Crack measurement device based on grating measurement principle

Abstract

The utility model discloses a crack measuring device based on a grating measurement principle. The crack measuring device comprises a main graduated scale and an auxiliary graduated scale, the main graduated scale is provided with two gaps matched with the auxiliary graduated scale in width, and the auxiliary graduated scale is inserted into the main graduated scale to move; gratings are uniformly engraved on the main graduated scale and the auxiliary graduated scale, and the gratings are bright and dark alternated thin lines with equal angular distances; alternately transparent and non-transparent radial stripes are carved on the main graduated scale and the auxiliary graduated scale according to a certain density; scales are engraved under the radial stripes of the auxiliary graduated scale, each scale is a unit length, and the width between the stripes and the gap is alpha; after the two gratings with the same density are overlapped, the scribed lines of the two gratings are mutually inclined by an angle theta, and alpha is equal to tan theta * 1 unit length. The main graduated scale and the auxiliary graduated scale are made of soft transparent materials. The method can be widely applied to engineering crack detection, and the crack state can be known conveniently and quickly.

Description

Technical Field

[0001] The utility model belongs to the technical field of crack measurement, and in particular relates to a crack measurement device based on a grating measurement principle. Background Art

[0002] Cracks are an important indicator for judging the stability of rock mass. The appearance of cracks reduces the firmness and integrity of buildings, increases risk factors, and causes the buildings to tilt and crack, affecting their appearance and use. In severe cases, they lead to collapse, causing irreversible economic losses and personal safety issues. It is very important to monitor the initiation and development of rock mass cracks in real time.

[0003] Since the causes of cracks are complex, they are not easy to detect, change slowly, and once they appear, they will cause irreversible effects. They are very harmful to the project. The causes of cracks are complex and difficult to detect and measure, so the difficulty of crack monitoring is also increasing. Being able to accurately measure the changes in cracks is of great significance to project safety monitoring.

[0004] The grating measurement principle is based on the interference and diffraction of light and the moiré fringe phenomenon. It can accurately measure physical quantities by precisely controlling the movement of the grating and detecting the changes in the interference fringes. This method is widely used in CNC machine tools, precision measuring instruments and other fields.

[0005] A crack monitor is an instrument specifically used to measure and monitor crack width and depth on structures such as buildings, bridges, and tunnels. It can accurately measure crack width through numerical display and image analysis, and continuously observe and record crack width changes under real-time monitoring. However, the installation of complex crack monitoring instruments will increase the cracking speed to a certain extent.

[0006] Therefore, there is an urgent need for a lightweight, convenient, high-precision and accurate crack measurement device to solve the above-mentioned technical problems. Utility Model Content

[0007] In order to solve the above technical problems, the utility model provides a crack measuring device based on the grating measurement principle. The measuring device is light and convenient, can solve the problem that the installation of the existing complex crack monitor increases the cracking speed to a certain extent, and has low cost, is easy to carry and install, improves the measurement accuracy, and can be widely used;

[0008] In order to achieve the above technical objectives, the utility model is implemented through the following technical solutions:

[0009] A crack measuring device based on grating measurement principle, comprising: a main scale and a sub-scale;

[0010] The main scale has two gaps matching the width of the auxiliary scale, and the auxiliary scale is inserted and moved inside the main scale;

[0011] The main scale and the auxiliary scale are uniformly engraved with gratings, and the gratings are thin lines of light and dark with equal angular distances; the main scale and the auxiliary scale are engraved with alternating transparent and opaque radial stripes at a certain density; scales are engraved under the radial stripes of the auxiliary scale, each scale is a unit length, and the width of the stripes and gaps is α; after two gratings with the same density are overlapped, the engraved lines of the two gratings are inclined to each other at an angle θ, α=tanθ*1 unit length;

[0012] Furthermore, the main scale and the auxiliary scale are both made of soft transparent material;

[0013] A crack measurement method, using a crack measurement device based on a grating measurement principle, comprises the following steps:

[0014] S1: insert the sub-scale along the two gaps on the main scale, align the zero line of the main scale with the crack on one side, and align the arrow zero line pointer of the sub-scale with the crack on the other side. During the crack measurement process, the main scale is fixed and the sub-scale moves with the movement of the crack on the other side, that is, the arrow zero line pointer of the sub-scale moves with the crack on the other side and marks the reading on the scale line of the main scale;

