Striking system

Abstract

To propose a hitting system that does not require water, for example, for hitting to be supplied from the outside when a hit test is run.SOLUTION: A hit system 1 provides a hit to an object 4 to run a hit test of an object 4. The hit system 1 has a hit provision device 5 including an annular string 7 and a shooter unit 13 for discharging the string 7 to a test surface of the object 4. A site of the string 7 which was discharged by the shooter unit 13 returns to the shooter unit 13 after a hit is provided to the object 4, and is discharged to the object 4 by the shooter unit 13. Also, the hit provision device 5 has a route adjusting unit 14 for changing the route of the string 7.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a striking system, and more particularly to a striking system that strikes an object for the purpose of inspecting the striking sound of the object.

Background Art

[0002] The inventors have developed a water hammer acoustic method as a method capable of performing a striking sound inspection even when the distance between the inspection device and the inspection surface varies (see Patent Document 1, etc.). The water hammer acoustic method applies vibration by hitting the inspection surface with water droplets and detects defects from the sound.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the water hammer acoustic method requires water in principle, the supply of water is essential. Therefore, it has been impossible to apply it to drones.

[0005] Therefore, an object of the present invention is to propose a striking system that does not require the supply of water or the like for striking from the outside when performing a striking sound inspection.

Means for Solving the Problems

[0006] A first aspect of the present invention is a striking system that strikes an object for the purpose of inspecting the striking sound of the object, comprising a striking device including a string and a shooter unit that releases the string toward the object, wherein the string is annular, and a part of the string released by the shooter unit returns to the shooter unit after striking the object and is released toward the object by the shooter unit.

[0007] A second aspect of the present invention is the impact system of the first aspect, wherein the string has different weights at one or more locations and / or different shapes of the surface for hitting the object.

[0008] A third aspect of the present invention is the impact system of the first aspect, wherein the impact imparting device includes an orbit adjusting unit for changing the orbit of the string.

Advantages of the Invention

[0009] According to each aspect of the present invention, by using an annular string to remotely apply an impact to the inspection surface of an object, continuous impacts can be realized without the need for a new supply such as external water.

Brief Description of the Drawings

[0010]

Figure 1

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Figure 8

Embodiments for Carrying Out the Invention

[0011] Hereinafter, with reference to the drawings, embodiments of the present invention will be described. It should be noted that the present invention is not limited to these embodiments.

Embodiment

[0012] FIG. 1 is a block diagram showing an example of the configuration of a striking system 1 according to an embodiment of the present invention.

[0013] The striking system 1 includes a striking device 5 (an example of the "striking device" in the claims of the present application), a string 7 (an example of the "string" in the claims of the present application), and an inspection device 25.

[0014] The striking device 5 applies a strike to the object 4 on the wall 3 by means of the string 7 for the purpose of impact sound inspection. The wall 3 is, for example, a wall of a structure such as a bridge, a building, a tunnel, etc. The object 4 is a tile attached to the wall, etc. It should be noted that the object may be a part of the wall of the structure.

[0015] The inspection of the structure is performed by impact sound inspection and scratch sound test (detecting defects by the sound generated when a hammer or a percussion hammer is rubbed against the inspection surface) using a hammer or a percussion hammer. When automating this impact sound inspection and scratch sound test, it is necessary to hold the inspection device at a certain distance from the inspection surface.

[0016] The suspension method is to suspend the inspection device with respect to the wall surface. The suspension method enables high-precision movement in a direction parallel to the wall surface, but the sway in the direction perpendicular to the wall surface becomes a problem. This is because the sway in the direction perpendicular to the wall surface makes it difficult to strike the inspection wall surface.

[0017] The suction method is to suction the inspection device to the wall surface. The suction method has problems with obstacles on the wall surface. For example, windows and eaves on the outer wall of a building become obstacles.

[0018] The drone method involves attaching an inspection device to a flying device such as a drone. Similar to the suspension method, the drone method faces the challenge of maintaining the distance from the inspection surface.

[0019] Thus, particularly in the suspension method and the drone method, a striking method that enables sound inspection even when the distance between the inspection device and the inspection surface fluctuates is desired.

[0020] The inventors developed the water hammer acoustic method (see Patent Document 1, etc.) as a method that enables sound inspection even when the distance between the inspection device and the inspection surface fluctuates. The water hammer acoustic method strikes the inspection surface with water droplets to vibrate it and detects defects from the resulting sound.

