JP6877098B2 - High-strength bolt tightening condition detection system and method - Google Patents

Description

The present invention relates to, for example, a high-strength bolt tightening state detection system and method for detecting a state after final tightening of high-strength bolts.

Conventionally, when detecting the state after the final tightening of high-strength bolts, the rotation angle of the nut with respect to the bolt center axis of the markings on the bolts, nuts, washers, and plates after the primary tightening can be measured with a divider or visually. Since the state of high-strength bolt tightening, such as the co-rotation of the nut and washer and the axial rotation of the bolt, was visually judged, inspection omissions and measurement errors were likely to occur, and the inspection took time and effort. Further, the method of visually measuring the rotation angle of the nut has a problem that an error is likely to be included.

FIG. 7 shows a state after the high-strength bolt is finally tightened. (1) is axial rotation, (2) is normal, and (3) is co-rotation. As shown in this figure, when marking 5 is applied to the high-strength bolt 1, nut 2, washer 3, and plate 4 after the primary tightening and the final tightening is performed, it is overlooked unless all of the co-rotation and axial rotation are carefully observed. It may end up.

On the other hand, as a conventional method of detecting looseness by marking bolts and nuts, for example, the method of Patent Document 1 is known. In this method, when checking for looseness of bolts that fasten structures, the bolts and the steel material of the bolt mounting part are marked in advance with paint with excellent weather resistance, and when checking for looseness of bolts, images are taken from the ground. From the image of the structure, the bolt portion is enlarged, and the looseness of the bolt to be inspected is determined by the deviation between the marking on the bolt and the marking on the steel material of the bolt mounting portion. However, with this method, it is not possible to detect the state of high-strength bolt tightening such as the co-rotation of the nut and washer and the axial rotation of the bolt. Further, it has not been shown that the rotation angles of a plurality of nuts are measured and used for calculating the average value and detecting the state of variation.

Japanese Unexamined Patent Publication No. 2005-3658

For this reason, there has been a demand for the development of a technique capable of detecting a high-strength bolt tightening state such as the co-rotation of a nut and a washer and the axial rotation of a bolt.

The present invention has been made in view of the above, and an object of the present invention is to provide a high-strength bolt tightening state detection system and method capable of detecting a high-strength bolt tightening state such as co-rotation and axial rotation. ..

In order to solve the above-mentioned problems and achieve the object, the high-strength bolt tightening state detection system according to the present invention sets the tightening state of the high-strength bolts tightened to the plate via the washer and the nut before tightening each. It is a system that detects using the markings on the plate, and it is a shooting means that captures the tightening state of the washer, nut, and high-strength bolt to the plate, and based on the captured image, the plate, washer, nut, and high-strength bolt. It is characterized by including a marking angle detecting means for detecting a marking angle for each of the markings applied to each of the above, and a determining means for determining a tightening state based on the detected marking angle.

Further, in another high-strength bolt tightening state detection system according to the present invention, in the above-described invention, the marking angle detecting means determines the central axis of the high-strength bolt based on the pintail fracture surface of the high-strength bolt in the captured image. It is characterized in that it detects bolts, nuts, washers and plates based on the calculated distance from the calculated central axis, and also detects the marking angle.

Further, in the other high-strength bolt tightening state detection system according to the present invention, in the above-described invention, the photographing means simultaneously photographs the tightening states of a plurality of high-strength bolts, and the marking angle detecting means has a plurality of high-strength bolts. The marking angle is detected for the bolt, and the determination means determines the tightening state of the plurality of high-strength bolts.

Further, in the other high-strength bolt tightening state detection system according to the present invention, in the above-described invention, the determination means calculates the difference between the marking angle of the plate and the marking angle of the nut for each high-strength bolt, and also as a whole. The average value is calculated, and if the difference between the calculated average value of all the bolts and the marking angle of each high-strength bolt is greater than or equal to the specified angle, it is determined that the variation in the nut rotation angle exceeds the specified specified range. It is characterized by having a variation determination portion of the nut rotation angle.

Further, in the other high-strength bolt tightening state detection system according to the present invention, in the above-described invention, the determination means causes co-rotation when the difference between the marking angles of the washer and the plate is equal to or more than a predetermined angle. It is characterized by having a co-rotation determination unit that determines that the engine is rotating.

