JP2000262793A - Light transmissive textural dislocation detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect textural dislocation regardless of a kind of texture by detecting a light receiving quantity of a light receiver in plural points of a sewing object texture, and automatically adjusting sensitivity of the light receiver and/or a light projecting quantity of a light projector so that a maximum detecting value amond plural detecting values coincides with a reference value. SOLUTION: Before sewing a new texture, first of all, trial sewing is performed by superposing new sewing object textures 6, 7. At this time, an initial sensitivity value of a variable resistor 16 is set. A rotation signal from a rotation detector 21 is inputted to a CPU 19 every time when a main shaft of a sewing machine rotates once according to progress of the trial sewing, and a pluse-like transmitted beam of light is irradiated from a light projector 12 in synchronism with the rotation to detect a light receiving quantity of a light receiver 14 in plural points of the textures 6, 7. Next, sensitivity of the variable resistor 16 is automatically adjusted by increasing/decreasing the sensitivity by a feedback signal from the CPU 19 to the initial sensitivity value so that a maximum detecting value among plural detecting values coincides with a textural dislocation detecting reference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly detects whether or not overlapping fabrics are displaced from each other when sewing over a plurality of fabrics, such as overlock sewing using an overlock sewing machine. The present invention relates to a light-transmissive cloth shift detecting device used to prevent sewing failure by notifying a worker or the like when a cloth shift occurs.

[0002]

2. Description of the Related Art This kind of light-transmissive cloth shift detecting device is
A light projector arranged on one surface side of the sewn cloth which is fed to the needle drop section of the sewing machine in a state of being overlapped and moves through the needle drop section, and on the other surface side of the sewn cloth opposed to the light projector And a light receiver disposed therein, and is configured to detect a cloth shift based on a change in the amount of light when light from the light projector passes through the cloth to be sewn and is received by the light receiver. That is, the non-overlapping portion is larger in the transmitted light amount in the overlapping portion and the transmitted light amount in the non-overlapping portion of the sewn cloth, and a reference value is set between the transmitted light amounts of both portions having a difference therebetween, and the actual sewing is performed. By determining whether or not the amount of transmitted light received by the light receiver exceeds the reference value, the presence or absence of a fabric shift is detected and output.

If the thickness of the cloth to be sewn is different, the amount of transmitted light of the non-overlapping part as well as the overlapping part is different, and it is difficult to detect a predetermined cloth deviation with a reference value set for a cloth of a certain thickness. is there. For example, if it is attempted to detect the displacement of the cloth of a thin cloth with the reference value set for the cloth of a large thickness, the transmitted light amount exceeds the reference value even at the overlapping part of the cloth. There is a possibility that an erroneous detection operation may be performed if the fabric is misaligned even though it is not misaligned. Therefore, in the light transmission type cloth shift detecting device, it is necessary to change the reference value in accordance with the thickness of the cloth to be sewn. Means for detecting the transmitted light amount of the overlapping portion and the non-overlapping portion of the trial sewing cloth, respectively, and manually adjusting the sensitivity of the light receiver by manually operating the variable resistor so that the reference value is between the detected transmitted light amounts. Was taken.

[0004]

However, in the above-described conventional light-transmitting cloth shift detecting apparatus, not only a troublesome sensitivity adjustment operation by manual operation is required every time the cloth to be sewn is changed, but also the sewing operation is performed. If the target fabric has a pattern, the amount of transmitted light may change and an erroneous detection operation may be performed depending on the situation of the pattern at the position where light is transmitted. In other words, the sensitivity of the receiver is set so that the reference value is between the amount of transmitted light at the pattern position where light is difficult to transmit in the overlapping portion of the trial sewing material and the amount of transmitted light at the pattern position where light is difficult to transmit even in the non-overlapping portion. If the setting is set, the amount of transmitted light at the pattern position where light in the overlapping portion is easy to transmit exceeds the reference value, and false detection operation may be performed when there is no fabric displacement even though fabric displacement has not occurred. There is a problem that the detection function as a cloth shift detecting device is impaired.

The present invention has been made in view of the above circumstances, and not only does not require troublesome sensitivity adjustment work by manual operation, but also aims to sew cloth having a pattern in which the amount of transmitted light changes greatly. Even in such a case, an object of the present invention is to provide a light-transmissive cloth shift detecting device which can accurately and accurately detect the original cloth shift.

