JP3961118B2 - Seam detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seam detection device that detects a seam of a web-like article that moves continuously and outputs a signal.
[0002]
[Prior art]
For example, a resin or paper sheet, an aluminum foil, or a web-like article formed by laminating these is connected via a joint 1 as shown in FIG. The seam 1 is formed by sticking the tape 3 across the end portions of the web-like article 2 arranged so that the end faces face each other.
[0003]
When detecting the seam 1, a method of detecting the seam 1 from a change in the thickness of the web-like article 2 at the seam 1 is employed. The structure of this type of joint detection device is shown in FIG. Reference numeral 4 in the figure denotes a guide roll (cylindrical) for guiding the web-like article 2. The guide roll 4 is made of iron, and a magnet bridge is provided at a position facing the guide roll 4 with a gap S having a predetermined width. 5 and a transducer (conversion device) 7, which is schematically configured from a coil 6 wound around the bridge 5, is disposed. Reference numeral 8 denotes a meter connected to the transducer 7, and reference numeral 9 denotes a roller disposed on both sides of the transducer 7 to urge the web-like article 2 from above to the guide roll 4 side. Here, the transducer 7 and the roller 9 are installed on the same carriage (not shown).
[0004]
In this joint detection device, a change in inductance (electric signal) generated in the transducer 7 due to a change in thickness of the web-like article 2 passing through the gap S is converted into a change in mechanical signal (movement of the needle of the meter 8). is doing. When the mechanical signal exceeds a certain value, the joint 1 is detected by determining that the joint 1 has passed through the gap S.
[0005]
[Problems to be solved by the invention]
However, in the case of the conventional joint detection device, the inductance is converted into a mechanical signal, and the joint 1 is detected from the change in the mechanical signal. Therefore, there is a problem that a time lag of about 300 to 400 milliseconds occurs between the time when the joint 1 passes through the gap S and the time when the joint 1 is detected, and the responsiveness is low. Further, since the responsiveness is low, if the moving speed of the web-like article 2 is fast, the movement of the needle of the meter 8 cannot follow the actual change in thickness, and there is a problem that the detection accuracy is lowered.
[0006]
Furthermore, when the moving speed of the web-like article 2 is high, the web-like article 2 flutters up and down, and as a result, the inductance changes even though the thickness of the web-like article 2 is constant, and the seam detection device malfunctions. There was a case. Therefore, in the conventional seam detection device, the detection sensitivity is lowered according to the moving speed of the web-like article 2, but there is a problem that the operation is complicated because the detection sensitivity is adjusted manually. It was.
[0007]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a seam detection device that is quick in response, excellent in detection accuracy, and easy to adjust detection sensitivity.
[0008]
That is, the invention according to claim 1 is a seam detection device for a web-like article that continuously moves, and a magnetic cylinder supported rotatably around an axis, and the web-like article from above. A carriage provided with a roller urging to the cylinder side, and the web-like article and the roller as a conversion device that is opposed to the cylinder and the web-like article and converts the thickness of the web-like article into a change in electric signal Detecting a change in inductance due to the upward movement of the carriage due to the contact of the transducer, and a periodic change of an electrical signal due to the roundness of the transducer installed in the carriage and the cylinder is stored in advance, and By subtracting the periodic change of the electrical signal stored in advance from the actual detected value of the change of the electrical signal generated in the transducer, the electrical signal caused by the roundness of the cylinder A correction mechanism having a function of removing-term changes, compares the magnitude of the electrical signal corrected by the previously stored threshold value and the correction mechanism, it outputs a signal when said electrical signal exceeds said threshold And an output device.
[0009]
Further, the invention according to claim 2 is a seam detection device for a web-like article that moves continuously, the magnetic cylinder supported rotatably around an axis, and the web-like article from above. A carriage provided with a roller urging to the cylinder side, and the web-like article and the roller as a conversion device that is opposed to the cylinder and the web-like article and converts the thickness of the web-like article into a change in electric signal A transducer installed on the carriage for detecting a change in inductance due to the upward movement of the carriage due to contact with the carriage, a high-pass filter for removing minute changes in electrical signals caused by the cylinder, and a perfect circle of the cylinder It consists of a low-pass filter that removes periodic changes in the electrical signal caused by the degree, and has a function to remove periodic changes in the electrical signal caused by the roundness of the cylinder A positive mechanism, and an output device that compares the threshold value stored in advance with the electric signal corrected by the correction mechanism and outputs a signal when the electric signal exceeds the threshold value. Yes.
[0010]
Further, the invention according to claim 3 is a seam detection device for a web-like article that moves continuously, the magnetic cylinder supported rotatably around an axis, and the web-like article from above. A carriage provided with a roller urging to the cylinder side, and the web-like article and the roller as a conversion device that is opposed to the cylinder and the web-like article and converts the thickness of the web-like article into a change in electric signal Detecting a change in inductance due to the upward movement of the carriage caused by the contact of the carriage, the first transducer installed on the carriage, the cylinder and the web-like article sandwiched therebetween, and the first transducer A second transducer that is fixed forward or backward in the moving direction of the web-like article and does not detect a change in inductance due to the movement of the carriage. From the detected value of the inductance in the p o, by subtracting the detection value of the inductance at the second transducer, a correction mechanism having a function of removing a periodic change in the electrical signal due to the roundness of the cylinder, An output device is provided that compares the threshold value stored in advance with the electric signal corrected by the correction mechanism and outputs a signal when the electric signal exceeds the threshold value .
