JPH11179635A - Clamp confirming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clamp confirming device whereby a clamped condition of a workpiece in a rotatable manual clamp device can be surely detected. SOLUTION: In a device, a reference plate 3, a tightening plate 5, and tightening bolt/nut 6, 7 connecting both the reference plate 3 and the tightening plate 5 are provided, by tightening in the tightening nut 7, a clamp device 10 is provided so as to clamp a workpiece 9 between the reference plate 3 and the tightening plate 5, a clamped condition of the workpiece 9 in the clamp device 10 is confirmed. The device is provided with a camera means 11 photographing the tightening bolt/nut 6, 7 to obtain an analog image data related thereto, an A/D converter means 14 converting the analog image data into a digital image data, an image data memory means 15 storing the digital image data, a characterized data extracting means 16 calculating a characteristic data related to the tightening bolt 6 and/or the tightening nut 7 based on the digital image data stored in the image data memory means, and a discrimination means 17 discriminating a clamped condition of the workpiece 9 from the calculated characteristic data. As compared with visual confirmation by a worker, an error is eliminated, the clamped condition of the workpiece 9 can be surely discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a reference plate and a tightening plate, a tightening bolt and a tightening nut for connecting the reference plate and the tightening plate, and tightening the tightening nut. The present invention relates to a clamp confirmation device for confirming a clamping state of the work in a clamping device provided to clamp the work between the reference plate and the clamping plate.

[0002]

2. Description of the Related Art For example, in the case of processing an outer peripheral surface of a cylindrical portion of a deformed work having a cylindrical portion (hereinafter referred to as a "deformed work"), or a deformed work having a large inner diameter portion. When processing the inner diameter portion, it is easier to perform the processing using a lathe, rather than using a machine tool using a rotating tool such as a machining center, and the deformed workpiece is processed with high precision. It is conventionally known that this is possible. As a device for fixing the work to the main shaft of the lathe in this case, for example, a clamp device as shown in FIG. 7 has been conventionally used.

[0003] As shown in FIG.
Are a face plate 2 fixed to an end of a spindle 1 of a lathe, a reference plate 3 suspended from the face plate 2, a support 4 suspended from the reference plate 3, and one end at the tip of the support 4 Are fastened to each other by a pin or the like, and are provided so as to be swingable in a direction of being separated from and brought into contact with the reference plate 3 around the joint, and the reference plate 3 penetrating through the fastening plate 5. A tightening bolt 6 vertically suspended above, a tightening nut 7 screwed into the tightening bolt 6 and tightened to make the tightening plate 5 approach the reference plate 3 side; And a spring 8 which is externally fitted to the tightening bolt 6 between the first and second tightening plates 5 and biases the tightening plate 5 in a direction away from the reference plate 3.

In order to clamp the work 9 by the clamping device 10 having the above-described structure, first, the work piece 9 is clamped between the end of the clamping plate 5 on the opposite side of the support 4 and the reference plate 3. After the work 9 is placed on the work piece, the tightening nut 7 is rotated to the tightening side. As a result, the clamping plate 5 is swung about the joint portion in a direction approaching the reference plate 3, and the work 9 is sandwiched between the reference plate 3 and the clamping plate 5. On the other hand, when the clamped work 9 is unclamped, the tightening nut 7 is rotated in a loosening direction.
As a result, the clamping plate 5 is swung in the direction away from the reference plate 3 by the biasing force of the spring 8 to increase the interval between the reference plate 3 and the clamping plate 5, whereby the work 9 can be removed. become able to.

As described above, when a deformed work is machined by a lathe, a manual clamping device that does not use power has been conventionally used instead of a clamping device driven by power such as hydraulic pressure. This is because the clamping device described above rotates together with the main shaft of the lathe, and it is structurally difficult to supply power such as hydraulic pressure to the clamping device.

[0006] The manual clamping device described above is inexpensive as compared with a clamping device driven by power. Therefore, not only machining using a lathe but also machining using a machining center is performed on a table. It is widely used as a means for fixing a workpiece to a workpiece.

[0007]

If the clamping of the work in the clamp device described above is insufficient, the work is detached from the clamp device due to cutting resistance or the like during processing, and the work itself or the work is performed by the work. This causes problems such as damage to the machine. In particular, a manual clamping device is liable to cause a human error and to cause such a problem.

