JPS6312756A - Weaving falw detector - 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] (Industrial Application Field) This invention relates to an improvement in a sewing defect detection device capable of detecting sewing defects, in other words skipped seams of sewn products, with high accuracy. It is.

(Prior art) For example, as shown in the cross-sectional view and bottom view in FIG.
The outer fabric 1, the lining fabric 2, and the foamed urethane resin 3 interposed between them are connected to a seam in which a needle thread 4 of the same color as the outer fabric 1 and a bobbin thread 5 whose color can be appropriately selected are intertwined. When sewing by forming, skipped stitch portions 6 often occur where the upper thread 4 and lower thread 5 do not intertwine as expected, and when such skipped stitch portions 6 occur, As the fraying of the threads 4 and 5 progresses, the sewn product 7
Among them, those with skipped stitches 6 or those parts need to be removed from the line as defective products or defective parts.

Therefore, in order to automatically detect the skipped stitch portion 6 as described above and facilitate extraction of the defective sewing portion, a sewing defect detection device as shown in the route map in FIGS. 9 and 10, for example, has been proposed. has been done.

Here, the apparatus shown in FIG. 9 includes a two-dimensional camera 8 that reads the stitch pattern of the sewn product 7, and a video signal inputted from this camera 8 to detect irregularities in the appearance of the upper thread 4 and lower thread 5. This device is comprised of a determination device 9 that determines whether stitch skipping exists or not, and this device determines the presence or absence of skipped stitches based on pattern recognition.

Further, the device shown in FIG. 10(a) includes a bobbin 10 and a sewing needle 11.
A pulley 12 on which the upper thread 4 is wound is provided between the Boo IJ 12 and the rotary encoder 13 attached to the Boo IJ 12 is connected to a counter 14, and the counter 14 is further connected to the central processing unit 15. Here, the rotational speed of the pulley 12 and the feeding speed of the upper thread 4 are measured by the counter 14 based on the number of pulses generated from the rotary encoder 13, and the measurement results are observed by the central processing unit 15. By doing this, the occurrence of skipped stitches is detected. That is, in this device, when the feeding speed of the upper thread 4 is in a pulsating state as shown in FIG. 10(b), skipped stitches 6 are not generated. If this occurs, it can be known that a skipped stitch portion 6 has occurred.

(Problems to be Solved by the Invention) However, among such conventional techniques, the apparatus shown in FIG. 9, which determines skipped stitches based on pattern recognition, has the following problems:
For example, if the field of view of Tamera 8 is set to 300X300 +n2, 1 × 1 ” 11
It is necessary to detect differences in patterns of degree size, in other words, differences within an area of 1/90,000.Since the differences in patterns are extremely small, it is extremely difficult to detect them within a plane. This is difficult, and as a result, there is a problem in that the accuracy of determining sewing defects is inevitably lowered.

Furthermore, in the device shown in FIG. 10, there is an extremely high possibility that false detection will occur due to the upper thread 4 slipping on the pulley 12, and the tension applied to the upper thread 4 to rotate the pulley 12 will increase. However, there was a problem in that it became a new cause of skipped stitches.

This invention was made by focusing on the problems of the prior art, and by microscopically optically detecting seams, it is possible to sew with extremely high precision without having any adverse effect on the sewing. It is possible to detect skipped eyes, and
An object of the present invention is to provide a sewing defect detection device that is free from erroneous detection.

(Means for Solving the Problems) The device of the present invention is provided with an optical sensor that traces the seams of a sewn product, and a determination circuit that determines the presence or absence of seams based on the signal from the optical sensor. Further, a signal generating means for generating a signal, for example, a pulse, according to the moving amount of the sewn product with or without measuring the moving amount is provided, and the signal generating means and the determination circuit generate signals according to the moving amount. A measuring circuit is provided which measures the stitch spacing based on the signal and generates a signal when the measured stitch spacing becomes larger than a predetermined stitch spacing.

