KR102230165B1 - Fine metric crack gauge - Google Patents

Abstract

The present invention relates to a crack gauge for detecting cracks in a concrete structure, and constitutes a moving plate 40 and an inhibiting plate 24 on the inner plate 10 and the outer plate 20, which are overlapping plates constituting the crack gauge, respectively, The distal end of the inhibiting plate 24 is in close contact with the inclined surface 41 formed on one side of the moving plate 40 so that the moving plate 40 can be activated according to the relative movement of the inner plate 10 and the outer plate 20, thereby cracking This is to enable immediate and minute confirmation of the state of fluctuations.
Through the present invention, it is possible to quickly, simply and accurately grasp the fluctuation of the crack area of the structure to which the crack gauge is attached, thereby improving the accuracy, efficiency, and convenience of safety diagnosis work for concrete structures including crack inspection.

Description

Micro-measurement type crack gauge {FINE METRIC CRACK GAUGE}

The present invention relates to a crack gauge for detecting cracks in a concrete structure, and constitutes a moving plate 40 and an inhibiting plate 24 on the inner plate 10 and the outer plate 20, which are overlapping plates constituting the crack gauge, respectively, The distal end of the inhibiting plate 24 is in close contact with the inclined surface 41 formed on one side of the moving plate 40 so that the moving plate 40 can be activated according to the relative movement of the inner plate 10 and the outer plate 20, thereby cracking This is to enable immediate and subtle confirmation of the state of fluctuations.

Cracks are a key indicator in determining the integrity of a concrete structure, and by detecting the size, location and progress of the crack, the stability and performance of the concrete structure can be grasped.

In particular, changes in crack conditions over time are essential information in diagnosing the long- and short-term safety of a structure, and in most concrete structures, periodic detection of crack occurrence points is performed.

Periodic detection of cracks in concrete structures is performed by attaching a crack gauge to the cracking area and observing it, and this crack gauge is a measuring instrument composed of a pair of plates that overlap each other, and is a related prior art patent No. 2083255. Etc. are mentioned.

Conventional crack gauges, including Patent No. 2083255, are composed of a pair of plate bodies that overlap each other, as shown in FIG. 1, and an inner plate 10 with a surface 92 marked and an outer plate of a transparent material marked with a leader line 93 ( 20), and a fixing part 91 is formed at the rear end of each of the inner plate 10 and the outer plate 20, and these fixing parts 91 are attached to the surface of the concrete structure to be inspected through an adhesive or the like.

That is, as shown in Fig. 1, by attaching crack gauges to both surfaces of the crack occurrence point of the concrete structure, the inner plate 10 is fixed on the surface of the structure at a point slightly spaced in one direction orthogonal to the linear crack. Attach the part 91, and attach the fixing part 91 of the outer plate 20 to the surface of the structure at a point slightly spaced in the other direction orthogonal to the linear crack, but the surface of the front end of the inner plate 10 (92) The display portion and the display portion of the indicator line 93 at the front end of the outer plate 20 overlap each other.

Therefore, by periodically checking the position of the indicator line 93 of the outer plate 20 overlaid on the surface of the surface 92 of the inner plate 10, it is possible to grasp the change with time of the crack width, and thereby, the expansion rate of the crack and whether the allowable value has been reached. Etc. can be checked.

As such, the conventional crack gauge as shown in FIG. 1 has the advantage of being able to accurately grasp the progress of cracks generated in the concrete structure even with a relatively simple configuration consisting of a pair of plate bodies, but checks the expansion of the crack width. It has a limit that depends entirely on the visual inspection of the inspector.

That is, the conventional crack gauge visually reads the position of the indicator line 93 indicated on the transparent outer plate 20 on the surface of the surface 92 indicated on the inner plate 10 at the overlapping portion of the inner plate 10 and the outer plate 20 The fluctuations of cracks are detected in such a way that the fluctuations of cracks in general concrete structures are inevitably very small, so it is impossible for the inspector to directly grasp the small fluctuations of cracks from a distance. Actual measurement is possible only when observing properly or using auxiliary means such as a magnifying glass.