For this reason, it is particularly required in the manual clamping device to automatically detect whether or not the work is sufficiently clamped without using any artificial means.

However, in the case of a clamp device used for a lathe, as described above, the clamp device rotates with the main shaft of the lathe. Therefore, according to the existing detector using a detector such as a proximity switch, the clamp device is not used. There is a problem that the wiring cannot be taken out, and this cannot be adopted, and an actual clamp confirmation device in the clamp device used in the lathe has not been developed yet.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a clamp confirmation device capable of reliably detecting a clamping state of a work even in a manual clamp device which rotates itself.

[0011]

Means for Solving the Problems and Effects There is provided an invention according to claim 1 of the present invention for solving the above-mentioned problems, in which a reference plate and a clamping plate are connected to each other. A clamping bolt and a clamping nut are provided, and the clamping state of the workpiece is confirmed by a clamping device provided to clamp the workpiece between the reference plate and the clamping plate by tightening the clamping nut. An apparatus for imaging an image of the tightening bolt and the tightening nut to obtain analog image data related to the tightening bolt and the tightening nut, and an A / D converter for converting the analog image data into digital image data Means, image data storage means for storing the digital image data, and characteristic data of the tightening bolts and / or nuts based on the digital image data stored in the image data storage means. Feature data extraction means for calculating,
A determination unit configured to determine a holding state of the workpiece from the calculated characteristic data.

According to the clamp device, the work is clamped between the reference plate and the tightening plate by tightening the tightening nut screwed into the tightening bolt. Therefore, by detecting the tightening state of the tightening nut, the clamping state of the work can be confirmed. That is, if the tightening nut is tightened to the tightening bolt by a predetermined amount or more, it can be determined that the work is sufficiently clamped by the reference plate and the tightening plate, and the tightening nut is in place. If not fixedly fixed, it can be determined that the clamping of the workpiece by the reference plate and the clamping plate is insufficient.

According to the present invention, the screwing state of the tightening bolt and the tightening nut is detected by the imaging means, the A / D conversion means, the image data storage means and the characteristic data extraction means, and the obtained detection result is obtained. Since the holding state of the work is determined by the determination means based on the above, the holding state of the work can be reliably determined without errors compared to the conventional worker's visual check.

Further, the clamp confirmation device can be separated from the clamp device and provided at a position remote from the clamp confirmation device.
The above-described wiring problems associated with the rotation of the clamp device together with the main shaft of the lathe do not occur, and
It is also possible to prevent malfunction of the clamp confirmation device due to the adhesion of chips and the like.

According to a second aspect of the present invention, in the first aspect of the present invention, the feature data extracting unit inputs the digital image data from the image data storage unit and binarizes the digital image data. And a bolt extracting unit for extracting image data of the tightening bolt portion protruding from the tightening nut portion from the image data binarized by the binarizing unit, and the extracted tightening bolt portion A shape value calculating unit that calculates the area or length of the image of the tightening bolt portion as a shape value from the image data of (a), the discriminating unit presets the shape value calculated by the shape value calculating unit. When the shape value is equal to or more than the reference value, it is determined that the work is held. On the other hand, when the shape value is less than the reference value, the work is sufficiently held. It is intended to determine that is not.

The tightening state of the above-mentioned tightening nut can be determined by the length or area of the tightening bolt protruding from the tightening nut, whereby the state of clamping the work can be determined. In other words, if the tightening nut is tightened by a predetermined amount or more with respect to the tightening bolt and the tightening bolt projects beyond a predetermined length or area from the tightening nut, the work is sufficiently held by the reference plate and the tightening plate. If the tightening nut is not tightened by the specified amount and the protruding length or area of the tightening bolt protruding from the tightening nut is less than the specified length or area, the standard It can be determined that the work and the clamping plate have insufficient clamping of the work.

Therefore, in the present invention, the image data obtained by imaging by the imaging means is binarized in a binarizing section, and the obtained binary image data is used for the tightening projecting from the tightening nut. The image data of the bolt portion is extracted by the bolt extracting unit, and the length or area of the image of the tightening bolt portion is calculated as the shape value by the shape value calculating unit from the extracted image data of the tightening bolt portion. On the basis of the obtained shape values, the gripping state of the work is determined by the determining means. It should be noted that the present invention has the same effect as the first aspect of the present invention.

