Bolt looseness detection device

Abstract

To provide a bolt looseness detection device capable of detecting generation of loosening of a bolt regardless of a viewing direction of the bolt.SOLUTION: A bolt looseness detection device according to the present invention comprises: a detection plate 2 one end part of which is fixed to a bolt 1 or a nut, and which rotates when the bolt 1 or the nut is loosened; a fixed member 4 which is installed in contact with the other end part of the detection plate 2 or in close contactable proximity; and a looseness detection member 5 which is installed on the detection plate 2 or the fixed member 4, and falls off when the detection plate 2 rotates. The looseness detection member 5 falls off as the detection plate 2 rotates when the bolt 1 or the nut is loosened.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] The present invention relates to a device for detecting loosening of a fastening element such as a bolt. [Background technology]

[0002] Fastening elements are elements that connect parts (fastened objects), such as bolts, washers, nuts, and rivets, and are used in assembling machines, buildings, and the like. In general, when multiple fastened objects are tightened and fixed with a fastening element, such as a bolt, an axial force is generated in the bolt, compressing and connecting the fastened objects. When the bolt becomes loose in a fastening part, the axial force decreases or becomes zero, and the load transmission force of the fastening part intended at the time of design is reduced or lost.

[0003] Loosening of a bolt can be detected, for example, by measuring the axial force of the bolt. Known methods for measuring the axial force of a bolt include using a strain gauge, an ultrasonic axial force meter, a load cell type axial force meter, and a hydraulic axial force meter. However, these methods do not necessarily efficiently and effectively detect loosening of a bolt.

[0004] An example of an efficient and effective method for detecting loosening of a bolt is to mark (match marks) on the bolt, nut, washer, or fastened object. Although this method does not allow quantitative measurement of the axial force of the bolt, it is possible to visually detect the occurrence of loosening of the bolt from the change in the position of the match marks without using special measuring equipment.

[0005] Patent Document 1 discloses a technique for managing bolt tightening using a match mark and an angle scale attached to the fastened object as marks similar to match marks. The technique described in Patent Document 1 makes it possible to detect loosening of the bolt from changes in the position of the vertical ridge of the bolt corner relative to the match mark and angle scale. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 3-130907 Summary of the Invention [Problem to be solved by the invention]

[0007] In a method of detecting loosening of a fastening element (e.g., a bolt) using a mark such as a match mark attached to a fastened object, if the match mark cannot be seen, it is not possible to detect the occurrence of loosening of the bolt. For example, it is difficult to see the match mark attached to the fastened object from the side direction of the bolt and nut (i.e., the direction intersecting the axial direction of the bolt), and it is difficult to detect the occurrence of loosening of the bolt. In addition, it is difficult to accurately see the match mark at a position away from the bolt unless a high-precision or high-performance optical device is used, and the accuracy of recognizing loosening of the bolt may decrease or it may become impossible to recognize it.

[0008] As described above, with conventional techniques, depending on the viewing direction of a fastening element such as a bolt, it is difficult to visually detect the occurrence of loosening of the fastening of the bolt.

[0009] An object of the present invention is to provide a bolt loosening detection device that can detect the occurrence of loosening of a bolt regardless of the viewing direction of the bolt. [Means for solving the problem]

[0010] The bolt loosening detection device according to the present invention comprises a detection plate having one end fixed to a bolt or a nut and rotating when the bolt or the nut is loosened, a fixing member installed in contact with or in close proximity to the other end of the detection plate so as to be contactable, and a loosening detection member installed on the detection plate or the fixing member and falling off when the detection plate rotates. When the bolt or the nut is loosened, the loosening detection member falls off when the detection plate rotates. Effect of the Invention

[0011] According to the present invention, it is possible to provide a bolt loosening detection device that can detect the occurrence of loosening of a bolt regardless of the viewing direction of the bolt.

[0012] Problems, configurations and effects other than those described above will become apparent from the following description of the preferred embodiment of the invention. [Brief description of the drawings]

