Cable tray

Abstract

To provide a cable tray which is excellent in arrangement and has high earthquake resistance.SOLUTION: A cable tray includes: a plurality of trays 2 which can store cables 1; a support member 4 which supports the plurality of trays 2 and is fixed at an installation site 5; and elastic bearing members 3 being elastic members with rigidity. In the plurality of trays 2, at least one tray 2A is fixed to the support member 4 through the elastic bearing members 3, and all the other trays 2B and 2B are directly fixed to the support member 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cable tray on which cables for transmitting power, signals, etc. are laid.

Background Art

[0002] A cable tray is a facility on which cables (such as power cables, control cables, and communication cables) for transmitting power, control signals, or communication signals to electrical equipment or instrumentation equipment are laid. The cable tray is installed on a ceiling, floor, or wall in facilities such as plant facilities in factories and power plants, stations, and buildings, and includes cables, a tray for housing the cables, and a support member fixed to the installation location to support the tray.

[0003] The tray is a steel container, has a shape extending in the extending direction (axial direction) of the housed cables, and the shape in a cross section orthogonal to the axial direction is a U-shape with an open upper part. The tray is supported at regular intervals in the axial direction by support members and is fixed to the ceiling, floor, or wall of the facility. In particular, in plant facilities such as factories and power plants where many devices are operating, many cables for sending power and control signals to these devices are required. For this reason, in such facilities, the cable tray may include multi-stage support members that support a plurality of trays.

[0004] When strong seismic vibrations act on plant facilities such as factories and power plants and the cable tray is damaged, it may be difficult for these facilities to maintain an appropriate operating state. Also, when the cable tray is damaged by an earthquake, it takes time to repair after the earthquake, and the plant facilities may not be able to operate until the repair is completed. For this reason, an improvement in seismic resistance is desired for the cable tray.

[0005] Prior art for improving the seismic resistance of cable trays is described, for example, in Patent Document 1. The cable support device described in Patent Document 1 comprises a cable housing structure that houses multiple cables and includes a support member, and two support mechanisms that connect the side wall of the support member to the structure and apply elastic force to the side wall. These support mechanisms apply elastic force alternately from both sides of the support member when the cable housing structure shakes due to an earthquake, thereby reducing the shaking of the cable housing structure and improving the seismic resistance of the cable housing structure. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-139908 [Overview of the project] [Problems that the invention aims to solve]

[0007] Conventional cable trays have a problem in that installing mechanisms to improve seismic resistance increases the space required for installation, reducing their placement flexibility. For example, in the cable support device described in Patent Document 1, the support mechanism is located on the outside of the support member in order to connect the side wall of the support member to the structure. That is, one support mechanism is located on the outside of one side of the support member, and the other support mechanism is located on the outside of the other side of the support member. Therefore, space is required to connect the support mechanism to the structure, which can reduce placement flexibility. Reduced placement flexibility for cable trays limits the places where cable trays can be installed, and it may be difficult to install the necessary cable trays in facilities that require highly seismic-resistant cable trays.

[0008] The objective of the present invention is to provide a cable tray that offers excellent placement flexibility and high seismic resistance. [Means for solving the problem]

[0009] The cable tray according to the present invention comprises a plurality of trays capable of storing cables, a support member that supports the plurality of trays and is fixed to the installation location, and an elastic bearing member which is a rigid elastic member. Of the plurality of trays, at least one tray is fixed to the support member via the elastic bearing member, and all other trays are fixed directly to the support member. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a cable tray that offers excellent placement advantages and high seismic resistance. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view (vertical cross-section) of a cable tray according to an embodiment of the present invention, taken in a plane perpendicular to the extension direction of the stored cables. [Figure 2] This is a perspective view of the cable tray according to this embodiment. [Figure 3] This figure shows the vibration model of the cable tray according to this embodiment. [Figure 4] This is a cross-sectional view (vertical section) of the cable tray according to this embodiment, taken from a plane parallel to the direction of extension of the stored cables. [Figure 5A] This is a cross-sectional view of the cable tray according to this embodiment, taken in a plane perpendicular to the extension direction of the stored cables, and shows an enlarged view of the area around the elastic support member. [Figure 5B] This is a cross-sectional view of the cable tray according to this embodiment, taken in a plane parallel to the extension direction of the stored cables, and shows an enlarged view of the area around the elastic support member. [Figure 6] This is a cross-sectional view (vertical section) of the cable tray according to this embodiment, which is fixed to the floor, in a plane perpendicular to the direction of extension of the stored cables. [Figure 7] This is a cross-sectional view (vertical section) of the cable tray according to this embodiment, which is fixed to the wall, in a plane perpendicular to the direction of extension of the stored cables. [Figure 8]This is a cross-sectional view (vertical section) of a cable tray according to this embodiment, which has multiple trays arranged horizontally, in a plane perpendicular to the direction of extension of the stored cables. [Figure 9] This is a cross-sectional view (vertical section) of a cable tray according to this embodiment, in which elastic support members are installed on multiple trays in the height direction, in a plane perpendicular to the extension direction of the stored cables. [Modes for carrying out the invention]