According to a third aspect of the present invention, in the first aspect of the present invention, the characteristic data extracting means inputs the digital image data from the image data storing means,
A binarization unit for binarizing the digital image data, and a bolt extraction for extracting image data of the tightening bolt projecting from the tightening nut from the image data binarized by the binarization unit And a shape value calculating unit that calculates the number of threads in the image of the tightening bolt portion as a shape value from the extracted image data of the tightening bolt portion, and wherein the determination unit performs the shape value calculation. The shape value calculated by the unit is compared with a preset reference value, and if the shape value is equal to or more than the reference value, it is determined that the workpiece is held, while the shape value is less than the reference value. If so, it is determined that the work is not sufficiently clamped.

The tightening state of the tightening nut described above can be determined by the number of threads of the tightening bolt projecting from the tightening nut, and thereby the state of clamping of the work can be determined. That is, if the number of threads of the tightening bolt protruding from the tightening nut is equal to or more than a predetermined number, it is determined that the work is sufficiently clamped. If the number of threads is less than the predetermined number, the work is insufficiently clamped. Can be determined.

Therefore, according to the present invention, the image data obtained by the image pickup means is binarized in a binarizing section, and the obtained binary image data is used to obtain a tightening protruding from the tightening nut. The image data of the bolt portion is extracted by the bolt extraction unit, and from the extracted image data of the fastening bolt portion, the shape value calculation unit calculates the number of threads of the fastening bolt portion as the shape value, and the calculated shape value Based on
The determination means determines the state of holding the workpiece. It should be noted that the present invention has the same effect as the first aspect of the present invention.

According to a fourth aspect of the present invention, there is provided a clamp mark having a brightness different from that of the tightening bolt or the tightening nut according to the first aspect of the present invention, the size of which varies depending on the tightening state of the tightening nut. Is provided on the tightening bolt or the tightening nut, and the imaging unit is configured to image the tightening bolt, the tightening nut, and the clamp mark, and the feature data extracting unit is configured to store the image data from the image data storing unit. A binarization unit that inputs the digital image data and binarizes the digital image data, and a mark extraction unit that extracts image data of the clamp mark unit from the image data binarized by the binarization unit And a shape value calculation unit that calculates the area or length of the image of the clamp mark portion as a shape value from the extracted image data of the clamp mark portion. The determination unit compares the shape value calculated by the shape value calculation unit with a preset reference value, and determines that the workpiece is held if the shape value is equal to or greater than the reference value. On the other hand, if the shape value is less than the reference value, it is determined that the work is not sufficiently held.

According to the present invention, the same effects as those of the first aspect of the invention can be obtained.

According to a fifth aspect of the present invention, in the invention of the second, third or fourth aspect, the discriminating means determines the shape value calculated by the shape value calculating section as an upper reference value and a lower reference value which are set in advance. If the shape value is equal to or greater than the lower reference value and equal to or less than the upper reference value, it is determined that the workpiece is held, while the shape value is greater than the upper reference value or the lower reference value. If it is smaller, it is determined that the work does not exist or that the work is not sufficiently clamped.

Some of the above-mentioned human mistakes in clamping work include insufficient clamping of the work,
An error corresponding to a so-called “poka”, in which the tightening nut is tightened without mounting the work itself on the clamp device, is also included. When the tightening nut is tightened without mounting the work on the clamp device, the tightening nut is tightened more than when the work is mounted on the clamp device and the tightening nut is normally tightened. Therefore, the shape value calculated by the shape value calculation unit is larger than a value in a normal state.

