JP2834638B2 - Automatic thickness gauge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic thickness measuring apparatus for optically measuring the thickness of a plate-like object to be conveyed on a conveying line, and more particularly to a method for calibrating a reference distance.

[0002]

2. Description of the Related Art As is well known, an automatic plate thickness measuring device is a device for measuring a plate thickness by using a laser distance measuring type distance detector. There are a U-shaped (C-shaped gantry) and a ring-shaped (O-shaped gantry). The C-type mount is used to measure the thickness of only one side of the plate-shaped object to be measured by a one-point measuring device.
The type mount is mainly used in a multi-point measuring device for continuously measuring the thickness of the plate-shaped object to be measured on both the left and right sides and the central portion.

Next, an outline of the operation of a conventional automatic thickness measuring apparatus will be described with reference to FIG. FIG. 5 shows a C-type base 1
The operating principle of the device for point measurement is shown. In FIG. 5, a U-shaped pedestal 14 is provided on one side of a transport line 12 on which a plate-shaped measuring object 10 (10-1 and 10-2) is transported in the direction of an arrow by a roller 13 as the opposite end portion 14a. 14b are disposed above and below the transport line 12, and a distance detector (laser displacement meter) 18a and a laser detector 18b of a laser ranging type are provided on the opposite ends 14a and 14b. Each is attached toward the measured object 10.

The laser displacement gauges 18a and 18b emit laser light from their optical heads toward the side ends of the plate-like measurement object 10 moving on the transport line 12, receive the reflected light, and receive the plate-like measurement light. distance to the measurement object 10 (L _1, L ₂₎
Is measured. Reference numeral 11 denotes a trajectory of the plate thickness measurement, which is formed in parallel with a side edge of the plate-shaped measured object 10. Further, the distance L ₀ between the two optical heads is a predetermined value (reference distance).
Therefore, the plate thickness L of the plate-shaped measurement object 10 is obtained by Expression 1.

[0005]

L = L ₀ − (L ₁ + L ₂ )

Here, the reference distance L ₀ depends on the distance between the opposing ends of the gantry 14. However, as can be easily understood from the installation environment of the apparatus, the opposing end of the gantry 14 has a change in the environmental temperature or the like. There is an essential problem that it is directly affected by radiant heat or the like from the plate-like measurement object 10 and easily undergoes thermal deformation.

That is, assuming that the opposite end of the gantry 14 undergoes thermal deformation and the reference distance L ₀ changes to L ₀ ′, the plate thickness L ′ of the plate-like measured object 10 becomes A measurement error δ shown in FIG.

[0008]

[Number 2] _{L '= L 0' - (} L 1 + L 2)

[0009]

Δ = L′−L

Therefore, in order to maintain the reliability and to measure the thickness accurately, it is necessary to periodically calibrate the reference distance L ₀ to maintain the accuracy.
Calibration methods such as those disclosed in Japanese Patent Application Laid-Open No. 1605 and Japanese Utility Model Application Laid-Open No. 59-41711 have been proposed.

The calibration method proposed in the prior art is, for example, as shown in FIGS. 5 (c) and 5 (d), a calibration plate 28 whose plate thickness has been precisely measured in advance, The height is set to be substantially the same as that of the object to be measured 10, and the opposite ends 14 a and 14 b of the gantry 14 are allowed to enter and exit the transport line 12 as indicated by arrows in the drawing. The gantry 14 is configured to be slidable, and at the time of measurement, the gantry 14 is moved toward the transport line 12 to a position where the optical heads of the laser displacement gauges 18a and 18b can be opposed to the side ends of the plate-like measurement object 10 (FIG. 5). (C)) During calibration, the optical heads of the laser displacement gauges 18a and 18b are
The gantry 14 is moved in a direction away from the transfer line 12 (FIG. 5D) to a position where the gantry 14 can be opposed.

In this method, the thickness L _{S of the} calibration plate can be obtained from Equation 1 (Equation 4). Since this thickness L _S is a known value, the calibrated reference distance L ₀ is calculated from Equation 4 to Equation 5
Is required.