[0012] The cable tray according to the present invention comprises a plurality of trays capable of storing cables, a support member that supports the plurality of trays, and an elastic bearing member. Of the plurality of trays, at least one tray is fixed to the support member via the elastic bearing member, while all other trays are directly fixed to the support member without the elastic bearing member. In the cable tray according to the present invention, even when a strong seismic motion acts, the tray fixed to the support member via the elastic bearing member acts as a dynamic vibration absorber, thereby suppressing the response (vibration) of the tray directly fixed to the support member and the support member during an earthquake, and improving the seismic resistance of the cable tray.

[0013] In the cable tray according to the present invention, it is not necessary to add a support mechanism located outside the support member or new reinforcing material to the support member in order to improve the seismic resistance of the cable tray, so the space required for the cable tray does not increase. For this reason, the cable tray according to the present invention has high seismic resistance and excellent placementability, and can be easily installed even in narrow spaces, for example.

[0014] Hereinafter, a cable tray according to an embodiment of the present invention will be described with reference to the drawings. In the drawings used herein, the same or corresponding components are denoted by the same reference numerals, and repeated descriptions of these components may be omitted. [Examples]

[0015] The cable tray according to this embodiment can be fixed to installation locations such as ceilings, floors, and walls. First, an example in which the cable tray according to this embodiment is fixed to a ceiling will be described.

[0016] FIG. 1 is a cross-sectional view (vertical cross-sectional view) of the cable tray according to this embodiment in a plane perpendicular to the extending direction of the housed cables. FIG. 2 is a perspective view of the cable tray according to this embodiment.

[0017] The cable tray according to this embodiment includes a cable 1, a plurality of trays 2, a support member 4, and an elastic support member 3. The cable tray shown in FIGS. 1 and 2 is fixed to a ceiling 5 which is the installation location.

[0018] The cable 1 is, for example, a cable that transmits power or signals.

[0019] The tray 2 is a container capable of housing the cable 1. The cable tray according to this embodiment can include any plurality of trays 2. The plurality of trays 2 are arranged side by side in the height direction (vertical direction) and supported by the support member 4, and each houses one or more cables 1. In the example shown in FIGS. 1 and 2, the cable tray includes three trays 2A, 2B, and 2C. The trays 2A, 2B, and 2C are arranged from bottom to top in this order and supported by the support member 4, and each houses four cables 1.

[0020] The support member 4 is a member that supports the plurality of trays 2 and is fixed to the installation location. In the example shown in FIGS. 1 and 2, since the installation location is the ceiling 5, the upper end portion of the support member 4 is connected and fixed to the ceiling 5. The support member 4 includes a plurality of placement portions 41 juxtaposed in the height direction, and each tray 2 is placed on the placement portion 41 to support the tray 2. The placement portion 41 is a member that extends in the horizontal direction (the left-right direction in FIG. 1) and can be composed of a rod-shaped or plate-shaped member.

[0021] Of the three trays 2A, 2B, and 2C, tray 2A, which is located furthest from the part where the support member 4 is fixed (the ceiling 5 in Figures 1 and 2, which is the installation location), has an elastic support member 3 installed between tray 2A and the support member 4. In other words, tray 2A is fixed to the support member 4 via the elastic support member 3. All other trays 2B and 2C are fixed directly to the support member 4 without the elastic support member 3. The elastic support member 3 suppresses vibrations of tray 2A.

[0022] In this embodiment of the cable tray, at least one of the multiple trays 2 is fixed to the support member 4 via an elastic support member 3, while all other trays 2 are directly fixed to the support member 4 without the elastic support member 3. In a more preferred configuration, at least one of the multiple trays 2 (2A) located furthest from the part to which the support member 4 is fixed is fixed to the support member 4 via the elastic support member 3, while all other trays 2 (trays 2B, 2C) are directly fixed to the support member 4. In an even more preferred configuration, only the tray 2 located furthest from the part to which the support member 4 is fixed is fixed to the support member 4 via the elastic support member 3, while all other trays 2 are directly fixed to the support member 4.

