JPH04148775A - Detecting method for thread breakage - Google Patents

Abstract

PURPOSE:To detect thread breakage without giving any influence on the thread by detecting existence of running air current generating around running thread with a sensor, and discriminating running thread or thread breakage based on the detected result. CONSTITUTION:A sensor 5 is provided in the running air current generating by running of a thread line T, and a discriminating circuit 6 is connected to the output side of the sensor 5. When temperature variation or pressure variation of an atmosphere around the thread line T due to existence or non-existence of the running air current are sensed with the sensor 5, existence or non-existence of thread breakage is discriminated from difference of output with the discriminating circuit 6. Namely, existence of running air current is detected from temperature or pressure variation to indirectly discriminate thread breakage. Hereby, thread breakage can be discriminated without any influence on the thread line T.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for detecting breakage of running yarn in a fiber spinning and winding process.

<Prior Art> Conventionally, the following methods are known as yarn breakage detection methods.

(b) A method of detecting thread breakage using a photoelectric sensor described in Japanese Patent Application Laid-Open No. 62-168082, in which a light source and a light receiving section are arranged to sandwich the thread running line, and the light receiving section detects the thread breakage. Thread breakage is detected by changes in the luminous flux.

(b) A method of detecting thread breakage using a detection device described in Japanese Patent Application Laid-open No. 48-41068, in which a thread hook is brought into contact with the running thread, and a mechanical signal is generated from the running thread. to detect running or cutting of the thread.

(c) Using the method described in Japanese Patent Application Laid-open No. 50-111319, a spray is ejected against the running airflow generated around the running yarn, and a temperature sensor is provided in the spray. When a running airflow is generated, the ejection of the spray is blocked and the temperature sensor is exposed outside the spray, but when no traveling airflow is generated, the temperature sensor is installed inside the spray. By detecting the temperature difference in each of these states, it is possible to detect the presence or absence of running airflow and, by extension, the presence or absence of yarn breakage.

<Problems to be Solved by the Invention> However, each of the conventional yarn breakage detection methods described above has the following problems.

Generally, in the fiber spinning and winding process, water, oil, etc. are often applied to the multifilament (yarn) in order to prevent static electricity and maintain cohesiveness. Oil splatters. Therefore, (a)
The detection method described in 1. has a problem in that the scattered lubricating oil adheres to the photoelectric sensor, especially the light receiving part, resulting in a decrease in detection sensitivity. Furthermore, if the thread sways (thread vibration) and the thread travel line deviates from the light beam, the charging sensor will malfunction.

In the method described in (b), since the thread hook is brought into contact with the running thread, extra tension is applied to the thread.

In the winding process, winding is performed with a predetermined tension.
An inconvenience arises in that the added extra tension must be removed. Furthermore, since the sensor is attached directly to the yarn, there is a possibility that the yarn may be damaged.

In the method described in (c), a spray is ejected into the airflow flowing through the yarn, but this spray also extends to the yarn itself, resulting in the inconvenience that excess moisture is added to the yarn. Furthermore, the presence or absence of a running airflow is not detected directly, but is detected from the degree of spray ejection, which changes depending on the presence or absence of a running airflow, resulting in a slow response speed.

Taking all of the above into account, the conditions required for thread breakage detection are: - There is no contact with the running thread, and - The sensor is not affected by oil or moisture adhering to the thread T. , ■Response is prompt.

An object of the present invention is to provide a yarn breakage detection method that can satisfy the above conditions.

<Means for Solving the Problems> In order to achieve the above object, the present invention takes the following method.

(1) Check the presence or absence of running airflow that occurs around the thread during running.
Detected using sensors such as temperature detectors and pressure detectors,
Based on the detection results, running or cutting of the thread is detected.

(2) In the method described in (1) above, a yarn guide tube of the II cane is arranged around the traveling yarn, and the sensor is provided in the yarn guide tube to determine whether or not there is a traveling airflow generated in the yarn guide tube. is detected, and based on the detection result, running or cutting of the thread is detected.

(3) In the method described in (sub)) above, a branch pipe that communicates with the thread pipe is provided on the side circumferential surface of the thread pipe, and the sensor is provided in the branch pipe, and the sensor is provided to accompany the traveling airflow. The presence or absence of an accompanying flow generated within the branch pipe is detected, and running or cutting of the thread is detected based on the detection result.