[0013]

L _S = L ₀ − (L ₁ + L ₂ )

[0014]

L ₀ = L _S + L ₁ + L ₂

[0015]

However, the calibration method proposed in the prior art is a method in which measurement and calibration are interrupted by moving the gantry to perform one of the other operations. It takes a considerable amount of time from the start to the start of the measurement work, and it cannot be said that this is a simple calibration method. The measurement target is a long plate at high temperature and is continuously exposed to high heat during the measurement. However, a method in which the measurement operation is interrupted and the calibration operation is performed cannot eliminate the influence during the measurement. In addition, there are various problems such as difficulty in application to a multi-point measurement device using an O-type gantry.

The present invention has been made in view of such a conventional problem, and has as its object to provide a means capable of calibrating in a short time without interrupting the measurement work and immediately reflecting the result in the measurement. Another object of the present invention is to provide an automatic thickness measuring apparatus.

[0017]

To achieve the above object, an automatic thickness measuring apparatus according to the present invention has the following configuration. That is, the automatic thickness measuring apparatus according to the first aspect of the present invention has a configuration in which distance detectors are arranged at predetermined reference distances above and below a transport line on which a plate-like measurement object is transported, respectively. An automatic thickness measuring device for measuring the thickness of the plate-shaped object based on the distance between the plate-shaped object and the plate-shaped object;
An end sensor that is provided above and / or below the transport line and optically detects the front and rear ends of the plate-like measurement object; and a calibration that is provided on one of the two distance detectors. A calibration mechanism comprising: a support having one end rotatably supported by the support; and a calibration plate fixed to the other end of the support; and the end sensor is a plate-like measurement object. In response to the detection of the rear end, the support plate is rotationally driven so that the calibration plate is located at the transport position of the plate-like measurement object and is interposed between the two distance detectors, and an end sensor is provided. Means for rotating the column so that the calibration plate is retracted to a position off the transport line in response to detecting the front end of the next plate-shaped measurement object; and The thickness of the calibration plate and the distance between the calibration plate and the Means for calibrating the reference distance using a distance to a detector; and responding to the end sensor detecting a front end of the next plate-like measured object. Means for updating a reference distance used for measurement with the calibrated reference distance.

An automatic thickness measuring apparatus according to a second aspect of the present invention is the automatic thickness measuring apparatus according to the first aspect of the present invention; a reference distance used in measurement of the plate-like measurement object and a reference obtained by a calibration operation after the measurement. When the difference value from the distance is equal to or more than a predetermined value, the difference value is proportionally distributed according to the measurement position in the longitudinal direction of the plate-like measurement object, and the reference distance corresponding to the measurement position is obtained, thereby obtaining the plate-like shape. Means for correcting the measured value of the thickness of the object to be measured.

The automatic thickness measuring apparatus according to the third invention is the automatic thickness measuring apparatus according to the first or second invention;
The distance detector is movable together with the calibration mechanism in a direction perpendicular to the transport direction of the plate-like measured object; and a reference distance is set for each unit movement distance; When the difference value between the reference distance obtained by the calibration operation immediately after the end and the set reference distance at the position of the distance detector at the end of the measurement is equal to or greater than a predetermined value, the difference value is determined in the length direction of the plate-shaped measuring object. Apportioned in accordance with the measurement position, each measurement using the apportioned value in the length direction and the set reference distance of each position where the distance detector moved from the start of measurement to the end of measurement of the plate-like measurement object Means for determining a reference distance corresponding to the position and correcting a measured value of the thickness of the plate-like measured object based on the reference distance.

[0020]

Next, the operation of the thus-configured automatic thickness measuring apparatus of the present invention will be described. The present invention focuses on the fact that there is a gap between the plate-shaped objects to be conveyed, and performs a calibration operation in the gap so that the measurement operation and the calibration operation can be performed alternately.

More specifically, as shown in FIG. 1, the plate-like measuring objects (A ₁ , A ₂ ,...) Are conveyed on a conveying line with a certain gap therebetween. DUT A
_When the rear end of ₁ is detected, the calibration plate is set to rotate on the transport line until the front end of the next plate-shaped measuring object A ₂ is detected, and the reference plate is set at the same time interval as the measurement, for example. Perform the calibration operation to find the distance. Then, when detecting the front end portion of the plate-shaped object to be measured A _2, until detecting the rear end portion of the plate-shaped object to be measured A _2, normal measuring operation in a state of being rotated retracted calibration plate from the conveyor line do. The measurement operation is performed using the reference distance at the end of the calibration operation.

