JPH0781841B2 - Thickness measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a thickness measuring apparatus using laser light.

[Conventional technology]

When measuring the thickness, it is normal to measure it with a ruler with scales on both sides of the object to be measured, or contact with contactors such as calipers, but it is sent continuously. When measuring an object (for example, a plate) or the like, it is difficult to measure by such a method.

Therefore, as shown in FIG. 5, the object 10 to be measured is
Laser displacement gauges 11 and 12 are arranged on both sides of the plate at a predetermined interval (A) using laser light, and the distance (B ₁ ,
Thickness (T) by measuring the B _2), since the _{T = A-B 1 -B 2} , is considered to be capable of continuously measuring the thickness in a non-contact state.

[Problems to be solved by the invention]

However, when the above theory is actually applied to a thickness measuring device for steel plates or stainless steel plates used in steel mills, etc., there is a width in the measurement object and there are vibrations around it. There is a problem in that a deviation occurs due to bending and vibration of the member, which causes a measurement error.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a thickness measuring device capable of accurately measuring the thickness of an object even when vibration or bending occurs.

[Means for solving problems]

The thickness measuring device according to claim 1, which is in line with the above object, comprises a non-contact type displacement gauge provided above and below a horizontally arranged plate which is an object to be measured, and the upper and lower non-contact type displacement gauges or the non-contact type displacement gauge. The upper and lower light passing type optical axis position detectors are respectively provided on the mounts for mounting the contact type displacement gauges, and the upper and lower light passing type optical axis position detectors are centrally provided to face each other on both sides thereof. Upper and lower laser light oscillators, and upper and lower light-receiving type optical axis position detectors that respectively receive laser beams from the laser light oscillators, and a sensor that measures the lateral movement of the non-contact type displacement gauge provided opposite to each other. A vertical distance between the upper and lower laser light oscillators, a vertical distance between the upper and lower laser lights measured by the upper and lower light-receiving type optical axis position detectors, and the upper and lower non-contact types measured by the sensor. Displacement gauge The lateral distance to the laser light oscillator and the light-receiving optical axis position detector, the vertical distance to the plate respectively measured using the upper and lower non-contact displacement meters, and the upper and lower light-passing light. Based on the vertical displacement amount of the laser light measured by the axial position detector, the vertical height of each of the upper and lower light-passing type optical axis position detectors and the corresponding upper and lower non-contact type displacement gauges. The thickness of the plate is measured.

Here, the non-contact type displacement meter means a device capable of measuring the distance to the object without directly contacting the object, and specifically, there is a displacement meter using a laser beam or the like.

[Action]

The thickness measuring device according to claim 1 is provided with non-contact type displacement gauges facing each other on both sides in the thickness direction of the plate to be measured, that is, upper and lower sides, and the absolute position of each non-contact type displacement gauge is measured. An optical passage type optical axis position detector is attached to each of the non-contact type displacement gauges or their mounts, and a laser light oscillator and a light receiving type optical axis position detector are attached to both sides thereof.

Therefore, even if the position of the light passing type optical axis position detector shifts due to vibration, bending, etc., or even if the position of the laser light oscillator shifts, the shift of the laser light is measured by the light receiving type optical axis position detector. , The non-contact type displacement meter can detect the position deviated from the regular position, and the absolute distance of the non-contact type displacement meter is measured by this, and the plate surface of each non-contact type displacement meter is measured from this value. By subtracting the distance up to, the thickness of the plate will be accurately measured.

〔Example〕

Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

Here, FIG. 1 is a schematic configuration diagram of a thickness measuring device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a laser displacement meter used in the device, and FIG. 3 is an optical diagram used in the device. FIG. 4 is a schematic configuration diagram of a transmission type optical axis position detector, and FIG. 4 is a schematic configuration diagram of an optical transmission type optical axis position detector according to another embodiment.

As shown in FIG. 1, a thickness measuring device 15 according to an embodiment of the present invention includes a laser displacement gauge 17, which is an example of a non-contact displacement gauge provided on an upper portion and a lower portion of a plate 16 to be measured,
18 and the optical transmission type optical axis position detectors 19 and 20 provided on the mounts of the laser displacement gauges 17 and 18, respectively, and the optical transmission type optical axis position detectors 19 and 20 that are provided on opposite sides of the optical transmission type optical axis position detectors 19 and 20, respectively It is configured to include laser light oscillators 21 and 22 and light receiving type optical axis position detectors 23 and 24. These will be described in detail below.

As shown in FIG. 2, the laser displacement meter 17 (same as 18) includes a light emitting diode 25 for emitting a laser beam, a condenser lens 26 arranged in front of the light emitting diode 25, and a light receiving lens 27 for collecting reflected light. , A position detection element (PSD element or one-dimensional CCD) 28, detects a spot of laser light projected on the surface of the plate 16 to be measured as a displacement on the position detection element 28, and a displacement coordinate processing circuit 28a. Vertical distance from laser displacement gauge 17, 18 to plate 16 through W ₁ (same for W ₂ )
Is output as an electric signal.

The gantry 29, 30 of the laser displacement meter 17, 18 is provided with a light-passing type optical axis position detector 19, 20, but the optical axis center m _{1 of} the light-passing type optical axis position detector 19, 20 is m ₂ has a distance of X ₁ and X ₂ (that is, a vertical height) from the measurement reference position of the laser displacement gauges 17 and 18.

