JPH0352886B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for detecting unevenness in fabric, which can accurately and quickly detect the occurrence of unevenness in the sewing process of various fabrics using a sewing machine.

<Prior Art> For example, remarkable progress has been made in the technology for automating the sewing process, such as line closers for sewing the panty part of pantyhose fittings. However, it is not possible to completely prevent the so-called unevenness of the waist elastic part in this sewing process, which is a fatal drawback for sewing manufacturers. For this reason, conventionally, a large amount of manpower and time has been expended to test for the presence or absence of this, and there is a strong desire for a means to easily detect this.

<Means for Solving the Problems> The present invention has been provided for the purpose of solving the above problems, and as a specific means for that purpose, it is possible to solve the problems by solving the problem. The expected occurrence position is located between a light emitting element and two light receiving elements that are provided facing each other, and the amount of transmitted light is actually measured using the light receiving element, and the two actual values from the two light receiving elements are calculated. The uneven portion is detected by taking the difference.

<Function> When sewing two pieces of fabric one on top of the other, either the upper or lower fabric may become uneven due to wrinkles, scratches, turns, etc. If this is sewn as is, a sewing defect such as unevenness will occur. Therefore,
After sewing, the presence or absence of unevenness is actually measured using two light-receiving elements and detected as a difference in the amount of transmitted light. In addition, products with misalignment errors are separately excluded as defective products, making it possible to omit the inspection process.

<Example> Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 schematically shows a line closer that automatically sews the panty part of panty-tight fittings. In FIG. 1, 1 is a circumferential orbit, and 2 is a clamper that moves along this circumferential orbit 1. 3 is a sewing machine, and a detector including a light emitting element 6 and two light receiving elements 4 and 5 vertically opposed to each other is disposed immediately after the sewing machine 3. 7 is an air suction pipe for sucking and removing defective products.

When sewing panty pants, please refer to Figure 2 A.
As shown in the figure, cuts 12 and 13 are made in the two stockings 8 and 9 by a predetermined dimension from the rubber parts 10 and 11 of the upper edges thereof, and then both ends of the rubber parts 10 and 11 of both stockings 8 and 9 are cut. After aligning them, pull them so that the cuts 12 and 13 are in a straight line as shown in Figure B, and the sewing line 15 of the straight part is
Then, both stockings 8 and 9 are sewn together to form a panty part 14, and a panty stocking 16 as shown in FIG. 1C is completed.

In this way, when sewing the panty stockings 16, attach the two stockings 8 and 9 to the clamper 2.
Sewing line 1 of the panty part 14 is set using the sewing machine 3 with the cut part stretched out in a straight line.
5 is sutured. However, if the rubber parts 10, 11 at the upper ends of the two stockings 8, 9 are misaligned, the ends 17, 18 of the rubber parts will become misaligned after sewing, resulting in a so-called wrong level defect. Therefore, the rubber part ends 17, 18
It is detected whether the upper and lower fabrics are aligned using a light-emitting element 6 and two light-receiving elements 4 and 5 provided immediately after the sewing machine 3.

In this case, if the upper and lower rubber parts 10 and 11 are accurately aligned, the amount of transmitted light per one of the light emitting elements 4 and 5 will be as shown in FIG. If there is a case where there is only one sheet at different levels as shown in FIG. 5, the waveform will be as shown in FIG. 4. In FIGS. 3 and 4, the irregularities in the waveforms are due to the thickness of the fabric, and the rubber parts 10 and 1
No. 1 is thick, so the amount of transmitted light is small. In addition, b and e are when there is nothing at the detection position, a is when there is one rubber part, c is when there are two rubber parts,
d indicates the panty portion.

Since the two light-receiving elements 4 and 5 are lined up consecutively in the direction of movement of the stockings after they are sewn, as shown in FIG. . Therefore, the two signals are determined by signal processing as shown in FIG.
That is, FIG. 7A shows the amount of transmitted light of the light receiving element 5,
Figure B shows the amount of light transmitted through the light receiving element 4. When this signal is inputted to inputs 19 and 20 of the operational amplifier 21 shown in FIG. 8, and the difference between the signals is determined by the operational amplifier 21, the waveform shown in FIG. 7C is obtained. However, in order to obtain a stable waveform, it is necessary to use light-receiving elements 4 and 5 that are very small compared to the step width that you want to detect, and to set the spacing between the light-receiving elements 4 and 5 to be smaller than the step width. .