[0015] S2: Install the two combined rulers at the appropriate position of the crack for measurement; observe the graduation of the secondary scale;

[0016] S3: After a period of time, find the scale of the main scale on which the arrow zero line pointer of the sub-scale is aligned at this moment, that is, the two numbers before and after the decimal point are determined;

[0017] S4: Look at the digit X that completely overlaps the main scale and the auxiliary scale, each unit is one of the divisions, and the third digit is obtained as the division*X;

[0018] S5: Observe the gratings of the main scale and the auxiliary scale, and the position of the interlaced shadow part is the last digit that can be estimated;

[0019] The beneficial effects of the utility model are:

[0020] The utility model provides a crack measuring device based on the grating measurement principle. Compared with traditional crack detection instruments, the device is light and convenient. It can solve the problem that the existing complex crack monitor increases the crack opening speed to a certain extent during installation and use. It has low cost, is easy to carry and install, improves measurement accuracy, and can be widely used. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a structural schematic diagram of the main scale of the measuring device of the utility model;

[0023] Figure 2 It is a structural schematic diagram of the auxiliary scale of the measuring device of the utility model;

[0024] Figure 3 A schematic diagram of the grating measurement principle of the measuring device of the utility model;

[0025] Figure 4 It is a schematic diagram of Example 1 of the measuring device of the utility model;

[0026] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0027] 1-main scale fixing hole, 2-main scale fixing hole, 3-main scale fixing hole, 4-main scale fixing hole, 5-main scale scale, 6-slit, 7-slit, 8-inclined grating strip, 9-sub-scale fixing hole, 10-sub-scale fixing hole, 11-sub-scale fixing hole, 12-sub-scale fixing hole, 13-sub-scale scale, 14-translucent grating, Figure 3 , satisfies a=tanθ*1 unit length. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Example 1

[0029] In this embodiment, a crack measurement device based on the grating measurement principle includes: a main scale and a sub-scale;

[0030] In this embodiment, two gaps matching the width of the auxiliary scale are provided on the main scale, and the auxiliary scale is inserted and moved inside the main scale;

[0031] In this embodiment, the main scale and the auxiliary scale are uniformly engraved with gratings, and the gratings are thin lines of light and dark with equal angular distances; the main scale and the auxiliary scale are engraved with alternating transparent and opaque radial stripes at a certain density; scales are engraved under the radial stripes of the auxiliary scale, each scale is a unit length, and the width of the stripes and gaps is α; after two gratings of the same density are overlapped, the engraved lines of the two gratings are inclined to each other at an angle θ, α=tanθ*1 unit length;

[0032] In this embodiment, the main scale and the auxiliary scale are both made of soft transparent material; the soft material here refers to lightweight soft plastic with stable structure. Example 2

[0033] Based on the above embodiment 1, in this embodiment, the implementation steps of a crack measurement device based on the grating measurement principle applied to crack measurement include the following steps:

[0034] S1: insert the sub-scale along the two gaps on the main scale, align the zero line of the main scale with the crack on one side, and align the arrow zero line pointer of the sub-scale with the crack on the other side. During the crack measurement process, the main scale is fixed and the sub-scale moves with the movement of the crack on the other side, that is, the arrow zero line pointer of the sub-scale moves with the crack on the other side and marks the reading on the scale line of the main scale;

[0035] S2: Install the two combined rulers at the appropriate position of the crack for measurement; observe the graduation of the secondary scale;

[0036] S3: After a period of time, find the scale of the main scale on which the arrow zero line pointer of the sub-scale is aligned at this moment, that is, the two numbers before and after the decimal point are determined;

[0037] S4: Look at the digit X that completely overlaps the main scale and the auxiliary scale, each unit is one of the divisions, and the third digit is obtained as the division*X;

[0038] S5: Observe the gratings of the main scale and the auxiliary scale, and the position of the interlaced shadow part is the last digit that can be estimated; Example 3

[0039] Based on the above-mentioned Embodiment 1 and Embodiment 2, in this embodiment, the actual use process of a measuring device based on the grating measurement principle is as follows:

[0040] First, the auxiliary scale is inserted into the main scale through the gap in the main scale. When measuring, it can be moved in the main scale to display the reading. The main scale and the auxiliary scale are fixed in the appropriate position of the gap by a fixing device, such as Figure 4As shown. The conditions are as follows: the 0 scale of the main scale is aligned with the crack on one side, and the zero scale arrow of the sub-scale is aligned with the crack on the other side. At this time, the main scale scale, sub-scale scale, and grating scale will read the corresponding readings;

[0041] After a specified period of time, the grating ruler moves slowly through the crack, and a new reading is obtained by observing again. Subtracting the two readings is the cracking state that is desired to be obtained this time.

