RFID unit and method for installing RFID unit

Abstract

To provide a technique for allowing an RFID unit to be properly inserted into concrete after the concrete is poured.SOLUTION: An RFID unit to be inserted into concrete includes an RFID module 4 having a communication antenna 40, and a plate-shaped protective case 3 that houses the RFID module 4. When viewed from a line of sight parallel to a thickness direction Z, the protective case 3 has a shape that tapers toward a first side X1 in a first direction X that is perpendicular to the thickness direction Z.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to RFID units for insertion into concrete and methods of installing RFID units. [Background technology]

[0002] In general concrete construction, installation, or product manufacturing, formwork is assembled, concrete is poured into the formwork, and after a period of curing, the concrete is removed from the formwork once it is estimated to have reached a predetermined strength that allows it to be removed.

[0003] For example, Patent Document 1 describes a method for estimating the strength of concrete by embedding an RFID module equipped with a temperature sensor in poured concrete, continuously measuring and storing temperature changes with the temperature sensor in the RFID module, and reading temperature history data from the RFID module with a reader. The temperature history data is used to calculate important information during the concrete construction.

[0004] Patent Document 2 discloses that a thin-plate RFID module is wrapped to form an RFID unit, and the RFID unit is inserted from the surface of poured ready-mixed concrete and embedded inside the ready-mixed concrete. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4633416 [Patent Document 2] Patent No. 2008-137284 Summary of the Invention [Problem to be solved by the invention]

[0006] When inserting a plate-shaped RFID unit into poured concrete, depending on the shape of the RFID unit, the size of the sand in the concrete, and the viscosity of the concrete, the resistance during insertion may be too great, making it impossible to insert it to the desired position.

[0007] The present disclosure provides a technique that allows an RFID unit to be properly inserted into concrete after it has been poured. [Means for solving the problem]

[0008] The RFID unit to be inserted into concrete of the present disclosure comprises an RFID module having a communication antenna and a plate-shaped protective case that houses the RFID module, and the protective case has a shape that tapers toward a first side in a first direction perpendicular to the thickness direction when viewed from a line of sight parallel to the thickness direction.

[0009] The method of installing an RFID unit disclosed herein includes a step of inserting an RFID unit having an RFID module and a plate-shaped protective case that houses the RFID module into poured concrete, wherein the protective case has a shape that tapers in the insertion direction when viewed from a line of sight parallel to the thickness direction. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to reduce resistance when inserting the RFID unit into concrete, avoid deformation of the protective case, and facilitate the insertion process, thereby enabling the RFID unit to be properly inserted into poured concrete. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 10 is a cross-sectional view showing a schematic view of an RFID unit being inserted into concrete from the surface of the concrete. [Figure 2] FIG. 2 is a perspective view showing an RFID unit. [Figure 3] 3A and 3B are front and right side views of the protective case. [Figure 4] Figure 4A is a rear view of the protective case, Figure 4B is a plan view of the protective case, and Figure 4C is a bottom view of the protective case. [Figure 5] FIG. 4B is a cross-sectional view of the VV portion in FIG. 4A. [Figure 6] Fig. 6A is a perspective view showing an RFID unit according to another embodiment, and Fig. 6B is a perspective view showing an RFID unit according to yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a cross-sectional view that schematically shows how an RFID unit 2 is inserted into concrete 11 from a concrete surface 11a.

[0014] As shown in FIG. 1, the method for constructing concrete 11 includes the steps of pouring concrete 11 into formwork 10 and inserting (installing) an RFID unit 2 into the poured concrete 11. As shown in FIG. 1, the RFID unit 2 is placed in the concrete 11 by inserting it in an insertion direction UD1 (downward) from the concrete surface 11a. In FIG. 1, the up-down direction is represented as UD. The RFID unit 2 is an integrated unit of a protective case 3 (described later) and an RFID module 4 (described later). The RFID unit 2 inserted into the concrete 11 is not fixed to the rebar in the concrete 11.

[0015] FIG. 2 is a perspective view showing the RFID unit 2. FIG. 3A is a front view showing the protective case 3. FIG. 3B is a right side view showing the protective case 3. The left side view of the protective case 3 is the same as the right side view, so it is omitted. FIG. 4A is a rear view showing the protective case 3. FIG. 4B is a plan view showing the protective case 3. FIG. 4C is a bottom view showing the protective case 3.