<Operation> According to the detection method described in (1), the presence or absence of running airflow generated near the running yarn is detected from temperature changes and pressure changes in the atmosphere surrounding the yarn, and based on the detection results, Since it is configured to detect whether the thread is running or stopped (cut), it is possible to detect thread breakage without touching the thread at all.

Further, according to the method described in (2), a cylindrical yarn guide tube is arranged around the running yarn, and the presence or absence of running airflow generated in the yarn guide tube is detected in the same manner as in (1). Therefore, the running airflow is not affected by disturbances, and the detection sensitivity can be improved, which in turn improves the sensitivity of thread breakage detection.

Furthermore, according to the method described in (3), a branch pipe communicating with the yarn guide pipe is provided, and the presence or absence of an accompanying flow generated in the branch pipe with the traveling airflow generated in the thread guide pipe is determined. Since the sensor is detected in the same manner as above, even if water or oil applied to the thread to prevent static electricity or improve convergence is scattered as the thread runs, the sensor can be protected from contamination.

<Example> Embodiments of the present invention will be described below based on the drawings.

First, with reference to FIG. 7, a yarn winding process to which the yarn breakage detection method of the present invention is applied will be briefly described.

The yarn T, which is made up of 2 to 50 single yarns pulled out from the spinneret 1 of the spinning device, is filled with water to prevent static electricity and maintain cohesiveness of the yarn when passing through an oiling roller 2. , oil, etc. are applied thereto, and then it is wound onto a rotationally driven winding drum 4 via two Godet rollers 3a and 3b.

Since the traveling speed of the yarn as it is wound around the winding drum 4 is high, approximately 3000 to 5000 m/min, yarn breakage is likely to occur between the godet roller 3b and the winding drum 4.

An example of the method of the present invention for detecting this thread breakage is given below.

As shown in Figure 1, a sensor 5 is installed in the running airflow generated by the running of the yarn T, and a detection circuit 6 is connected to the output of the sensor 5 to detect the movement of the yarn T. Based on the presence or absence of running airflow, it is detected whether the thread is running, that is, whether the thread is broken or not.

A temperature sensor such as a platinum resistance thermometer, an infrared sensor, a thermocouple or a thermistor, or a diaphragm pressure sensor is used as a sensor for detecting the presence or absence of a traveling airflow. The reason why a temperature sensor is used to detect the presence or absence of running airflow is because there is a difference between the ambient temperature when running airflow is generated and the ambient temperature when there is no running airflow. Generally, the ambient temperature when running airflow is generated is: The ambient temperature is lower than the ambient temperature when there is no running airflow. In addition, the reason why a pressure sensor is used is because the pressure around the yarn T varies depending on the presence or absence of running airflow.Generally, the pressure around the yarn T when running airflow is generated is The pressure will be lower than that without.

In this way, when the sensor 5 senses the temperature and pressure changes in the atmosphere surrounding the yarn due to the presence or absence of running airflow, the detection circuit 6 detects the presence or absence of yarn breakage from the output difference, as shown in FIG. It is structured like this.

When the sensor 5 is a temperature sensor, the temperature compensation sensor 7 and the sensor 5 are connected to two adjacent sides of the bridge circuit 6a, and the resistances R and R' (R, +VR) on the other two adjacent sides are connected. The connection point a is connected to a predetermined ts+v, and the connection point between the temperature compensation sensor 7 and the sensor 5 is connected to ground. Connection points c and d between the resistors R and R' and the temperature repair sensor 7 and sensor 5 are connected to a differential amplifier 8.8 in the amplifier circuit 6b.

The bridge circuit 6a is adjusted so that the resistances R and R' and the resistance of the temperature repair sensor 7 are balanced when the sensor 5 has a certain temperature, that is, a certain resistance value.

Therefore, the difference in the output voltage of the differential amplifier 8.8 (■.,
-V. , ) changes according to the potential difference with the connection points c and d, the tightness, and the resistance value change of the sensor 5, and a thread breakage detection signal (a signal indicating the presence or absence of running airflow) is output from the terminal 9. .

