JPS61159987A - Automatic control apparatus of stitch balancing thread tention - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention supplies the needle thread consumed in stitch formation by a forced needle thread feeding device without using a thread take-up action.
The balance relates to a sewing machine that performs only a cloth tightening action.

In conventional sewing machines, when the needle thread required for stitch formation is supplied to the thread take-up side by the thread take-up device, the end of the needle thread is Since it is necessary to grip and fix the thread, it is necessary to ensure that the needle thread feeding device has sufficient gripping force. For this reason, the needle thread unwinding device required a large capacity device, and therefore its response speed could not be very fast.

h The present invention configures the needle thread unwinding device part and the cloth swapping device part using the thread take-up separately, and uses a device in which the needle thread gripping force is small and the response speed is fast in the needle thread pulling device. , an attempt is made to use a device with a larger needle thread gripping force in the cotton swaddling device to meet both the conditions required for the needle thread pay-out device and the conditions required for the cotton swaddling device. 6 1. The present invention configures the upper thread unwinding device and the cloth wadding device separately and independently, so that the thread gripping force is small in the upper thread unwinding device, but the response speed is accurate. By using a cloth cotton device with a large needle thread gripping force, the needle thread supply amount can be controlled accurately, and
The cloth wadding action is made to withstand the tension caused by the cloth wadding action by a balance using a device having a strong gripping force, and will be described below with reference to the embodiments shown in the drawings.

Figure 1 shows a needle thread feeding device using two rollers to feed out the needle thread, an electromagnetic needle thread gripper that grips the needle thread and supplies the necessary amount of needle thread to the thread take-up side. A schematic configuration explanatory diagram showing an embodiment in which the needle thread is gripped by another electromagnetic needle thread gripper and the thread take-up action is performed by a thread take-up. 3 is a sectional view showing an example L of an electromagnetic needle thread gripper, FIG. 4 is a block diagram of automatic needle thread feeding control, and FIGS. 5(a) to (e) ) are motion diagrams related to upper thread control.

In Figure 1, l is a suture cloth, 2 is a sewing needle, 3 is a balance, and 4
5 and 6 are guides; 7 is an electromagnetic needle thread gripper for fabric using a thread take-up; 8 is an encoder inner layer thread delivery roller; 9
is a presser roller, 10 is an electromagnetic needle thread gripper for controlling needle thread delivery, 11 is a paste tension plate, 12 is a needle thread bobbin,
Reference numeral A constitutes a cloth wadding device portion using a thread take-up, and B constitutes an upper thread feeding device portion.

The upper thread from the upper thread bobbin 12 is transferred to the past tension disc 11.
This gives enough tension to the threads so that they do not become disordered.

Electromagnetic needle thread gripper 10 for controlling needle thread delivery in an inoperative state
After passing through the encoder, inner layer yarn feeding roller 8 and presser roller 9
The feeding amount is controlled by stopping the running of the needle thread by gripping the needle thread with an electromagnetic needle thread gripping device 1O, and by connecting the encoder inner layer thread delivery roller 8 and the upper thread This is carried out by a small yarn winding control device that causes a sliding action with the yarn and causes the encoder inner layer yarn delivery roller 8 to continue rotating but stops supplying the upper yarn.

The needle thread fed out to the thread take-up side in this way is moved by the electromagnetic needle thread gripper 7, the guide 6.5, and the light spring 4, which are in an inoperative state.
Then, at the time when the electromagnetic upper thread gripper 7 is gripping the upper thread, the sewing needle 2 is used to form 1 stitches of the sewing cloth 1 by the thread take-up action of the thread take-up 3.

By the way, when the cloth is swathed by the thread take-up, tension is applied to the upper thread for the swaddle, so the electromagnetic upper thread gripper 7 for the cloth swaddle is
Since a large needle thread gripping force is required for this purpose, if you try to do this with an electromagnetic needle thread gripper for feeding out the upper thread as in the conventional device, it is difficult to use an electromagnetic needle thread gripper with a large capacity as an electromagnetic needle thread gripper. Although a gripper is required, increasing the capacity inevitably slows down the response speed, making it difficult to accurately and quickly control needle thread delivery.

The present invention focuses on this point, and uses an electromagnetic upper thread gripper 10 for controlling upper thread feeding that has a small gripping force but has an accurate and quick response speed, and uses an electromagnetic upper thread gripper 10 that grips the upper thread when threading the cloth. The electromagnetic type upper thread gripper 7 is provided separately, and since the electromagnetic type upper thread gripper 7 only needs to grip the upper thread while the cloth is being swung, response speed is not required. Not done.

The embodiment shown in FIG. 2 shows a case where a step motor 8' is used as the needle thread feeding device, and the needle thread feeding and gripping are performed simultaneously by the step motor. If such an electromagnetic upper thread gripper 7 for cloth is not provided, a step motor with a large capacity will be required in order to enable the thread control ability of the step motor to counteract the tension of the right lung of the balance. In this case, since the required amount of upper thread is stopped and gripped by rotating and stopping the step motor, the upper thread is wound around the outer periphery of the roller attached to the step motor 8'.