[0013] [Figure 1A] FIG. 1 is a diagram showing an outline of a bolt loosening detection device according to a first embodiment of the present invention, and is a front view of the bolt loosening detection device. [Figure 1B] FIG. 1 is a diagram showing an outline of a bolt loosening detection device according to a first embodiment of the present invention, and is a side view of the bolt loosening detection device. [Figure 1C] 1 is a side view of the bolt loosening detection device in accordance with the first embodiment, in which the loosening detection member has fallen off the detection plate. FIG. [Figure 1D] FIG. 2 is a diagram showing a schematic front view of the bolt loosening detection device in the first embodiment. [Figure 1E] 4 is another diagram showing a schematic front view of the bolt loosening detection device in the first embodiment. FIG. [Figure 2A] 13A and 13B are diagrams showing an example of a rectangular loosening detection member smaller than the detection plate. [Figure 2B] 13A and 13B are diagrams showing an example of a loosening detection member that is installed on a detection plate and protrudes from the detection plate. [Figure 2C] 13A and 13B are diagrams showing examples of loosening detection members that are sized to protrude from the fixed member when the detection plate comes into contact with the fixed member; [Figure 2D] 13A and 13B are diagrams showing an example of a circular loosening detection member that is smaller than the detection plate. [Figure 2E] 11A and 11B are diagrams showing examples of loosening detection members attached to a detection plate by spot welding. [Figure 2F] 13A and 13B are diagrams showing an example of a loosening detection member fixed by a pin and installed on a detection plate. [Figure 2G]13A and 13B are diagrams showing examples of loosening detection members that are attached to a detection plate at protrusions. [Figure 2H] 13A and 13B are diagrams showing examples of loosening detection members attached to a detection plate at a bent portion. [Figure 2I] 13A and 13B are diagrams showing examples of loosening detection members that are attached to a detection plate by magnetic force. [Figure 2J] 13A and 13B are diagrams showing another example of a loosening detection member that is attached to a detection plate by magnetic force. [Figure 2K] 13A and 13B are diagrams showing still another example of a loosening detection member that is attached to a detection plate by magnetic force. [Figure 3A] 1A and 1B are diagrams showing an example of a fixing member having a cylindrical shape and installed on a fastened body. [Figure 3B] 1A and 1B are diagrams showing an example of a fixing member having a rectangular parallelepiped shape and installed on a fastened body. [Figure 3C] 13A and 13B are diagrams illustrating examples of fixing members mounted on washers. [Figure 3D] FIG. 13 is a diagram showing an example of a fixing member installed in a large screw seat. [Figure 3E] 13A and 13B are diagrams showing an example of a fixing member formed of a part of a large screw seat. [Figure 3F] 1A and 1B are diagrams showing an example of a fixing member made of a structure that is not directly connected to a fastened body. [Figure 4A] FIG. 13 is a front view of a bolt loosening detection device showing an example of a cap shaped to cover the head of a bolt. [Figure 4B] FIG. 13 is a side view of a bolt loosening detection device showing an example of a cap shaped to cover the head of a bolt. [Figure 4C] FIG. 13 is a front view of a bolt loosening detection device showing an example of a cap shaped to surround the entire outer periphery of the head of a bolt. [Figure 4D] FIG. 13 is a diagram showing an example of a cap shaped to completely surround the outer periphery of the head of a bolt, and is a side view of a bolt loosening detection device. [Figure 4E] FIG. 13 is a front view of a bolt loosening detection device showing an example of a cap shaped to surround part of the outer periphery of the head of a bolt. [Figure 4F]FIG. 13 is a diagram showing an example of a cap shaped to surround part of the outer periphery of the head of a bolt, and is a side view of a bolt loosening detection device. [Figure 4G] FIG. 13 is a diagram showing an example of a bolt loosening detection device that does not have a cap. [Figure 5A] FIG. 10 is a diagram showing an outline of a bolt loosening detection device according to a fifth embodiment of the present invention, and is a front view of the bolt loosening detection device. [Figure 5B] FIG. 10 is a diagram showing an outline of a bolt loosening detection device according to a fifth embodiment of the present invention, and is a side view of the bolt loosening detection device. [Figure 5C] FIG. 13 is a diagram showing an example of a cap having a shape that surrounds the entire outer periphery of the head of the bolt in the fifth embodiment, and is a front view of a bolt loosening detection device. [Figure 5D] FIG. 13 is a diagram showing an example of a cap having a shape that surrounds the entire outer periphery of the head of the bolt in the fifth embodiment, and is a side view of a bolt loosening detection device. [Figure 5E] FIG. 13 is a diagram showing an example of a cap shaped to surround part of the outer periphery of the head of a bolt in the fifth embodiment, and is a front view of a bolt loosening detection device. [Figure 5F] FIG. 13 is a diagram showing an example of a cap shaped to surround part of the outer periphery of the head of a bolt in the fifth embodiment, and is a side view of a bolt loosening detection device. [Figure 5G] FIG. 13 is a diagram showing an example of a bolt loosening detection device not provided with a cap in the fifth embodiment. [Figure 6A] FIG. 13 is a diagram showing an outline of a bolt loosening detection device according to a sixth embodiment of the present invention, and is a front view of the bolt loosening detection device. [Figure 6B] FIG. 13 is a diagram showing an outline of a bolt loosening detection device according to a sixth embodiment of the present invention, and is a side view of the bolt loosening detection device. [Figure 6C] FIG. 13 is a schematic front view of a bolt loosening detection device in a sixth embodiment; [Figure 6D] FIG. 23 is a side view of the bolt loosening detection device in the sixth embodiment, in which the loosening detection member has fallen off the detection plate. [Figure 7A]13 is a diagram showing an example of a portion of a detection plate where a loosening detection member 5 is provided. FIG. [Figure 7B] 13 is a diagram showing another example of a portion of the detection plate where the loosening detection member is provided. FIG. [Figure 7C] 13 is a diagram showing another example of a portion of the detection plate where the loosening detection member is provided. FIG. [Figure 7D] 13 is a diagram showing another example of a portion of the detection plate where the loosening detection member is provided. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A fastening element, for example a bolt, fastens and fixes multiple fastened objects, but loosening may occur due to thermal deformation, vibration, etc. By using the bolt loosening detection device of the present invention, it is possible to visually detect the occurrence of loosening of the bolt, regardless of the viewing direction of the bolt. Therefore, by using the bolt loosening detection device of the present invention, it is possible to visually detect the occurrence of loosening of the bolt, for example, even in cases where the bolt is placed in a narrow section and the bolt can only be viewed from a specific direction such as the side direction (i.e., the direction intersecting the axis of the bolt) or where only the side of the bolt can be viewed from the position of a monitor or monitor device for loosening of the bolt.