In short, the measurement operation and the calibration operation are performed alternately, and the calibration value can be immediately reflected in the measurement operation. Therefore, the influence of the temperature change of the installation environment and the radiant heat from the plate-shaped object to be measured are considered. It can be minimized and the measurement accuracy can be maintained and improved. It is clear from the configuration that the calibration system according to the present invention can be easily applied to the O-type gantry as well as the C-type gantry.

The second invention is suitable for the case where the plate-shaped object to be measured is long and it is necessary to take thermal deformation into consideration during the period from the front end to the rear end. The present invention is a configuration suitable for a case where a plate-like measurement object is installed obliquely on a transport line.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. Since the basic electrical configuration of the automatic thickness measuring apparatus is well known, illustration and description thereof will be omitted, and the description will focus on the portion relating to the present invention, that is, the calibration method of the present invention. This clarifies the configuration of the part added according to the present invention.

FIGS. 2 to 4 show the calibration method of the present invention.
Various aspects when applied to the apparatus of the mold stand are shown. Note that the same components as those in the related art (FIG. 5) are given the same reference numerals.

In FIG. 2, reference numeral 15 denotes an O-type base,
The transport line 12 is set horizontally near the center of the gantry 15, and the plate-like measurement objects (10-1 and 10-2) are transported as in the related art.

In the upper frame portion and the lower frame portion of the gantry 15,
Distance detectors (laser displacement meters) 18 (18a, 18b) are respectively set at positions corresponding to both side ends and the vicinity of the center of the plate-like measurement object. That is, this is a case of three-point measurement, and the above is the same as the conventional case.

In the present invention, as shown in FIG.
An end sensor 16 is provided on the frame of the gantry 15 in the vicinity of the central laser displacement meter among the laser displacement meters. The end sensor 16 optically detects the front and rear ends of the plate-like measurement object.

In this embodiment, as shown in FIG.
The light emitter 16a is provided on the upper frame of the gantry 15 and the light receiver 16 is provided on the lower frame.
b is provided, and the time when the optical path is not blocked by the plate-like measured object and light can be received is defined as the time when the front and rear ends can be detected. Whether it is the front end portion or the rear end portion can be determined at either the start or end of the measurement operation.

When the reflected light is used to detect the front and rear ends of the plate-like measured object when there is no reflected light, both the light projector and the light receiver are connected to the upper frame and the lower frame of the frame 15. It may be set to either one.

In the present invention, for example, FIG.
(C) As shown in (d), a calibration mechanism (support 26, calibration plate 27) is provided near each of the three laser displacement meters 18b attached to the lower frame of the gantry 15.

The support 26 has one end rotatably supported by the lower frame of the gantry 15. Although not shown, this rotation drive is performed by a motor. The calibration plate 27 is fixed to the other end of the column 26. It is a plate member of a predetermined size whose plate thickness has been precisely measured in advance.

This calibration mechanism is operated as follows. That is, the end sensor 16 has detected the rear end of the plate-shaped measured object 10-1, that is, the gap between the plate-shaped measured objects 10-1 and 10-2 in the illustrated example. In response to the detection, the column 26 is rotationally driven so that the calibration plate 27 is located at the transport position of the plate-like measured object and is interposed between two corresponding laser displacement gauges. In short, prop 26
Is of such a suitable length. With such a configuration, a multi-point measurement device can be easily attached.

As a result, as shown in FIG. 2D, the calibration plate 27 is set at the same height position as the plate-like measured object 10-2. Thick L
Calibration operation of the reference distance L ₀ using _S is performed. The measurement interval may be the same as that at the time of the measurement operation or a different interval, but this calibration operation is repeated until the end sensor 16 detects the front end.

Next, when the front end of the plate-shaped object to be measured 10-2 reaches the position where the gantry 15 is disposed, and the end sensor 16 detects it, the calibration plate 27 responds to the detection and the calibration plate 27 moves. Post 2 so that it can retreat to a position off of 12
6 is rotationally driven. As shown in FIGS. 2B and 2C, the plate thickness measurement operation is performed on the plate-shaped measurement object 10-2.