[0006]

In order to achieve the above-mentioned object, a light-transmissive cloth shift detecting apparatus according to the present invention comprises a light-transmitting light from a light emitting device arranged on one side of a superposed cloth to be sewn. A light-transmitting cloth shift detecting device configured to determine whether the amount of transmitted light received by a light receiver arranged on the other side of the cloth exceeds a reference value and to detect the presence or absence of a cloth shift. Along with the sewing operation of the sewn cloth, the light receiving amount of the light receiver at a plurality of points of the sewn cloth is detected,
Calculating means for automatically adjusting the sensitivity of the light receiver or / and the light emission amount of the light projector so that the largest detected value among the plurality of detected values matches the reference value. It is.

According to the present invention having the above-described structure, the fabric to be sewn is preliminarily sewn before the actual sewing operation, so that light reception at a plurality of points of the sewn fabric detected at the time of the trial sewing is performed. The sensitivity of the light-receiving device and / or the amount of light emitted from the light-emitting device is automatically adjusted so that the detected value of the largest light-receiving amount among the detected values of the light-receiving amount obtained by the light-receiving device matches the reference value. In this way, when fabrics having different thicknesses are to be sewn, regardless of the thickness of the fabric to be sewn, it is possible to adjust the sensitivity and / or the amount of projected light so that a predetermined fabric misalignment detection function can be reliably performed accurately. It is. In addition, when fabrics having a pattern in which light is easily transmitted and locations where light is hardly transmitted are sewn, the maximum transmitted light amount at the pattern position where light is most easily transmitted among the overlapping portions of the fabric is set to Since it is set to the reference value, it is possible to adjust the sensitivity or / and the projected light amount so that the predetermined cloth shift detection function can be accurately performed regardless of the pattern of the cloth having any pattern. is there.

In the case where the cloth to be sewn is such that the largest detected value among the detected values of the received light amount at a plurality of points does not reach the above-mentioned reference value even by adjusting the sensitivity of the light receiver or / and the light emission amount of the light emitter. As described in claim 2, by determining a value corresponding to the highest sensitivity of the light receiver or / and the maximum light emission amount of the light emitter as the reference value, it is impossible to set the reference value at the time of trial sewing. It is possible to avoid occurrence of a problem in using the sewing machine that the sewing operation itself becomes impossible.

In addition, the sensitivity of the photodetector or /
And automatically adjusting the amount of light emitted from the projector.
As described in, by using a value corrected to an average value or an integrated value for each sewing operation (trial sewing) as a plurality of received light amount detection values, a cloth having any light transmission characteristics can be sewn. Even in the case of, the sensitivity of the light receiving device for setting the reference value and / or the accuracy of adjusting the light emitting amount of the light emitting device can be increased, and the predetermined cloth shift detection performance can be further improved.

Further, in this type of light-transmissive cloth shift detecting device, dust or the like adheres to the light-receiving surface of the receiver and the light-emitting surface of the light transmitter while repeating the sewing operation, and the amount of light received by the light receiver changes with time. However, there is an inconvenience that the predetermined cloth shift detection performance is deteriorated due to a decrease in the amount of light or a decrease in the amount of light emitted from the light projector over time. In view of this, as described in claim 4, by providing a means for detecting the presence or absence of a change in the amount of light received by the light receiver and performing self-diagnosis of the quality of the light receiver or / and the light projector, Based on the results of self-diagnosis when the amount of light received by the receiver decreases or the amount of light emitted by the projector decreases, the light receiving surface and the light emitting surface are cleaned to restore the original amount of received light and the amount of emitted light. It can be used in such a state that even when used for a long period of time, the predetermined cloth shift detection performance and the automatic adjustment of the received light amount or / and the projected light amount corresponding to the change of the cloth can be reliably and accurately exhibited.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of an overlock sewing machine M provided with a light-transmitting cloth shift detecting device according to the present invention, and FIG. 2 is a right side view of a main part of the sewing machine. The needle plate 2 is fixed to the cross plate 1 of the overlock sewing machine M such that the upper surface thereof is flush with the upper surface of the cross plate 1. At the lower part of the needle plate 2 and at the front and rear positions sandwiching the needle drop part 5 of the sewing needle 4 supported by the sewing head 3 so as to be able to reciprocate up and down, two pieces of sewing material vertically overlapped with each other. A front feed dog 8 and a rear feed dog 9 for feeding the fabrics 6 and 7 in the sewing traveling direction Y are provided, and the fabrics 6 and 7 to be sewn are pressed on the upper surface of the needle plate 2 on the needle plate 2. As shown in FIG. 3, the sewing machine 4 and a looper (not shown) cooperate with each other while sequentially feeding the fabrics 6 and 7 in the sewing progress direction Y by the front and rear feed teeth 8 and 9. In addition, the overlock stitch forming the seam 11 having a width in the cloth width direction X orthogonal to the sewing progress direction Y is configured to be performed.