According to this invention, the discriminating means sets two reference values, an upper reference value and a lower reference value, and if the calculated shape value falls within the range between the lower reference value and the upper reference value, the discriminating means normally operates. It is determined that the workpiece is clamped, and if the shape value is smaller than the lower reference value, it is determined that the workpiece is not
When the shape value is larger than the upper reference value, it is determined that the work does not exist. Therefore, in addition to the case where the work is not properly held, the artificial work corresponding to the so-called “poka” described above is performed. Mistakes can also be detected.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing a partial block diagram of an overall configuration of a clamp confirmation device and a clamp device according to a first embodiment of the present invention. As shown in the figure, the clamp checking device according to the present embodiment is configured to check the clamping state of the work 9 in the clamp device 10 mounted on the spindle 1 of the NC lathe. It should be noted that the clamp device 10 has the same configuration as the conventional clamp device 10 shown in FIG. 7 described above. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the clamp checking device according to the present embodiment includes a CCD camera 11 which obtains a gray-scale image by imaging the tightening bolt 6 and the tightening nut 7 of the clamp device 10, and a tightening bolt. An illumination device 12 for illuminating a portion relating to 6 and the fastening nut 7, and a clamp confirmation means 13 for processing (shading) image data obtained by imaging with the CCD camera 11 to determine a clamping state of the work 9. It becomes. Also, the tightening bolt 6, the tightening nut 7
The color of the fastening plate 5 is steel (silver), while the color of the background is black, so that the two can be clearly distinguished in lightness. I have.

The clamp confirmation means 13 is an A / D conversion means 1 built in the numerical control device 21 of the NC lathe.
4, image data storage means 15, feature data extraction means 16
And determination means 17. Hereinafter, the details of each means will be described.

The A / D conversion means 14 is for inputting analog image data obtained by imaging by the CCD camera 11 and converting it into digital image data, and the image data storage means 15 is for A / D conversion. The digital image data converted by the conversion means is stored in a two-dimensional array.

The characteristic data extracting means 16 inputs the digital image data stored by the image data storing means 15 and processes the digital image data to calculate the characteristic relating to the tightening bolt 6 and the tightening nut 7 as a shape value. As shown in FIG. 1, the binarizing unit 18 and the screw extracting unit 19
And each unit of the shape value calculation unit 20.

The binarizing section 18 inputs the (shaded) image data stored in the image data storage means 15 and converts it into binary data of "0" and "1" at a preset threshold value. In this example, the threshold value is set to an intermediate value between a steel color (silver), which is the color of the tightening bolt 6, the tightening nut 7, and the tightening plate 5, and a black color, which is the color of the background portion. The image data is binarized so that the density is set and the portions of the tightening bolt 6, the tightening nut 7, and the tightening plate 5 become "1" and the background portion becomes "0". . FIG. 2 shows the binary image converted by the binarizing unit 18 in this manner.

FIG. 2 shows the obtained binary image in an XY coordinate system, in which the axial direction of the main shaft 1 is the X axis, the axial direction of the tightening bolt 6 is the Y axis, and The upper left pixel of the image is set as the origin of the XY coordinate system. In the XY coordinate system, an arbitrary pixel is represented by F (X, Y), and when the size of the binary image is M × N, the lower right pixel of the binary image is F (M−1, N-1). A, which is the background portion of the binary image represented by such an XY coordinate system,
The value of each pixel F (X, Y) of the portion B regarding the fastening bolt 6, the fastening nut 7, and the fastening plate 5 is "1". It has become.

The screw extracting section 19 extracts image data on a portion where the tightening bolt 6 protrudes from the tightening nut 7 from the binary image data converted by the binarizing section 18. As shown in FIG. 2, the width of the obtained binary image in the X-axis direction is clearly different in each part of the tightening bolt 6, the tightening nut 7, and the tightening plate 5. Therefore, the width of the binary image is calculated by sequentially scanning in the X-axis direction, and the pixels having the calculated image width in a specific range are extracted, thereby extracting image data relating to the protruding portion of the tightening bolt 6. be able to. In this example, scanning is performed in the X-axis direction while sequentially changing Y from 0 to N−1, and the number of pixels Na having a value of “1” is calculated, and the number of pixels Na is 0 <Na
For Y such that <Ns, “1” in the line
Is extracted. Here, Ns is a threshold value for separating the tightening bolt 6 portion and the tightening nut 7 portion. In this example, Ns is an intermediate value between the outer diameter of the tightening bolt 6 and the width across flats of the tightening nut 7. The number of pixels corresponds to the length.

The shape value calculator 20 calculates the maximum value Ymax in the Y-axis direction and the minimum value Y in the image (FIG. 3) of the tightening bolt 6 extracted by the screw extractor 19.
min is calculated, the difference between the obtained Ymax and Ymin is calculated, and the length of the image in the Y-axis direction is calculated as a shape value.