Therefore, it can be said that the conventional crack gauge can be normally operated only in a situation where close observation of an inspector is premised, and this causes various problems as follows.

First of all, in the conventional crack gauge, the position of the indicator line 93 on the surface 92 must be visually confirmed by the inspector, and there is inevitably a limit to its accuracy in reading the crack fluctuation width measurement value. If the amount of fluctuation is insignificant, there is a problem that measurement itself is impossible.

That is, in the conventional crack gauge, the position of the indicator line 93 on the surface 92 is visually read through a magnifying glass while the inspector is close to the crack gauge. Not only is it difficult to check accurately, but also requires detailed observation by mobilizing auxiliary devices such as a magnifying glass throughout the measurement process, which takes a considerable amount of time and requires a high level of skill.

In particular, in the case of large-scale structures, separate crack gauges need to be installed at each of the multiple cracking points, and even for a single crack, separate crack gauges at multiple points along the crack line to accurately grasp the crack progression mode. Is installed, it takes a long time in the process of checking each crack gauge one by one, which directly leads to a decrease in work efficiency and an increase in inspection cost.

The present invention was devised in view of the above-described problems, and a part of the tip of the inner plate 10 attached to one side of the cracked portion of the structure and a part of the tip of the outer plate 20 attached to the other side of the cracked portion overlap each other, so that the crack width In a crack gauge in which the overlapping portion is changed while the inner plate 10 and the outer plate 20 move relative to each other in the direction of fluctuation of the crack width in a state where the back surface of the outer plate 20 is close to the surface of the inner plate 10 according to this variation, the inner plate In (10), a pair of guide walls 12 orthogonal to the relative movement direction of the inner plate 10 and the outer plate 20 are formed to be spaced apart from each other, and between the guide walls 12, an inclined surface 41 on the side of the outer plate 20 side. ) Is formed moving plate 40 is coupled so as to be freely slidable in a direction parallel to the guide wall 12, but the angle between the inclined surface 41 and the adjacent guide wall 12 is set to be less than 45 degrees. , At the front end of the outer plate 20, a protruding inhibition plate 24 is formed, so that when the inner plate 10 and the outer plate 20 are overlapped and installed, the end of the inhibition plate 24 is the inclined surface 41 of the moving plate 40 While in contact with, the movement of the moving plate 40 is inhibited, and the contact point between the inhibiting plate 24 and the inclined surface 41 changes according to the relative movement of the inner plate 10 and the outer plate 20, and the moving plate 40 moves. It is a micro-measurement type crack gauge characterized in that it is.

In addition, a background portion 15, which is an arm portion, is formed on the surface of the moving plate 40, and a display portion 16 that is a bright portion as an object orthogonal to the direction of movement of the moving plate 40 is formed inside the background portion 15. ) A number of are formed at equal intervals, a see-through plate 45 made of a transparent material is attached to the induction wall 12, and a concealed part that is a dark object in a direction parallel to the display part 16 ( 25) A number of transparent portions 26 formed between the concealing portions 25 are formed at equal intervals, and a number of the transparent portions 26 formed between the concealing portions 25 are formed at equal intervals, but the distance between the display unit 16 and the transparent portion 26 is In the same way, as the moving plate 40 is moved in a state in which the display unit 16 of the moving plate 40 and the concealing unit 25 of the see-through plate 45 are overlapped, the display unit 16 and the see-through unit 26 are It is a micro-measurement type crack gauge characterized in that the entire display unit 16 is exposed at the same time while being overlapped.

Through the present invention, it is possible to quickly, simply and accurately grasp the fluctuation of the crack area of the structure to which the crack gauge is attached, thereby improving the accuracy, efficiency, and convenience of safety diagnosis work for concrete structures including crack inspection.