According to a fourth aspect of the present invention, in the joint detection device according to any one of the first to third aspects, a specific threshold value is determined according to a change in the moving speed of the web-shaped article from a plurality of threshold values stored in advance. It is characterized by having a sensitivity adjustment mechanism for selecting.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, members having the same configurations as those of the conventional seam detection device are denoted by the same reference numerals and description thereof is omitted.
[0012]
An example of the structure of a seam detection device according to the present invention is shown in FIG. In this joint detection device, a detection unit 10 is connected to the transducer 7. The detection unit 10 stores in advance a value of a predetermined inductance as a threshold value, and compares this threshold value with an inductance generated in the transducer 7 as the thickness of the web-like article 2 that passes through the gap S changes. When the inductance generated in the transducer 7 exceeds the threshold value, the detection unit 10 determines that the joint 1 has passed through the gap S, whereby the joint 1 is detected. The detection unit 10 outputs a signal simultaneously with the detection of the joint 1, and based on this signal, an output device (not shown) indicates that the joint 1 has passed through the gap S by a signal such as light or sound. Notify workers. The position of the joint 1 may be recorded as data.
[0013]
In this joint detection device, the change in inductance generated in the transducer 7 is directly used for detection of the joint 1 without being converted into a mechanical signal. Therefore, there is almost no time lag from when the joint 1 passes through the gap S until the joint 1 is detected, and high responsiveness is obtained. Moreover, since the responsiveness is high, even if the moving speed of the web-like article 2 is increased, the detection accuracy does not decrease.
[0014]
The detection unit 10 may be provided with a sensitivity adjustment mechanism that increases the threshold value according to an increase in the passing speed of the web-like article 2 in the gap S. In this case, the detection unit 10 stores in advance the relationship between the passage speed of the web-like article 2 and the threshold value so that the threshold value increases as the passage speed of the web-like article 2 increases. Here, the increase in the threshold corresponds to a change in inductance due to flapping of the web-like article 2 as the passing speed increases.
[0015]
When the seam 1 is inspected, the passage speed of the web-like article 2 is measured, and the threshold value is adjusted based on the result, so that only the seam 1 is detected with the optimum sensitivity according to the passage speed of the web-like article 2. This prevents malfunction of the seam detection device. Further, all actual sensitivity adjustments are automatically performed by the detection unit 10.
[0016]
On the other hand, when detecting the joint 1, the roundness of the guide roll 4 and the difference in thickness along the axial direction are also affected. In this case, the mechanical accuracy of the guide roll 4 is increased so that the change in inductance caused by the roundness of the guide roll 4 and the thickness difference along the axial direction is within the detection error range of the joint detection device. (For example, within 0.02 mm), the malfunction of the joint detection device is prevented.
[0017]
Similarly, a partial variation in the material of the guide roll 4 may cause a malfunction of the joint detection device, so it is desirable to use a material that is as homogeneous as possible. That is, by selecting the material of the guide roll 4 so that the change in inductance caused by the material of the guide roll 4 is within the detection error range of the joint detection device, malfunction of the joint detection device is prevented. Specifically, the above malfunction can be prevented by using a cylindrical material that has been annealed at 850 ° C. or higher, which is the iron transformation point.
[0018]
The joint detection device may have a correction mechanism that corrects the above-described change in inductance caused by the guide roll 4 as noise. An example of the correction mechanism is shown below.
[0019]
(1) The periodic inductance change caused by the guide roll 4 is stored in advance, and the joint 1 is detected by subtracting the stored periodic inductance change from the actual detection value when detecting the joint. Only the change in inductance caused by is detected.
[0020]
(2) A high-pass filter is used to remove minute inductance changes due to the guide roll 4, and a low-pass filter is used to remove periodic changes in inductance caused by the guide roll 4, thereby providing the seam 1. Only the resulting inductance change is detected. Here, the set frequency of the filter is arbitrarily set according to the moving speed of the web-like article 2, the diameter of the guide roll 4, and the like. For example, when the moving speed of the web-like article 2 is 50 to 100 m / min and the diameter of the guide roll 4 is 100 mm, the setting frequency of the low-pass filter is 15 to 20 Hz and the setting frequency of the high-pass filter is 100 Hz.
[0021]
(3) A new transducer is fixed in front of or behind the moving direction of the web-like article 2 of the transducer 7, and the change in inductance detected by the transducer 7 and the new transducer is compared. In this case, since the transducer 7 is installed on the carriage together with the roller 9, the detected value of the inductance in the transducer 7 also changes as the carriage moves upward due to the contact between the joint 1 and the roller 9 when the gap S passes. To do. On the other hand, the detected inductance value in the new fixed transducer does not detect a change in inductance due to movement of the carriage.