[0021] However, since this method requires water in principle, water supply is essential. Therefore, its application to drones was impossible. Thus, a method of hitting an object (test piece) remotely like a water flow instead of water has been desired.

[0022] The string 7 is in the form of an annular (loop-shaped) cord. In this example, a weight 9 is attached to the string 7.

[0023] In the present invention, the string may be constituted by, for example, a chain. In this case, a weight or the like may or may not be provided. Also, by changing the surface shape such that the outer surface (the surface of the string that hits the object) has irregularities, the impact given to the object may vary depending on the position. It may also be one having a change in linear density, a change in flexibility, etc. Specifically, it may be one in which a striking ball is attached to a flexible and lightweight string, one in which abrasive particles are attached to a flexible and lightweight string, or one in which the string itself has a chain structure. The material of the string 7 is preferably non-tangling, light, and wear-resistant.

[0024] The impact imparting device 5 includes a measurement unit 11, a shooter unit 13 (shooter device) (an example of the "shooter unit" in the claims of the present application), and an orbit adjustment unit 14.

[0025] The shooter unit 13 includes a first roller 19, a second roller 21, and a drive unit 23.

[0026] The drive unit 23 rotates the first roller 19 and the second roller 21. The first roller 19 and the second roller 21 rotate with the string 7 sandwiched therebetween. The first roller 19 rotates counterclockwise. The second roller 21 rotates clockwise.

[0027] The first roller 19 and the second roller 21 sandwich the string 7 and release it toward the object 4. The part of the released string 7 is launched in the tangential direction of the first roller 19 and the second roller 21. For example, when the part of the string 7 is launched horizontally, it is held horizontally. The principle is due to the parabolic motion of the string 7 due to inertia and the air resistance of the string 7. Depending on the material of the string 7 and the launch speed, its reach distance can reach several meters.

[0028] The part of the released string 7 moves toward the object 4 according to the position above the string 7 in FIG. 1 and imparts an impact to the object 4. The part of the string 7 that has imparted an impact to the object 4 returns to the shooter unit 13 according to the position below the string 7 in FIG. 1. The rotation of the first roller 19 and the second roller 21 also contributes to recovering the part of the string 7 that has imparted an impact to the object 4. The first roller 19 and the second roller 21 rotate with the returned part of the string 7 sandwiched therebetween, release the string 7 toward the object 4, and impart an impact to the object 4 by the string 7.

[0029] In this way, by the shooter unit 13, each part of the string 7 imparts a plurality of impacts to the object 4 while rotating clockwise in FIG. 1. Therefore, the shooter unit 13 can remotely and continuously impart impacts to the inspection surface of the object 4 by the string 7.

[0030] Here, the impact imparted to the object 4 by the string 7 is different depending on whether it is imparted by the weight 9 or by other parts. Thus, for the impact by the string 7, the impact by one part is made different from that by other parts.

[0031] In this example, the weight 9 functions as a striking ball for the striking sound. When the first roller 19 and the second roller 21 hit out the string 7, the weight 9 is also hit out. When the string 7 is hit against the inspection surface of the object 4, continuous impacts become possible.

[0032] The inspection device 25 includes a recording unit 27 and a processing unit 29.

[0033] The recording unit 27 is realized by a recording device such as a microphone, etc., and collects the impact sound generated by the impact imparted to the object 4 by the string 7 to obtain an acoustic signal.

[0034] The processing unit 29 is realized by a processor that operates under the control of a program, etc., analyzes the sound recorded by the recording unit 27, and determines whether there is an abnormality in the object 4. For example, when the object 4 is a tile, it determines whether the tile is fixed to the wall 3, whether there is a non-fixed part (a part floating from the wall), whether there are cracks in the tile, etc. Also, for example, when the object 4 is a part of the wall, it determines whether there are abnormalities such as cracks.

[0035] The measuring unit 11 measures the distance between the impact imparting device 5 and the wall 3 (the distance between the impact imparting device 5 and the object 4).

[0036] The orbit adjusting unit 14 includes a third roller 17 and an adjusting unit 15.

[0037] The third roller 17 is positioned inside and moves along the string 7 to adjust the trajectory of the string 7. The third roller 17 is located at a portion of the string 7 from the point where it strikes the object 4 to the point where it returns to the shooter unit 13. The third roller 17 may rotate according to the movement of the string 7 or may apply force to the string 7 by a driving unit.