In particular, in the conventional crack gauge, even minute crack fluctuations that are difficult to read with the naked eye can be read without additional equipment, so that the progress of concrete structure cracks and the resulting risk can be detected early, thereby reducing structural stability and performance of the structure. By quickly grasping, it is possible to effectively cope with serious damage or collapse of the structure.

1 is a perspective view of a conventional crack gauge
Figure 2 is a perspective view of the present invention
Figure 3 is an exploded perspective view of the main part of the present invention
Figure 4 is an explanatory diagram of the operation method of the present invention
Figure 5 is a perspective view of an embodiment of the present invention to which a spring is applied
6 is a perspective view of a modified embodiment of the present invention
7 is an explanatory diagram of an operation method of the embodiment of FIG. 6
8 is an explanatory diagram of a display state for each situation in the embodiment of FIG. 6

The detailed configuration and operation of the present invention will be described with reference to the accompanying drawings.

First, Figure 2 is a perspective view showing the appearance of the present invention, as shown, the present invention is a crack gauge composed of a pair of plate bodies overlapping with each other, the front end 92 is displayed and the rear end is a fixing unit Consisting of an inner plate 10 having 91 formed thereon, and an outer plate 20 having an indication line 93 at the front end and a fixing unit 91 at the rear end thereof, the front surface 92 of the inner plate 10 and The indicator line 93 of the outer plate 20 is attached and installed on the surface of the cracked concrete structure in a state of overlapping each other.

In the present invention, the attachment of the crack-generating concrete structure between the inner plate 10 and the outer plate 20 includes a fixing unit 91 formed at the rear end of the inner plate 10 and a fixing unit 91 formed at the rear end of the outer plate 20, respectively. Based on the crack line, it is carried out by bonding at one point in the direction orthogonal to the crack line and the other point using a bonding bracket such as an adhesive for concrete or screws, and therefore, the installation of the crack gauge of the present invention for the crack area of the concrete structure under test The inner plate 10 and the outer plate 20 are attached in a form that crosses a line-shaped crack in a direction orthogonal or approximate to orthogonal to each other in a state in which some of the tip portions are overlapped.

That is, in the present invention, a part of the front end of the inner plate 10 attached to one side of the cracked portion of the structure and a part of the front end of the outer plate 20 attached to the other side of the cracked portion overlap each other, so that the inner plate 10 As a crack gauge in which the overlapping portion is varied while the inner plate 10 and the outer plate 20 move relative to each other in the variation direction of the crack width while the back surface of the outer plate 20 is close to the surface, as in Figs. 2 to 4, the inner plate In (10), a pair of guide walls 12 perpendicular to the relative movement direction of the inner plate 10 and the outer plate 20 are formed to be spaced apart from each other, and an inclined surface 41 on the side of the outer plate 20 between the guide walls 12 The moving plate 40 on which the) is formed is coupled so as to be freely slidable in a direction parallel to the guide wall 12, and a protruding inhibition plate 24 is formed at the front end of the outer plate 20, The end of 24) is configured to come into contact with the inclined surface 41 of the moving plate 40.

Here, the relative movement of the inner plate 10 and the outer plate 20 refers to the relative movement of the inner plate 10 or the outer plate 20 according to fluctuations in the crack state such as expansion or reduction of the crack width. When considering the applied crack detection method, the direction of the relative movement is set to be orthogonal to the crack line or close to orthogonal to the crack line to reflect the increase or decrease of the crack width, and the inner plate constituting the crack gauge of the present invention according to the set relative movement direction ( 10) and the outer plate 20 are attached to one side and the other side of the crack line, respectively.

That is, considering that the overlapping plate-like crack gauge including the present invention is installed in a direction orthogonal to the linear crack, the relative movement direction of the inner plate 10 or the outer plate 20 described above is the inner plate 10 or the outer plate 20 It can be referred to as its own central axis direction, and in the relative movement of the inner plate 10 or the outer plate 20, only one of the inner plate 10 or the outer plate 20 can move depending on the progression of the crack. Of course, as the inner plate 10 and the outer plate 20 move simultaneously, the crack width may increase or decrease. In analyzing the behavior of the crack gauge, the other side, even if either of the inner plate 10 and the outer plate 20 is in a stopped state. It is preferable to introduce a relative movement state of the inner plate 10 and the outer plate 20 so that the crack fluctuation can be reflected through the movement of the inner plate 10 and the outer plate 20.