Further, in the other high-strength bolt tightening state detection system according to the present invention, in the above-described invention, the determination means is around the axis when the difference between the marking angles of the high-strength bolt and the plate is equal to or more than a predetermined angle. It is characterized by having an axial rotation determination unit for determining that

Further, the method for detecting the tightened state of the high-strength bolt according to the present invention is a method of detecting the tightened state of the high-strength bolt tightened on the plate via a washer and a nut by using markings applied to each of them before tightening. There is a shooting step to shoot the tightening state of the washer, nut and high-strength bolt to the plate, and the marking angle for the markings applied to each of the plate, washer, nut and high-strength bolt based on the shot image. It is characterized by including a marking angle detection step to be detected and a determination step to determine a tightening state based on the detected marking angle.

According to the high-strength bolt tightening state detection system according to the present invention, the tightening state of the high-strength bolts tightened to the plate via the washer and the nut is detected by using the markings applied to each of them before tightening. There is a shooting means to photograph the tightening state of the washer, nut and high-strength bolt to the plate, and the marking angle for the markings applied to each of the plate, washer, nut and high-strength bolt based on the photographed image. Since it is provided with a marking angle detecting means for detecting and a determining means for determining a tightening state based on the detected marking angle, it is possible to detect a high-strength bolt tightening state such as co-rotation or axial rotation. Play.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the marking angle detecting means calculates the central axis of the high-strength bolt based on the pintail fracture surface of the high-strength bolt in the captured image. Since the bolt, nut, washer, and plate are detected and the marking angle is detected based on the calculated distance from the central axis, the marking angle can be detected with high accuracy.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the photographing means photographs the tightening states of a plurality of high-strength bolts at the same time, and the marking angle detecting means marks the plurality of high-strength bolts. Since the angle is detected and the determining means determines the tightening state of the plurality of high-strength bolts, it is possible to quickly determine the tightening state of the plurality of high-strength bolts.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the determination means calculates the difference between the marking angle of the plate and the marking angle of the nut for each high-strength bolt, and calculates the overall average value. When the difference between the calculated average value of all the numbers and the marking angle of each high-strength bolt is greater than or equal to a predetermined angle, it is determined that the variation of the nut rotation angle exceeds the predetermined specified range. Since it has an angle variation determination unit, it has an effect that the variation of the nut rotation angle can be efficiently determined.

Further, according to another high-strength bolt tightening state detection system according to the present invention, when the difference between the marking angles of the washer and the plate is greater than or equal to a predetermined angle, the determination means causes co-rotation. Since it has a co-rotation determination unit for determination, it has an effect that the co-rotation can be efficiently determined.

Further, according to another high-strength bolt tightening state detection system according to the present invention, when the difference between the marking angles of the high-strength bolt and the plate is greater than or equal to a predetermined angle, the determination means is rotated around the axis. Since it has an axial rotation determining unit for determining that the shaft is present, it has an effect that the axial rotation can be efficiently determined.

Further, according to the method for detecting the tightened state of the high-strength bolt according to the present invention, the tightened state of the high-strength bolt tightened on the plate via the washer and the nut is detected by using the markings applied to each of them before tightening. The method is a shooting step that captures the tightening of the washer, nut, and high-strength bolt to the plate, and markings on the plate, washer, nut, and high-strength bolt, respectively, based on the captured image. Since it includes a marking angle detection step for detecting an angle and a determination step for determining a tightening state based on the detected marking angle, it is possible to detect a high-strength bolt tightening state such as co-rotation or axial rotation, for example. It works.

FIG. 1 is a schematic block diagram showing an embodiment of a high-strength bolt tightening state detection system and method according to the present invention. FIG. 2 is a photographic diagram showing an area to be detected. FIG. 3 is a diagram showing a marking angle detection flow. FIG. 4 is a diagram showing a flow for determining variation in the nut rotation angle. FIG. 5 is a diagram showing a co-rotation determination flow. FIG. 6 is a diagram showing an axial rotation determination flow. FIG. 7 shows a state after the high-strength bolt is finally tightened, in which (1) is axial rotation, (2) is normal, and (3) is co-rotation.