At a position behind the needle drop portion 5 of the needle plate 2 in the sewing progressing direction Y, a light projector fixed to an upper portion of the needle plate 2 and transmitting a transmitted light beam to the fabrics 6 and 7 to be sewn. 12 and a lower portion of the needle plate 2, which are arranged and fixed via a mounting member 13 at a position facing the light projector 12,
And a light receiver 14 for receiving the light beam transmitted through the light source 7.

This light transmission type cloth shift detecting sensor 15
By judging whether or not the amount of transmitted light received by the light receiver 14 exceeds the reference value, it is detected whether the number of overlaps of the two fabrics 6 and 7 is one or two. It is configured to detect the presence / absence of a fabric shift. Also,
Floodlight 1 in this light transmission type cloth shift detection sensor 15
Reference numeral 2 denotes a state in which the front and rear feed teeth 8 and 9 are in a non-feed operation state by the action of a chopper (not shown), and
Is configured to irradiate the sewn fabrics 6 and 7 with a transmitted light beam in a pulsed manner when the fabric is in the fabric pressing action state.

FIG. 4 is a block diagram showing a circuit configuration of a cloth shift detecting device including the cloth shift detecting sensor 15.
The transmitted light amount signal S1 from the light receiver 14 in the cloth shift detection sensor 15 is input to the amplifier 17 through the variable resistor 16, where it is amplified and the A / D converter 18
The digital value is input to the CPU 19, and the digital value is compared with a preset reference value to determine the presence / absence of a fabric shift. At this time, the cloth shift notification unit 20 such as turning on a lamp, sounding a buzzer, or displaying a screen.
Is configured to output an operation command signal S2.

In addition to the transmitted light amount signal S1 from the light receiver 14, the CPU 19 in the cloth shift detecting device having the above-described circuit configuration includes, for example, a rotation detector attached to a main shaft (not shown) of the overlock sewing machine M. A rotation signal S3 generated every one rotation is input by 21. By irradiating a plurality of times of pulsed transmitted light from the light projector 12 in synchronization with the rotation signal S3, the sewing cloths 6 and 7 are The received light amount of the light receiver 14 at a plurality of points is detected, and the digital value (detected value) of each of the received light amount signals S1 is detected.
Is input to the CPU 19. The CPU 19 feeds back the adjustment signal S4 to the variable resistor 16 so as to feed back the adjustment signal S4 to the variable resistor 16 so that the largest digital value among the plurality of digital values input here becomes the reference value of the cloth to be sewn. It has a calculation function to adjust automatically.
The calculation function for automatic sensitivity adjustment by the CPU 19 can be switched on and off by operating the manual switch 22.

Next, in the light-transmitting cloth shift detecting device configured as described above, the light receiving sensitivity adjusting operation for setting the cloth shift detecting reference value when the sewing target cloths 6 and 7 are changed. This will be described with reference to the flowchart of FIG.

Prior to sewing new fabric, the operator instructs the CPU 19 to turn on the manual switch 22 and start automatic sensitivity adjustment. Then, new sewing target fabrics 6 and 7 are overlapped and trial sewing is performed. At this time, the initial sensitivity value of the variable resistor 16 is set to A, and half of the value, that is, (A / 2) is set to B (step S31).

With the progress of trial sewing, overlock sewing machine M
A rotation signal S3 generated by the rotation detector 21 each time the main shaft makes one rotation is input to the CPU 19, and a pulsed transmitted light is emitted from the light projector 12 in synchronization with the rotation signal S3 to overlap the sewing target fabric. The amount of light received by the light receiver 14 at a plurality of points 6 and 7 is detected. The received light amount has, for example, a waveform as shown in FIG. 6. By averaging the received light amount of such a waveform, a light reception detection value corrected to a waveform as shown in FIG. 7 is obtained. The maximum light reception detection value Z among the detection values is compared with the reference value α stored in the CPU 19 (step S32).