[0022]
Therefore, by subtracting the detected inductance value in the new transducer from the detected inductance value in the transducer 7, only the change in inductance due to the joint 1 is detected. Here, in order to eliminate the difference in inductance caused by the guide roll 4 in both transducers, it is desirable to place the new transducer as close to the transducer 7 as possible.
[0023]
【The invention's effect】
As described above, in the joint detection device according to the present invention, the electrical signal generated in the transducer is compared with the threshold value stored in advance, and the signal is output when the electrical signal generated in the transducer exceeds the threshold value. The change in inductance that occurs in the transducer is directly used for seam detection without being converted into a mechanical signal. As a result, there is almost no time lag until the joint is detected after the joint passes through the gap, and high responsiveness can be obtained. Moreover, since the responsiveness is high, even if the passage speed of the web-like article increases, the detection accuracy does not decrease.
[0024]
Furthermore, when a sensitivity adjustment mechanism for increasing the above-mentioned threshold is provided in accordance with an increase in the passage speed of the web-like article, it becomes possible to detect only the seam with the optimum sensitivity according to the passage speed of the web-like article. A malfunction of the seam detection device is prevented. Further, since sensitivity adjustment by the sensitivity adjustment mechanism is automatically performed, detection sensitivity can be easily adjusted.
[0025]
On the other hand, the malfunction of the joint detection device is also prevented by the correction mechanism that corrects the change in the electrical signal caused by the guide roll as noise.
[Brief description of the drawings]
FIG. 1 is a diagram showing the structure of a seam detection device according to the present invention.
FIG. 2 is an upper perspective view showing the structure of a seam in a web-like article.
FIG. 3 is a diagram showing the structure of a conventional seam detection device.
[Explanation of symbols]
1 Seam 2 Web-shaped Article 4 Guide Roll (Cylinder)
7 Transducer
S Gap between guide roll and transducer

Claims (4)

A seam detection device for continuously moving web-shaped articles,
A magnetic cylinder supported rotatably about an axis;
A carriage provided with a roller for urging the web-shaped article from above to the cylindrical side;
As a conversion device that opposes the cylinder and the web-like article and converts the thickness of the web-like article into a change in an electric signal , accompanying the upward movement of the carriage by the contact between the web-like article and a roller A transducer installed in the carriage for detecting a change in inductance ;
Periodic changes in the electrical signal due to the roundness of the cylinder are stored in advance, and the periodic changes in the electrical signal stored in advance are subtracted from the actual detected value of the change in the electrical signal generated in the transducer. A correction mechanism having a function of removing a periodic change of the electrical signal due to the roundness of the cylinder,
A seam detection device comprising: an output device that compares a threshold value stored in advance with an electric signal corrected by the correction mechanism and outputs a signal when the electric signal exceeds the threshold value . A seam detection device for continuously moving web-shaped articles,
A magnetic cylinder supported rotatably about an axis;
A carriage provided with a roller for urging the web-shaped article from above to the cylindrical side;
As a conversion device that opposes the cylinder and the web-like article and converts the thickness of the web-like article into a change in an electric signal , accompanying the upward movement of the carriage by the contact between the web-like article and a roller A transducer installed in the carriage for detecting a change in inductance ;
It consists of a high-pass filter that removes minute changes in the electrical signal caused by the cylinder and a low-pass filter that removes periodic changes in the electrical signal caused by the roundness of the cylinder, resulting from the roundness of the cylinder A correction mechanism having a function of removing a periodic change in the electrical signal;
A seam detection device comprising: an output device that compares a threshold value stored in advance with an electric signal corrected by the correction mechanism and outputs a signal when the electric signal exceeds the threshold value . A seam detection device for continuously moving web-shaped articles,
A magnetic cylinder supported rotatably about an axis;
A carriage provided with a roller for urging the web-shaped article from above to the cylindrical side;
As a conversion device that opposes the cylinder and the web-like article and converts the thickness of the web-like article into a change in an electric signal , accompanying the upward movement of the carriage by the contact between the web-like article and a roller A first transducer installed on the carriage for detecting a change in inductance ;
A second transducer that is opposed to the cylinder and the web-like article, is fixed to the front or rear of the first transducer in the movement direction of the web-like article, and does not detect a change in inductance due to the movement of the carriage. A correction having a function of removing a periodic change in the electrical signal caused by the circularity of the cylinder by subtracting the detected inductance value in the second transducer from the detected inductance value in the first transducer. Mechanism,
A seam detection device comprising: an output device that compares a threshold value stored in advance with an electric signal corrected by the correction mechanism and outputs a signal when the electric signal exceeds the threshold value . The joint detection according to any one of claims 1 to 3, further comprising a sensitivity adjustment mechanism that selects a specific threshold value from a plurality of threshold values stored in advance according to a change in a moving speed of the web-like article. apparatus.

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