[0015] The bolt loosening detection device of the present invention comprises a detection plate one end of which is fixed to a bolt or a nut, a fixing member capable of abutting the other end of the detection plate, and a loosening detection member attached to the detection plate or the fixing member, and when the bolt or the nut becomes loose, the detection plate rotates, and when the detection plate rotates, the loosening detection member falls off. A bolt loosening monitor can detect the occurrence of loosening of the bolt by the falling off of the loosening detection member.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The examples are illustrative for explaining the present invention, and are omitted and simplified as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0017] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0018] When there are multiple components having the same or similar functions, they may be described by using the same reference numerals with different subscripts, or when there is no need to distinguish between these multiple components, the subscripts may be omitted. EXAMPLES

[0019] A bolt loosening detection device according to a first embodiment of the present invention will be described.

[0020] 1A and 1B are schematic diagrams showing a bolt loosening detection device according to the present embodiment, in which Fig. 1A is a front view of the bolt loosening detection device, and Fig. 1B is a side view of the bolt loosening detection device.

[0021] The bolt loosening detection device according to this embodiment includes a detection plate 2, a cap 3, a fixing member 4, and a loosening detection member 5, and is installed on a bolt or a nut. In the following, as an example, an example in which the bolt loosening detection device is installed on a bolt 1 will be described. The bolt 1 and the nut will be represented by the bolt 1. For example, loosening of the fastening of the bolt 1 or the nut will be described as the fastening of the bolt 1 being loosened. Note that, as will be described in Example 4, the bolt loosening detection device does not have to include the cap 3.

[0022] The bolt 1, together with a nut, fastens a fastened object 17. A plurality of fastened objects 17 are fastened to one another and fixed by the bolt 1 and the nut.

[0023] The detection plate 2 is a plate-like member extending from the bolt or nut (bolt 1 in this embodiment) toward the fixed member 4, and one end in the extension direction is indirectly or directly fixed to the bolt 1. When the bolt loosening detection device is equipped with a cap 3, one end of the detection plate 2 is indirectly fixed to the bolt 1 via the cap 3. When the bolt loosening detection device is not equipped with a cap 3, one end of the detection plate 2 is directly fixed to the bolt 1 without the cap 3.

[0024] In this embodiment, since the bolt loosening detection device includes the cap 3, one end of the detection plate 2 is indirectly fixed to the bolt 1 via the cap 3. That is, in this embodiment, one end of the detection plate 2 is fixed to the cap 3.

[0025] The detection plate 2 is a member that undergoes bending deformation, and flexes to detect loosening of the bolt 1. The detection plate 2 can be made of, for example, metal or resin. The orientation of the face of the detection plate 2 can be determined arbitrarily. Figs. 1A and 1B show, as an example, a case in which the face of the detection plate 2 faces in the direction of rotation of the bolt 1. The detection plate 2 can also be made of a rod-shaped member.