(Function) In this device, an optical sensor that microscopically traces stitches generates a signal depending on the presence or absence of stitches, in other words, the presence or absence of entanglement between upper thread and lower thread. After determining the presence or absence of a seam based on the determination circuit, the determination result and a signal generated by the signal generation means according to the movement amount of the sewn product are input to the measurement circuit, where, for example, , the stitch spacing is measured by counting the number of pulses input from the signal generating means until the signal from the determination circuit is input thereto, and the measured stitch spacing is greater than the predetermined stitch spacing. By outputting a signal to, for example, an alarm means when the stitch size increases, skipped stitches can be detected with extremely high accuracy without false detection, and without affecting the sewing work. (Can be detected.

(Example) The present invention will be explained below based on illustrated examples.

FIG. 1 is a diagram showing an embodiment of the present invention, with 21
shows an optical fiber sensor as an example of an optical sensor.

Here, this optical fiber sensor 21 is connected to the feed roller 2.
2 is disposed close to one of the stitch rows 23 from the bottom side of the sewn product 7 that is run by the sewing machine 2 to trace the stitches, and then continuously irradiates light toward the stitches. By receiving reflected light of different intensities from the upper thread 4 and lower thread 5 of mutually different colors, it functions to generate a voltage signal proportional to the intensity of the reflected light.

The optical fiber sensor 21 is connected to a determination circuit 24, and the determination circuit 24 determines whether the upper thread 4 is entangled with the lower thread 5 and whether or not there is a stitch, based on the voltage signal from the optical fiber sensor 21. do.

Here, this determination circuit 24 and a pulse generator 25, which is an example of a signal generating means and which is attached to the feed roller 22, are connected to a counter 26, which is an example of a measuring circuit. Here, the pulse generator 25
In this case, a number of pulses proportional to the amount of rotation of the feed roller 22 and the amount of movement of the sewn product 7 are input to the counter 26 at intervals sufficiently smaller than the predetermined stitch interval.
counts its pulses. Here, such counting of pulses is continued until a reset signal generated when the determination circuit 24 detects that the upper thread 4 is entangled is input thereto.

Note that if the measured stitch interval calculated from the count result before inputting the reset signal becomes larger than a predetermined stitch interval, the counter 26 controls the control circuit 27 connected thereto. This control circuit 27 outputs a signal based on the input signal thereto, for example.
It functions to generate a speed control signal for the feed roller 4, a skipped stitch alarm signal, and other necessary signals.

FIG. 2 is an enlarged plan view and side view showing the floating support mechanism of the optical fiber sensor 21 in the device configured as described above, and here, the sewn product 7
A shaft member 29 facing in the width direction of the sewn product 7 is rotatably supported by a bearing 30 on a gate-shaped pedestal 28 that straddles the sewn product 7 . The base 31a is attached to the shaft member 29 so as to be swingable in a horizontal plane, and the tip of the arm member 31 and the pedestal 2
8 at a predetermined position by a spring 32, and by attaching an optical fiber sensor 21 to the tip of the arm member 31, the sensor 21 can be moved in a vertical plane and a horizontal plane. .

The operation of the apparatus described above will be explained below with reference to FIG.

The optical fiber sensor 21 here generates a voltage signal as shown in the figure in accordance with the difference in color of the thread of the seam moving directly below it, specifically in accordance with the strength of reflected light caused by the difference in color. 24. This judgment circuit 24 judges whether the input voltage value exceeds the set value or not, and when the upper thread 4 intertwined with the lower thread 5 passes through the sensor 21, the voltage value exceeds the set value. The counter 26 reset signal is input only when the counter 26 is reset.

On the other hand, the counter 26 counts the pulses manually inputted thereto from the pulse generator 25 until the reset signal is input thereto, and if the counted pulse number exceeds the set value, in other words, , outputs a signal to the control circuit 27 when the measured stitch interval calculated from the counted pulse number becomes larger than the predetermined stitch interval. That is, when the measured stitch interval is less than the predetermined stitch interval and the reset signal is input before the number of pulses reaches the set value, no signal is output to the control circuit 27; When the number exceeds a set value, a signal is output to the control circuit 27, which can emit an alarm signal, for example.

