JPH042865A - Sensor for inspecting material of continuous length - Google Patents

Abstract

PURPOSE:To accurately and quantitatively sense pulled yarn by applying vibration to a beltlike cloth of continuous length running in a tensed state and scanning a propagation state of the produced elastic waves with a laser beam and sensing the disturbance of elastic wave propagation caused by the pulled yarn. CONSTITUTION:A beltlike cloth of continuous length is run in a tensed state between two feed rollers 2 having a difference in feed speed and a vibrator 1 arranged near one of the feed rollers 2 is simultaneously operated to apply vibration to the cloth. The propagation state of the produced elastic waves is scanned with a laser beam emitted from a laser scanner 3 so as to describe a lattice pattern on the cloth. The disturbance of the propagation state of the above-mentioned elastic waves caused by variation in tension of the cloth due to pulled yarn is sensed with a TV camera 4 and the signal thereof is subjected to figure display through a signal processing circuit 5 on a display device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inspection device for woven or knitted fabrics or film-like sugar long articles. More specifically, the present invention relates to a detection device that detects "hanging threads" which are a type of defect inherent in textiles.

(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, 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, the current situation is that they supplement the information obtained from vision with the information obtained from the tactile sensation of directly touching the fabric with their fingers, especially when it comes to detecting "hanging threads."

(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 state, a woven fabric has an extremely complex structure, and there is no small variation in the tension of warp and weft yarns. Detecting hanging threads is the process of extracting particularly large deviations from this variation.
Essentially, certain standards should be set for this.

However, even if it is done by the eyes and hands of experts,
It is virtually impossible to constantly inspect many fabrics with constant standards.

In recent years, it has become possible to stabilize the quality of industrial products at a high level through thorough QCl, or 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,
We have achieved the next invention related to a device that can detect hanging threads with good reproducibility and with a certain standard.

(Means for Solving the Problems) That is, the present invention includes a conveying section that causes a long object to travel in a belt shape under tension, a mechanism section that applies a predetermined vibration to the long object, and a mechanism that applies predetermined vibrations to the long object. This long object inspection device is characterized by being equipped with a monitor that detects the propagation state of elastic waves.

The present invention is an apparatus for detecting hanging threads and the like by detecting tension fluctuations in a material that is caused by hanging threads and the like inherent in a fabric. Further, the means for detecting this tension variation is to detect it from the propagation state of elastic waves propagating in the fabric.

Such a detection device conveys the fabric continuously or intermittently using, for example, a roller system, applies tension to a specific area of the fabric, and applies a predetermined vibration to the area where the tension is applied. This is achieved by providing a device that monitors the vibration propagation state.

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 10Hz.
This is an extremely low frequency range of Hz.

The monitor for the vibration propagation state is not particularly limited, but one that can be monitored in a non-contact manner is preferable. For example, optical sensors, electrostatic sensors, ultrasonic sensors, etc. can be used.

(Function) It is very difficult to directly and non-destructively measure the tension fluctuations of a long object caused by the hanging string or the like inherent in the long object.

In the present invention, "miso" is used to detect tension fluctuations of a long object from the propagation state of elastic waves propagating to the long object.
There is.

That is, the propagation state of elastic waves is influenced by various acoustical and physical factors of the medium, and in particular, the tension of the medium greatly affects the propagation speed and amplitude of elastic waves, as well as the attenuation characteristics. Therefore, by monitoring the elastic waves propagating through the fabric, it is easy to discover if there is a tension abnormality in the fabric, that is, a ``slip''.

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

(Examples) Example 1 FIG. 1 is a schematic explanatory diagram showing a detection portion of a fabric inspection device according to the present invention. As shown in the figure, two feed rollers are installed as part of the roller system that continuously or intermittently conveys the fabric to be inspected, and by making a difference in the feeding speed of the two rollers, the fabric can be conveyed to a predetermined position. It applies the tension of A vibrator using a solenoid coil is provided near one of the feed rollers, and applies a low frequency vibration of 5.4 Hz to the fabric.

The vibrations applied to the fabric propagate toward the other roller as elastic waves. Its propagation status is monitored by an optical sensor system described below.

Laser light emitted from a laser scanner is scanned to draw a checkered pattern on the fabric. The TV left camera is installed to observe the fabric from an oblique direction, and the obtained signals are displayed after predetermined signal processing.

The width of the roller is 190 cm, and the feeding speed of the fabric is 0 to 75 m by controlling the drive motor of the conveyance system with an inverter.
It was made variable between / minutes.

Figure 2 is an example of a signal obtained from a normal part without a hanging line. You can see how the vibrations applied to the fabric are propagating clearly.

FIG. 3 is an example of a signal obtained from a certain part of the fishing line. It is shown that the propagation state of elastic waves traveling through the fabric is disturbed due to tension fluctuations in the fabric due to the hanging thread.

(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]

FIG. 1 is a schematic diagram of the apparatus according to the present invention, FIG. 2 shows an example of a signal of a fabric without a hanging thread detected by the apparatus of the invention, and FIG. 3 shows an example of a signal of a fabric with a hanging thread. 1... Vibrator, 2... Feed roller 3... Laser scanner 4... TV left camera 5... Signal processing circuit, 6... Display unit

Claims (1)

[Claims] (1) Provided with a conveyance section that causes the long object to travel in a belt shape under tension, a mechanism section that applies a predetermined vibration to the long object, and a monitor that detects the propagation state of elastic waves generated in the long object due to the vibration. A long object inspection device that is characterized by a long object inspection device.