On the other hand, threshold values (D and E in FIG. 7C) are appropriately set in the comparator 23 using the threshold setting device 22. This threshold value D is set to detect the rising edge of the output of the operational amplifier 21,
The threshold value E is set to detect the period from falling to falling.

By the way, in the present invention, what is desired to detect the difference in level is the line closer clamper 2 shown in FIG.
As shown in the enlarged view of the rubber part end 17,
It is 18. An example of the uneven state is shown in FIG. 10 as an enlarged view of the rubber portion end 17 in FIG. 9.

Here, in FIG. 7C, the rubber portion ends 17 and 18 in FIG. 9 correspond to X and Y, respectively. Therefore, the threshold value D has only X in its operating range,
Since the threshold value E has an operating range only in Y, a gate signal as shown in FIG. The comparator 23 thereby receives the signal C from the operational amplifier 21.
Since the comparator 23 compares the threshold values D and E, an output as shown in FIG. 7H is obtained from the comparator 23. Then, when a signal output as shown in FIG. 7G is obtained through a logic circuit that sets the pulse-like waveform of this signal H at a high level from rising to rising,
Based on the signal output, it is possible to detect whether or not there is an accurate match. Moreover, since the difference between the signals of the two light-receiving elements 4 and 5 is determined, it can be seen that the width of the signal is proportional to the width of the difference between the rubber portion ends 17 and 18. In other words, the level difference state can be reliably detected by the rise of the output G. When a defective part is detected, the defective part is removed by suction with an air suction pipe 7 after sewing according to the signal, and is distinguished from a non-defective part.

During normal operation with no deviation, inputs 19 and 20 are the first
Since the solid line and dotted line in FIG. 1A are the same, the output of the operational amplifier 21 is as shown in FIG. 1B.

Note that the present invention is not limited to the line closer for panty pants 16, but can be applied to various sewn products and various sewing machines. For example, it can be applied to overlap stitching of two or more pieces of fabric, and can also be applied to detect misalignment of widely overlapped fabrics. It is also possible to detect the presence or absence of an object to be detected.

Furthermore, during detection while sewing, the process continues from sewing start → misalignment detection → stop → correction → restart.
There are two ways to use it: start of sewing → misalignment detection → completion of sewing → removal of defective products and subsequent processing.

Further, the detector may be fixed to the machine stand, or may be movable.

<Effects of the Invention> As described above in detail in the examples, the present invention uses a light emitting element and two light receiving elements to measure the amount of transmitted light at the detection position, so it is possible to avoid misalignment errors during the automated sewing process. occurrence can be detected accurately and quickly. Also, by taking the difference between the two light receiving elements,
The influence of external light can be removed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of a line closer, FIG. 2 is a diagram showing a sewing method for panty pants, FIG. 3 is a diagram showing the amount of transmitted light in normal conditions, and FIG. Figure 4 is a diagram showing the amount of transmitted light in an abnormal situation, Figure 5 is a cross-sectional view showing the misalignment of the fabric, and Figure 6 is a diagram showing the amount of transmitted light in an abnormal situation.
The figure shows the relationship between the light emitting element and the light receiving element.
The figure is a signal waveform diagram, Figure 8 is a block diagram of the signal processing system, Figure 9 is an enlarged view of the clamper section, and Figure 10 is a block diagram of the signal processing system.
The figure is a partially enlarged view of FIG. 9, and FIG. 11 is a waveform diagram of a signal during normal operation. 3... Sewing machine, 4, 5... Light receiving element, 6... Light emitting element, 10, 11... Rubber part, 16... Panty gripping, 21... Arithmetic amplifier, 22...
Threshold setter, 23... comparator.

Claims (1)

[Claims] 1. The expected position of unevenness in the fabric sewn by the sewing machine is determined by comparing the light emitting element and the 2.
The amount of transmitted light is actually measured by the light receiving element, and the amount of light transmitted from the two light receiving elements is measured.
A method for detecting unevenness in fabric, characterized in that an uneven part is detected by taking the difference between two actual measured values.