The light passing type optical axis position detector 19 (same for 20) is provided with a half mirror 31 arranged on the optical axis as shown in FIG. 3, and the light reflected by the half mirror 31 to receive the optical axis. A mirror 32 that reflects light orthogonal to the, and a position detection element 33 that receives the light of the mirror 32 and measures the amount of displacement of the optical axis,
The vertical displacements e ₁ and e ₂ from the optical axis centers m ₁ and m _{2 of the} laser light can be electrically measured.

The laser light oscillators 21 and 22 for generating the laser light are D ₁
Are arranged with a vertical distance of, a gas laser is used in this embodiment, but a semiconductor laser can also be used, and a light-receiving optical axis position detector 23 that receives this laser light, 24 is composed of a condenser lens and the position detection element described above, and measures the displacement with respect to the reference position,
The vertical distance D ₂ of the laser light received by the light receiving type optical axis position detectors 23 and 24 can be measured.

On the other hand, a pedestal provided with the non-contact type displacement gauges 17 and 18
29 and 30 are placed on rails (not shown) and are always
16 non-contact displacement gauges at the upper and lower points in the plate thickness direction 17,
As 18 measures, it can move laterally synchronously while holding its position.

Then, this lateral movement amount is measured by a sensor (not shown), and as shown in FIG.
And the light receiving type optical axis position detector 23
It is designed to measure L ₁ and L ₂ .

The outputs of the position detecting elements 28, 33, etc. are subjected to displacement coordinate processing and then input to the microcomputer, which is an example of a control device, together with the measured values.

Therefore, the laser light irradiation interval P at the positions of the light passing type optical axis position detectors 19 and 20 is P = (L ₁ D ₁ + L ₂ D ₂ ) / (L ₁ L ₂ ). From the values, (e ₁ + X ₁ + W ₁ ) and (e ₂ + X ₂ +
If W ₂ ) is subtracted, the plate thickness t is obtained by the following equation, and this calculation is performed by the microcomputer and displayed on the printer or the display.

t = P- (e ₁ + X ₁ + W ₁ ) and (e ₂ + X ₂ + W ₂ ) ... FIG. 4 shows a light passage type optical axis position detector 34 according to another embodiment.
Shows a half mirror tilted at 45 degrees as shown
The reflected light 35 is detected by a position detection element (PSD, linear array) 36.

〔The invention's effect〕

As is apparent from the above description, the thickness measuring device according to claim 1 accurately measures the plate thickness even if the mounting position of the non-contact displacement gauge fluctuates from the reference position due to vibration or bending of the gantry. Can be measured.

Then, even if the position and angle of the laser light emitted from the laser light oscillator fluctuates, this can be corrected and the correct plate thickness can be measured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a thickness measuring device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a laser displacement meter used in the device, and FIG. 3 is a light-transmitting light used in the device. FIG. 4 is a schematic configuration diagram of an axial position detector, FIG. 4 is a schematic configuration diagram of an optical passage type optical axis position detector according to another embodiment, and FIG. 5 is a schematic configuration diagram of a thickness measuring device which is the basis of the present invention. is there. [Explanation of symbols] 15 …… Thickness measuring device, 16 …… Plate, 17, 18 …… Laser displacement meter (non-contact displacement meter), 19, 20 …… Light passing type optical axis position detector, 21, 22 ...... Laser light oscillator, 23, 24 …… Receiving type optical axis position detector, 25 …… Light emitting diode, 26 …… Condensing lens, 27 …… Receiving lens, 28 …… Position detecting element, 29,
30 …… Stand, 31 …… Half mirror, 32 …… Mirror, 33…
… Position detection element, 34 …… Light-transmitting optical axis position detector, 35…
… Half mirror, 36 …… Position detector

Claims (1)

[Claims] 1. Non-contact type displacement gauges 17, 18 provided on the upper and lower sides of a horizontally arranged plate 16 which is an object to be measured, and the upper and lower non-contact type displacement gauges 17, 18 or the non-contact type. Displacement gauge 17, 18
The upper and lower light passing type optical axis position detectors 19 and 20 respectively provided on the mounts 29 and 30 to be mounted, and the upper and lower light passing type optical axis position detectors 19 and 20 respectively on the both sides of the center. The upper and lower laser light oscillators 21, 22 provided facing each other and the upper and lower light-receiving type optical axis position detectors 23, 24 respectively receiving the laser light from the laser light oscillators 21, 22 are provided so as to face each other. And a sensor for measuring the lateral movement of the non-contact displacement gauges 17, 18, the vertical distance D ₁ between the upper and lower laser light oscillators 21, 22 and the upper and lower light-receiving type optical axis position detectors 23, 24. The vertical distance D ₂ of the upper and lower laser beams measured by the laser light oscillators 21 and 22 of the upper and lower non-contact type displacement gauges 17 and 18 and the light receiving type optical axis position detector measured by the sensor.
Horizontal distances L ₁ and L ₂ up to 23 and 24, and vertical distances W ₁ and W ₂ to the front and back surfaces of the plate 16 measured using the upper and lower non-contact displacement gauges 17 and 18, respectively, Corresponding to the vertical displacement amounts e ₁ and e _{2 of the} laser light measured by the upper and lower light passing type optical axis position detectors 19 and 20, and the upper and lower light passing type optical axis position detectors 19 and 20. The upper and lower non-contact displacement meters
The plate based on the vertical height X ₁ , X _{2 of} 17 and 18, respectively
Thickness measuring device characterized by measuring 16 thicknesses