The discriminating means 17 includes the shape value calculating section 2
The shape value calculated according to 0 is input and compared with a preset reference value. If the shape value is equal to or more than the reference value, it is determined that the work 9 is sufficiently held, while the shape value is determined as the reference value. If the value is less than the value, it is determined that the work 9 is not sufficiently held.

As described above, the clamp device 10 clamps the work 9 between the reference plate 3 and the tightening plate 5 by tightening the tightening nut 7 screwed to the tightening bolt 6. is there. Accordingly, if the tightening nut 7 is tightened to the tightening bolt 6 by a predetermined amount or more and the tightening bolt 6 protrudes from the tightening nut 7 by a predetermined length or more, the workpiece 9 is fixed by the reference plate 3 and the tightening plate 5. Can be determined to be sufficiently clamped, while the tightening nut 7 is not tightened by the predetermined amount and the length of the tightening bolt 6 protruding from the tightening nut 7 is less than the predetermined length. It can be determined that the work 9 is not sufficiently held by the reference plate 3 and the fastening plate 5. Therefore, the discriminating means 17 compares the shape value representing the length of the tightening bolt 6 protruding from the tightening nut 7 with a preset reference value. Are determined to be sufficiently clamped, while if the shape value is less than the reference value, it is determined that the work 9 is not sufficiently clamped.

As described above, the clamp confirmation means 1
Numeral 3 is incorporated in a numerical control device 21 for controlling the operation of the spindle 1 and the like, and the numerical control device 21 controls the operation of each part of the NC lathe based on the detection result of the clamp confirmation means 13. ing. That is, when it is confirmed by the clamp confirming means 13 that the work 9 is sufficiently held by the clamp device 10, the NC lathe is controlled so as to process the work 9, and conversely, the work 9 is sufficiently processed. When it is confirmed that the workpiece 9 is not pinched, the NC lathe is controlled so that the workpiece 9 is not processed.

According to the clamp checking device according to the present embodiment having the above configuration, the tightening bolt 6 and the tightening nut 7 of the clamp device 10 are imaged by the CCD camera 11,
The clamping state of the workpiece 9 can be determined by processing the obtained image data by the clamp confirmation unit 13. That is, since the state of holding the work 9 can be confirmed without using any artificial means, it is possible to reliably determine the state of holding the work 9 without errors, as compared with the case of visual confirmation by an operator.

Further, the clamp confirmation device is connected to the clamp device 1.
0, the clamp device 10 does not cause a wiring problem due to the rotation of the clamp device 10 together with the main shaft 1. Further, the clamp confirmation device may be provided at a position distant from the clamp device. Accordingly, it is possible to prevent chips and the like from adhering to the CCD camera 11, thereby preventing malfunction of the clamp checking device.

As described above, the numerical controller 21
The lathe is controlled based on the discrimination result of the clamp confirming device. When the work 9 is sufficiently clamped, machining is performed. When the work 9 is not sufficiently clamped, an alarm is output without performing the machining. With such control, it is possible to prevent machining in a state where the work 9 is insufficiently clamped, and to prevent damage to the work 9 and a lathe, etc., which occur when machining is performed in a state where the work 9 is insufficiently clamped. can do.

In this embodiment, the tightening bolt 6, the tightening nut 7
And the color of the fastening plate 5 is steel (silver) and the background color is black so that the two are clearly distinguished from each other. However, the present invention is not limited to this, and only the fastening bolt 6 is made of steel.
The fastening nut 7, the fastening plate 5, and the background may be black. By doing so, the binary image data obtained by the processing by the binarizing unit 18 directly shows the tightening bolt 6 protruding from the tightening nut 7, so that the subsequent processing by the screw extracting unit 19 This facilitates efficient clamp confirmation processing.

In this embodiment, the clamping state of the work 9 is detected based on the length of the tightening bolt 6 protruding from the tightening nut 7. However, this point is not limited to such a detecting method. By detecting the area of the tightening bolt 6 protruding from the mounting nut 7 or the number of threads, the tightening state of the tightening nut 7, that is, the clamping state of the work 9 can be detected.

