding lock position, you can sew as well as normal lock stitches. Good sewing can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic structure of a lock sewing machine according to the present invention, FIGS. 2 (a) and 2 (b) are front views showing a structural arrangement of the thread tension regulator shown in FIG. 1, and FIG. 4 is a graph of experimental data showing a relationship between thread tension devices in FIG. 4, FIG. 4 is a graph of experimental data showing a relationship between thread tension devices in modified winding lock sewing, and FIG. 5 is a perspective view of a conventional lock sewing machine. FIG. 6 is a perspective view showing seams of ordinary lock stitch, and FIG. 7 is a perspective view showing seams of modified roll lock stitch. 1 ... Needle thread tension device, 2 ... Upper looper thread tension device, 3 ...
Lower looper thread tensioner, 1a ... Needle thread, 2a ... Upper looper thread, 3a ... Lower looper thread, A ... Lock sewing machine, B ...
Cloth.

Claims (6)

[Claims] 1. An adjusting set position in which the thread tension values of the upper looper thread tensioner and the lower looper thread tensioner are fixed to respective constant values, and only the needle thread tensioner corresponds to the cloth thickness of thin cloth, plain cloth, thick cloth, etc. A thread tension device for a lock sewing machine, characterized in that the thread tension device is structured so that it can be removed. 2. The thread tension of the lock sewing machine according to claim 1, wherein the adjustment set positions corresponding to the cloth thickness of the needle thread tension device are two adjustment set positions of thin cloth and plain cloth or thick cloth. apparatus. 3. The thread of the lock sewing machine according to claim 1, wherein the adjusting set positions corresponding to the cloth thickness of the needle thread tension adjuster are three adjusting set positions of thin cloth, plain cloth and thick cloth. Condition device. 4. A thread tension value of the upper looper thread tensioner is fixed to a constant value, two adjusting set positions of a normal lock and a winding lock are provided on the lower looper thread tensioner, and the needle thread tensioner is also thin. The lock sewing machine is characterized in that a winding lock set position is provided in addition to the adjustment set position corresponding to the cloth thickness of ordinary ground, thick cloth, etc., and normal lock sewing and winding lock sewing can be sewn by switching the set position. Thread tension device. 5. The thread tension of the lock sewing machine according to claim 4, wherein the adjustment set positions corresponding to the cloth thickness of the needle thread tension adjuster are two adjustment set positions of thin cloth and plain cloth or thick cloth. apparatus. 6. The thread of a lock sewing machine according to claim 4, wherein the adjusting set positions corresponding to the cloth thickness of the needle thread tension adjuster are three adjusting set positions of thin cloth, plain cloth and thick cloth. Condition device.