As shown in FIGS. 2 and 3, the moving plate 40 coupled between the pair of guide walls 12 spaced apart from each other has a rectangular shape as a whole, and its front width is between the pair of guide walls 12 spaced apart from each other. By coinciding with the width of the space, the moving plate 40 coupled between the guide walls 12 can move freely in the up and down directions on the drawing, which is a direction parallel to the guide wall 12.

In the embodiment shown in Figs. 2 and 3, the moving plate 40 performs an activity of descending by its own weight, and a see-through plate 45 made of a transparent material is attached to the surfaces of the guide walls 12 on both sides to move. While suppressing the separation of the plate 40, it is possible to check the position and state of the moving plate 40 coupled between the guide walls 12, and as in the same drawing and 4, the suppression plate of the outer plate 20 ( As the inclined surface 41 of one side of the moving plate 40 is contacted and supported by 24), when the inner plate 10 and the outer plate 20 are overlapped and installed, the end of the inhibiting plate 24 is the inclined surface of the moving plate 40 While in contact with (41), the movement of the moving plate (40) is inhibited.

Therefore, as shown in FIG. 4, the contact point between the inhibiting plate 24 and the inclined surface 41 is changed according to the relative movement of the inner plate 10 and the outer plate 20, and the moving plate 40 moves. ) And the outer plate 20 are spaced apart from each other, that is, the inner plate 10 moves to the left, the outer plate 20 moves to the right, or the inner plate 10 and the outer plate 20 move to the left and When moving to the right at the same time, while the inhibiting plate 24 moves in a direction away from the moving plate 40, the moving plate 40 is actively moved in the downward direction in the same drawing. Conversely, the inner plate 10 and the outer plate In other words, the inner plate 10 moves to the right, the outer plate 20 moves to the left, or the inner plate 10 and the outer plate 20 move to the right and left, respectively. In the case of movement, while the inhibiting plate 24 moves in a direction closer to the moving plate 40 side, the moving plate 40 is actively moved in the upward direction in the drawing.

On the other hand, as shown in Figs. 3 and 4, the situation in which the moving plate 40 is completely separated between the guide walls 12 and lost during the installation work of the crack gauge of the present invention or during the descending activity of the moving plate 40 In order to prevent this, a stopper 19 as a protrusion may be installed on the surface of the inner plate 10 under the moving plate 40.

In the active structure of the moving plate 40 of the present invention, by introducing a part that actually moves, the inner plate 10 and the outer plate according to the fluctuation of cracks ( It can be said to be able to visually and easily determine whether the relative movement of 20).

That is, from the standpoint of an inspector who utilizes a crack gauge in tasks such as actual safety diagnosis, the conventional crack gauge precisely shows the indicator line 93 of the outer plate 20 moving above the surface 92 of the inner plate 10. The relative movement of the inner plate 10 and the outer plate 20 and fluctuations in cracks can be confirmed only after observation and reading, but in the present invention, the fluctuation of cracks is immediately determined by only checking whether the moving plate 40, which is an actual moving member, has moved. It can be confirmed with.

In addition, as shown in FIG. 3, the magnifying scale 13 is displayed on one side of the guide wall 12 and the indicator 49 is displayed on the surface of the moving plate 40, so that it can be confirmed through the see-through plate 45, which is a transparent material. By checking the indication state of the magnified scale 13 of the moving plate 40 and the surface indicator 49, the position change of the moving plate 40 according to the relative movement of the inner plate 10 and the outer plate 20 is detected as a specific value. can do.