In order to detect the clamping state of the work 9 from the area of the tightening bolt 6 projecting from the tightening nut 7, first, the binary value of the tightening bolt 6 portion extracted by the screw extracting unit 19 is detected. Based on the image data, the shape value calculation unit 20 indicates the tightening bolt 6 part, that is, the number of pixels whose value is “1” is counted and the area thereof is calculated. By comparing a preset reference value with the area calculated by the shape value calculation unit 20, if the calculated area is equal to or larger than the reference value, it is determined that the work is sufficiently clamped, and the calculated area is set to the reference value. If it is below, it is configured to judge that the work 9 is insufficiently held.

On the other hand, when the clamping state of the work 9 is detected by detecting the number of threads of the tightening bolt 6 protruding from the tightening nut 7, first, the screw extracting unit 19 is used.
Based on the binary image data of the part of the tightening bolt 6 extracted by
The number of threads of the portion is calculated as a shape value, and the discriminating means 17 compares a preset reference value with the number of threads calculated by the shape value calculation unit 20 to determine the number of threads as a reference. If the number is equal to or greater than the reference value, it is determined that the work is sufficiently held.
Is determined to be insufficient.

The calculation of the number of threads in the shape value calculating section 20 can be performed, for example, by the following procedure.

First, as shown in FIG. 3, based on the binary image data of the tightening bolt 6 extracted by the bolt screw extracting section 19, the binary image data is changed from Ymin to Ymax and sequentially scanned in the X direction. After calculating the coordinates of the pixel located at the center in the X direction among the pixels that are “1” for the value of the line, these are averaged, and the center axis coordinates Xc of the binary image are calculated.
Is calculated.

Next, coordinates X1 and X2 of a position corresponding to the effective diameter of the screw are calculated for the binary image. The coordinates X1 and X2 can be calculated by the following equations, where X is the length corresponding to the effective diameter of the tightening bolt 6 obtained in advance, and X1 = Xc-e / 2 and X2 = Xc + e / 2.

Next, the coordinates X1 and X2 are scanned in the Y direction, and the number of times the pixel value changes from "0" to "1" is counted, and the number of threads K1, K2 is calculated.
Is calculated. Then, K1 and K2 are averaged to obtain the above 2
This is the number of threads in the value image.

(Second Embodiment) Next, a second embodiment according to the present invention will be described with reference to FIGS.

FIG. 4 is a perspective view partially showing the overall structure of the clamp checking device and the clamp device according to the second embodiment of the present invention in a block diagram, and FIG. 5 is a view from the direction of arrow C in FIG. It is the elements on larger scale which show the fastening bolt and the fastening nut which were seen. As shown in FIGS. 4 and 5, in the present embodiment, the functions of the mark extracting unit 33, the shape value calculating unit 34 and the determining unit 32 of the clamp checking unit 31, and the point that the clamp bolt 30 is provided with the clamp mark 30 is provided. Are different from the first embodiment only, and the rest of the configuration is the same as the first embodiment. Therefore, in the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, the clamp mark 3
Numeral 0 is attached to the tightening bolt 6 along the axial direction of the tightening bolt 6. For example, a groove is formed in the axial direction of the tightening bolt 6, and the bottom surface of the groove is coated with black paint. By applying, the clamp mark 30 can be attached to the tightening bolt 6.

In this embodiment, the fastening bolt 6, the fastening nut 7, the fastening plate 5, and the background are set to have a steel color. As a result, the image data captured by the CCD camera is binarized by the binarization unit 18 so that the clamp mark 30 is represented by "0" and the rest is represented by "1". It becomes value image data. The exposed area of the clamp mark 30 increases as the tightening nut 7 is tightened.

The mark extraction unit 33 extracts image data relating to the clamp mark 30 represented by “0” from the binary image data processed by the binarization unit 18 and calculates the shape value. The section 34 calculates the area of the image as the shape value from the image data of the clamp mark 30 extracted by the mark extracting section 33.

The discriminating means 32 inputs the shape value calculated by the shape value calculating section 34 and compares it with a preset reference value. While it is determined that
If the shape value is less than the reference value, it is determined that the work 9 is not sufficiently held.