FIG. 4 is a diagram showing another embodiment of the present invention.
3 shows a one-dimensional image camera placed on the lower surface side of the sewn product 7.

This one-dimensional image camera 33, which serves as an optical sensor, is positioned and fixed in a position in which its field of view faces in a direction perpendicular to the moving direction of the sewn product 7, and its field of view is, for example, a fluorescent lamp or a plurality of tungsten lamps. It is illuminated by light Fi, 34, which can be e.g.

Further, in the figure, 35 indicates a dark value setting circuit connected to the -dimensional image camera 33, and 36 indicates a comparator connected to both the -dimensional image camera 33 and the threshold value setting circuit 35.
Here, the dark value setting circuit 35 and the comparator 36 constitute a determination circuit 37. Here, the threshold value setting circuit 35 binarizes the video signal obtained by the -dimensional image camera 33 and automatically generates a dark value signal for detecting the stitch, and also the needle thread 4 intertwined with the bobbin thread 5. The comparator 36 detects passage of the upper thread 4 from the video signal from the -dimensional image camera 33 and the darkness value signal.

Furthermore, 38 in the figure is connected to the comparator 36 and the sewing product 7 is connected to the comparator 36.
This counter 38 serving as a measuring circuit also includes a boolean IJ3 that functions to contact the sewn product 7 and convert its linear movement amount into a rotation amount.
A rotary encoder 4o, which is an example of a signal generating means, is connected to the rotary encoder 4o. As a result, the counter 38 is rotated at intervals sufficiently smaller than the predetermined stitch interval until a reset signal is input to the comparator 36 based on the detection result of the upper thread 4 by the comparator 36. Pulses generated from the encoder 40 are counted to measure the amount of movement of the sewn product 7 between the previous reset signal and the subsequent reset signal, and thus the stitch interval.

This counter 38 also indicates that the measured stitch spacing is
If the stitch spacing is larger than a predetermined stitch spacing, a warning signal, for example, is outputted via a buffer 41 connected thereto.

Note that 42 in the figure indicates an external output terminal of the buffer 41.

The operation of the apparatus constructed as described above will be explained below with reference to FIGS. 5-6.

When the sewn product 7 is moved upward in the figure by the feed roller 22, the upper thread 4 and lower thread 5 of the stitch appear and then disappear in the field of view of the -dimensional image camera 33. That is, since the structure of the lower side of the seam is as shown in FIG. 5, when the field of view of the -dimensional image camera 33 is at the position When the field of view reaches the Y-Y position, the upper thread 4 is threaded.

First, the field of view of the -dimensional image camera 33 is
Regarding the case where it is in the -X position, in this case,
The video signal from the camera 33 becomes a substantially linear signal as shown at 33a in FIG. Since the comparator 36 generates a linear signal substantially parallel to the needle thread 4 on the side, the comparator 36 does not generate a signal based on the detection of the needle thread 4, in this case a reset signal. Because of this,
The counter 38 continues to count the pulses from the rotary encoder 40.

Next, when the field of view of the -dimensional image camera 33 is relatively displaced to the Y-Y position, the video signal from the camera 33 is transmitted to a deep valley 33c in the middle, as shown by 33b in FIG. 6(b). becomes the signal that exists, and the dark value signal is
As shown by 35b, the signal is almost linear, and since there is an intersection between the two signals, the comparator 36 generates a pulse-like reset signal indicating the appearance of the upper thread 4. As a result, the count result of the counter 38 is reset.

Here, in order to prevent slipping between the pulley 39 and the sewn product 7, it is preferable that the pulley 39 is provided with an uneven member or the like on its peripheral surface to increase the frictional force with the sewn product 7. By doing so, the rotary encoder 40 can generate a number of pulses that is exactly proportional to the amount of movement of the sewn product 7. Therefore, when the counter 38 counts the pulses as described above, it is possible to measure the amount of movement of the sewn product 7 between the previous and subsequent reset signals, as well as the stitch spacing, with sufficient accuracy.

