JPS609475B2 - sewing machine drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises an electric motor having an electromagnetic clutch and an electromagnetic brake, a sewing machine head driven by the electric motor, and a backstitch solenoid built into the sewing machine head for reversing cloth feed. The present invention relates to a drive device for an industrial sewing machine.

Recently, control technology for industrial sewing machines has made rapid progress.
The efficiency of sewing work has been significantly improved, and at the same time, even unskilled line workers can now perform uniform and fine sewing. With the advancement of semiconductor logic technology, which advances year by year to IC, fake 1, and even microcomputers, many solenoids are used to control sewing machines, such as reverse stitch solenoid, thread trimming solenoid, thread removal solenoid, presser foot solenoid, etc. This is because it has become possible to freely control sewing machine speed and needle position in relation to the sewing machine speed and needle position.However, despite these advances in logical technology, there is little room for improvement when it comes to solenoids, and it is difficult to create a uniform and highly efficient sewing machine drive system. The delay and non-uniformity of this solenoid are the biggest bottlenecks.Especially with regard to the solenoid for reverse stitching, this response delay directly appears in the formation of the reverse stitching seam, which is a fatal problem. The present invention focuses on this solenoid for backstitching, and aims to obtain good backstitch seam formation even when the sewing speed changes by electrically covering up this response delay. .

FIGS. 1, 2, 3, and 4 show operation patterns and seam formations in backstitching at the beginning of sewing of a follower. 1st
The figure shows a case where the sewing machine pedal is strongly depressed and sewing is started at a high speed and reverse stitching is performed.

For industrial sewing machines, the maximum sewing speed is usually 4000 to 6
00 pm, and the reverse stitching speed is normally limited to about 200 pm when the pedal is depressed to the maximum. In FIG. 1, A indicates the sewing machine speed, B indicates the needle lowering signal obtained from the needle position signal generator, C indicates the drive signal to the reverse stitch solenoid, and D indicates the operation of the reverse stitch solenoid. This operation pattern is when reverse stitching at the beginning of sewing is set for four stitches, and the stitches are completed as shown in FIG. When the solenoid suction signal is given at the edge after the fourth needle down signal n4 by pressing the bevel,
After a response delay time t when the solenoid is turned on, the solenoid completes suction and the cloth feed is reversed. If the sewing machine speed during reverse stitching is 200 pm, one stitch is 30 seconds,
This approximately coincides with the time t. Therefore, as shown in FIG. 2, the seam formation progresses in the forward direction until the time of successful seam formation, and then reverses. After that, the needle down signal n
When a solenoid off signal is applied at the edge after 8, the solenoid completes its return after a delay of time t2. If the sewing machine speed is 200 ratio pm, this time t2 is still approximately one stitch, so as shown in Fig. 2, the sewing machine proceeds in the opposite direction until the needle down signal ~, and then reverses to the forward direction.
The position of n and the position of n9 match, and good seam formation can be obtained. FIGS. 3 and 4 show the operation pattern and stitch formation when the sewing machine starts sewing at low speed and performs reverse stitching by lightly pressing down on the bevel of the sewing machine.

As in the case of FIG. 1, A' indicates the sewing machine speed, 8 indicates the needle lowering signal, ◯ indicates the drive signal to the reverse stitch solenoid, and ◯ indicates the operation of the reverse stitch solenoid. The on-time response delay time t and the off-time response delay time t2 of the solenoid are both independent of the sewing machine speed and are approximately 30 ws.
As in the case of Fig. 1, when the solenoid suction signal is applied at the edge after the fourth needle down signal n'4 after the bevel is depressed, the solenoid completes suction after a period of time, and the cloth feed is reversed. . Assuming that the sewing machine speed at this time is extremely low, such as 20 ratio pm, the point at which the cloth feed is reversed is the needle lower signal n'
4, and the next needle n'5 has already moved in the opposite direction. Therefore, only 3 stitches can be formed in the forward direction, and the same situation applies when the solenoid is turned off. As a result, the stitch formation is n as shown in Figure 4.
A difference of one stitch occurs between the position ', and the position n'8, resulting in a defective stitch. The problem with this follow-up example is that regardless of the sewing machine speed, the solenoid is pressed one stitch before the required stitch. It is clear that there is something in the operating program that attempts to provide an on/off signal for the field.

SUMMARY OF THE INVENTION The present invention aims to eliminate the drawbacks of the conventional example described above and to provide a sewing machine driving device that can form a good backstitch at the beginning of sewing regardless of the sewing machine speed.

FIG. 5 is a block diagram showing one embodiment of the present invention, and a detailed explanation will be given below with reference to this diagram. In FIG. 5, 1 is an automatic reverse stitch control command input, 2 is an automatic reverse stitch number setting input, 3 is an input for switching between needle up and middle settings, and 4 is a needle down signal obtained from a needle position signal generator. 5 is a needle up signal obtained from a needle position signal generator, 6 is a reverse stitch switching command circuit, 7 is a position measurement circuit, 8 is a needle up middle and needle down middle setting memory, 9 is a needle up middle and needle down middle measuring circuit , 10 indicates a needle top middle and needle bottom middle comparison circuit, 11 a reverse stitch solenoid on/off switching circuit, and 12 a reverse stitch solenoid.