[0042] It should be noted that due to differences in human vision and natural environment influences during measurement, in order to ensure accuracy, two or more people are required to observe at the same time and take the average of the readings. The number of people is determined by actual conditions. Example 4

[0043] In the present embodiment, a crack measuring device based on the grating measurement principle is provided. The device is made of two parts of transparent, soft plastic material, which are divided into a main scale a and a sub-scale b. It is light, easy to carry, and fixed. It is not easy to deform and age, and is heat-resistant and waterproof. The main and sub-scales are placed on both sides of the crack and fixed by a fixing device. The main scale a is fixed to the crack on one side and aligned with the 0 scale line. The sub-scale b with an arrow indicating the grating is fixed on the crack on the other side for precision reading. There are two gaps on the main scale a with the same width as the sub-scale b, so that the sub-scale b can be inserted and moved in the main scale a. The main and sub-scales are evenly engraved with light and dark equidistant thin lines to form a grating. Alternating transparent and opaque radial stripes are evenly engraved at a certain density, such as Figure 3 As shown, there may be scales under the stripes of the secondary scale, with 1 unit between each scale, and the width of the stripes and gaps is a. If two gratings of the same density are overlapped, their scale lines are tilted by a very small angle "θ" to each other, and the relationship between a and θ is determined so that a=tanθ*1 unit length, light and dark stripes will appear. The main and secondary scales can read the scale reading and the precise reading by slowly moving the cracks to interweave the grating grid. The scale pointed to by the intersecting dark stripes is the precise value of the reading.

[0044] A crack measuring device based on the grating measurement principle, the measuring method of which comprises the following steps:

[0045] a) Insert the secondary scale b along the two gaps (6, 7) on the main scale a, requiring the zero scale line of the main scale a to be aligned with the crack on one side, and the arrow 0 scale line pointer of the secondary scale b to be aligned with the crack on the other side. Ensure that during the crack measurement process, the main scale a is fixed and the secondary scale b moves with the movement of the crack on the other side, that is, the arrow 0 scale line pointer of the secondary scale b moves with the crack on the other side and marks the reading on the scale line of the main scale a.

[0046] b) Install the two combined rulers at the appropriate position of the crack for measurement. Observe the graduation (accuracy) of the secondary ruler b. In this example, the device has 20 grids, 20 graduations, and an accuracy of 0.05mm.

[0047] c) After installation, start measuring as the crack slowly changes. After a period of time, find the scale of the main scale a where the arrow 0 line pointer of the secondary scale b is aligned, and the two numbers before and after the decimal point are determined, that is, "X.Xcm"

[0048] d) Look at the digit X where the main scale a and the secondary scale b completely overlap, each unit is 0.05, and the three-digit number is 0.05*X;

[0049] e) Now look at the two ruler gratings again. The position of the interlaced shaded parts is the last digit that can be estimated.

[0050] The preferred embodiments of the utility model disclosed above are only used to help explain the utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the utility model to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the utility model, so that technicians in the relevant technical field can well understand and use the utility model. The utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A crack measurement device based on grating measurement principle, characterized in that: include: Main scale and secondary scale; The main scale has two gaps matching the width of the auxiliary scale, and the auxiliary scale is inserted and moved inside the main scale; The main scale and the auxiliary scale are uniformly engraved with gratings, and the gratings are thin lines of light and dark with equal angular distances; the main scale and the auxiliary scale are engraved with alternating transparent and opaque radial stripes at a certain density; scales are engraved under the radial stripes of the auxiliary scale, each scale is a unit length, and the width of the stripes and the gap is α; after two gratings with the same density are overlapped, the engraved lines of the two gratings are inclined to each other at an angle θ, α=tanθ*1 unit length.

2. A crack measurement device based on the grating measurement principle according to claim 1, characterized in that: The main scale and the auxiliary scale are both made of soft transparent material.

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