Therefore, through the present invention, it is possible to not only improve the convenience of work in performing structure maintenance tasks such as safety diagnosis, but also to perform periodic inspection of a plurality of points to be tested, first, the moving plate 40 at a distance. It is also possible to introduce a method of acquiring the fluctuation value by checking whether the movement of the device is moved, first checking the station where the fluctuation occurred, and then performing a close precision inspection only on the station where the movement was confirmed, thereby dramatically improving the efficiency of safety diagnosis work. Can be improved with.

In particular, the movable plate 40 forming the one side inclined surface 41 of the present invention sets the inclination angle of the inclined surface 41, that is, the angle θ between the inclined surface 41 and the adjacent guide wall 12 to less than 45 degrees. By doing so, it is possible to obtain an effect of amplifying the relative moving distance between the inner plate 10 and the outer plate 20 according to the crack fluctuations, and thereby, it is possible to accurately detect the minute crack fluctuation value, which was not practically possible to read with the naked eye in the prior art.

4 illustrates the effect of amplifying the crack fluctuation distance by the moving plate 40, the angle between the inclined surface 41 of the moving plate 40 and the adjacent guide wall 12 in the embodiment shown in the figure. (θ) is set to less than 45 degrees, and the horizontal distance vs. vertical distance in the drawing of the inclined surface 41 formed by the intervening angle (θ) is h vs. v, and when the intervening angle (θ) is less than 45 degrees, v/h exceeds 1, and v/h can be converted to the ratio of the vertical movement distance of the moving plate 40 to the horizontal moving distance of the inhibiting plate 24 in the drawing, so that v/h is the inner plate It can be said that it is an amplification ratio of the active moving distance of the moving plate 40 that amplifies the relative moving distance between (10) and the outer plate 20.

Therefore, as illustrated in FIG. 4, when v/h is set to 2, the relative movement distance between the inner plate 10 and the outer plate 20 according to the crack fluctuation is doubled, so that the moving distance of the moving plate 40 is increased. As it is expressed, it is possible to secure much improved precision compared to the method of reading the position of the indicator line 93 on the front surface 92, and if the interposition angle θ is further reduced to increase v/h, the detection precision You can also improve it further.

As described above, the moving plate 40 of the present invention is configured to move in a direction parallel to the guide wall 12 in a state coupled to the space between the pair of guide walls 12 spaced apart from each other. Since silver is performed by the self-weight of the moving plate 40, there may be restrictions on smooth movement of the moving plate 40.

Thus, as shown in FIG. 5, a spring 47 connecting the upper end of the moving plate 40 and the inner plate 10 is mounted so that the elastic force pressing the moving plate 40 downward in the drawing always acts. , This makes it possible to move the moving plate 40 smoothly.

In addition, as shown in Figure 5, as a configuration capable of suppressing the relative movement of the inner plate 10 and the outer plate 20 in the overlapping state of the inner plate 10 and the outer plate 20, the inner plate 10 and the outer plate ( 20) A pin hole 37 is drilled in each, and a binding pin 38 having a diameter that matches the inner diameter of the pin hole 37 penetrates the pin hole 37 of the outer plate 20 to pass through the pin hole 37 of the inner plate 10. ), it is possible to temporarily fix the inner plate 10 and the outer plate 20.

In the fixing of the inner plate 10 and the outer plate 20, as shown in FIG. 5, the elastic force of the spring 47 acts on the moving plate 40, so that the downward pressure of the moving plate 40 is again suppressed plate 24 ) And the outer plate 20 by being transmitted to the inner plate 10 and the outer plate 20 to prevent the phenomenon that the inner plate 10 and the outer plate 20 are unnecessarily separated from each other.In installing the crack gauge of the FIG. 5 embodiment on the structure to be examined, once the binding pin 38 ) To the outer plate 20, the pin hole 37 and the inner plate 10, the pin hole 37 to suppress the movement of the inner plate 10 and the outer plate 20, the inner plate 10 and the outer plate 20 fixed Attach the part 91 to the detection point, and remove the binding pin 38 after fixing of the inner plate 10 and the outer plate 20 and the fixing part 91 is completed, and the inner plate 10 and the outer plate ( It is used in a way that allows relative movement of 20).