[0026] Cap 3 is a member that is attached to bolt 1, and one end of detection plate 2 is fixed thereto. Cap 3 is a member that surrounds the head of bolt 1, and surrounds at least a portion of the outer periphery of the head of bolt 1. Cap 3 is fixed to bolt 1, and rotates together with bolt 1 when bolt 1 loosens and rotates. Cap 3 can be made of, for example, metal or resin.

[0027] When the bolt 1 is loosened and rotates, the detection plate 2 rotates together with the bolt 1 and cap 3, or together with the bolt 1, due to the rotating force of the bolt 1.

[0028] The fixed member 4 is a member that can come into contact with the other end of the detection plate 2 in the extension direction. The fixed member 4 is installed in contact with the other end of the detection plate 2, or installed close to the other end of the detection plate 2 so as to be able to come into contact with it. The fixed member 4 is fixed against the rotational movement of the detection plate 2, and is a member that prevents the rotation of the detection plate 2. When the detection plate 2 rotates and applies a force to the fixed member 4, the fixed member 4 bends the detection plate 2 by its reaction.

[0029] The loosening detection member 5 is a plate-like member that is installed on the detection plate 2. The loosening detection member 5 is made of a material having a higher bending rigidity than the detection plate 2, and can be made of, for example, metal, magnetic material, resin, or rubber. The loosening detection member 5 can be installed on the detection plate 2 by, for example, adhesion. Another example of a method for installing the loosening detection member 5 on the detection plate 2 will be described in Example 2.

[0030] When the bolt 1 loosens and rotates, the detection plate 2 rotates. When the detection plate 2 comes into contact with the fixed member 4 and its rotation is prevented by the fixed member 4, the detection plate 2 undergoes bending deformation and bends. When the detection plate 2 bends, the looseness detection member 5, which has a higher bending rigidity than the detection plate 2, is partially peeled off from the detection plate 2 and falls from the detection plate 2. In this way, the looseness detection member 5 falls off from the detection plate 2 when the detection plate 2 rotates.

[0031] Fig. 1C is a side view of the bolt loosening detection device in which the loosening detection member 5 has fallen off the detection plate 2. Fig. 1C shows a portion 6 of the detection plate 2 where the loosening detection member 5 was installed. The portion 6 is the part of the detection plate 2 that was hidden by the loosening detection member 5 before it fell off.

[0032] Figures 1D and 1E are schematic diagrams showing the front of the bolt loosening detection device. In Figures 1D and 1E, the upper diagram shows the state before the detection plate 2 is deflected. The center diagram shows the state in which the detection plate 2 has begun to deflect and the loosening detection member 5 has partially peeled off from the detection plate 2. The lower diagram shows the state in which the detection plate 2 has further deflected and the loosening detection member 5 has fallen off from the detection plate 2.

[0033] In the bolt loosening detection device shown in Fig. 1D, the loosening detection member 5 is attached to the surface of the detection plate 2 that bends and contracts. In the bolt loosening detection device shown in Fig. 1E, the loosening detection member 5 is attached to the surface of the detection plate 2 that bends and expands. Regardless of which surface of the detection plate 2 the loosening detection member 5 is attached to, it will fall off from the detection plate 2 when the detection plate 2 bends.

[0034] A monitor for loosening of bolts can detect the occurrence of loosening of the fastening of bolt 1 by ascertaining that loosening detection member 5 is not present at portion 6 ( FIG. 1C ) of detection plate 2 where loosening detection member 5 was installed, or by recognizing loosening detection member 5 that has fallen off detection plate 2. The monitor may directly confirm by visual inspection that there is no loosening detection member 5 on detection plate 2 or that there is a loosening detection member 5 that has fallen off detection plate 2, or may confirm from an image captured by a photographing device.

[0035] In the bolt loosening detection device of this embodiment, the occurrence of loosening of the fastening of the bolt 1 can be detected regardless of the viewing direction of the bolt 1 by utilizing the fact that the detection plate 2 bends and deforms, causing the loosening detection member 5 to fall off from the detection plate 2. EXAMPLES

[0036] A second embodiment of the present invention will be described. In this embodiment, the loosening detection member 5 will be described. The shape of the loosening detection member 5 and the method of installing it on the detection plate 2 can be determined arbitrarily. In this embodiment, an example of the shape of the loosening detection member 5 and the method of installing it on the detection plate 2 will be described. Note that, regarding this embodiment, the description of the configuration and effects common to the first embodiment will be omitted.

[0037] 2A is a diagram showing an example of a rectangular loosening detection member 5 smaller than the detection plate 2. The shape of the loosening detection member 5 can be, for example, a rectangle smaller than the detection plate 2.