[0023] The elastic support member 3 is a rigid elastic member having desired rigidity and damping characteristics. The elastic support member 3 can be made of any material as long as the desired rigidity and damping characteristics can be set, for example, it can be made of high-damping rubber, a sliding bearing, or a coil spring and damper. The number of elastic support members 3 can be arbitrarily determined, but it is preferable to have multiple members for one tray 2. The elastic support members 3 are installed on the mounting portion 41 of the support member 4.

[0024] As described above, the elastic support member 3 does not necessarily have to be installed for all trays 2A, 2B, and 2C. Of the multiple trays 2A, 2B, and 2C, tray 2A, which is located furthest from the part where the support member 4 is fixed, experiences the greatest vibration. Therefore, if the elastic support member 3 is installed for tray 2A among the multiple trays 2A, 2B, and 2C, the vibration of tray 2A can be suppressed, thereby effectively suppressing the vibration of the entire cable tray. However, the elastic support member 3 can be installed between tray 2 and the support member 4 for any one or more of the multiple trays 2. For example, the elastic support member 3 may be installed only for tray 2A, or it may be installed for all trays 2A, 2B, and 2C.

[0025] Figure 3 shows a vibration model of the cable tray according to this embodiment. This vibration model consists of a main vibration system 12 and a secondary vibration system 13.

[0026] The main vibration system 12 comprises a spring 9A and a dashpot 10A, which are positioned side-by-side and fixed to the fixed part 11, and a mass 8A connected to the spring 9A and the dashpot 10A. The secondary vibration system 13 comprises a spring 9B and a dashpot 10B, which are positioned side-by-side and fixed to the mass 8A of the main vibration system 12, and a mass 8B connected to the spring 9B and the dashpot 10B, and operates as a dynamic vibration absorber. In the cable tray according to this embodiment shown in Figures 1 and 2, the fixed part 11 is the ceiling 5, which is the installation location.

[0027] In the cable tray according to this embodiment shown in Figures 1 and 2, the main vibration system 12 consists of a support member 4, tray 2B, tray 2C, and cables 1 housed in trays 2B and 2C, while the secondary vibration system 13 consists of tray 2A, cables 1 housed in tray 2A, and an elastic bearing member 3. In the secondary vibration system 13, the elastic bearing member 3 is represented by a spring 9B and a dashpot 10B.

[0028] The secondary vibration system 13 acts as a dynamic vibration absorber when it vibrates, absorbing the vibrations of the main vibration system 12. In other words, the vibrations of the main vibration system 12 are suppressed by the vibrations of the secondary vibration system 13. In the cable tray according to this embodiment, the vibrations of the entire cable tray are suppressed by the vibrations of the secondary vibration system 13 suppressing the vibrations of the main vibration system 12, thereby improving seismic resistance.

[0029] In the cable tray according to this embodiment, if the natural frequency of the secondary vibration system 13 is close to the natural frequency of the main vibration system 12, the secondary vibration system 13, which is a dynamic vibration absorber, can more effectively suppress the vibration of the main vibration system 12, thereby improving the seismic resistance of the cable tray. For this reason, it is preferable that the ratio of the natural frequency of the secondary vibration system 13 to the natural frequency of the main vibration system 12 is within a specific range predetermined by assuming that the natural frequencies of the secondary vibration system 13 and the main vibration system 12 are approximately equal to each other. This range is the range of natural frequency ratio values ​​in which the secondary vibration system 13 effectively absorbs and suppresses the vibration of the main vibration system 12.

[0030] Therefore, it is preferable that the elastic bearing member 3 has a rigidity such that the ratio of the natural frequency of the secondary vibration system 13 to the natural frequency of the main vibration system 12 falls within a predetermined range. This range is a specific range predetermined by assuming that the natural frequencies of the secondary vibration system 13 and the main vibration system 12 are approximately equal to each other.

[0031] For example, the ratio of the natural frequency of the secondary vibration system 13 to the natural frequency of the main vibration system 12 is preferably between 0.9 and 1.1, that is, the natural frequency of the secondary vibration system 13 is preferably within ±10% of the natural frequency of the main vibration system 12. Therefore, it is preferable that the elastic bearing member 3 has a rigidity such that the natural frequency of the secondary vibration system 13 is within ±10% of the natural frequency of the main vibration system 12.