On the other hand, FIGS. 6 to 8 are embodiments in which the visual display effect according to the actual movement of the above-described moving plate 40 is maximized, and a background part 15 and a display part 16 are formed on the moving plate 40, A concealed portion 25 and a see-through portion 26 are formed on the see-through panel 45, which is transparent, and the visual display state is configured to change dramatically depending on the overlapping position between the display portion 16 and the see-through portion 26.

The background portion 15, the display portion 16, the concealment portion 25, and the see-through portion 26 of the present invention change as the moving plate 40 behind the see-through panel 45 moves, the overlapping state thereof is changed. Inside the dark portion formed by the concealed portion 25 and the background portion 15, the bright portion formed by the display portion 16 and the see-through portion 26 is dramatically displayed at a certain level. In grasping whether or not the above crack fluctuations occur, visibility has been remarkably improved compared to the conventional method of utilizing the surface surface 92 and the indicator line 93 as well as the above-described embodiments of FIGS. 2 to 5 of the present invention. can do.

In the present invention, the background portion 15 and the concealment portion 25 formed as a dark portion may be formed in the form of a printed layer, a coating layer of a paint, or an adhesion layer of a thin film, and a moving plate as shown in FIGS. 6 to 8 A background portion 15, which is a dark portion, is formed on the surface of the 40, and inside the background portion 15 is a bright portion as an object orthogonal to the relative movement direction of the inner plate 10 and the outer plate 20 described above. A number of the display portions 16, which are the tops, are formed at equal intervals.

Here, as in the dictionary meaning, the dark and bright areas represent dark and bright areas, and the dark areas are composed of colors with low brightness including black and high concealment for the background, and bright areas such as white or yellow. It is composed of a color that is high and has a clear contrast with the dark.

Therefore, when the moving plate 40 on which the background portion 15 is formed has a surface having a high brightness color such as white, the background portion 15, which is a dark portion, is formed by printing or painting, excluding the portion where the display portion 16 is formed. The display unit 16, which is a bright area, may be formed by printing or painting the color of the background unit 15 only on the part.

In addition, as shown in FIGS. 6 and 7, a plurality of concealing portions 25, which are dark objects in a direction parallel to the display unit 16, are formed at equal intervals on the see-through panel 45 made of a transparent material. A number of the transparent portions 26 formed therebetween are formed at equal intervals, and as shown in FIG. 7, the separation interval of the display unit 16 and the separation interval of the see-through portion 26 are set to be the same.

That is, as shown in FIG. 7, a plurality of display units 16 are arranged at equal intervals in the background portion 15 that is the dark portion on the moving plate 40, and the concealing portion 25 that is the dark portion on the see-through plate 45, which is a transparent plate. ), a transparent part, which is a transparent part, is repeatedly formed to form a multi-slit structure as a whole.As shown in FIGS. 7 and 8, the display part 16 of the moving plate 40 and the see-through plate ( As the inner plate 10 and the outer plate 20 move relative to each other in the state where the concealment portion 25 of 45) is overlapped, the moving plate 40 follows and moves, and accordingly, the display unit 16 of the moving plate 40 ) And the see-through portion 26 of the see-through panel 45 are overlapped and the entire display portion 16 is exposed at the same time.

In forming the background portion 15, the display portion 16, the concealed portion 25 and the see-through portion 26, parallax, refraction or distortion due to the thickness of the transparent plate 45, which is an outer transparent plate In order to prevent this, the background portion 15 and the display portion 16, which are rear display objects, are formed on the surface of the moving plate 40, and the concealed portion 25, which is a surface display object, is a see-through panel 45. ), it is preferable to overlap the background portion 15, the display portion 16, and the concealed portion 25 on the same plane without any difference in thickness when overlapping the background portion 15, the display portion 16, and the concealed portion 25.