[0016] As shown in FIGS. 2 and 3A, the protective case 3 can accommodate the RFID module 4 and protects the RFID module 4 from external forces from the concrete 11. The protective case 3 may be made of any non-metallic material, such as resin or wood. The protective case 3 can be made by molding, cutting, or using a resin 3D printer. The specific gravity of the protective case 3 is often smaller than that of the concrete 11. As shown in FIGS. 1 and 2, the protective case 3 is inserted into the concrete 11 with the first side X1 of the first direction X as the insertion direction UD1. In the first embodiment, as shown in FIGS. 3A-B and 4A-C, the protective case 3 is formed in a plate shape. The dimension of the thickness direction Z of the protective case 3 is approximately 15 mm, but is not limited to this. The surface direction of the protective case 3 is parallel to the first direction X and a second direction Y perpendicular to the first direction X. The second direction Y is perpendicular to both the thickness direction Z and the first direction X. The first direction X is perpendicular to the thickness direction Z.

[0017] As shown in FIGS. 2, 3A, and 4A, the protective case 3 has a shape in which a rectangular plate portion and a triangular plate portion are combined. The tapered shape of the triangular plate portion thus serves to indicate the up-down orientation of the protective case 3. When viewed parallel to the thickness direction Z (see FIGS. 3A and 4A), the protective case 3 has a shape that tapers toward the first side X1. When inserting the protective case 3 into the concrete 11, the tapered tip 31 of the triangular plate portion is inserted toward the concrete 11. Furthermore, when viewed parallel to the thickness direction Z (see FIGS. 3A and 4A), the flat surface of the tip 31 is inclined with respect to the second direction Y. This allows the concrete 11 to be guided from the inside toward the outside in the second direction Y, thereby reducing resistance during insertion of the protective case 3.

[0018] As shown in FIG. 3B , the thickness of the tip of the first side X1 of the protective case 3 decreases toward the first side X1. Specifically, the protective case 3 has a front surface 35 on one side in the thickness direction Z and a back surface 36 on the other side in the thickness direction Z. The front surface 35 and the back surface 36 are surfaces parallel to the first direction X and the second direction Y. The tip of the first side X1 of the protective case 3 includes the back surface 36, a tip 31 (flat surface), and an inclined surface 32. The inclined surface 32 is inclined with respect to the first direction X and the thickness direction Z. The back surface 36, the tip 31, and the inclined surface 32 form the tip of the first side X1 of the protective case 3 into a tapered shape, such as a triangular shape, in a side view (as viewed from a line of sight parallel to the second direction Y). As shown in FIG. 3B , the thickness of the tip of the first side X1 of the protective case 3 is determined by the distance along the thickness direction Z between the back surface 36 and the inclined surface 32.

[0019] A slit 30 for inserting the sheet-shaped RFID module 4 is formed on a second side X2 in the first direction X of the protective case 3 (the side that faces upward during insertion). The second side X2 is opposite to the first side X1 in the first direction X. The slit 30 is an opening of an accommodation space 33 for accommodating the RFID module 4 within the protective case 3. After the RFID module 4 is inserted, the opening of the slit 30 may be sealed with a sealant such as an adhesive.

[0020] The RFID module 4 of this embodiment has a sheet-like base, an IC chip (not shown) attached to the base, a communication antenna 40, a battery (not shown), and a sensor 41 such as a temperature sensor. The sensor 41 continuously measures the temperature of the concrete 11, and the IC chip records the temperature history. This RFID module 4 is an example, and is not limited to this.

[0021] In the storage space 33 in the protective case 3, the communication antenna 40 is offset to the second side X2 in the first direction X (the side that faces upward when inserted), and the communication antenna 40 is disposed in a position close to the upper end of the protective case 3. This makes it possible to bring the reader located above the concrete surface 11a and the communication antenna 40 as close as possible. The distance from the concrete surface 11a to the communication antenna 40 is preferably 12 mm or more and 20 mm or less. The distance from the protective case 3 to the concrete surface 11a is preferably 10 mm or more so as not to become a weak point in the concrete. Furthermore, since communication is performed from above the protective case 3, it can be installed at any location away from the formwork 10 (for example, more than 3 cm away from the formwork 10, or 5 cm or more away), and can be installed in a strong location near the center of the concrete. Furthermore, if the RFID module 4 has a sensor 41, it can measure the properties of concrete in a location that is less affected by the surrounding environment. Compared to when the surface direction of the plate-shaped RFID unit 2 is along the horizontal direction, the surface direction is along the vertical direction, making it easier to pour concrete and less likely to interfere with the pouring of concrete. Also, if the surface direction of the protective case 3 were along the horizontal direction, there is a risk that the concrete above the protective case 3 would become a weak spot and the concrete would be prone to peeling, but since the surface direction of the protective case 3 is along the vertical direction Z, it is possible to prevent weak spots from occurring in the concrete. Therefore, it is suitable for concrete pavement or slab (floor surface) where there are few or no formworks 10 and where repeated pressure is applied in the up and down direction.