[0038] 2B is a diagram showing an example of a loosening detection member 5 that is installed on the detection plate 2 and protrudes from the detection plate 2. The loosening detection member 5 can be installed on the detection plate 2, for example, protruding from the detection plate 2. The loosening detection member 5 shown in FIG. 2B may be of a size that protrudes from the fixed member 4 when the detection plate 2 abuts against the fixed member 4.

[0039] FIG. 2C is a diagram showing an example of a loosening detection member 5 that is sized to protrude from fixed member 4 when detection plate 2 comes into contact with fixed member 4. As shown in FIG.

[0040] 2D is a diagram showing an example of a circular loosening detection member 5 that is smaller than the detection plate 2. The shape of the loosening detection member 5 can be, for example, a circle that is smaller than the detection plate 2.

[0041] 2E is a diagram showing an example of a loosening detection member 5 attached to the detection plate 2 by spot welding 9. The loosening detection member 5 can be attached to the detection plate 2 by spot welding 9, for example.

[0042] 2F is a diagram showing an example of a loosening detection member 5 fixed by a pin 10 and installed on the detection plate 2. The loosening detection member 5 can be fixed by a pin 10 and installed on the detection plate 2, for example.

[0043] 2G is a diagram showing an example of a loosening detection member 5 that is attached to the detection plate 2 by a protrusion 11. The loosening detection member 5 includes, for example, a protrusion 11, and can be attached to the detection plate 2 by inserting or crimping the protrusion 11 into a hole provided in the detection plate 2.

[0044] 2H is a diagram showing an example of a loosening detection member 5 that is attached to the detection plate 2 at a bent portion 12. The loosening detection member 5 includes, for example, a bent portion 12 that is a folded portion, and can be attached to the detection plate 2 by placing (or hooking) the bent portion 12 on a side surface of the detection plate 2.

[0045] 2I is a diagram showing an example of a loosening detection member 5 that is magnetically attached to the detection plate 2. The loosening detection member 5 is made of a magnet, for example, and can be magnetically attached to the detection plate 2 that is made of a magnetic material.

[0046] 2J is a diagram showing another example of loosening detection member 5 that is magnetically attached to detection plate 2. Loosening detection member 5 is made of, for example, a magnet, and can be magnetically attached to detection plate 2 by sandwiching detection plate 2 made of a non-magnetic material between member 14 made of a magnetic material (for example, a steel member).

[0047] 2K is a diagram showing yet another example of loosening detection member 5 that is attached to detection plate 2 by magnetic force. Loosening detection member 5 is made of, for example, a magnetic material (e.g., a piece of iron), and can be attached to detection plate 2 by magnetic force by sandwiching detection plate 2 made of a non-magnetic material between member 16 made of a magnet.

[0048] For example, by having the configuration as described in this embodiment, the loosening detection member 5 is peeled off and falls off the detection plate 2 when the detection plate 2 is bent and deformed. EXAMPLES

[0049] Example 3 of the present invention will be described. In this example, the fixing member 4 will be described. The shape and arrangement of the fixing member 4 can be determined arbitrarily. In this example, an example of the shape and arrangement of the fixing member 4 will be described. Note that, in this example, the description of the configuration and effects common to Example 1 will be omitted.

[0050] 3A is a diagram showing an example of a fixing member 4 that has a cylindrical shape and is installed on a fastened body 17. The fixing member 4 can be, for example, cylindrical and fixed to the fastened body 17.

[0051] 3B is a diagram showing an example of a fixing member 4 that has a rectangular parallelepiped shape and is installed on a fastened body 17. The fixing member 4 can be, for example, a rectangular parallelepiped shape and fixed to the fastened body 17.

[0052] 3C is a diagram showing an example of a fixing member 4 installed on a washer 19. The fixing member 4 may be, for example, cylindrical in shape and fixed to the washer 19.

[0053] 3D is a diagram showing an example of a fixing member 4 installed in a large screw seat 20. The large screw seat 20 is a washer larger than the washer 19 shown in FIG. 3C. The fixing member 4 may be, for example, cylindrical in shape and fixed to the large screw seat 20.

[0054] 3E is a diagram showing an example of a fixing member 4 configured as a part of the large screw seat 20. For example, the large screw seat 20 has a bent portion in a part (for example, an end portion), and this bent portion can be used as the fixing member 4.

[0055] 3F is a diagram showing an example of a fixing member 4 composed of a structure that is not directly connected to the fastened body 17. For example, structures such as parts, devices, and piping that exist near the fastened body 17, and protrusions of these structures can be the fixing member 4. In addition, for example, the floor, wall, and ceiling of a building that exists near the fastened body 17, and protrusions of these can be the fixing member 4.