When the comparison result is Z <α, the CPU 1
9, the sensitivity of the variable resistor 16 is increased (A + B is reset to A) by the adjustment signal S4 fed back from
If it is not <α, the sensitivity of the variable resistor 16 is reduced (AB is reset to A) by the adjustment signal S4 fed back from the CPU 19, and the initial set value B (= A / 2)
Until the value becomes 1, the initial set value B is sequentially divided into two equal parts (B /
2) While repeating, the sensitivity of the variable resistor 16 is repeatedly and automatically adjusted (steps S33 to S36).

When the initial value B of the variable resistor 16 is set to 1 by repeated automatic adjustment of the sensitivity of the variable resistor 16, the initial sensitivity value A of the variable resistor 16 becomes the maximum sensitivity Amax.
Is determined (step S37), and A = Ama
x. If it is determined that there is a difference (constant K) or more between the reference value α and the maximum light reception detection value Z in order to reliably detect a fabric shift, That is, it is determined whether or not α−Z> K (step S3).
8). If α-Z> K, the reference value α in the CPU 19 is updated to the maximum light reception detection value Z (step S39).

As described above, before starting sewing of a new cloth to be sewn, it is only necessary to overlap the cloths to be sewn and to perform trial sewing. The reference value can be set to an optimum value without erroneous detection operation. After the setting of the reference value for detecting the material deviation for the new sewing target materials 6 and 7,
By determining whether or not the amount of light received by the light receiver 14 during the actual sewing on the new sewing target fabrics 6 and 7 exceeds the reference value set as described above, the two sewing fabrics 6 and 7 Detects whether the number of overlapping sheets is 1 or 2 and accurately detects the presence or absence of a fabric shift. When there is a fabric shift, informs of a fabric shift such as turning on a lamp, sounding a buzzer, or displaying a screen. The operation command signal S2
Can be output.

In the above-described embodiment, of the light receiving amounts detected by the light receiver 14 at a plurality of points of the fabric to be sewn during the trial sewing, the light receiving amount Z is set so that the maximum light receiving detection value Z matches the reference value α. Although the description has been given of a method for automatically adjusting the sensitivity of the light detector 14, instead of this, though not shown, the light amount of the light projector 12 may be automatically adjusted via a variable resistor, or the sensitivity of the light receiver 14 may be adjusted. Even if both the light emission amount of the light projector 12 and the light source 12 are automatically adjusted, it is possible to set the cloth deviation detection reference value to an optimum value without erroneous detection operation in the same manner as described above.

Further, in the light-transmissive cloth shift detecting device, dust or the like adheres to the light-receiving surface of the light-receiving device 14 while repeating the sewing operation, and the amount of received light decreases with time.
There is an inconvenience that dust or the like adheres to the light projecting surface of the light projector 12 and the amount of projected light decreases with time, thereby lowering predetermined cloth shift detection performance. In order to deal with this point, the CPU 19 includes the light receiver 14 or the light projector 12.
It has a function to self-diagnose the quality of the product.

That is, in a sewing machine equipped with a light-transmissive cloth shift detecting device such as an overlock sewing machine,
Generally, a cloth presence / absence sensor (not shown) for determining whether or not there is a cloth to be sewn on the upper surface of the needle plate 2 is provided. Therefore, during the actual sewing operation, as shown in the flowchart of FIG. 8, based on the detection result of the cloth presence sensor (step S41), when there is cloth, sewing is performed in a state where the original cloth shift detection function is exhibited. (Step S42), the self-diagnosis function is performed on the light receiver 14 or the light projector 12 when the sewing is completed and each time the cloth presence / absence sensor detects the absence of the cloth (Step S42).
43) By doing so, each time sewing is performed, the quality of the light receiver 14 or the light emitter 12 is determined, and the amount of received light is reduced. If the amount of emitted light is reduced, the light receiving surface or the light emitting surface is cleaned. The light receiving amount of the light receiving device 14 or the light emitting amount of the light emitting device 12 is always properly maintained, and even when used for a long period of time, the predetermined cloth shift detection performance and the automatic adjustment performance of the sensitivity corresponding to the change of the cloth are surely and accurately performed. It can be used in a state where it is exhibited.