[0022] As shown in FIG. 3A , a window 34 is formed on the front surface 35 of the protective case 3, which exposes the sensor 41 of the RFID module 4 to the outside of the protective case 3. As a result, after the protective case 3 is inserted into the concrete 11, the concrete 11 comes into contact with the sensor 41 through the window 34, and the sensor 41 can directly measure the physical properties of the concrete 11 (for example, temperature, capacitance, potential difference, corrosion, strain, etc.). Because the sensor 41 can measure the physical properties by coming into contact with the concrete 11, the accuracy of the measurement can be improved. The window 34 is rectangular, but the shape can be changed as appropriate.

[0023] 2, 3A-3B, and 4A, a plurality of holes 51 are provided at both ends of the protective case 3 in the second direction Y. These holes 51 are used for another purpose, such as fixing the protective case 3 to reinforcing bars. Therefore, when inserting the protective case 3 (RFID unit 2) into poured concrete 11, the holes 51 may be omitted, as shown in FIG. 6A.

[0024] After the protective case 3 (RFID module 4) is inserted into the concrete 11, the protective case 3 is subject to buoyancy from the concrete 11, which can cause it to float and become misaligned. In particular, if the protective case 3 is made of a non-metal such as resin, which often has a lower specific gravity than the concrete 11, it may be prone to floating due to buoyancy. Furthermore, finishing treatment using a vibrator to smooth the concrete surface 11a can easily cause the protective case 3 to float.

[0025] To suppress or prevent the protective case 3 from floating up, as shown in FIGS. 2 and 4A , a recess 7 is provided on at least one of the two surfaces (front surface 35, back surface 36) of the protective case 3 in the thickness direction Z. Even if concrete 11 enters the recess 7 and buoyancy acts on the protective case 3, the concrete 11 that has entered the recess 7 is caught, suppressing or preventing the protective case 3 from floating up. In the first embodiment, the back surface 36 has the recess 7. The recess 7 in the first embodiment has an elongated shape that is long along the first direction X. A plurality of recesses 7 are lined up along the second direction Y. FIG. 5 is a cross-sectional view of the VV section in FIG. 4A. The RFID module 4 is not shown in FIG. 5. As shown in FIG. 5 , the recess 7 has a bottom surface 70, a first surface 71, and a second surface 72 in a cross section passing through the first direction X and the thickness direction Z.

[0026] The first surface 71 is a surface that forms the end of the first side X1 of the recess 7, and is preferably a surface parallel to the thickness direction Z. The first surface 71 is connected to the bottom surface 70, but is not limited to this. The first surface 71 may be connected to the bottom surface 70 via a straight line or a curved surface. By having the end of the first side X1 of the recess 7 have the first surface 71 parallel to the thickness direction Z (a surface perpendicular to the insertion direction UD1), even if buoyancy acts on the protective case 3 embedded in concrete, the first surface 71 perpendicular to the buoyancy will catch on it, making it possible to further prevent the protective case 3 from floating up due to buoyancy.

[0027] The second surface 72 is a surface that forms the end of the second side X2 of the recess 7, and the depth of the recess 7 becomes shallower toward the second side X2. The outer end of the second surface 72 in the thickness direction Z is located closer to the second side X2 than the inner end of the second surface 72 in the thickness direction Z. This makes it easier for the concrete 11 that seeps into the recess 7 to escape upward (to the second side X2) when the protective case 3 is inserted, and makes it possible to reduce the resistance of the protective case 3 during insertion.