[0056] The fixed member 4 has a configuration, for example, as described in this embodiment, so that when the detection plate 2 rotates and applies force to the fixed member 4, the detection plate 2 is bent and the loosening detection member 5 falls off from the detection plate 2. EXAMPLES

[0057] A fourth embodiment of the present invention will be described. In this embodiment, the cap 3 will be described. The shape of the cap 3 can be determined arbitrarily. In this embodiment, an example of the shape of the cap 3 will be described. Below, the cap 3 shaped to surround the bolt 1 will be described, but the cap 3 can also surround the nut. Note that, regarding this embodiment, the description of the configuration and effects common to the first embodiment will be omitted.

[0058] Figures 4A and 4B are diagrams showing examples of a cap 3 shaped to cover the head of a bolt 1. Figure 4A is a front view of a device for detecting loosening of a bolt. Figure 4B is a side view of a device for detecting loosening of a bolt. The cap 3 can be shaped to surround the head of the bolt 1 by covering the head (or nut) of the bolt 1, for example.

[0059] Figures 4C and 4D are diagrams showing examples of cap 3 shaped to surround the entire outer periphery of the head of bolt 1. Figure 4C is a front view of a bolt loosening detection device. Figure 4D is a side view of a bolt loosening detection device. Cap 3 can be shaped to surround the entire outer periphery of the head (or nut) of bolt 1, for example.

[0060] Figures 4E and 4F are diagrams showing examples of cap 3 shaped to surround part of the outer periphery of the head of bolt 1. Figure 4E is a front view of a device for detecting loosening of a bolt. Figure 4F is a side view of a device for detecting loosening of a bolt. Cap 3 can be shaped to surround part of the outer periphery of the head (or nut) of bolt 1 (e.g., a wrench shape).

[0061] As described in the first embodiment, the bolt loosening detection device does not need to include the cap 3. Below, a bolt loosening detection device not including the cap 3 will be described.

[0062] Fig. 4G is a diagram showing an example of a bolt loosening detection device that does not have a cap 3. Fig. 4G shows a front view of the bolt loosening detection device.

[0063] The bolt 1 does not include a cap 3. One end of the detection plate 2 is directly joined to the head (or nut) of the bolt 1 by any method, such as spot welding, adhesive bonding, or caulking.

[0064] By having the configuration as described in this embodiment, for example, the cap 3 rotates together with the bolt 1 when the bolt 1 rotates, rotating the detection plate 2 and causing the loosening detection member 5 to fall off from the detection plate 2. Even if the bolt loosening detection device does not have the cap 3, the detection plate 2 is fixed to the bolt 1, so that when the bolt 1 rotates, the detection plate 2 rotates and the loosening detection member 5 falls off from the detection plate 2. EXAMPLES

[0065] A fifth embodiment of the present invention will be described. In this embodiment, the loosening detection member 5 is not provided on the detection plate 2 but on the fixed member 4. Note that, regarding this embodiment, the description of the configuration and effects common to the first embodiment will be omitted.

[0066] 5A and 5B are schematic diagrams showing a bolt loosening detection device according to this embodiment, in which Fig. 5A is a front view of the bolt loosening detection device, and Fig. 5B is a side view of the bolt loosening detection device.

[0067] One end of the detection plate 2 is fixed to the cap 3. That is, one end of the detection plate 2 is indirectly fixed to the bolt 1 via the cap 3. No loosening detection member 5 is provided on the detection plate 2.

[0068] A loosening detection member 5 is provided on the fixed member 4. A part of the loosening detection member 5 is a protruding portion 5a that protrudes from the fixed member 4. The detection plate 2 can come into contact with this protruding portion 5a.

[0069] When the bolt 1 is loosened and rotates, the detection plate 2 rotates. The detection plate 2 then comes into contact with the protruding portion 5a of the loosening detection member 5, and the force of the contact repels the protruding portion 5a. The protruding portion 5a of the loosening detection member 5 is repelled by the detection plate 2, and the loosening detection member 5 falls from the detection plate 2. In this way, when the detection plate 2 rotates, the loosening detection member 5 falls off the fixed member 4.

[0070] In the bolt loosening detection device of this embodiment, since the detection plate 2 does not have a loosening detection member 5, the length of the detection plate 2 (the length extending from the bolt 1 toward the fixing member 4) can be short, and it can be installed in a narrower space.

[0071] In the bolt loosening detection device according to this embodiment, the shape of the cap 3 can be determined arbitrarily, as described in the fourth embodiment.