[0024]

As described above, according to the present invention, prior to the actual sewing operation, there is no need to perform any troublesome sensitivity adjustment work by manual operation, and only the trial sewing of the overlapped sewing target fabric is performed. Irrespective of the thickness of the fabric to be sewn, it is possible to automatically adjust to the optimum light receiving sensitivity and / or the optimum projection light amount, which ensures that the predetermined cloth shift detection function is reliably performed. In addition, even when fabrics having a pattern in which light-transmitting portions and light-transmissive portions are scattered are to be sewn, the pattern position at which the maximum amount of transmitted light in the overlapping portion of the fabric is obtained by trial sewing. It is possible to easily and accurately adjust the light receiving sensitivity and the amount of projected light so that the detection value is set to the reference value. This has the effect that the function can be reliably and accurately exhibited.

[0025] In particular, by providing means for self-diagnosing the quality of the light receiving device or the light emitting device by detecting the presence or absence of a change in the amount of input transmitted light to the light receiving device as described in claim 4, Based on the result of self-diagnosis when the amount of received light decreases or the amount of light emitted from the projector decreases, it is recommended to restore the original amount of received light and the light emitting performance by cleaning the light receiving surface and the light emitting surface, etc. Even when used for a long period of time, the apparatus can be used in a state where the predetermined cloth shift detection performance and the sensitivity and automatic adjustment of the projected light amount corresponding to the change of the cloth are always accurately exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an overlock sewing machine provided with a light-transmissive cloth shift detecting device according to the present invention.

FIG. 2 is a right side view of a main part of the sewing machine.

FIG. 3 is a plan view of a main part for explaining a state of a material shift;

FIG. 4 is a block diagram showing a circuit configuration of a light transmission type cloth shift detecting device.

FIG. 5 is a flowchart illustrating an operation of adjusting the light receiving sensitivity for setting a reference value for detecting a cloth shift.

FIG. 6 is a detection waveform diagram of the amount of light received by the light receiver at a plurality of points on the fabric to be sewn.

FIG. 7 is a waveform diagram after correcting a detection waveform according to the first embodiment.

FIG. 8 is a flowchart illustrating a self-diagnosis operation of the amount of light received by the light receiver.

[Explanation of symbols]

 6, 7 Fabric to be sewn 12 Projector 14 Receiver 15 Fabric displacement detection sensor 16 Variable resistor 19 CPU

Continued on front page F-term (reference) 2F065 AA15 AA20 CC02 DD00 FF02 FF66 GG08 HH12 HH15 JJ08 LL30 NN01 NN13 NN18 NN19 PP11 QQ03 QQ23 QQ25 RR08 SS09 SS13 2G051 AA40 AB20 BA20 BC01 CA02 CB02 FA03 CE04 CE24 CE25 CE27 GD03 GD08 GD14 GD22 GD25 GD26 LA34 LA40 LB01 MA05 MA16 NA80 NB18 QA06 QA07

Claims (4)

[Claims] 1. A method according to claim 1, further comprising the step of determining whether or not the amount of light transmitted from a light emitter disposed on one side of the sewn cloth received by a light receiver disposed on the other side of the sewn cloth exceeds a reference value. A light-transmitting cloth shift detecting device configured to determine and detect the presence or absence of a cloth shift, the amount of light received by a light receiver at a plurality of points of the cloth to be sewn with the sewing operation of the cloth to be sewn. , So that the largest detected value among the plurality of detected values matches the reference value,
A light transmissive cloth shift detecting device, comprising a calculating means for automatically adjusting the sensitivity of the light receiving device and / or the light emitting amount of the light emitting device. 2. If the largest detected value among the plurality of detected values does not reach the reference value even by adjusting the sensitivity of the light receiving device and / or the amount of light emitted by the light emitting device, the highest sensitivity or / and / or the light receiving device has. 2. The light-transmissive cloth shift detecting device according to claim 1, wherein a value corresponding to a maximum light projecting amount of the light projector is determined as the reference value. 3. The light-transmissive cloth shift detecting device according to claim 1, wherein the plurality of detected light-receiving amounts are values corrected to an average value or an integrated value for each sewing operation. 4. The light transmission according to claim 1, further comprising means for detecting whether or not the amount of light received by said light receiver has changed, and performing self-diagnosis of the quality of said light receiver and / or light projector. Type cloth shift detector.