Hereinafter, embodiments of a high-strength bolt tightening state detection system and method according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

The high-strength bolt tightening state detection system according to the present invention detects the tightening state of high-strength bolts tightened on a gusset plate (plate) via washers and nuts by using markings applied to each of them before tightening. It is a system. As shown in FIG. 1, the high-strength bolt tightening state detection system 10 according to the present invention is based on a photographing means 12 including a camera for photographing a washer, a nut, and a high-strength bolt tightening state with respect to a plate, and an image taken. The marking angle detecting means 14 for detecting the marking angle for the markings applied to the plate, the washer, the nut, and the high-strength bolt, and the determining means 16 for determining the tightening state based on the detected marking angle. Be prepared.

The marking angle detecting means 14 and the determining means 16 can be configured by using, for example, a computer having various arithmetic processing functions and a database. The determination means 16 includes a nut rotation angle variation determination unit 18, a co-rotation determination unit 20, and an axial rotation determination unit 22.

(Detection of marking angle for each part)
Next, the detection flow of the marking angle of each part by the marking angle detecting means 14 will be described.

FIG. 3 is a diagram showing a marking angle detection flow. In this flow, the marking angles of the bolt shaft, the nut, the washer, and the plate are detected by analyzing the image taken by the camera of the photographing means 12.

First, as shown in FIG. 2, after the pre-marked high-strength bolts are finally tightened, the inspection area R to be detected is photographed by the camera of the photographing means 12 to acquire a color image (step S11). In the example of the figure, a plurality of 4 × 9 = 36 high-strength bolts arranged in a grid pattern are fully tightened on the plate of the inspection area R.

Next, as shown in FIG. 3, the acquired color image is analyzed by a well-known image analysis processing method, and the positional relationship between the gusset plate and the high-strength bolt is detected. Further, the amount of deformation is calculated by comparing with the design dimensions recorded in advance in a database or the like, and the camera position is calculated from the posture of the camera body at the time of shooting (step S12). The posture of the camera body can be acquired by a posture sensor such as an IMU (Inertial Measurement Unit) provided in the body.

Next, the pintail fracture surface is color-identified, the shape is approximated by an ellipse in consideration of the amount of deformation of each bolt cross section, and the bolt position is specified (step S13). Since the pintail fracture surface of the high-strength bolt is located farthest from the plate surface, it is possible to take a picture of the entire cut surface without being shaded by other objects. Further, the color of the cut surface immediately after the pintail is broken has little variation, and is suitable for identification by a color sample of the pintail fracture surface previously recorded in a database or the like.

Next, the long side and the short side of the ellipse are detected by image analysis, and the intersection of them is calculated as the center position of each bolt (step S14).

Next, each bolt center position is calculated from the bolt arrangement position data recorded in advance in a database or the like, and each bolt center position is corrected (step S15).

Next, the central axis of each bolt is calculated by superimposing the three-dimensional shapes of bolts, nuts, and washers recorded in advance in a database or the like and the dimensional data (step S16).

Next, the bolt, the nut upper part, the nut side part, the washer upper part, the washer side part, and the plate part are identified by the distance from each bolt center axis, and the marking angle of each part is detected (step S17).

In steps S14 to S17 described above, the shooting position and posture of the camera body differ depending on the individual bolts, so they are calculated individually.

(Judgment of variation in nut rotation angle)
Next, the flow of determining the variation of the nut rotation angle by the variation determination unit 18 of the nut rotation angle will be described.

FIG. 4 shows a flow for determining variation in the nut rotation angle. As shown in this figure, after detecting the marking angles of the bolt, nut upper part, nut side part, washer upper part, washer side part, and plate based on the distance from the bolt center axis (step S21), the variation of the nut rotation angle is determined. The portion 18 calculates the difference A between the marking angle of the plate and the marking angle of the upper portion of the nut or the side portion of the nut for the total number of bolts (step S22). It is determined whether the difference between the average value of A and A of each bolt is within a predetermined angle (for example, ± 30 degrees) (steps S23 and S24), and if this condition is not satisfied, the nut rotation angle varies. It is determined that the predetermined range has been exceeded, and an alarm indicating this is issued via, for example, a monitor or a speaker provided in the computer (step S25).