As described above, the calibration mechanism rotates the calibration plate 27 on the transport line during the passage of the gap between the plate-shaped test objects, and performs calibration during the passage of the plate-like test object. The plate 27 is rotated and retracted, and the calibration operation and the measurement operation are alternately repeated as shown in FIG.

Here, in the present invention, when the end sensor 16 detects the front end of the plate-shaped measuring object 10-2 and ends the calibration operation, it is used for the measurement of the plate-shaped measuring object 10-2. The reference distance is updated with the reference distance obtained at the end of the calibration operation performed immediately before. As a result, basically, the influence of the temperature change of the installation environment and the radiation heat from the plate-like measurement object can be minimized, and the measurement accuracy can be maintained and improved.

However, for example, when the object to be measured is long and the minimization of the influence of radiant heat or the like is insufficient, a correction means as shown in FIG. 3 may be provided. That is, to detect the difference value between the thickness reference distance measurement starts when the updated set of L ₀ and the reference distance L ₀ obtained in the first round of the calibration operation is started after the plate thickness of the end of measurement ', the The difference value σ is a predetermined value σ ₀
In the above case, the difference value is proportionally divided by the number of measurements N in the length direction of the plate-like measured object, and the reference distance L _0n used for the thickness measurement at n points in the length direction is expressed as L _0n = L ₀₊ (σ / N) · n, thereby correcting the measured thickness of the plate-shaped object. Since this correction operation can be performed during the period of the calibration operation, it does not hinder the measurement of the thickness of the next plate-shaped measurement object.

In general, the plate-shaped object to be measured is positioned so as to be set substantially in parallel along the transport line. However, when such a positioning mechanism is not provided,
For example, as shown in FIG. 4A, there is a case where the plate-shaped measured object 10 is set so as to be inclined with respect to the transport line 12. In such a case, it is preferable to provide a correction unit as shown in FIG.

That is, in FIG. 4A, the left base 1
5 shows the position before measurement and the right frame 15 shows the position after measurement, respectively. As shown in the figure, the laser displacement gauge 18 and the corresponding calibration mechanism are movably mounted on the frame of the frame 15, and The target object can be moved in the direction Y perpendicular to the transport direction (the reverse direction is the measurement direction X), and a reference distance (design value) is set and set for each unit movement distance.

As is well known, the measurement of the plate thickness is generally performed by using FIG.
The measurement is performed so as to be parallel to the side edge of the plate-like measured object as shown by a locus 11 in (a). The same applies to the case where the plate-like measurement object is skewed. However, in the case shown in FIG. 4A, the so-called skew tracking in which the laser displacement gauge 18 is moved so that the locus of the measurement position becomes 11. Adopt it because the mechanism is already known. Roughly speaking, the oblique angle sensor detects the oblique angle of the plate-like object to be measured, and moves the laser displacement gauge 18 according to the oblique angle.

[0042] Now, a measurement operation, as shown in FIG. 4 (b), the measurement operation is terminated at the position P _0Y from here begins at position P ₀₀ was appropriately distance in the Y direction. Reference distance at the start of measurement is a value L ₀₀ obtained at the calibration operation is completed,
The measurement operation performed by the calibrated reference distance L _00. However, although the calibrated reference length L ₀₀ can be effectively used only at the start of measurement, then the thickness measurements not become the correct reference distance measurement will include errors.

Therefore, the set reference distance at the position P _0Y where the thickness measurement ends is L _0Y , but the reference distance obtained in the first calibration operation starting from the position P _0Y is L _0Y. ′, The difference value between the two is detected, and when the difference value σ is equal to or greater than the predetermined value σ ₀ , the difference value is proportionally divided by the number of measurements N in the length direction X of the plate-like measured object, The reference distance L _xy used in the thickness measurement at the position P _xy determined by the y point in the Y direction and the x point in the X direction is calculated as L _xy = L _0y using the set reference distance L _0y of the y point.
+ (Σ / N) · x, thereby correcting the measured value of the thickness of the plate-like measured object. Since this correction operation can be performed within the period of the calibration operation as in the case of FIG. 3, there is no hindrance to the next measurement of the plate thickness of the plate-like measurement object.

The correction means shown in FIG. 4 may be used together with the correction means shown in FIG.