Here, the width of the concealing portion 25 is formed to be enlarged compared to the width of the see-through portion 26 and the display portion 16, so that when a movement of less than a certain level occurs during the movement of the moving plate 40, the display portion 16 is not exposed. If a movement exceeding a certain level occurs while being suppressed, the entire display unit 16 can be displayed at once, and thus, the simple surface 92 and the indicator line 93 overlapping method as well as the moving plate 40 indicator It is possible to obtain a remarkably improved visual display effect compared to the method of applying (49) and the enlarged scale (13).

In other words, when the initial installation relative of the inner plate 10 and the outer plate 20 is maintained or the relative movement distance is small due to insignificant crack width expansion, the above-described background portion 15, display portion 16, concealment portion 25, and perspective portion (26) The overlapping state is formed as in the upper drawing of Fig. 8 so that only the dark part is displayed, but as soon as the crack is enlarged and the relative movement distance between the inner plate 10 and the outer plate 20 exceeds a certain level, a number of display units (16) As the whole is expressed through a number of perspective parts 26 at a time, as in the lower drawing of the same drawing, a list that encroaches on the area of the arm is dramatically displayed, so that the inspector can quickly and easily grasp it. It can be.

In particular, when the reflector is exposed or a reflective or fluorescent paint is applied in forming the display unit 16, which is a bright area, further improved visibility can be provided. It is possible to check the reflected light by using the light source of, so the detection work can be performed even in a remote location that is separated by a considerable distance.

10: inner plate
12: guide wall
13: magnification
15: background
16: display
19: stopper
20: outer plate
24: hard plate
25: concealment
26: see-through
37: pin ball
38: binding pin
40: moving plate
41: slope
45: see-through
47: spring
49: indicator
91: settlement unit
92: front view
93: leader line

Claims (2)

A part of the front end of the inner plate 10 attached to one side of the cracked portion of the structure and a part of the front end of the outer plate 20 attached to the other side of the cracked portion overlap each other. ) In a crack gauge in which the overlapping portion is changed while the inner plate 10 and the outer plate 20 move relative to each other in the direction of fluctuation of the crack width while the back surface is close,
In the inner plate 10, a pair of guide walls 12 orthogonal to the relative movement direction of the inner plate 10 and the outer plate 20 are formed to be spaced apart from each other;
Between the guide walls 12, a moving plate 40 having an inclined surface 41 formed on the side of the outer plate 20 is coupled so as to be freely slidable in a direction parallel to the guide wall 12, but the inclined surface 41 The angle between the and the adjacent guide wall 12 is set to less than 45 degrees;
A protruding inhibition plate 24 is formed at the front end of the outer plate 20, so that when the inner plate 10 and the outer plate 20 are overlapped and installed, the end of the inhibition plate 24 is on the inclined surface 41 of the moving plate 40. Inhibiting the movement of the moving plate 40 while being in contact;
Micro-measurement type crack gauge, characterized in that the moving plate 40 moves as the contact point between the inhibiting plate 24 and the inclined surface 41 changes according to the relative movement of the inner plate 10 and the outer plate 20.
The method according to claim 1,
A background portion 15, which is a dark portion, is formed on the surface of the moving plate 40, and a number of display portions 16, which are bright portions, are objects orthogonal to the movement direction of the moving plate 40 in the background portion 15. Formed at equal intervals apart;
A see-through plate 45 made of a transparent material is attached to the guide wall 12, and a plurality of concealing portions 25, which are dark objects in a direction parallel to the display portion 16, are formed at equal intervals on the see-through plate 45. A number of the see-through portions 26 formed between the concealing portions 25 are formed at equal intervals, but the separation interval of the display portion 16 and the separation interval of the see-through portion 26 are the same;
As the moving plate 40 is moved in a state in which the display unit 16 of the moving plate 40 and the concealing unit 25 of the see-through plate 45 are overlapped, the display unit 16 and the see-through unit 26 are overlapped. Micro-measurement type crack gauge, characterized in that the display unit 16 is exposed at the same time.

Images