(Judgment of co-rotation)
Next, the co-rotation determination flow by the co-rotation determination unit 20 will be described.

FIG. 5 shows a co-rotation determination flow. As shown in this figure, after detecting the marking angles of the bolt, the nut upper part, the nut side part, the washer upper part, the washer side part, and the plate from the distance from the bolt center axis (step S31), the co-rotation determination unit 20 , It is determined whether the difference between the marking angle between the upper part of the washer or the side part of the washer and the plate is within ± X degrees (steps S32 and S33). The judgment value X is set for each inspection. If this condition is not satisfied, it is determined that the rotation is co-rotation, and an alarm indicating the co-rotation is issued via, for example, a monitor or a speaker provided in the computer (step S34).

(Judgment around the axis)
Next, the axis rotation determination flow by the axis rotation determination unit 22 will be described.

FIG. 6 shows an axial rotation determination flow. As shown in this figure, after detecting the marking angles of the bolt, the nut upper part, the nut side part, the washer upper part, the washer side part, and the plate from the distance from the bolt center axis (step S41), the axis rotation determination unit 22 , It is determined whether the difference between the marking angles of the bolt and the plate is within ± Y degrees (steps S42 and S43). The judgment value Y is set for each inspection. If this condition is not satisfied, it is determined that the axis is around the axis, and an alarm indicating the axis is issued via, for example, a monitor or a speaker provided in the computer (step S44).

As described above, according to the present embodiment, it is possible to immediately detect the state such as the co-rotation and the axial rotation after the high-strength bolt is finally tightened on the spot. In addition, the state of a plurality of high-strength bolts and nuts can be detected at the same time in one shooting. Further, the detection accuracy can be improved by adjusting the shooting angle and the enlargement ratio with respect to the object and reacquiring the image data.

As described above, according to the high-strength bolt tightening state detection system according to the present invention, the tightening state of the high-strength bolts tightened to the plate via the washer and the nut is marked on each of them before tightening. It is a system that uses and detects, and it is applied to each of the plate, washer, nut, and high-strength bolt based on the photographed means to photograph the tightening state of the washer, nut, and high-strength bolt to the plate, and the photographed image. Since it is provided with a marking angle detecting means for detecting a marking angle for marking and a determining means for determining a tightening state based on the detected marking angle, for example, a high-strength bolt tightening state such as co-rotation or axial rotation is detected. be able to.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the marking angle detecting means calculates the central axis of the high-strength bolt based on the pintail fracture surface of the high-strength bolt in the captured image. Since the bolt, nut, washer, and plate are detected and the marking angle is detected based on the calculated distance from the central axis, the marking angle can be detected accurately.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the photographing means photographs the tightening states of a plurality of high-strength bolts at the same time, and the marking angle detecting means marks the plurality of high-strength bolts. Since the angle is detected and the determining means determines the tightening state of the plurality of high-strength bolts, the tightening state of the plurality of high-strength bolts can be quickly determined.

Further, according to another high-strength bolt tightening state detection system according to the present invention, the determination means calculates the difference between the marking angle of the plate and the marking angle of the nut for each high-strength bolt, and calculates the overall average value. When the difference between the calculated average value of all the numbers and the marking angle of each high-strength bolt is greater than or equal to a predetermined angle, it is determined that the variation of the nut rotation angle exceeds the predetermined specified range. Since it has an angle variation determination unit, it is possible to efficiently determine the variation in the nut rotation angle.

Further, according to another high-strength bolt tightening state detection system according to the present invention, when the difference between the marking angles of the washer and the plate is greater than or equal to a predetermined angle, the determination means causes co-rotation. Since it has a co-rotation determination unit for determination, co-rotation can be efficiently determined.

Further, according to another high-strength bolt tightening state detection system according to the present invention, when the difference between the marking angles of the high-strength bolt and the plate is greater than or equal to a predetermined angle, the determination means is rotated around the axis. Since it has an axial rotation determination unit that determines that the shaft rotation is present, the axial rotation can be efficiently determined.