Also, the counter 38 is connected to the rotary encoder 4
When counting pulses from 0, if each stitch interval (as shown in Fig. 5), the needle thread interval, falls below a predetermined interval, in other words, if there is no skipped stitches, then the number of pulses counted will not reach the predetermined value. Since the reset signal is input there before reaching the set value corresponding to the stitch interval of If the interval becomes larger than the predetermined value at any point, the number of count pulses will exceed the set value before the reset signal is input from the comparator 36, and therefore the counter 38 will A skipped stitch warning signal will be output.

Therefore, if a buzzer, light, etc. are connected to the external output terminal 42 of the buffer 41, a warning can be given to the operator by turning them on. It is also possible to sort out sewn products 7 in which skipped stitches have occurred.

FIG. 7 is a diagram showing still another embodiment of the present invention,
In this example, a pulse oscillator 43 is provided in place of the rotary encoder 400 as a signal generating means in the embodiment shown in FIG. is provided with a counter 44 for measuring the time interval between stitches.

In this example, in a sewn product 7 that travels at a constant speed, if the stitch spacing is appropriate, the time from when a - stitch appears in the video signal to when the next stitch appears is always constant. Based on this, the stitch spacing can be measured indirectly by directly measuring the time.

Therefore, here, the pulse oscillator 43 generates pulses with a cycle sufficiently shorter than the time interval corresponding to the predetermined stitch interval, and the counter 44 counts the pulses.

Here, if the number of pulses counted until the reset signal from the comparator 36 is input to the counter 44 exceeds a set value corresponding to a predetermined stitch interval, the counter 44 outputs a signal from the counter 44 via the buffer 41 For example, by outputting an alarm signal, it is possible to reliably detect the occurrence of skipped stitches.

Here, if the number of count pulses from the - reset signal to the next reset signal is less than or equal to the set value, the counter 44 does not issue a signal (and repeats the same counting).

(Effects of the Invention) As is clear from the above, according to the present invention, by microscopically tracing the seams using an optical sensor, the presence or absence of the seams, or in other words, the presence or absence of the needle thread, can be determined with extremely high precision. It becomes possible to judge, and therefore,
The accuracy of detecting sewing defects will be significantly improved. Moreover, since the detection here is performed without contacting the thread or other objects, there is no risk of false detection, and
There is no risk of adversely affecting sewing work.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing a floating support mechanism of an optical fiber sensor, Fig. 3 is a time chart of the device shown in Fig. 1, and Fig. 4 is a diagram showing an embodiment of the present invention. 5 is a diagram showing the structure of the lower side of the seam, FIG. 6 is a diagram showing the relationship between the video signal and the dark value signal, and FIG. 7 is a diagram showing still another embodiment of the present invention. A diagram showing an example, Figure 8 is la
Figures 9 and 10 showing manufacturing defects are diagrams showing conventional examples, respectively. 4... Upper thread 5... Lower thread 6... Skip-stitch portion 7... Sewn product 21... Optical fiber sensor 23... Stitch row 24.37... Judgment circuit 25...・Pulse generator 26.38...Counter 27...Control circuit 33...-Dimensional image camera 34...Light source 35...Threshold value setting circuit 36...Comparator 39...Pulley 40
...Rotary encoder 43...Pulse oscillator 44...Counter Patent applicant Nissan Motor Co., Ltd. Figure 3 Figure 5 Figure 6 (a) (b) Figure 8 (a)

Claims (1)

[Claims] 1. Optical sensor (
21, 33), a determination circuit (24, 37) that determines the presence or absence of a seam based on the signal from the optical sensor, and a signal generating means (24, 37) that generates a signal corresponding to the amount of movement of the sewn product.
5, 40, 43), and a measurement method that measures the stitch spacing based on the signal from the signal generating means and the determination circuit, and outputs a signal when the measured stitch spacing becomes larger than a predetermined stitch spacing. A sewing defect detection device comprising a circuit (26, 38, 44).