[0032] Here, we will explain the behavior of the cable tray when it vibrates during an earthquake. When seismic motion acts on the building in which the cable tray is installed, horizontal seismic motion, which is vibration acting in the horizontal direction (left-right direction in Figure 1), is input to the cable tray from the ceiling 5.

[0033] Conventional cable trays (i.e., cable trays without elastic support members 3) respond to horizontal seismic motion input from the ceiling 5 by exhibiting horizontal displacement and acceleration. In particular, the response is greater at the lower end of the support member 4, which is far from the ceiling 5, which is the fixed part 11, and the stress at the connection point between the support member 4 and the ceiling 5 increases. When a strong seismic motion acts, stress exceeding the allowable value is generated near the connection point between the support member 4 and the ceiling 5, potentially damaging the support member 4.

[0034] In this embodiment, when horizontal seismic motion is input from the ceiling 5, the cable tray responds in the same way as a conventional cable tray, with a particularly large response at the lower end of the support member 4. However, in this embodiment, the secondary vibration system 13 (tray 2A, the cable 1 housed in tray 2A, and the elastic bearing member 3) acts as a dynamic vibration absorber, so the response of the main vibration system 12 is suppressed by the interaction between the main vibration system 12 and the secondary vibration system 13, thereby suppressing vibration of the entire cable tray.

[0035] As described above, in the cable tray according to this embodiment, the tray 2A, which is located furthest from the part where the support member 4 is fixed, has an elastic bearing member 3 installed on it and is fixed to the support member 4 via the elastic bearing member 3. Therefore, in the cable tray according to this embodiment, the secondary vibration system 13, which is tray 2A, the cable 1 housed in tray 2A, and the elastic bearing member 3, act as a dynamic vibration absorber during an earthquake, suppressing the earthquake response of the main vibration system 12, which is the support member 4, tray 2B, tray 2C, and the cable 1 housed in trays 2B and 2C, thus providing high seismic resistance.

[0036] Furthermore, in the cable tray according to this embodiment, the tray 2A and the cable 1 stored in the tray 2A are treated as the mass 8B of the secondary vibration system 13. Therefore, when adding mass to the secondary vibration system 13, which is a dynamic vibration absorber, the mass can be added without changing the support member 4. For this reason, existing cable trays can be easily replaced with the cable tray according to this embodiment. In other words, the cable tray according to this embodiment can be easily applied to existing cable trays.

[0037] In this embodiment of the cable tray, an elastic bearing member 3 having desired rigidity and damping characteristics is installed between the tray 2A and the support member 4, forming a secondary vibration system 13 which is a dynamic vibration absorber. Therefore, the space required for the cable tray does not increase, and it has high seismic resistance and excellent placement properties.

[0038] Figure 4 is a cross-sectional view (vertical section) of the cable tray according to this embodiment, taken in a plane parallel to the extension direction of the stored cable 1. Figure 4 shows the portion of the cable tray in which trays 2A, 2B, and 2C are supported by four support members 4A, 4B, 4C, and 4D.

[0039] The upper ends of support members 4A to 4D are fixed to the ceiling 5. Elastic support members 3A, 3B, 3C, and 3D are installed between tray 2A and support members 4A, 4B, 4C, and 4D, respectively. Tray 2A is the tray 2 located furthest from the part (ceiling 5) to which support members 4A to 4D are fixed. Tray 2A is fixed to support members 4A to 4D via elastic support members 3A to 3D. Trays 2B and 2C are fixed directly to support members 4A to 4D without using elastic support members 3.

[0040] Figure 5A is a cross-sectional view of the cable tray according to this embodiment, taken in a plane perpendicular to the extension direction of the stored cable 1, and shows an enlarged view of the area around the elastic support member 3. Figure 5B is a cross-sectional view of the cable tray according to this embodiment, taken in a plane parallel to the extension direction of the stored cable 1, and shows an enlarged view of the area around the elastic support member 3.

[0041] The elastic support member 3 is fastened and fixed to the tray 2A and the mounting portion 41 of the support member 4 with bolts 14.