[0072] 5A and 5B show examples of a cap 3 shaped to cover the head (or nut) of the bolt 1 and surround the head of the bolt 1. FIG.

[0073] Figures 5C and 5D are diagrams showing examples of cap 3 shaped to surround the entire outer periphery of the head of bolt 1. Figure 5C is a front view of a device for detecting loosening of a bolt. Figure 5D is a side view of a device for detecting loosening of a bolt. The shape of cap 3 can be, for example, a shape that surrounds the entire outer periphery of the head (or nut) of bolt 1.

[0074] Figures 5E and 5F are diagrams showing examples of cap 3 shaped to surround part of the outer periphery of the head of bolt 1. Figure 5E is a front view of a device for detecting loosening of a bolt. Figure 5F is a side view of a device for detecting loosening of a bolt. The shape of cap 3 can be, for example, a shape (e.g., a wrench shape) that surrounds part of the outer periphery of the head (or nut) of bolt 1.

[0075] As described in the first and fourth embodiments, the bolt loosening detection device does not need to include the cap 3.

[0076] Fig. 5G is a diagram showing an example of a bolt loosening detection device that does not have a cap 3. Fig. 5G shows a front view of the bolt loosening detection device.

[0077] The bolt 1 does not include a cap 3. One end of the detection plate 2 is directly joined to the head (or nut) of the bolt 1. When the bolt 1 rotates, the detection plate 2 rotates and the loosening detection member 5 falls off the fixing member 4.

[0078] In the bolt loosening detection device of this embodiment, the detection plate 2 abuts against the protrusion 5a of the loosening detection member 5, causing the loosening detection member 5 to fall off from the fixed member 4, so that loosening of the fastening of the bolt 1 can be detected regardless of the viewing direction of the bolt 1. EXAMPLES

[0079] A sixth embodiment of the present invention will be described. In this embodiment, the detection plate 2 is in contact with the fixed member 4 before the fastening of the bolt 1 is loosened and the bolt 1 rotates. Note that, regarding this embodiment, the description of the configuration and effects common to the first embodiment will be omitted.

[0080] Figures 6A and 6B are schematic diagrams showing a bolt loosening detection device according to this embodiment. Figure 6A is a front view of the bolt loosening detection device. Figure 6B is a side view of the bolt loosening detection device. Detection plate 2 is in contact with fixed member 4 in a deflected state even before bolt 1 is loosened and rotates.

[0081] Fig. 6C is a schematic diagram showing the front of the bolt loosening detection device. As shown in Fig. 6C, the detection plate 2 is bent in the initial state, and the other end is in contact with the fixed member 4. In the bent state, the detection plate 2 is held by the fixed member 4. Note that Fig. 6C shows the detection plate 2 bent significantly in order to emphasize the bending of the detection plate 2.

[0082] When the bolt 1 loosens and rotates, the detection plate 2, whose rotation is prevented by the fixing member 4, is subjected to a force in the rotational direction and bends further. As this bending progresses, the force that the detection plate 2 applies to the fixing member 4 increases, and the fixing member 4 can no longer hold the detection plate 2. The bent detection plate 2 is then released from the holding by the fixing member 4 and begins to vibrate. This vibration of the detection plate 2 causes the loosening detection member 5 to fall off the detection plate 2.

[0083] Fig. 6D is a side view of the device for detecting loosening of a bolt, in which the loosening detection member 5 has fallen off the detection plate 2. Fig. 6D shows a state in which the detection plate 2 has vibrated and the loosening detection member 5 has fallen off from the detection plate 2.

[0084] In this embodiment, the loosening detection member 5 falls off the detection plate 2 due to vibration of the detection plate 2, making it possible to detect the occurrence of loosening in the fastening of the bolt 1. For example, in this embodiment, even if the detection plate 2 is intentionally deflected in the initial state or if the detection plate 2 is unintentionally deflected in the initial state, it is possible to detect the occurrence of loosening in the fastening of the bolt 1. For example, even if the detection plate 2 is deflected unexpectedly in the initial state because the position of the fixing member 4 cannot be adjusted or the initial position of the detection plate 2 in the rotation direction is a position that causes the detection plate 2 to bend, in this embodiment, the loosening detection member 5 falls off the detection plate 2, making it possible to detect the occurrence of loosening in the fastening of the bolt 1. EXAMPLES

[0085] Example 7 of the present invention will be described. In this example, the part 6 of the detection plate 2 where the loosening detection member 5 was installed, shown in Fig. 1C and Fig. 6D, will be described. Note that, regarding this example, the description of the configuration and effects common to Example 1 will be omitted.