In addition, if the sensor is a pressure sensor, the sensor 5 may be configured such that the opening of the cylindrical body is fixed so as to be covered with a diaphragm integrated with a strain gauge.
The pressure change of the traveling airflow can be detected as a resistance change of the strain gauge, and basically the same detection circuit 6 as shown in FIG. 2 above can be used.

In this way, the presence or absence of running airflow is detected from temperature or pressure changes, and yarn breakage is indirectly detected, so yarn breakage is detected without affecting the yarn T in any way.

II Engineering ■ As shown in FIG. The presence or absence of airflow running through the yarn T is detected to detect yarn breakage.

The yarn guide tube 10 has a cylindrical shape in which a yarn guide slit 11 for guiding the yarn T into the tube is formed along its longitudinal direction, and a sensor 5 is attached to the inner circumferential wall.

In this way, by installing the sensor 5 in the yarn guide tube 10 and detecting the traveling airflow of the yarn T, detection sensitivity can be improved without being affected by external disturbances. Note that the detection circuit 6 connected to the sensor 5 is the same as that in the first embodiment, and this is also the same in each embodiment described below.

Moreover, this second embodiment can be modified as follows.

(2) As shown in FIG. 4 (6), the sensor 5 is fixed to the inner peripheral surface of the yarn duct 10 with a resin mold 12. In this way, oil scattered by the running of the yarn T can be prevented from adhering to the sensor 5.

As the molding resin 12, it is desirable to use one with excellent thermal conductivity so as not to reduce the detection sensitivity of the sensor 5.

(2) Alternatively, as shown in FIG. 3(C), a part of the yarn guide tube 10 is made to protrude in the radial direction, and the sensor 5 is buried within the protrusion 13.

As shown in the perspective view of FIG. 5(a) and the vertical cross-sectional view of FIG. A T-shaped pipe 15 is formed, and a branch pipe 14 is formed.
By providing a sensor 5 inside, the presence or absence of an accompanying flow A inside the branch pipe 14 generated by the running of the yarn T is detected.

In other words, when the yarn T is inserted into the yarn guide tube 10 from the yarn guide sulin 11 and winding of the yarn T is started, the yarn T runs and the above-mentioned running air flows inside the yarn guide tube 10. occurs. Accompanied by this traveling airflow, an accompanying flow A toward the yarn guide tube 10 is generated within the branch pipe 14.

Therefore, there is a difference between the atmospheric temperature (or pressure) inside the branch pipe 14 when the accompanying flow A is generated and the atmospheric temperature (or pressure) when the accompanying flow A is not generated. If the difference is detected by the sensor 5, the presence or absence of the accompanying flow A and, in turn, the presence or absence of the running airflow of the yarn T can be detected.

In this way, newly installing the branch pipe 14 and installing the sensor 5 therein, as in the modification of the second embodiment,
This is to prevent oil from adhering to the sensor 5 without molding the sensor 5 with resin or burying it.

Furthermore, as a method of preventing oil from adhering to the sensor 5,
The opening 14a of the branch pipe 14 may be blocked by a filter 16.
If oil is scattered to the outer peripheral space of the branch pipe 14, there is a possibility that oil particles may be included in the air sucked through the opening 14a of the branch pipe 14. This prevents the particles from adhering to the sensor 5.

Below, an example of the dimensions of the T-shaped tube 15 will be introduced for reference.

The inner diameter φD of the thread guide tube 1G is about 0.1 to 100 m5, preferably in the range of 4 to 20 mm, and the inner diameter φd of the branch pipe 14 is about 0.1 to 100 m5, preferably 0.5 to 20 mm. lo
The range of w, the pipe length of thread pipe lO is about 5 to 101
The pipe length it of the branch pipe 14 is about 2 to 10,100 O, preferably in the range of 10 to 200 O.

1. As shown in FIG. 6, the T-shaped pipe 15 described in the third embodiment
The communication pipe 1 further branches from the side circumferential portion of the branch pipe 14.
7 are connected for communication, and a sensor 5 is installed in this communication pipe 17 to detect the accompanying flow generated in the communication pipe 17. A cleaning brush 18 is provided at the opening 14a of the branch pipe 14.

In this way, by retracting the sensor 5 from the branch pipe 14 and cleaning the oil adhering to the inner peripheral surface of the branch pipe 14 with the cleaning brush 18, the accompanying oil generated in the branch pipe 14 and the communication pipe 17 can be removed. can improve the flow efficiency of the flow,
The sensitivity of the sensor 5 can be improved.