[0042] Preferably, the elastic support member 3 has different rigidity in the direction perpendicular to the extension direction of the cable 1 stored in the tray 2 and in the direction parallel to it. In the cable tray according to this embodiment, the rigidity of the support member 4 differs in the direction perpendicular to the extension direction of the cable 1 stored in the tray 2 and in the direction parallel to it, and the natural frequencies of the cable tray also differ. Therefore, if the elastic support member 3 has rigidity such that the natural frequency of the secondary vibration system 13 is within ±10% of the natural frequency of the main vibration system 12 in each of these directions, the elastic support member 3 will have different rigidity in the direction perpendicular to the extension direction of the cable 1 stored in the tray 2 and in the direction parallel to it.

[0043] If the elastic support member 3 has different rigidity in the direction perpendicular to the extension direction of the cable 1 stored in the tray 2 and in the direction parallel to the extension direction, then the cross-sectional area in the plane perpendicular to the extension direction and the cross-sectional area in the plane parallel to the extension direction will also differ. Which cross-sectional area is larger depends on the rigidity of the support member 4. In this embodiment, the cross-sectional area in the perpendicular plane (Figure 5A) is smaller than the cross-sectional area in the parallel plane (Figure 5B).

[0044] The elastic support member 3 has different rigidity (or cross-sectional area) in the direction perpendicular to the extension direction of the cable 1 stored in the tray 2 and in the direction parallel to it. This allows the secondary vibration system 13 to have a natural frequency that has a large effect in reducing the response of the main vibration system 12 in each of these directions, thereby more effectively suppressing the vibration of the main vibration system 12 and improving the seismic resistance of the cable tray.

[0045] The rigidity of the elastic bearing member 3 can be set, for example, by measuring the natural frequencies of the tray 2 and support member 4 in a striking test. The striking test is performed, for example, on the portion of the cable tray that spans multiple support members 4 (for example, on the support members 4A to 4C in Figure 4). The elastic bearing member 3 can have a rigidity set using, for example, the natural frequencies of the tray 2 and support member 4 measured in the striking test, the mass of the tray 2, and the mass of the cable 1 housed in the tray 2.

[0046] Next, we will describe an example in which the cable tray according to this embodiment is fixed to the floor.

[0047] Figure 6 is a cross-sectional view (vertical section) of the cable tray according to this embodiment, taken in a plane perpendicular to the extension direction of the stored cable 1. The cable tray shown in Figure 6 is fixed to the floor 6, which is the installation location.

[0048] The support member 4 is fixed to the floor 6 at its lower end.

[0049] Of the three trays 2A, 2B, and 2C, tray 2C, which is located furthest from the support member 4 (the floor 6 in Figure 6, which is the installation location), has an elastic support member 3 installed between it and the support member 4. In other words, tray 2C is fixed to the support member 4 via the elastic support member 3. All other trays 2A and 2B are fixed directly to the support member 4 without the elastic support member 3. The elastic support member 3 suppresses vibrations of tray 2C.

[0050] The vibration model of the cable tray according to this embodiment (Figure 6), which is fixed to the floor 6, has the same configuration as the vibration model of the cable tray according to this embodiment (Figure 3), which is fixed to the ceiling 5, but with the top and bottom reversed. The main vibration system 12 consists of a support member 4, tray 2A, tray 2B, and cables 1 housed in trays 2A and 2B, and is fixed to the floor 6, which is the fixing part 11. The secondary vibration system 13 consists of tray 2C, cables 1 housed in tray 2C, and an elastic bearing member 3.

[0051] In the cable tray fixed to the floor 6 (Figure 6), the principle for suppressing vibration of the cable tray during an earthquake is the same as that for the cable tray fixed to the ceiling 5 (Figures 1 to 3). Therefore, the cable tray according to this embodiment has excellent placement capabilities and high seismic resistance, even when fixed to the floor 6.

[0052] Next, we will describe an example in which the cable tray according to this embodiment is fixed to a wall.

[0053] Figure 7 is a cross-sectional view (vertical section) of the cable tray according to this embodiment, taken in a plane perpendicular to the extension direction of the stored cable 1. The cable tray shown in Figure 7 is fixed to the wall 7, which is the installation location.

[0054] The support member 4 is fixed to the wall 7 by connecting one end in the horizontal direction (left-right direction in Figure 7).

[0055] Of the three trays 2A, 2B, and 2C, tray 2A has an elastic support member 3 installed between it and the support member 4. In other words, tray 2A is fixed to the support member 4 via the elastic support member 3. All other trays 2B and 2C are fixed directly to the support member 4 without the elastic support member 3. The elastic support member 3 suppresses vibrations of tray 2A.