As described above, the clamp device 10 clamps the work 9 between the reference plate 3 and the tightening plate 5 by tightening the tightening nut 7 screwed to the tightening bolt 6. is there. Therefore, if the tightening nut 7 is tightened to the tightening bolt 6 by a predetermined amount or more and the clamp mark 30 is exposed by a predetermined area, the work 9 is sufficiently held by the reference plate 3 and the tightening plate 5. On the other hand, if the tightening nut 7 is not tightened by a predetermined amount and the exposure of the clamp mark 30 is less than a predetermined area, the work 9 by the reference plate 3 and the tightening plate 5 can be determined. Can be determined to be insufficient. Therefore, the discriminating means 32 compares the shape value representing the exposed area of the clamp mark 30 with a preset reference value,
If the shape value is equal to or more than the reference value, it is determined that the work 9 is sufficiently held, while if the shape value is less than the reference value, it is determined that the work 9 is not sufficiently held.

As described above, according to the present embodiment, as in the first embodiment described above, it is possible to check the clamping state of the work 9 without using any artificial means. There is no error as compared with the visual confirmation, and the holding state of the work 9 can be reliably determined. Also,
The other effects are the same as those in the first embodiment.

In the present embodiment, focusing on the fact that the exposed area of the clamp mark 30 changes according to the amount of tightening of the tightening nut 7, the clamping state of the work 9 is determined based on the magnitude of the exposed area. However, as a matter of course, the clamp mark 3 exposed according to the tightening amount of the tightening nut 7 is
Since the length in the longitudinal direction of 0 also changes, the shape value calculation unit 34
In the configuration, the length of the binary image in the longitudinal direction may be calculated as a shape value, and the determination unit 32 may determine the sandwiching state of the work 9 based on the calculated value.

Further, since the tightening nut 7 is to be tightened by being rotated, the tightening nut 7
The tightened state can be determined by detecting the rotational state of the. In this case, for example, as shown in FIG. 6, a clamp mark 35 is provided on one side surface of the tightening nut 7, the clamp mark 35 is imaged by the CCD camera, and the above-described series of processing is performed. The holding state can be determined. That is, 2 of the clamp marks 35 extracted by the mark extraction unit 33.
Since the value image changes according to the rotation state of the tightening nut 7, the area of the image is calculated by the shape value calculation unit 34, and the calculated area is compared with the reference value by the discriminating means 32, thereby clamping the work 9. The state can be determined. Note that the clamp mark 35 may be a character, a figure, or the like.

Although the embodiments of the present invention have been described in detail, it goes without saying that specific embodiments of the present invention are not limited to these embodiments. In particular, it is possible to perform a process in which the above-described first embodiment and the second embodiment are combined. In addition, the clamp marks 30 and 35 in the second embodiment are tightened respectively. It may be attached to the bolt 6 and the tightening nut 7 to perform a process combining the two.

Further, the discriminating means 1 in the first embodiment
7 and the discriminating means 32 in the second embodiment compares the shape value calculated by the shape value calculation units 20 and 34 with a preset upper reference value and lower reference value, and determines that the shape value is equal to or greater than the lower reference value. If the shape value is larger than the upper reference value or smaller than the lower reference value, it is determined that the work 9 is not sandwiched. You may comprise so that it may judge that the said workpiece | work 9 is not clamped enough. When the tightening nut 7 is tightened without mounting the work 9 on the clamp device 10, the tightening is performed more than when the work 9 is mounted on the clamp device 10 and the tightening nut 7 is normally tightened. Since the nut 7 is tightened, the shape value calculated by the shape value calculation units 20 and 34 is larger than a value in a normal state. Therefore, by detecting this, it is also possible to detect a human error corresponding to so-called “pocha”, in which the tightening nut 7 is tightened without mounting the work 9 itself on the clamp device 10.

Needless to say, the shape of the work 9 to be detected in the present invention is not particularly limited. Is included.

[Brief description of the drawings]

FIG. 1 is a perspective view partially showing a block diagram of an entire configuration of a clamp confirmation device and a clamp device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing binary image data obtained by processing by a binarizing unit;

FIG. 3 is an explanatory diagram showing binary image data extracted by a bolt extraction unit.

FIG. 4 is a perspective view showing a partial block diagram of an overall configuration of a clamp confirmation device and a clamp device according to a second embodiment of the present invention.

