JPH042875A - Method for sensing pulled yarn and sensor therefor - Google Patents

Abstract

PURPOSE:To enable accurate and quantitative sensing by bringing a tension sensor into contact with a running fabric, sensing displacement in the direction perpendicular to the running direction of the above-mentioned fabric and discriminating pulled yarn present in the fabric based on the output signal thereof. CONSTITUTION:A load cell 1 is brought into contact with a cloth 5 in the central part between two feed rollers 4 for running the cloth 5 to sense displacement in the direction perpendicular to the running direction of the cloth. The resultant output signal from the aforementioned load cell 1 is then inputted to a signal processing circuit 2 and subjected to signal processing. The signal level pattern thereof is subsequently displayed on a display device 3 to discriminate the presence of pulled yarn from the signal level modulation based on the variation in tension due to the pulled yarn present in the cloth 5.

Description

[Detailed description of the invention] (Industrial application field) TECHNICAL FIELD The present invention relates to a hanging line detection method and detection device.

More specifically, the present invention relates to a method for detecting hanging thread, which is a type of defect inherent in textiles, and to a hanging thread detection device using the method.

(Prior Art) A "hanging thread" is a type of defect inherent in textiles. In other words, in a textile structure formed by warp and weft threads crossing each other, threads with abnormally high tension may be mixed into some of the warp threads or weft threads, and these are called "hanging threads".
This is called a defect and is treated as a defect.

Traditionally, inspection of defects inherent in textiles has relied solely on the visual or tactile sense of an expert. In recent years, in order to automatically detect defects in these textiles using machines,
Several proposals have been made. However, the detection of the "hanging thread" still relies heavily on the visual sense and tactile sense of an expert, and no method or device for automatically detecting this has been proposed. Even in its normal state, textiles have extremely complex structures. Even for experts, especially when it comes to detecting ``hanging threads,'' information obtained from vision is supplemented with information obtained from the tactile sensation of directly touching the fabric with the fingers.

(Problems to be Solved by the Invention) These inspections using human vision and tactile sense require skill on the part of the person performing the inspection, and are not always sufficient in terms of efficiency and accuracy. These problems are fatal when inspecting fabrics produced in large quantities using multiple looms. That is, as mentioned above, even in its normal portion, a woven fabric has an extremely complicated structure, and there is no small variation in the tension of the warp and weft yarns. Detection of hanging threads is the process of extracting particularly large deviations from this variation, and a certain standard should originally be set for this. However, even with the eyes and hands of an expert, it is virtually impossible to constantly inspect many fabrics with a constant standard.

In recent years, it has become possible to stabilize the quality of industrial products at a high level through thorough quality control (QC).In recent years, it has become possible to stabilize the quality of industrial products at a high level through thorough quality control. It is amazing how much quality control has been carried out.

In view of this situation, the present inventors have conducted extensive research, and as a result,
The following invention has been achieved regarding a method and device for detecting hanging threads with good reproducibility and with a certain standard.

(Means for Solving the Problems) That is, the present invention provides a method for detecting a hanging thread inherent in a fabric when the fabric is run in a belt shape, in which a change in the tension of the fabric caused by the hanging thread is detected by detecting a change in the tension of the fabric due to the hanging thread. A method for detecting a hanging thread detecting displacement in a direction different from the running direction; a conveying unit for running a fabric in a belt shape; This is a hanging line detection device that has a sensor installed above the conveyance section.

In the present invention, the "hanging thread" is detected by detecting the tension fluctuation of the textile fabric caused by the hanging thread inherent in the textile fabric.
It performs detection. Further, as means for detecting this tension variation, generally, it is detected as a displacement in a direction different from the moving direction of an object moving relatively on the surface of the fabric while in contact with the fabric.

In such a detection method, when detecting a hanging thread inherent in a weft thread, the textile is conveyed continuously or intermittently using a roller system, etc., and the textile is brought into contact with the textile with a certain amount of load. This is achieved by detecting the displacement of a movable object that can be raised and lowered to press against the fabric in a direction perpendicular to the fabric.