[0028] As described above, after the protective case 3 (RFID unit 2) is inserted into the poured concrete 11, the sensor 41 of the RFID module 4 periodically and continuously measures the temperature of the concrete 11. The temperature history of the concrete 11 is recorded. The temperature history is then read by a reader and used to determine whether the concrete 11 has reached a predetermined strength that allows it to be demolded.

[0029] [Another embodiment] (A) In the above embodiment, as shown in Fig. 3B, the thickness of the tip of the first side X1 of the protective case 3 decreases toward the first side X1, but this is not limited to this. Although the insertion resistance of the protective case 3 increases compared to the embodiment shown in Fig. 3B, the thickness of the tip of the first side X1 of the protective case 3 may be constant.

[0030] (B) In the above embodiment, the recesses 7 are formed on the rear surface 36, but this is not limiting. For example, the recesses 7 may be formed on the front surface 35, or may be formed on both the front surface 35 and the rear surface 36. Five recesses 7 are formed, but the number can be changed as long as there is one or more.

[0031] (C) In the above embodiment, the recess 7 is elongated along the first direction X, but is not limited to this. For example, the recess 7 may be elongated along the second direction Y, or may be circular, rectangular, or triangular with approximately the same aspect ratio in the first direction X and the second direction Y. For example, as shown in FIG. 6A, the recess 7 may be a single rectangle.

[0032] (D) In ​​the above embodiment, the elongated recesses 7 that are long in the first direction X are aligned along the second direction Y, but this is not limiting. For example, as shown in Fig. 6B, the elongated recesses 7 that are long in the second direction Y may be aligned along the first direction X.

[0033] (E) In the above embodiment, the first surface 71 is a surface that is parallel to the thickness direction Z and perpendicular to the insertion direction UD1, but is not limited to this. For example, the first surface 71 may intersect with the thickness direction Z. In the above embodiment, the first surface 71, the bottom surface 70, and the second surface 72 are flat surfaces, but is not limited to this. For example, the second surface 72 may be a curved surface, a flat surface, or a combination thereof.

[0034] (F) Although there is a possibility that the insertion resistance of the protective case 3 may increase compared to the above embodiment, the second surface 72 may be parallel to the thickness direction Z.

[0035] (G) In the above embodiment, the RFID module 4 has the sensor 41, but the RFID module 4 does not have to have the sensor 41. In that case, the protective case 3 does not have to have the window 34.

[0036] [1] As described above, the RFID unit 2 to be inserted into concrete 11 may include an RFID module 4 having a communication antenna 40 and a plate-shaped protective case 3 that houses the RFID module 4, and the protective case 3 may have a shape that tapers toward a first side X1 in a first direction X that is perpendicular to the thickness direction Z when viewed from a line of sight parallel to the thickness direction Z. In this way, if the protective case 3 has a shape that tapers toward the first side X1, resistance can be reduced when inserting it into the concrete 11 with the first side X1 facing downward, preventing deformation of the protective case 3 and making the insertion process easier.

[0037] [2] In the RFID unit 2 described in [1] above, the thickness of the tip of the protective case 3 on the first side X1 may decrease toward the first side X1. This makes it possible to further reduce the resistance during insertion, avoid deformation of the protective case 3, and facilitate the insertion work, even if the concrete 11 has hardened to some extent, such as before finishing.

[0038] [3] In the RFID unit 2 described in the above [1] or [2], at least one of the two surfaces of the protective case 3 in the thickness direction Z may have a recess 7 . After the RFID unit 2 is embedded in the concrete 11, the RFID unit 2 may float up due to buoyancy. By providing the recess 7 on at least one of the two surfaces (front surface 35, back surface 36) in the thickness direction Z (the surface that faces the side when inserted), the concrete 11 gets into the recess 7, and the recess 7 becomes a catch, making it possible to prevent the protective case 3 from floating up.

[0039] [4] In the RFID unit 2 described in [3] above, the end of the first side X1 of the recess 7 may have a first surface 71 parallel to the thickness direction Z. In this way, since the end of the first side X1 of the recess 7 (which becomes the lower end when inserted) has a first surface 71 parallel to the thickness direction Z, the first surface 71, which is perpendicular to the buoyancy, is caught, thereby improving the effect of preventing the protective case 3 from floating up.