An example of the contents of the needle up/down setting memory 8 is shown in FIG.

Depending on the 2-bit signal provided by the needle up/down setting switching input 3, one of the data X=0, 1, 2, and 3 stored in the needle up/down setting memory 8 is selected. When the automatic reverse stitching control command input 1 is given, the reverse stitching switching command circuit 6 becomes active, and when the automatic reverse stitching number setting input 2 and the needle lowering signal 4 are received and the conditions are established, the reverse stitching switching command signal 13 and the solenoid on/off are activated. A signal 14 is output.

When the reverse stitch switching command signal 13 is input, the position measurement circuit 7 becomes active and the input needle lower layer number 4 and needle upper signal 5 are input.
is converted into 2 bits and input into the needle up/down setting memory 8. The needle up/down setting memory 8 has a needle up/down setting (2 bit input
Depending on the bit input Y, one of the 32 types of data MOO to M37 shown in FIG. 6 is selected and output. The needle down signal 4 and the needle up signal 5 are input to a needle up/down measurement circuit 9, and the output thereof and the output of the needle up/down setting memory 8 are input to a needle up/down comparison circuit 10. When the needle up/down comparison circuit 10 becomes active in response to the reverse stitch switching command signal 13, this output signal is input to the reverse stitch solenoid on/off switching circuit 11, and on or off is selected by the solenoid on/off signal 14. After that, the solenoid 12 is turned on or off. FIG. 7 is an explanatory mock diagram for further embodying the above explanation. E is a needle down signal, F is a needle up signal, and G is a reverse stitch switching command signal, which corresponds to 13 in FIG. Now, when the trowel reverse stitch switching command signal G is outputted, the function of the present invention is set and becomes active.

Next, the time period of the needle up signal f, is measured by the needle up/down measuring circuit 9 in FIG. 5, and the data and the data in the needle up/down setting memory 8 in FIG. The upper and lower needles are compared by the comparator circuit 10', and if the conditions are met, the solenoid is turned on or off at a time ratio of 2 or after an appropriate delay time. If the conditions are not met, wait until the next needle down signal, measure during the time e using the same procedure as above, and if the conditions are met, set the time ratio to 3 and set an appropriate delay time. Turns the rear solenoid on or off.
If the conditions are not met, the signal is sequentially fed to the next needle up signal and then to the next needle down signal e2. The final goal is time t6
If the sewing machine speed is fast and the needle up and down time is narrow so that the solenoid completes suction or completes return at time t2.
The data in Figure 6 is structured so that an on or off signal is given to the solenoid at time 5, and when the sewing machine speed is slow and the needle up and down time is wide, an on or off signal is given to the solenoid at time &5. .

Assuming that the solenoid on/off response delay time is 30 ms, a rough calculation shows that the sewing machine speed during reverse stitching is 30 ms.
When it is 0pm, when it is 200pm at time t2, when it is 100pm at time t2, when the time L is also extremely low,
If you give an on/off signal to the timer 1 solenoid,
At time t6, the solenoid always completes suction or completes return.

In the above description, automatic switching control is performed in four stages, but stepless control is also possible by setting an appropriate delay time.

In addition, the response time of the solenoid differs due to variations in the solenoid or differences in the sewing pitch, so in order to compensate for this, an input for switching the needle up/down setting as shown in Figure 5 is provided, which allows external It is possible to select appropriate data.

The present invention is configured such that the reverse stitch solenoid always completes suction or returns to a fixed position, regardless of the reverse stitch speed at the start of sewing, which can be varied according to the amount of pedal depression of the sewing machine. The present invention provides a sewing machine driving device that can form stitches exactly as expected, and its effects are extremely great, such as even unskilled workers can expect uniform and excellent sewing results without mistakes.

[Brief explanation of the drawing]

Figure 1 is a diagram of the operation pattern during high-speed sewing of the subordinate bolt, Figure 2 is a diagram of the formation of a reverse seam at the beginning of sewing in the case of Figure 1, Figure 3 is a diagram of the operation pattern during conventional low-speed sewing, and Figure 4 is a diagram of the operation pattern when sewing at low speed. Fig. 3 is a diagram showing the formation of a reverse stitch at the beginning of sewing, Fig. 5 is a block diagram showing an embodiment of the present invention, Fig. 6 is a diagram showing an example of the needle upper/lower setting memory, and Fig. 7 is a diagram of the present invention. FIG. 4...Needle down signal, 5...Needle up signal, 8...
... Memory device, 12 ... Reverse stitch solenoid. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 5 Figure 6

Claims (1)

[Claims] 1. A sewing machine head driven by an electric motor, a reverse stitch solenoid built into the sewing machine head for reversing cloth feed, and a needle up signal and a needle down signal corresponding to the upper and lower positions of the needle. a needle position signal generator that generates a needle position signal generator, a counting device that counts the needle up and down signals, a time width measurement device that measures the time width of the needle up and down signals, and a storage device containing time data; comparing means, configured to select the time data of the storage device according to the count value of the counting means, the comparing means comparing the output of the time width measuring means and the output of the storage device, A sewing machine driving device that controls turning on or off of the reverse stitching solenoid based on a comparison result. 2. The sewing machine driving device according to claim 1, wherein the storage device is provided with a plurality of time data corresponding to the counted value of the counting means, and can be appropriately selected by a switching means.