In addition, in the detection of hanging threads inherent in the warp yarns, a device is installed so as to be pressed against the fabric with a certain amount of load while the fabric is being conveyed, and at right angles to the conveying direction of the fabric. This is achieved by detecting the displacement of a movable object in a direction perpendicular to the fabric.

For example, a load cell, a magnetic sensor, an optical sensor, etc. can be used to measure the displacement of a movable object.

It is difficult to easily specify the load for pressing a movable object against a fabric, as it depends on the characteristics of each fabric, the degree of hanging thread to be detected, etc., but it is approximately 1g to 1k.
g weight, preferably in the range of 5 g weight to 100 g weight.

The shape of the part of the movable object that comes into direct contact with the fabric is also difficult to specify because it depends on the characteristics of each individual fabric, the extent of the hanging thread to be detected, etc., but it is difficult to specify the shape of the part of the movable object that directly contacts the fabric, but it is difficult to specify the shape of the part of the movable object that directly contacts the fabric. For this purpose, a hemispherical shape is preferable as much as possible.

Furthermore, in the present invention, the detection rate of the "hanging thread" can be improved by adding a mechanism to the hanging thread detection section to apply tension in the transport direction of the fabric and in a direction perpendicular to the transport direction, if necessary. is also possible.

More specifically, such a detection method involves, for example, conveying the fabric continuously or intermittently using a roller system, applying Tensilon to a specific area of the fabric, and applying Tensilon to the area where Tensilon is applied. Examples include a method of applying vibration to generate a standing wave in a specific range of the textile and monitoring the state of the standing wave.

Although the mechanism for applying vibration to the fabric is not particularly limited, methods such as a piezoelectric vibrator, a solenoid coil, and rotation of an eccentric roller can be used. The frequency of vibration is easy to determine because it is influenced by factors such as the acoustical physical factors of the fabric itself, the tension that can be applied to the fabric, the ability to monitor the vibration propagation state, etc. Although it is difficult, the ultrasonic range of 20kHz abnormality or the low frequency range from 0.0IHz to 35Hz is preferable, and more preferably from 0.1Hz to 1Hz.
This is an extremely low frequency range of 0Hz.

The monitor for the vibration propagation state or the standing wave state is not particularly limited, but it is preferable to use one that can monitor in a non-contact state, such as an optical sensor, an electrostatic sensor, or a long wave sensor. Sensors, etc. can be used.

In the present invention, "hanging thread" detection can be performed by detecting changes in the weaving structure of a textile fabric caused by the hanging threads inherent in the textile fabric.

Generally, the means to detect changes in the weave structure are as follows:
A method using optical means can be exemplified. More specifically, while the fabric is conveyed continuously or intermittently, the light that passes through or reflects the fabric is observed with an optical sensor such as a linear sensor, COD element, or image pickup tube, and the From changes in transmitted light or reflected light,
For example, a method for detecting a "hanging thread" can be exemplified. In this case, "changes in weaving structure" include, for example, "weaving pitch", "weaving density", and "thickness of warp or weft".
, "thread spacing", "reflected light intensity from individual threads", "directivity of reflected light from individual threads", "gloss", etc.

The absolute value of the tension applied to a fabric depends on many factors, such as the physical and mechanical properties of the fabric itself, the extent of the hanging thread used for detection, and which changes in the physical properties of the fabric due to the hanging thread should be focused on. Although it is difficult to definitively determine this as it is affected by the following factors, it should preferably be kept to 60% or less of the tearing load of the target fabric.

A more preferable range is 35% of the tearing load of the fabric.
The range is as follows.

In addition, it is preferable to maintain the same tension in the "transport direction of the fabric" and the "direction perpendicular to the transport direction," and as a practical matter, it is required to suppress the tension imbalance to 50% or less. .

More specifically, such a detection method includes, for example, conveying the fabric continuously or intermittently using a roller system, applying tension to a specific area of the fabric, and applying tension to the area where the tension is applied. Examples include a method in which a predetermined vibration is applied to produce a standing wave in a specific range of the fabric, and the state of the standing wave is monitored.