Further, according to the method for detecting the tightened state of the high-strength bolt according to the present invention, the tightened state of the high-strength bolt tightened on the plate via the washer and the nut is detected by using the markings applied to each of them before tightening. The method is a shooting step that captures the tightening of the washer, nut, and high-strength bolt to the plate, and markings on the plate, washer, nut, and high-strength bolt, respectively, based on the captured image. Since a marking angle detection step for detecting the angle and a determination step for determining the tightening state based on the detected marking angle are provided, it is possible to detect a high-strength bolt tightening state such as co-rotation or axial rotation, for example.

As described above, the high-strength bolt tightening state detection system and method according to the present invention are useful for detecting, for example, the state after final tightening of high-strength bolts, and in particular, high-strength bolts such as co-rotation and axial rotation. Suitable for detecting the tightening state.

10 High-strength bolt tightening state detection system 12 Imaging means 14 Marking angle detection means 16 Judgment means 18 Nut rotation angle variation judgment unit 20 Co-rotation judgment unit 22 Axle rotation judgment unit

Claims (6)

It is a system that detects the tightened state of high-strength bolts tightened to the plate via washers and nuts using markings made before tightening each.
Photographing means to photograph the tightening state of washers, nuts and high-strength bolts on the plate,
A marking angle detecting means for detecting the marking angle of the markings applied to the plate, the washer, the nut, and the high-strength bolt based on the captured image.
A determination means for determining the tightening state based on the detected marking angle is provided.
The marking angle detecting means calculates the central axis of the high-strength bolt by color-identifying the pintail fracture surface of the high-strength bolt, and bases the high-strength bolt, nut, washer, and plate based on the calculated distance from the central axis. It detects and also detects the marking angle.
When calculating the central axis of a high-strength bolt with the marking angle detecting means, the shape of the color-identified pintail fracture surface is approximated by an ellipse, and the center of the approximated ellipse is calculated as the center position of the high-strength bolt. The feature is that the position is corrected based on the center position of the high-strength bolt calculated from the arrangement position data of the high-strength bolt recorded in advance, and the central axis of the high-strength bolt is calculated based on the corrected center position. High-strength bolt tightening state detection system. The shooting means is to shoot the tightened state of multiple high-strength bolts at the same time.
The marking angle detecting means detects the marking angle for a plurality of high-strength bolts.
The high-strength bolt tightening state detection system according to claim 1, wherein the determination means determines the tightening state of a plurality of high-strength bolts. The determination means calculates the difference between the marking angle of the plate and the marking angle of the nut for each high-strength bolt, and also calculates the overall average value, and the difference between the calculated average value of all the numbers and the marking angle of each high-strength bolt. The high force according to claim 2, further comprising a nut rotation angle variation determining portion for determining that the nut rotation angle variation exceeds a predetermined specified range when is greater than or equal to a predetermined angle. Bolt tightening detection system. Any of claims 1 to 3, wherein the determination means has a co-rotation determination unit that determines that co-rotation has occurred when the difference between the marking angles of the washer and the plate is equal to or greater than a predetermined angle. The high-strength bolt tightening state detection system described in one. Claims 1 to 4 are characterized in that the determination means has an axial rotation determining unit for determining that axial rotation has occurred when the difference between the marking angles of the high-strength bolt and the plate is equal to or greater than a predetermined angle. High-strength bolt tightening state detection system described in any one of. It is a method to detect the tightened state of high-strength bolts tightened to the plate via washers and nuts by using the markings applied to each before tightening.
Shooting steps to photograph the tightening state of washers, nuts and high-strength bolts on the plate,
A marking angle detection step that detects the marking angle for the markings on the plate, washer, nut, and high-strength bolt, respectively, based on the captured image.
A determination step for determining the tightening state based on the detected marking angle is provided.
The marking angle detection step calculates the central axis of the high-strength bolt by color-identifying the pintail fracture surface of the high-strength bolt, and bases the high-strength bolt, nut, washer, and plate based on the calculated distance from the central axis. It detects and also detects the marking angle.
When calculating the center axis of a high-strength bolt in the marking angle detection step, the shape of the color-identified pintail fracture surface is approximated by an ellipse, and the center of the approximated ellipse is calculated as the center position of the high-strength bolt. The feature is that the position is corrected based on the center position of the high-strength bolt calculated from the arrangement position data of the high-strength bolt recorded in advance, and the central axis of the high-strength bolt is calculated based on the corrected center position. How to detect the tightening state of high-strength bolts.

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