[0086] The area 6 of the detection plate 2 where the loosening detection member 5 was installed is a portion of the detection plate 2 that is hidden by the loosening detection member 5 before it falls off, and is a portion that was not visible before the loosening detection member 5 fell off from the detection plate 2. By improving the visibility of the area 6 where the loosening detection member 5 was installed, it is possible for a person monitoring for loosening of bolts to more easily recognize that the loosening detection member 5 has fallen off from the detection plate 2.

[0087] 7A is a diagram showing an example of a portion 6 of the detection plate 2 where the loosening detection member 5 was installed. Letters or a pattern are displayed on the portion 6. In the example shown in FIG. 7A, the letters "NG" are displayed on the portion 6 as an example. A person monitoring for loosening of bolts can recognize that the loosening detection member 5 has fallen off the detection plate 2 by visually checking the letters or pattern.

[0088] 7B is a diagram showing another example of a portion 6 of the detection plate 2 where the loosening detection member 5 was installed. Fluorescent paint is applied to the portion 6. Even if the detection plate 2 is located in a dark place, a person monitoring for loosening of bolts can recognize that the loosening detection member 5 has fallen off the detection plate 2 by visually checking the detection plate 2 lit up by the fluorescent paint.

[0089] 7C is a diagram showing another example of a portion 6 of the detection plate 2 where the loosening detection member 5 was installed. A reflecting plate that reflects light is installed at portion 6. A person monitoring for loosening of bolts can recognize that the loosening detection member 5 has fallen off the detection plate 2 by visually checking the detection plate 2 from which light is reflected.

[0090] 7D is a diagram showing another example of the portion 6 of the detection plate 2 where the loosening detection member 5 was installed. The portion 6 has an opening 6a that transmits light. A person monitoring the loosening of bolts can recognize that the loosening detection member 5 has fallen off the detection plate 2 by visually checking the light transmitted through the opening 6a of the detection plate 2.

[0091] In this embodiment, the visibility of the portion 6 of the detection plate 2 where the loosening detection member 5 was installed is improved, so that a person monitoring the loosening of bolts can easily recognize that the loosening detection member 5 has fallen off the detection plate 2 and can easily detect the occurrence of loosening of the fastening of the bolt 1. [Explanation of symbols]

[0092] 1...bolt, 2...detection plate, 3...cap, 4...fixing member, 5...loosening detection member, 5a...protrusion, 6...area where the loosening detection member was installed, 6a...opening, 9...spot weld, 10...pin, 11...protrusion, 12...bent portion, 14...member made of magnetic material, 16...member made of magnet, 17...fastened body, 19...washer, 20...screw seat.

Claims

1. A detection plate having one end fixed to a bolt or a nut and rotating when the bolt or the nut is loosened; a fixing member disposed in contact with or in close proximity to the other end of the detection plate so as to be able to contact the other end of the detection plate; a loosening detection member that is attached to the detection plate or the fixed member and falls off when the detection plate rotates; Equipped with When the bolt or the nut is loosened, the detection plate rotates and the loosening detection member falls off. A bolt loosening detection device comprising:

2. The loosening detection member is installed on the detection plate, the detection plate is a member that bends when rotation is prevented by the fixed member, The loosening detection member falls off from the detection plate when the detection plate is bent. The bolt loosening detection device according to claim 1.

3. The loosening detection member is attached to the detection plate by at least one of adhesion, spot welding, a pin, and magnetic force. The bolt loosening detection device according to claim 2.

4. The fixing member is a member that is installed on a washer or a member that is configured as a part of the washer, or a structure or building that is present in the vicinity of the object to be fastened to the bolt. The bolt loosening detection device according to claim 2.

5. The loosening detection member has a bending rigidity higher than that of the detection plate. The bolt loosening detection device according to claim 2.

6. the loosening detection member is attached to the fixed member and includes a protruding portion protruding from the fixed member and capable of being contacted by the detection plate, When the detection plate rotates and comes into contact with the protrusion, the loosening detection member falls off from the fixed member. The bolt loosening detection device according to claim 1.

7. the other end of the detection plate is held by the fixing member in a bent state, When a force in a rotational direction is applied to the detection plate and the detection plate is further bent, the detection plate is released from the holding by the fixing member and vibrates. the loosening detection member falls off from the detection plate due to vibration of the detection plate; The bolt loosening detection device according to claim 2.

8. The portion of the detection plate that is hidden by the loosening detection member before it falls off is provided with at least one of characters, a pattern, fluorescent paint, a light reflector, and an opening that transmits light. The bolt loosening detection device according to claim 2.

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