[0038] The adjustment unit 15 changes the position of the third roller 17 according to the distance measured by the measurement unit 11. For example, if the distance measured by the measurement unit 11 is far, the position of the third roller 17 is brought closer to the heights of the first roller 19 and the second roller 21 so that the string 7 has a long left - right trajectory in FIG. 1. For example, if the distance measured by the measurement unit 11 is near, the position of the third roller 17 is moved away from the heights of the first roller 19 and the second roller 21 so that the string 7 has a wide up - down trajectory in FIG. 1, for example, a trajectory close to a circle. In this way, the trajectory adjustment unit 14 changes the trajectory of the string 7 according to the distance measured by the measurement unit 11.

[0039] Note that in FIG. 1, the measurement unit 11 and the trajectory adjustment unit 14 may be omitted.

[0040] FIG. 2 is a diagram showing an example when the measurement unit 11 and the trajectory adjustment unit 14 are omitted in FIG. 1. The first roller 31 rotates counterclockwise. The second roller 33 rotates clockwise. A weight 37 is provided on the string 35. The first roller 31 and the second roller 33 rotate with the string 35 sandwiched therebetween and release the string 35 to the object 39. The string 35 continuously strikes the object 39 while rotating clockwise in FIG. 2. The string 35 can strike the object 39 differently depending on whether it strikes by the weight 37 or by other parts.

[0041] FIG. 3 shows an example of the weight 41 used in the inventors' experiments. The weight 41 can be attached to the string.

[0042] Figure 4 shows the experimental results when a normal tile 43 (without cracks and fully fixed to a wall or the like (in a non-floating state)) is struck by a string provided with the weight 41 in Fig. 3. Fig. 4(a) shows the situation where the tile 43 is struck. Fig. 4(b) shows the acoustic signal obtained by collecting the impact sound of the tile 43. The horizontal axis represents time (s), and the vertical axis represents amplitude (voltage). Fig. 4(c) shows the result of analyzing the spectrum of the acoustic signal in Fig. 4(b). Fig. 4(c) shows a spectrogram obtained by dividing the acoustic signal in Fig. 4(b) into 20-ms intervals, obtaining the frequency spectrum of each interval, and representing the intensity of the amplitude at each frequency by shading on the vertical axis with frequency. The horizontal axis is time (s), and the vertical axis is frequency (kHz). In this example, in Fig. 4(c), no obvious difference is observed between the case of striking with the weight 41 and the case of striking with other parts.

[0043] Figure 5 shows the experimental results when an abnormal tile 45 (not fully fixed to a wall or the like (in a floating state)) is struck by a string provided with the weight 41 in Fig. 3. Fig. 5(a) shows the situation where the tile 45 is struck. Fig. 5(b) shows the acoustic signal obtained by collecting the impact sound of the tile 45. The horizontal axis represents time (s), and the vertical axis represents amplitude (voltage). Fig. 5(c) shows the result of analyzing the spectrum of the acoustic signal in Fig. 5(b). Fig. 5(c) shows a spectrogram obtained by dividing the acoustic signal in Fig. 5(b) into 20-ms intervals, obtaining the frequency spectrum of each interval, and representing the intensity of the amplitude at each frequency by shading on the vertical axis with frequency. The horizontal axis is time (s), and the vertical axis is frequency (kHz). In this example, in Fig. 5(c), an obvious difference occurs between the case of striking with the weight 41 and the case of striking with other parts. That is, by striking with the weight 41, a sound from 0.5 kHz to 1 kHz is generated, which is different from other parts.

[0044] Comparing Fig. 4(c) with Fig. 5(c), it can be seen that in the spectrogram of the normal tile 43, there is almost no sound in the frequency range above 0.3 kHz, while in the spectrogram of the abnormal tile 45, sounds are generated in the frequency range from 0.5 kHz to 1.0 kHz at the times of 0.26 s, 0.56 s, and 0.86 s. This sound is the sound generated when the weight 41 strikes the abnormal tile 45, and the abnormal tile 45 can be detected from this sound.

[0045] Figs. 6 and 7 show the experimental results that can be obtained by applying impacts with a long string.

[0046] Referring to Fig. 6(a), the impact application device 51 includes a first roller 52, a second roller 53, and a guiding portion 54. A weight 56 is provided on the string 55. The first roller 52 and the second roller 53 rotate while sandwiching the string 55, thereby applying an impact to the part 57 of the object by the string 55. When the string 55 reaches a sufficient speed, the string 55 is held almost horizontally.

