JPS58111779A - Passage detection of steel material - Google Patents

Abstract

PURPOSE:To detect the tip of steel material quickly and accurately by setting a threshold level from a noise signal before the passage of the steel material from an accelerometer provided on a bearing of a conveying roller. CONSTITUTION:An output of acceleration 3 is taken out when a conveying roller 4 reaches specified revolutions thereof while the lifting, turning and rotating thereof are completed before the tip of a steel material 1 reaches the roller 4. This output is fed to a peak value hold circuit 9 as noise signal transmitted from an accelerometer 3 before the passage of the steel material. Based on an output L0 of the hold circuit 9, a threshold level La is set for a comparator 10. As soon as the tip of the steel material comes in contact with the roller 4, an output P of the accelerometer 3 is generated to the comparator 10. Thus, the tip of the steel material can be detected quickly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for quickly and accurately detecting passage of the leading end of an object being transported by rollers.

Steel materials are usually conveyed by rollers. Steel materials include steel plates, shaped steel, steel bars, and wire rods, but these have relatively heavy electrical power and are transported at high speeds. The contact with him was shocking. In production or processing processes, it is desirable to quickly and accurately detect the passage of these steel materials, especially the arrival of the tip, in order to adjust between processes and automatically operate processing machines and processing machines when transporting these steel materials. A method conventionally used as this detection means is a method of detecting infrared rays from red-hot steel.

A method of detecting a steel material by shielding or reflecting the signals of a pair of transceivers facing each other or of the transceivers installed at reflection angles when the steel material passes, and the rise of the electric motor drive current of the conveyance roller of the steel material. There are methods to detect the rise of the load on the steel material conveyance rollers, etc., but the thermal detection method described above detects the temperature drop or scale adhesion at the tip of the steel material. Detection is impossible, and the optical detection method using a pair of transmitters and receivers is affected by the environment of the installation site, such as water vapor and cooling water, and is less reliable. Furthermore, in the drive current detection method, there is a delay time until the stain current rises due to a response delay of the control device or the electric motor, so that the detection is not quick. Further, the roller load detection method is effective for rolling rollers, but general conveyance rollers simply convey or nip, and it is difficult to obtain a load signal for steel materials.

Due to these problems, rapid and accurate detection is difficult with conventional methods. However, the method of attaching an accelerometer to the steel material conveyance roller and detecting the impact acceleration generated when the tip of the copper material collides with the roller is accurate and detectable because it detects the impact that occurs due to direct contact with the steel material. Since the acceleration signal itself is a differential signal of the amount of roller displacement due to contact with the steel material, □, □, 1. -c Yawaeka 11 eh □gai wo, eh.

On the other hand, since the accelerometer is installed directly connected to the bearing of the steel material conveyance roller, if the conveyance roller rotates due to play due to the gap between the bearing and the frame or vibration of the roller holding mechanism, the bearing will Dark vibrations occur in the acceleration signal and appear as noise in the acceleration signal. Further, the amplitude level of this noise signal changes depending on the number of rotations of the roller or replacement of the roller. Furthermore, if the roller accelerates, decelerates, ascends and descends, or rotates while passing the steel material, an impact acceleration greater than the impact acceleration due to contact with the steel material will occur, causing false detection. Furthermore, the impact acceleration that occurs during a collision is determined by the conveyance speed and mass of the collided material, so as shown in Figure 1, the impact acceleration X8 when a steel material with a fast conveyance speed makes contact is large, resulting in a high S/N ratio. However, for steel materials with slow conveyance speeds, the impact acceleration X8 at the time of contact is small, and this value may be smaller than the noise XN generated by roller rotation in high-speed conveyance materials, so the threshold for impact acceleration signal detection is Unable to maintain a constant level.

The present invention provides an accelerometer on the bearing of the roller that conveys the steel material in a process that requires rapid and accurate detection of the tip of the steel material, and the conveyance roller reaches a predetermined number of revolutions and moves up and down, turns, and rotates. The output of the accelerometer at the time of completion is taken out, and this output is used as a noise signal that is emitted by the accelerometer before passing the steel material. Based on this, a threshold level is set and the output changes due to the passing of the tip of the transported object. This is a method for detecting tip passage that takes advantage of the advantages of accelerometers and fundamentally solves the problems described in the previous section. An embodiment of the present invention will be described below with reference to the drawings. Figure 2~
In FIG. 4, reference numeral 1 denotes a steel material to be transported, which is transported in the direction of the arrow by any means. Reference numeral 6 denotes an accelerometer as a detector, which is attached to the side surface of the bearing of the pair of upper and lower pinch rollers 4. Further, reference numeral 2 denotes an auxiliary tip detector (HMD) attached to the front side of the pinch roller 4 in the steel material conveying direction.