Although the mechanism for applying vibration to the fabric is not particularly limited, methods such as a piezoelectric vibrator, a solenoid coil, and rotation of an eccentric roller can be used. The frequency of vibration is easy to determine because it is influenced by factors such as the acoustical physical factors of the fabric itself, the tension that can be applied to the fabric, the ability to monitor the vibration propagation state, etc. Although it is difficult, the ultrasonic range of 20kHz abnormality or the low frequency range from 0.0IHz to 3Hz is preferable, and more preferably from 0.1Hz to 10Hz.
This is an extremely low frequency range of Hz.

The monitor for the vibration propagation state or the standing wave state is not particularly limited, but it is preferable to use one that can monitor in a non-contact state, such as an optical sensor, an electrostatic sensor, or an ultrasonic sensor. Sensors, etc. can be used.

(Function) It is very difficult to directly and non-destructively measure the tension fluctuation of a textile fabric caused by the hanging threads inherent in the textile fabric.

Textiles have elasticity and elasticity as their original properties, but abnormal tension caused by hanging threads also causes abnormalities in their elasticity and elasticity. When an object is pressed against the fabric with a certain amount of load and moves relative to the fabric surface, it is displaced in the vertical direction of the fabric in areas where the stretchability and elasticity are abnormal.

In the present invention, tension fluctuation is detected as a displacement in a direction different from the moving direction of an object moving relatively on the surface of the fabric while in contact with the fabric.

EXAMPLES The present invention will be explained in more detail by way of Examples below, but the present invention is not limited thereto.

(Example) Example 1 FIG. 1 is a schematic explanatory diagram showing the detection part of the "hanging line detection device" according to the present invention. As shown in the figure, two feed rollers are installed as part of the roller system that continuously conveys the fabric to be inspected, and a load cell is pressed against the fabric at the center of the two rollers, and a "hanging thread" is placed on the fabric. It detects tension fluctuations in textiles caused by

That is, in this case, the detection end of the load cell corresponds to the "movable object provided in contact with the textile" in the present invention, and the load cell body corresponds to "a sensor that detects displacement of the movable object in a direction perpendicular to the textile". ”.

Roller width is 190cm1 Fabric feed speed is 0 to 75m by inverter control of the drive motor of the conveyance system
It was made variable between / minutes. The load with which the load cell was pressed against the fabric was 50 g.

The signal obtained from the load cell is converted from the conveying speed into the moving distance of the detection end of the load cell on the fabric and displayed on the display.

FIG. 3 is an example of a signal obtained from a normal part without a hanging line. The low frequency components seen in the figure are noise components caused by eccentricity of the rollers, natural vibrations of the mechanical system, etc.

FIG. 4 is an example of a signal obtained when the detection end of the load cell passes through a certain part of the hanging string. As shown in the figure, it was possible to detect tension fluctuations in the fabric caused by the hanging thread as "displacement in the direction perpendicular to the fabric" at the detection end of the load cell.

Embodiment 2 FIG. 2 is a schematic explanatory diagram showing the detection portion of the "hanging line detection device" according to the present invention. As in Example 1, two feed rollers are provided as shown in the figure as part of the roller system that continuously conveys the fabric to be inspected, and a load cell is pushed onto the fabric at the center of the two rollers. It is used to detect tension fluctuations in the fabric caused by the "hanging thread".

The difference from Example 1 is that two fixed rollers were inserted at positions close to the load cell detection end. The frequency noise component is slightly reduced.

The roller width is 100cm, and the feeding speed of the fabric is 0 to 75m by controlling the drive motor of the conveyance system with an inverter.
It was made variable over a period of 7 minutes. The load with which the load cell was pressed against the fabric was 20 g.

In addition, four load cells are arranged in parallel at 20 cm intervals, and each load cell is placed in the direction perpendicular to the transport direction of the fabric (
= lateral direction of the fabric) at 60 m/min (effective traverse length of each load cell 20 cm 1 effective detection width 80 cm)
m).