Next, an experimental example of thread breakage detection using the method described in the third embodiment described above will be described.

! Armpit section (1) As the yarn T, use one with a filament count of 36, a denier of 75, and a crimped one, and as the yarn guide tube 10, an inner diameter φD of 8-1 and a cylinder length it. 50m
m, the inner diameter φd of the branch pipe 14 is 4 cm, and the pipe length 18 is 5 cm, and the thread T is 1000 m/m.
Changes in the output voltage (■.+Voz) of the detection circuit 6 before and after yarn breakage were recorded with a pen recorder when the yarn was run at a speed of 50 minutes. The result is the graph shown in FIG. 8(a).

As is clear from this graph, the difference in the output voltages before and after time L' when the yarn breakage occurs is very noticeable.

The voltage value between time 0 and t I J is the voltage output while the yarn T is running, and the voltage value between time rt' and Lm-xJ is the value output after the yarn breaks. Breakage of the yarn T is detected from a change in the voltage value.

(2) Next, the above yarn T is not crimped (
Figure (b) shows the results of an experiment to detect thread breakage in the raw silk state. Note that the running speed of the yarn T is as in Experimental Example (1).
It is similar to

As is clear from this graph, even in the state of raw silk, the difference in output voltage before and after yarn breakage was significant.

(3) Furthermore, the same figure (C ).

Looking at this graph, it cannot be said that the difference in the output voltage values before and after the thread breakage was clearly visible, but it was possible to detect the thread breakage.

<Effects of the Invention> As is clear from the above description, the yarn breakage detection method of the present invention has the following effects.

(1) Check the presence or absence of running airflow that occurs around the thread during running.
Since the detection is based on temperature and pressure changes in the surrounding atmosphere, it is possible to do so without contacting the yarn, and without having any negative impact on the yarn as with conventional spray methods.
Thread breakage detection is now possible.

(2) Since the yarn guide tube is placed around the running yarn and the presence or absence of running airflow generated within the yarn guide tube is detected, the presence or absence of running airflow can be detected while preventing the influence of disturbances. This makes it possible to improve thread breakage detection sensitivity.

(3) A branch pipe that communicates with the yarn guide pipe is installed, and thread breakage is detected by detecting the presence or absence of an accompanying flow in the branch pipe accompanying the running airflow generated in the thread guide pipe. The sensor can be protected from contamination such as water or oil that is scattered by the system, and thread breakage detection sensitivity can be improved.

[Brief explanation of the drawing]

1 to 8 relate to one embodiment of the present invention, in which FIG. 1 is a perspective view showing the yarn breakage detection method of the first embodiment, FIG. 2 is a diagram showing the configuration of a detection circuit, and FIG. Fig. 3 is a perspective view showing the thread breakage detection method of the second embodiment, Fig. 4 is a sectional view showing a modification thereof, and Fig. 5(a) shows the thread breakage detection method of the third embodiment. FIG. 6 is a perspective view showing the thread breakage detection method of the fourth embodiment, FIG. 7 is a simplified diagram illustrating the thread winding process, and FIG. The figure is a graph showing experimental results for thread breakage detection. 5...Sensor 6...Detection circuit 10...
Yarn guide tube 14... Branch tube T... Yarn thread Figure 1■ Figure 2

Claims (3)

[Claims] (1) Check the presence or absence of running airflow that occurs around the thread during running.
Detected using sensors such as temperature detectors and pressure detectors,
A yarn breakage detection method characterized by detecting yarn running or breakage based on the detection result. (2) In the thread breakage detection method according to claim (1),
A cylindrical yarn guide tube is arranged around the traveling yarn, and the sensor is provided inside the yarn guide tube to detect the presence or absence of traveling airflow generated in the yarn guide tube, and based on the detection result, the yarn travel is controlled. Or a thread breakage detection method that detects breakage. (3) In the thread breakage detection method according to claim (2),
A branch pipe communicating with the yarn guide tube is provided on a side peripheral surface of the yarn guide tube, and the sensor is provided in the branch tube to detect the presence or absence of an accompanying flow generated in the branch pipe accompanying the traveling airflow, A thread breakage detection method that detects thread running or breakage based on the detection results.