The host computer 6 determines when the pinch roller 4 reaches at least a predetermined number of rotations before the tip of the steel material 1 passes through the pinch roller 4, and when the lifting and lowering of the pinch roller 4 is completed.
The gate circuit 8 is opened, and the noise emitted by the accelerometer 3 is input to the peak value hold circuit 9. The hold circuit 9 is operated by the noise N at any time as shown in the LO shown in FIG.
The maximum value of is rewritten and stored as a setting level signal, and the maximum value is output. Thereafter, when the tip of the steel plate 1 passes through the auxiliary detector 2 and the auxiliary detector 2 is activated, the gate circuit 8 is closed, the input of the noise signal from the accelerometer 3 is stopped, and one gate circuit 7 is opened. The signal from the accelerometer 3 is input to the comparator 10. On the other hand, the output Lo of the peak value hold circuit 9 mentioned above is multiplied by a coefficient by the setter 11 and set as the threshold level La of the comparator 1°.

Next, when the tip of the steel plate contacts the pinch roller 4 and the output P of the accelerometer 3 is input, the passing of the tip is detected when the output P of the accelerometer 3 is higher than the threshold level La set based on the noise signal N. At the same time, the peak value hold circuit 9 is reset to erase its outputs Lo and La.

In this invention, when the tip of the steel material collides with the conveyance roller or is bitten by the pinch roll, the noise signal Lo generated by each roll in a steady state is smaller than the level of the acceleration signal generated to each roll. The noise signal Lo is set by the setter 11 of the comparator 10 so that the noise signal Lo is not erroneously detected.
Since the coefficient is multiplied by , or the bias is added using an adder (not shown), there is no false detection due to noise, and it is possible to detect 100 passes of the tip of the steel material.In addition, the tip of the steel material can be detected using the accelerometer described above According to the device, 1) There is no need to change settings from the outside in response to changes in acceleration signal noise and acceleration generated at the time of collision due to the rotation speed of the conveyance roller, the speed of the steel material to be conveyed, or the state of the conveyance roller bearing.

2) Even under conveyance conditions where the S/N ratio of the acceleration signal is poor, a threshold level is set for each steel material, so the detection rate is high.

3) Detection starts from the point when no disturbance is input to the accelerometer, so there is no malfunction.

By using an accelerometer on the roller, the above-mentioned problem in detecting the passing of the tip of a conveyed object can be fundamentally solved, making it possible to quickly and accurately detect the tip of a steel material without sacrificing the advantages of the accelerometer. .

[Brief explanation of the drawing]

Fig. 1 is a graph of the noise signal level of the accelerometer attached to the roller and the impact acceleration level when passing the o-roller rotation speed, Fig. 2 is an installation diagram of the accelerometer, and Fig. 3 is the acceleration signal processing of the present invention. FIG. 4, which is an embodiment diagram of the circuit, is a schematic diagram of the acceleration signals before and after passing the steel material and the setting level according to the present invention. 1: Steel material to be detected 6: Host computer 2: Auxiliary detector 7: Acceleration signal gate circuit 3: Accelerometer
8=Noise signal gate circuit 4: Pinch roller
9 = Peak value hold circuit 5: Conveyance roller 1
0: Acceleration detection comparator 11: Coefficient setter Applicant: Nippon Steel Corporation

Claims (2)

[Claims] (1) When detecting the passage of the leading end of the transported object by the transport roller, an accelerometer is provided on the bearing of the roller that transports the transported object, and the transport roller detects the passing of the leading end of the transported object before the leading end of the transported object reaches the roller. Set the rotation speed to the specified rotation speed,
A method for detecting passage of a conveyed object, characterized in that after lifting, turning, and rotation are completed, the output of an accelerometer is obtained after that, and passage of the tip of the conveyed object is detected based on a change in this output. (2) The detection level of the passing acceleration signal of the leading end of the transported object is set based on the output signal taken out from the accelerometer before the leading end of the transported object passes. Method for detecting passage of conveyed objects.