[0047] Fig. 6(b) is a figure following Fig. 6(a), and the weight 56 is moving from the impact application device 51 toward the part 57 of the object.

[0048] Fig. 7(a) is a figure following Fig. 6(b), and the weight 56 is moving further from the impact application device 51 toward the part 57 of the object.

[0049] Fig. 7(b) is a figure following Fig. 7(a), and the weight 56 is applying an impact to the part 57 of the object.

[0050] As shown in Figs. 6 and 7, even with a sufficiently long string, an impact can be applied to the object.

[0051] Fig. 8 is a diagram for explaining an example of the operation when the distance between the impact application device and the object is relatively short.

[0052] As shown in Fig. 8(a), even if the distance between the impact imparting device and the object is short, if the first roller 61 and the second roller 63 release the string 65 provided with the weight 67 toward the object 69 with the string 65 sandwiched therebetween, the string 65 moves toward the object 69 according to the momentum imparted when it is released. Therefore, the string 65 hits the appropriate position of the object 69. However, the momentum of the string 65 weakens when it hits the object 69. The rotation of the first roller 61 and the second roller 63 also contributes to recovering the string 65, but the force for recovery is weakest near the object 69. Therefore, the string 65 drops downward near the object 69 and then moves toward the first roller 61 and the second roller 63 by the rotation of the first roller 61 and the second roller 63.

[0053] The present invention is robust against distance and does not need to be set to a predetermined value. Even if the distance becomes short, the string 65 can impart an impact. However, in the case where the variation in distance is large, etc., there is a risk that the phenomenon of dropping near the object 69 has an adverse effect.

[0054] As shown in Fig. 8(b), a measuring machine 81 that measures the distance between the impact imparting device and the object and a third roller 83 inside the string 75 are provided. The first roller 71 and the second roller 73 release the string 75 provided with the weight 77 toward the object 79 with the string 75 sandwiched therebetween. The third roller 83 is located inside a portion of the string 75 from when it imparts an impact to the object 79 until it returns to the first roller 71 and the second roller 73. The third roller 83 is at a position lower than the first roller 71 and the second roller 73. If the distance measured by the measuring machine 81 is far, the third roller 83 moves to the upper right of the figure to approach the height of the second roller, making the trajectory of the string 75 longer horizontally. If the distance measured by the measuring machine 81 is short, the third roller 83 moves to the lower left of the figure to become lower, making the trajectory of the string 75 longer vertically. Thereby, even if the variation in the distance between the impact imparting device and the object is large, it is possible to reduce the deflection and realize smooth movement of the string 75.

[0055] When an impact is applied due to water hammer or the like as described in Patent Document 1, since water is heavy and it is necessary to continuously supply water, it has been difficult to incorporate it into a flying device such as a drone. On the other hand, since the present invention utilizes an annular string, water supply and the like are not required, and it is easy to incorporate it into a flying device or the like.

Explanation of Signs

[0056] 1 Impact system 3 Wall 4 Object 5 Impact applying device 7 String 9 Weight 11 Measuring unit 13 Shooter unit 14 Orbit adjusting unit 15 Adjusting unit 17 Third roller 19 First roller 21 Second roller 23 Driving unit 25 Inspection device 27 Recording unit 29 Processing unit 31 First roller 33 Second roller 35 String 37 Weight 39 Object 41 Weight 43 Normal tile 45 Abnormal tile 51 Impact applying device 52 First roller 53 Second roller 54 Induction unit 55 String 56 Weight 57 Part 61 First roller 63 Second roller 65 String 67 Weight 69 Object 71 First roller 73 Second roller 75 String 77 Weight 79 Object 81 Measuring instrument 83 Third roller

Claims

1. A striking system for imparting a strike to an object for impact sound inspection of the object, comprising: a string and a striking device having a shooter section; the string is loop-shaped and includes a first portion and a second portion; the shooter section releases each portion of the string toward the object to rotate the string; the first portion and the second portion released by the shooter section return to the shooter section after striking the object and are released toward the object by the shooter section; in the trajectory of the string, there are a first trajectory from the time of release by the shooter section to the object and a second trajectory from the object to the shooter section, the first trajectory and the second trajectory are different, and when the first portion is in the first trajectory, the second portion is in the second trajectory. A striking system.

2. The striking system according to claim 1, wherein the first portion and the second portion have different weights and / or different shapes of the surfaces for striking the object.

3. The striking system according to claim 1, wherein the striking device includes a trajectory adjusting section for changing the trajectory of the string.

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