[0040] [5] In the RFID unit 2 described in [3] or [4] above, the end of the recess 7 on the second side X2 opposite to the first side X1 in the first direction X may have a second surface 72 that makes the depth of the recess 7 shallower toward the second side X2. The second surface 72 allows the concrete 11 that has seeped into the recess 7 during insertion to easily escape upward (to the second side X2), thereby reducing the insertion resistance of the protective case 3 during insertion.

[0041] [6] In the RFID unit 2 described in any one of the above [1] to [5], the communication antenna 40 may be offset to a second side X2 opposite to the first side X1 in the first direction X. This allows the reader and the communication antenna 40 to be as close as possible.

[0042] [7] In the RFID unit 2 described in any one of [1] to [6] above, the RFID module 4 may have a sensor 41, and the protective case 3 may have a window 34 for exposing the sensor 41 to the outside of the protective case 3. This allows the sensor 41 to directly measure the physical properties such as the temperature of the concrete 11 outside the protective case 3.

[0043] [8] The method for installing an RFID unit 2 includes a step of inserting an RFID unit 2 having an RFID module 4 and a plate-shaped protective case 3 that houses the RFID module 4 into poured concrete 11, and the protective case 3 may have a shape that tapers toward the insertion direction UD1 when viewed from a line of sight parallel to the thickness direction Z. When the tapered shape is inserted into the concrete 11 in the insertion direction UD1, resistance can be reduced, deformation of the protective case 3 can be avoided, and the insertion work can be made easier.

[0044] [9] The method for installing the RFID unit 2 described in [8] above may include a step in which the RFID module 4 has a sensor 41 and includes a step of recording the temperature history measured by the sensor 41 after inserting the RFID unit 2 into the concrete 11. This makes it possible to know the temperature history of the concrete 11, and to estimate the physical properties of the concrete 11, such as its strength.

[0045]

[10] The method for installing the RFID unit 2 described in [9] above may include a step of reading the temperature history measured by the sensor 41 with a reader disposed above the protective case 3. This makes it possible to easily obtain the temperature history of the concrete.

[0046]

[11] In the method for installing the RFID unit 2 according to any one of the above [8] to

[10] , the RFID unit 2 may be inserted into the pavement, the slab, or the concrete at a location away from the formwork. This is a suitable example.

[0047] Although the embodiments of the present disclosure have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present disclosure is defined not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0048] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of the components are not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure. [Explanation of symbols]

[0049] 2: RFID unit 3: Protective case 4: RFID module 7: Recess 11: Concrete 31: Tip 34: Window 40: Communication antenna 41: Sensor 71: 1st page 72: 2nd side UD1: Insertion direction X: 1st direction X1 :1st side X2: 2nd side Z: Thickness direction

Claims

1. 1. An RFID unit for insertion into concrete, comprising: an RFID module having a communication antenna; a plate-shaped protective case that houses the RFID module; The protective case has a shape that tapers toward a first side in a first direction perpendicular to the thickness direction when viewed in a line of sight parallel to the thickness direction.

2. The RFID unit according to claim 1 , wherein a thickness of the tip of the protective case on the first side decreases toward the first side.

3. The RFID unit according to claim 1 , wherein at least one of the two surfaces of the protective case in the thickness direction has a recess.

4. The RFID unit according to claim 3 , wherein the first end of the recess has a first surface that is parallel to the thickness direction.

5. The RFID unit according to claim 3 , wherein an end of the recess on a second side opposite the first side in the first direction has a second surface that decreases the depth of the recess toward the second side.

6. The RFID unit of claim 1 , wherein the communication antenna is offset to a second side opposite the first side in the first direction.

7. the RFID module has a sensor; The RFID unit according to claim 1 , wherein the protective case has a window for exposing the sensor to the outside of the protective case.

8. The method includes a step of inserting an RFID unit having an RFID module and a plate-shaped protective case that houses the RFID module into poured concrete, The method for installing an RFID unit, wherein the protective case has a shape that tapers toward the insertion direction when viewed in a line of sight parallel to the thickness direction.

9. the RFID module has a sensor; The method for installing an RFID unit according to claim 8 , further comprising the step of recording a temperature history measured by the sensor after the RFID unit is inserted into the concrete.

10. The RFID unit installation method according to claim 9, further comprising the step of reading the temperature history measured by the sensor with a reader disposed above the protective case.

11. The RFID unit installation method according to any one of claims 8 to 10, wherein the RFID unit is inserted into concrete at a location away from the pavement, slab, or formwork.

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