JPS61126928A - Strip tip detecting device - Google Patents

Abstract

PURPOSE:To elevate the reliability in the detection of a strip tip by installing the strip tip detecting device with the use of a microwave in case of winding a strip by a mandrel. CONSTITUTION:A hot rolled strip 3 is wound by a mandrel 7 through a guide plate 4. In this case the strip tip detector consisting of a microwave transmitting antenna 13 and receiving antenna 14 is fitted to the outlet part of the guide plate 4. The strip 3 is pressed to the mandrel side by the unit rolls 5, 5a, 5b by hydraulic cylinders 9, 9a, 9b and coiled. When the strip tip comes in the detecting part in this case, the transmission loss of the microwave due to the strip is measured by a microwave strength level measurer 15, so the strip tip is always detected accurately without reducing the reliability in the detection degrees by a water for water cooling, steam or dust like the case of a hot rolled strip.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for detecting the tip of a strip when the strip is wound up, for example, by a down coiler.

<Prior Art> When winding a strip with a down coiler, it is necessary to detect the tip of the strip and start winding with an appropriate shape to avoid scratches on the strip at the beginning of winding. For this reason, the uncoiler has conventionally been provided with a device for detecting the tip of the strip.

FIG. 2 is an explanatory diagram conceptually showing a down coiler equipped with a conventional detection device. As shown in the figure, strip 3
is held between a top pinch roll 1 and a metham pinch roll 2, guided by a guide plate 4, and wound up by a mandrel 7. At this time, the unit rolls 5, 5a, 5b attached to the unit frames 6° 5a, 5b and arranged around the mandrel 7 are
The strip 3 is brought into contact with the surface of the mandrel 7 and forced to follow the shape of the mandrel 7, and the unit frame 6 is driven by hydraulic cylinders 9° 9a and 9b.
It comes into contact with and separates from the strip 3 via 5a, 5b and cylinder ronds s, sa, sb.

Thus, the tip of the strip 3 jumps into the down coiler, passes through the unit rolls 5.5JL and 5b in order, and then wraps when the strip 3 comes under the unit roll 5 again. In this state of deafness, the 22trol 5.5a15b continues to move away from the mandrel 7 for several turns of the IJ tube 3. That is, in such a separated state, the strip 3 is wound around the mandrel 7 while maintaining tension between the mandrel 7 and the top pinch roll 1 and the bottom pinch roll 2.

Incidentally, in such a down coiler, a strip tip detection device is provided at the entrance of the pinch rolls 1 and 2. This detection device is equipped with a light source 16 and a source sensor 17 that receives light from the light source 16, and detects the tip of the strip 3 when the light incident on the source sensor 17 is blocked by the traveling strip 3. do.

<Problems to be solved by the invention> In general, the inside of a factory is a relatively dusty environment, and in the case of IJ tubes, the surrounding area tends to get wet due to water cooling due to hot rolling. It's in the environment. Therefore, dust and water often adhere to the strip 3, the light source 16 of the detection device, and the original sensor 17.

However, since the conventional detection device uses a source, the source from the light source 16 may be reflected, scattered, or
It was easy to be refracted, and the reliability of its detection was low. Therefore, in order to maintain detection reliability, there is a problem in that maintenance to remove dust and water must be performed frequently.

The present invention was made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a strip tip detection device that does not require frequent maintenance and exhibits high detection reliability.

Means for Solving the Problems〉 The strip tip detection device according to the present invention
-'It is characterized in that a microwave transmitting antenna and a receiving antenna are installed facing each other with the J-tube in between, and the tip of the strip is detected from the transmission loss of the microwave as it passes through the strip.

Effect> Microwave is not easily affected by the presence of water, dust, etc.)
The tip of the strip is detected by measuring the transmission loss due to the IJ knob.

<Example> An embodiment of the present invention will be described below with reference to FIG.

Incidentally, the same parts as in the prior art are given the same reference numerals, and the explanation thereof will be omitted.

As shown in the figure, in the down coiler equipped with the detection device of this embodiment, a microwave transmitting antenna 13 and a microwave receiving antenna 14 are installed at the upper and lower parts of the tip of the guide plate 4, respectively. , transmitting antenna 13
is connected to the microwave oscillator 12 and the receiving antenna 14
is connected to a level measuring device 15 that measures the intensity of microwaves.

These transmitter 12, transmitting antenna 13, receiving antenna 1
4. The measuring device 15 constitutes a detection device as a whole,
Microwaves transmitted from a transmitter 12 via a transmitting antenna 13 are measured by a measuring device 15 via a receiving antenna 14. Therefore, the tip of the strip 3 can be detected by measuring the change in the intensity of the microwave due to the transmission loss in the strip 3 as it travels and passes between the transmitting antenna 13 and the receiving antenna 14.

Next, the degree of influence caused by the presence of water in the above-mentioned detection device will be explained.

The attenuation of the microwave is: Further, the penetration depth d, which is the depth at which the attenuation becomes e-1, is expressed as follows. Here, the microwave frequency is 100H2
Comparing the penetration depth d between iron forming the strip 3 and water, if μ = 200°a = 6000V/m for iron, then d = 4.5μm, and for water μ = 1. σ=107
If it is 7m, then d=0.15m.

Therefore, even if the strip cooling water adheres to the strip 3 or the detection device, this water will not affect the microwaves. On the other hand, microwaves have extremely low penetrability to iron, so they can hardly pass through the strip 3. As a result, even in the presence of water, it is possible to accurately measure the change in microwave intensity due to the strip 3 passing between the transmitting antenna 13 and the receiving antenna 14, and the strip can be used with extremely high reliability. ) The tip of the IJ knob 3 can be detected. The above-mentioned difference in the penetration depth of microwaves also applies to fine dust, and the tip of the strip 3 can be detected with extremely high reliability even in the presence of dust.

In the above embodiment, since the transmitting antenna 13 and the receiving antenna 14 are installed near the mandrel 7,
Although the timing at which the 30 strips begin is easily set, the present invention is not limited to this, and the antennas 13 and 14 may be installed at any other arbitrary positions. Further, the transmitting antenna 13 and the receiving antenna 14 may be installed so as to face each other at an angle other than facing each other from above and below the strip. Moreover, the present invention can of course be used to detect the tip of a strip for purposes other than winding by a down coiler.

<Effects of the Invention> According to the present invention, since the tip of the strip is detected from the transmission loss of microwaves, the strip tip can be detected with high reliability without requiring frequent maintenance even in the presence of dust, water, etc. The tip of the strip can be detected.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a strip tip detection device according to an embodiment of the present invention used in a down coiler, and FIG. 2 is a schematic configuration diagram of a conventional strip tip detection device used in a down coiler. In the drawing, 3 is a strip, 12 is a microwave oscillator, 13 is a transmitting antenna, 14 is a receiving antenna, and 15 is a level measuring device.

Claims (1)

[Claims] A detection device characterized in that a microwave transmitting antenna and a receiving antenna are installed facing each other across a traveling strip, and the tip of the strip is detected from the transmission loss of the microwave due to passage through the strip.