In this device as well, it was possible to detect hanging threads in the same manner as in Example 1. Also, for low frequency noise components, the amplitude ratio is approximately 2
It was on /3. It was also possible to detect hanging threads contained in the warp threads of the fabric by traversing the load cell.

Embodiment 3 FIG. 5 is a schematic explanatory diagram showing the detection portion of the "hanging line detection device" according to the present invention. As shown in the figure, two feed rollers are installed as part of the roller system that continuously conveys the non-inspection fabric, and a load cell is pressed against the fabric at the center of the two rollers, and a "hanging thread" is placed on the fabric. It detects tension fluctuations in textiles caused by Tensilon is applied to the fabric in the transport direction by slightly varying the rotational speed of the feed roller. Tensene is applied to the fabric in the transport direction by slightly varying the rotational speed of the feed roller. Furthermore, tension rollers are provided on both sides of the location where the opening-dossel is provided at a certain angle to the transport direction of the fabric, thereby applying tension to the fabric in the lateral direction.

The roller width is 120cm, and the feeding speed of the fabric is 0 to 75m by controlling the drive motor of the conveyance system with an inverter.
It was made variable between / minutes. The load with which the load cell was pressed against the fabric was 50 g.

The signal obtained from the load cell is converted from the conveying speed into the moving distance of the detection end of the load cell on the fabric and displayed on the display.

In FIG. 7, there is no hanging line, and the normal part is a noise component caused by eccentricity of the roller, natural vibration of the mechanical system, etc.

FIG. 8 is an example of a signal obtained when the detection end of the load cell passes through a certain part of the hanging string. As shown in the figure, it was possible to detect tension fluctuations in the fabric caused by the hanging thread as "displacement in the direction perpendicular to the fabric" at the detection end of the load cell.

Embodiment 4 FIG. 3 is a schematic explanatory diagram showing the detection portion of the "hanging line detection device" according to the present invention. As in Example 3, two feed rollers are provided as shown in the figure as part of the roller system that continuously conveys the fabric, which is a non-inspection object, and a load cell is pushed onto the fabric at the center of the two rollers. guess,
It detects tension fluctuations in textiles caused by "hanging threads."

The difference from Example 3 is that upper and lower rollers are provided instead of the tension rollers provided on both sides of the location where the load cell is installed, and these upper and lower rollers sandwich the side portions of the fabric and move the fabric in the transport direction. Tension is applied in the perpendicular direction, that is, in the lateral direction.

In this device, as in Example 3, it was possible to detect two threads.

(Effects of the Invention) As described above, the "fishing line detection method and detection device" of the present invention does not require skill and is more efficient and accurate than human visual and tactile inspections. It has many advantages, including the ability to quantitatively determine criteria.

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams showing the detection part of the device according to the present invention, Figure 3 is an example of a signal from a normal fabric with no hanging thread, and Figure 4 is an example of a signal when a hanging thread is detected. shows. 1...Load cell, 2...Signal processing circuit. 3...Display device, 4...Feed roller 5.
...Fabric, 6...Fixed Roller Patent Applicant Toyobo Co., Ltd. Load Cell Signal Processing Circuit Display Feed Roller Fabric 1: Load Cell 2: 43 Ri Convex 1 Ri Circuit 3: Display 4: Feed Roller 5: Fabric 6: Fixed roller Figure 5/? b-to t1v 7, ten>run 1 cone- distance distance kuku 40 figure 60 /j1 fu 1゛chi 1υ 2; two lower low fu

Claims (2)

[Claims] (1) In a method of detecting a hanging thread inherent in a fabric when the fabric is run in a belt shape, a change in the tension of the fabric due to the hanging thread is detected as a displacement in a direction different from the running direction of the fabric. How to detect hanging thread. (2) A suspension line comprising a conveyance section that runs the fabric in a belt shape, and a sensor provided above the conveyance section that senses tension fluctuations in the running direction of the fabric as displacement of an object that is in contact with the fabric by being in pressure contact with the fabric. Detection device.