Furthermore, Fig. 3 shows an example of an electromagnetic upper thread gripper.
Any other suitable material may be used.

FIG. 4 is a block diagram of automatic needle thread payout control, and FIG. 5 is a diagram of movement related to needle thread control. The operation of the device of the present invention will be explained with reference to the diagrams of FIG.

In Fig. 5 (a) and (b), the curve ■ is the needle thread slack amount curve created from the difference between the needle thread supply amount curve I of the thread take-up and the needle thread absorption amount curve ■ depending on the needle and hook number. be.

The amount between YY' and the baseline indicates the amount of needle thread absorption made by the thread take-up spring. Here, the part of the yarn slack amount curve (■) below the YY' line is absorbed by the thread take-up spring, and the upper thread is in a state of tension.

That is, as the balance descends from the top dead center A of the balance.

The thread begins to slacken, the thread take-up spring returns, the tension on the upper thread disappears, and the upper thread becomes completely slack at the point of opening.

After reaching the top dead center of the balance, the upper thread passes through the hook, passes through the hook, and releases the hook from the hook at points E, H, and E, respectively, and the thread becomes taut and the thread take-up spring is activated. And finally,
The thread take-up is tightened, and the maximum tension is exerted from point 1 to the top dead center of the thread take-up, and the thread is tightened.

(c) is a diagram of the amount of yarn fed out by the yarn feeding roller 8;
The maximum system amount fed out in a cycle must sufficiently satisfy the needle thread consumption amount S required for a good stitch under the loud sewing conditions of this sewing machine.

(e) The figure shows the action period from R to S of the electromagnetic upper thread gripper 7 for fabric cotton.The magnitude of the thread gripping force is as follows. is large enough to sufficiently cover and hold down the needle thread tension fluctuations due to the resistance that sometimes occurs, and the fabric tension at the top dead center of the thread take-up (A).

Next, the yarn letting-out action and the cotton-tapping action will be explained using diagrams (c), (d) and (b), (e).

First, the thread unwinding action will be described.

Let S be the amount of needle thread required for good sewing calculated by the microcomputer in a certain sewing cycle.

When the electromagnetic needle thread gripper IO is turned off at the set point P, which is past the opening when the tension disappears from the top dead center of the balance A,
The tensile tension of the yarn generated by the continuous rotation of the feeding roller 8 and the yarn measuring roller 9 is applied to the tension plate 1.
1, the thread travels as the delivery roller 8 rotates, and the thread begins to be delivered from the upper thread bobbin 12. At this time, since an encoder is attached to the shaft of the feeding roller, pulse information is generated as the shaft rotates. This information is transmitted to the microcomputer, and at a time point Q when the number of pulses has just reached the number of pulses set as the thread amount S for a good stitch.

The microcomputer issues a command to turn on the electromagnetic needle thread gripper lO,
The armature is suctioned and the thread path is closed.

Since the thread gripping force of the electromagnetic needle thread gripper IO is greater than the tensile force generated by the payout roller 8 and presser roller 9, the running of the thread is immediately stopped and the required thread amount S is ensured. After that, the thread continues to rotate while being fed out, but the thread is still held by the electromagnetic needle thread gripper lO, so the thread is held between the feeding roller 8 and the thread measuring roller 9, and is subjected to slight sliding friction. The machine continues to stand still and reaches the top dead center of the thread take-up (A) again, completing the sewing operation of cycle (1).

The yarn amount S is described as an example, but it is the amount that the circumference of the pay-out roller 8 has traveled from the time P to the time Q, and in order to maximize the required pay-out amount, it is necessary to This is the yarn amount S0 when the feed roller is run again from 1 cycle to point P after one cycle of the sewing machine.

Next, the operation of the electromagnetic upper thread gripper 7 for attaching cloth swath will be described.

As an example, consider the case where the sewing machine has the maximum sewing conditions according to its specifications.

First, the generation of needle thread tension in the needle thread path is shown in Fig. 5(b).
As shown in , there are four times: when the cloth is swung at the top dead center of the balance (A), when the needle thread passes over the hook (E), when the needle thread slips out of the hook, and when the hook's catching claw falls out (1-). be. This large amount of tension is generated during the needle thread tensioning period when the thread is tightened using a thread take-up. Of course, during this period, the electromagnetic upper thread gripper 7 for cloth must be completely closed, and any excess thread amount other than the predetermined thread amount S must not be drawn out.

The next largest tension is generated at the point of .If the sewing machine is running at a high speed, a considerably high tension is generated when the hook is unhooked. It is necessary to keep container 7 closed.

The tension generated at the time when the thread passes through the upper thread hook is A.

Therefore, the electromagnetic upper thread gripper 7 for final tightening is not closed, and in the present invention, the tensioning action of the thread take-up spring 4 generated at this time is utilized to allow the thread to be unreeled by the unreeler. The amount of yarn that has been removed is moved to the take-up side. In other words, the needle thread absorbing action of the hook can be regarded as a type of looper movement.

As mentioned above, the electromagnetic upper thread gripper 7 for final tightening is.