[0045]

As described above, the automatic thickness measuring apparatus of the present invention focuses on the fact that there is a gap between the conveyed plate-shaped measuring objects, performs a calibration operation in the gap, and performs a measuring operation. And the calibration operation can be performed alternately, and the calibration value can be immediately reflected in the measurement operation.This minimizes the effects of temperature changes in the installation environment and radiant heat from the plate-like measurement object. This has the effect of maintaining and improving accuracy. In addition, the calibration method of the present invention has an effect that it can be easily applied to O-type gantry as well as C-type gantry. In the case where the plate-like measured object is long and it is necessary to consider thermal deformation during a period in which measurement from the front end to the rear end is performed, the plate-like measured object is configured as in the second invention. In the case where is installed obliquely on the transport line, there is an effect that it can be appropriately configured according to the characteristics of the measurement object, such as the configuration of the third invention.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the operation principle of the automatic thickness measuring apparatus of the present invention.

FIG. 2 is an explanatory diagram of a specific configuration and operation for realizing alternate execution of a calibration operation and a measurement operation performed in the automatic thickness measuring apparatus of the present invention.

FIG. 3 is an explanatory diagram of a correcting operation of the automatic thickness measuring apparatus of the present invention.

FIG. 4 is an explanatory diagram of a correction operation of the automatic thickness measuring apparatus of the present invention.

FIG. 5 is an operation explanatory view of a conventional automatic thickness measuring apparatus.

[Explanation of symbols]

Reference Signs List 10 (10-1, 10-2) Plate-shaped object to be measured 11 Locus of plate thickness measurement 12 Conveyance line 15 Mount 16 End sensor 16a Projector 16b Receiver 18 (18a, 18b) Distance detector (laser displacement meter) 26 Prop 27 Calibration plate A ₁ , A ₂ Plate object

Claims (3)

(57) [Claims] 1. A distance detector is disposed above and below a transport line on which a plate-shaped measuring object is conveyed with a predetermined reference distance therebetween, and a distance between the reference distance and distance detector and the plate-shaped measuring object is set. In an automatic thickness measuring apparatus for measuring the thickness of a plate-shaped object to be measured based on the distance between them; optically provided front and rear ends of the plate-shaped object to be measured which are provided above and / or below a transport line; An end sensor for detecting a distance between the first and second distance detectors; a support mechanism rotatably supported by the support body at one end; A calibration mechanism having a calibration plate to be fixed; and wherein the calibration plate is at a transport position of the plate-like measurement object in response to the end sensor detecting a rear end of the plate-like measurement object. The column is driven to rotate between two distance detectors, and Means for rotating the column so that the calibration plate is retracted to a position off the transport line in response to detecting the front end of the next plate-shaped measurement object; and Means for calibrating the reference distance using the thickness of the calibration plate and the distance between the calibration plate and the distance detector during a period in which the body is at the transport position;
Means for updating a reference distance used for measurement on the plate-like measured object with the calibrated reference distance in response to the end sensor detecting the front end of the next plate-like measured object. An automatic thickness measuring apparatus. 2. The automatic thickness measuring apparatus according to claim 1, wherein a difference value between a reference distance used in measurement of the plate-like measurement object and a reference distance obtained by a calibration operation after the measurement is predetermined. If the difference is greater than or equal to the value, the difference value is proportionally distributed according to the measurement position in the length direction of the plate-like measured object, and the reference distance corresponding to the measurement position is obtained, thereby measuring the plate thickness of the plate-like measured object. Means for correcting a value; 3. The automatic thickness measuring apparatus according to claim 1, wherein the distance detector is movable together with the calibration mechanism in a direction perpendicular to a transport direction of the plate-like measurement object. A reference distance is set for each unit movement distance; the difference between the reference distance obtained by the calibration operation immediately after the end of the measurement of the plate-like measurement object and the set reference distance at the position of the distance detector at the end of the measurement. When the value is equal to or greater than the predetermined value,
The difference value is apportioned according to the measurement position in the length direction of the plate-like measured object, and the apportioned value in the length direction and the distance detector are measured from the start of the measurement of the plate-like measured object to the end of the measurement. Means for respectively determining a reference distance corresponding to each measurement position using the set reference distance of each moved position, and thereby correcting a plate thickness measurement value of the plate-like measured object. Automatic plate thickness measuring device.