FIG. 5 is an explanatory view showing a clamp mark attached to a tightening bolt.

FIG. 6 is an explanatory view showing a clamp mark attached to a tightening nut.

FIG. 7 is a perspective view showing a conventional clamping device.

[Explanation of symbols]

 Reference Signs List 6 Tightening bolt 7 Tightening nut 11 CCD camera 12 Illumination device 13, 31 Clamp confirmation unit 14 A / D conversion unit 15 Image data storage unit 16 Feature data extraction unit 17, 32 Judgment unit 18 Binarization unit 19 Screw extraction unit 20, 34 shape value calculation unit 21 numerical controller 30, 35 clamp mark 33 mark extraction unit

Claims (5)

[Claims] 1. A reference plate and a tightening plate, and a tightening bolt and a tightening nut for connecting the reference plate and the tightening plate. The tightening nut tightens the reference plate and the tightening plate. What is claimed is: 1. An apparatus for confirming a clamping state of a work in a clamping device provided to clamp the work between the clamping bolt and a clamping plate, wherein the clamping bolt and the clamping nut are imaged, and the clamping bolt and the clamping nut are imaged. Imaging means for obtaining analog image data, A / D conversion means for converting the analog image data into digital image data, image data storage means for storing the digital image data, and digital data stored in the image data storage means A feature data extracting means for calculating feature data on the tightening bolt and / or the tightening nut based on the image data; and Clamping confirmation device comprising a discriminating means for discriminating the lifting state. 2. A binarizing unit for inputting the digital image data from the image data storage unit and binarizing the digital image data, wherein the feature data extracting unit binarizes the digital image data. A bolt extracting unit that extracts image data of the tightening bolt portion protruding from the tightening nut portion from the extracted image data, and an image of the tightening bolt portion based on the extracted image data of the tightening bolt portion. A shape value calculation unit that calculates an area or a length as a shape value, wherein the determination unit compares the shape value calculated by the shape value calculation unit with a preset reference value, and the shape value is 2. The method according to claim 1, wherein if the shape value is less than the reference value, it is determined that the work is not sufficiently held. Pump verification device. 3. A binarization unit for inputting the digital image data from the image data storage unit and binarizing the digital image data, wherein the feature data extraction unit binarizes the digital image data. From the extracted image data, a bolt extracting unit that extracts image data of the tightening bolt portion protruding from the tightening nut portion, and the number of threads is calculated as a shape value from the extracted image data of the tightening bolt portion. The shape value calculating unit, wherein the determination unit compares the shape value calculated by the shape value calculating unit with a preset reference value, and if the shape value is equal to or more than the reference value, the work The clamp confirmation device according to claim 1, wherein it is determined that the workpiece is not clamped, while if the shape value is less than the reference value, the workpiece is determined not to be clamped sufficiently. 4. A clamp mark having a brightness different from that of the tightening bolt or the tightening nut, the size of which varies depending on a tightened state of the tightening nut, is provided on the tightening bolt or the tightening nut. The imaging means captures the tightening bolt, the tightening nut, and the clamp mark, and the feature data extracting means inputs the digital image data from the image data storing means and converts the digital image data. A binarizing unit for binarizing, a mark extracting unit for extracting image data of the clamp mark unit from the image data binarized by the binarizing unit, and a clamp unit for extracting the clamp mark unit from the extracted image data of the clamp mark unit A shape value calculation unit that calculates the area or length of the image of the mark part as a shape value, wherein the determination unit calculates the shape or the length by the shape value calculation unit. Comparing the shape value with a preset reference value, it is determined that the work is held if the shape value is equal to or greater than the reference value, while the work is determined if the shape value is less than the reference value. The clamp confirmation device according to claim 1, wherein the clamp confirmation device determines that the clamp is not sufficiently held. 5. The method according to claim 1, wherein the determination unit compares the shape value calculated by the shape value calculation unit with a preset upper reference value and a lower reference value, and the shape value is equal to or greater than a lower reference value; If the work value is equal to or less than the upper reference value, it is determined that the work is held, while if the shape value is larger than the upper reference value or smaller than the lower reference value, the work does not exist or the work is not sufficiently provided. The clamp confirmation device according to claim 2, wherein the clamp confirmation device determines that the clamp is not held.