In order to absorb the needle thread tension that occurs at the points , , and ,
It is closed for a period from R to S, and it goes without saying that the magnitude of the thread gripping tension must be sufficient to suppress the upper thread tension that occurs under the maximum lli manufacturing conditions according to the specifications of this sewing machine. .

Next, a description will be given of the entire process in which the thread amount S paid out by the feeding device is moved to the side of the thread take-up, and the stitches consumed for tightening the cloth are completed by the lifting operation of the take-up thread.

First, at the top dead point A of the thread take-up, the previous cloth tightening is completed, and the thread take-up 3 begins to descend and reaches the point of the first thread, and the tension on the needle thread is completely released.At the same time, from the point S, the electromagnetic The upper thread gripper 7 is released from gripping the thread.

The thread path is released. As can be seen from the thread amount diagram, the upper thread is in a relaxed state up to point E, so the thread is not moved from the electromagnetic upper thread gripper 7 for final tightening.

On the other hand, the payout device changes the payout amount S from point P to Q (this is the payout amount S in the cycle before the closing time R of the electromagnetic needle thread gripper for final tightening) at the time when the needle thread passes over the hook. Due to the tension of the thread take-up spring, the thread passes through the electromagnetic upper thread gripper 7 for final tightening, which is still released, and is moved toward the thread take-up lever, where it is absorbed by the thread take-up spring 4. Immediately thereafter, the electromagnetic upper thread gripper 7 for final tightening is turned on, the thread path is closed, the amount of thread fed out until the thread thread reaches the top dead center of the thread take-up is consumed, and the stitch is completed.

As explained above, the sewing needle automatic control device of the present invention has the following features:
Unlike traditional sewing machines, where the thread take-up and thread take-up are performed together through the action of the thread take-up and tension plate, this machine is designed to perform both functions independently.

As shown in Figures 1 and 2, the thread take-up unit in part B prepares to let out the required amount of thread for a good stitch as calculated by the microcomputer, and then the thread take-up, hook, and thread take-up in part A are used. Due to the cooperative action of the spring, the amount of thread prepared for feeding is moved toward the thread take-up side, and finally the thread take-up 3 and the electromagnetic needle thread gripper 7 for final tightening are moved.
Due to the cooperative action of the two, the amount of thread that is fed out is consumed in the stitches, and the good and uniform stitches required by the seamstress are formed.

The aim of the active fishing line pay-out control using the small thread pay-out device of the present invention is that, while conventional sewing machines use the same thread take-up and cloth tightening lever, they can be completely separated. The amount of thread that is fed out is made to match the amount of thread required for a good stitch, and it is supplied when the thread take-up is moving to make a good stitch, thereby forming a uniform and good stitch with no uneven seam tightness. It is something.

In addition, in conventional sewing machines, the thread is fed out for a short period near the top dead center of the thread take-up, whereas in the present invention, the thread feeding period can be used for the entire cycle of the sewing machine. Therefore, even when controlling the thread payout amount of the electromagnetic needle thread gripper at high speeds, there is a margin of response speed.

Furthermore, by using two electromagnetic upper thread grippers, one for gripping the thread and the other for final tightening, it is now possible to finely control the thread feeding action.
The electromagnetic needle thread gripper for final tightening can now have thread gripping performance for powerful cloth tightening.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration explanatory diagram showing an embodiment according to the present invention, Fig. 2 is a diagram similar to Fig. 1 showing another embodiment, and Fig. 3 is a cross section showing an example of an electromagnetic needle thread gripper. 4 is a block diagram of automatic upper thread payout control, and FIGS. 5(a) to 5(e) are motion diagrams related to upper thread control. l... Suture cloth, 2... Sewing needle. 3... Balance, 4... Thread take-up spring, 5.
6...Guide, 7...Electromagnetic needle thread gripper for cloth cotton, 8...Encoder inner layer thread feeding roller, 9...Press roller, lO...Electromagnetic needle thread gripping device for feeding needle thread Container, 11...Paste tension plate, 12...Needle thread bobbin.

Claims (1)

[Claims] In a sewing machine having a thread take-up, there is provided a thread take-up device that prepares to feed thread from the supply source into a thread path between the thread thread take-up and the needle thread supply source, and a cloth tightening device that includes the thread take-up spring, a thread take-up spring, and an electromagnetic needle thread gripper. The microcomputer built into the sewing machine
By detecting specifications such as cloth thickness and pitch in advance with a sensor under sewing conditions, the amount of thread required for one stitch is calculated to form a good seam. The amount of thread that has been prepared for being let out is let out by the thread unreeling device, and by using the tensioning action of the thread take-up spring when the thread take-up is passed over the needle thread hook by the thread take-up during one sewing cycle of the sewing machine, the amount of thread that has been prepared to be let out is transferred to the inactive electromagnetic The upper thread is passed through a thread take-up spring to be absorbed and accumulated, and then the electromagnetic upper thread gripper for cloth tightening is energized to grip and fix the upper thread, and the amount of thread is consumed when tightening the cloth with a thread take-up. An automatic sewing tension control device characterized in that the electromagnetic needle thread gripper for tightening the cloth is released again after the thread take-up has finished tightening the cloth.