[0056] In the cable tray fixed to wall 7, trays 2A to 2C are arranged in the vertical direction (up and down direction in Figure 7), making it difficult to determine which tray 2 is furthest from the part where the support member 4 is fixed (wall 7, which is the installation location in Figure 7). In other words, in the cable tray fixed to wall 7, it is difficult to determine which tray 2 will have the elastic support member 3 installed between it and the support member 4.

[0057] However, vibrations of the cable tray can be suppressed because at least one of the multiple trays 2 (tray 2A in Figure 7) is fixed to the support member 4 via an elastic bearing member 3, while all the other trays 2 (trays 2B and 2C in Figure 7) are directly fixed to the support member 4 without the elastic bearing member 3. In the cable tray shown in Figure 7, the main vibration system 12 consists of the support member 4, trays 2B and 2C, and the cables 1 housed in trays 2B and 2C, while the secondary vibration system 13 consists of tray 2A, the cables 1 housed in tray 2A, and the elastic bearing member 3. During an earthquake, the secondary vibration system 13 acts as a dynamic vibration absorber, suppressing vibrations of the main vibration system 12 and improving seismic resistance by suppressing vibrations of the entire cable tray.

[0058] Furthermore, if the cable tray is fixed to the wall 7, the elastic support member 3 may be installed on any of the multiple trays 2. In other words, in a cable tray fixed to the wall 7, at least one of the multiple trays 2 is fixed to the support member 4 via the elastic support member 3, and all other trays 2 are fixed directly to the support member 4 without the elastic support member 3.

[0059] Next, we will describe an example in which the cable tray according to this embodiment has multiple trays 2 arranged horizontally. This cable tray can be fixed to installation locations such as the ceiling 5, floor 6, and wall 7, but below we will describe an example in which this cable tray is fixed to the ceiling 5.

[0060] Figure 8 is a cross-sectional view (vertical section) of a cable tray according to this embodiment, which has multiple trays 2 arranged horizontally, in a plane perpendicular to the extension direction of the stored cables 1. The cable tray shown in Figure 8 has six trays 2A, 2B, 2C, 2D, 2E, and 2F. When a cable tray has many trays 2, multiple trays 2 may be arranged side by side in the horizontal direction (left-right direction in Figure 8), as shown in Figure 8.

[0061] Trays 2A, 2B, and 2C are supported by support member 4, arranged from bottom to top in that order. Trays 2D, 2E, and 2F are also supported by support member 4, arranged from bottom to top in that order. Trays 2A, 2B, and 2C and trays 2D, 2E, and 2F are each installed in a horizontal arrangement.

[0062] Support member 4 supports trays 2A, 2B, 2C and trays 2D, 2E, 2F, which are arranged horizontally, and its upper end is connected to and fixed to the ceiling 5.

[0063] Of the six trays 2A to 2F, trays 2A and 2D, which are located furthest from the part where the support member 4 is fixed (the ceiling 5 in Figure 8, which is the installation location), have elastic support members 3 installed between trays 2A and 2D and the support member 4. In other words, trays 2A and 2D are fixed to the support member 4 via the elastic support members 3. All other trays 2B, 2C, 2E, and 2F are fixed directly to the support member 4 without the elastic support members 3. The elastic support members 3 suppress vibrations of trays 2A and 2D.

[0064] In the cable tray shown in Figure 8, the main vibration system 12 consists of a support member 4, trays 2B, 2C, 2E, and 2F, and cables 1 housed in trays 2B, 2C, 2E, and 2F. The secondary vibration system 13 consists of trays 2A and 2D, cables 1 housed in trays 2A and 2D, and elastic bearing member 3. During an earthquake, the secondary vibration system 13 acts as a dynamic vibration absorber, suppressing the vibration of the main vibration system 12 and thereby suppressing the vibration of the entire cable tray, improving its seismic resistance.

[0065] The above description (excluding the description of the cable tray shown in Figure 7) describes a cable tray in which the elastic support member 3 is installed only on the tray 2 that is furthest from the part where the support member 4 is fixed. In the cable tray according to this embodiment, the elastic support member 3 can also be installed on trays 2 other than the tray 2 that is furthest from the part where the support member 4 is fixed. Below, an example of a cable tray according to this embodiment will be described in which the elastic support member 3 is installed on the tray 2 that is furthest from the part where the support member 4 is fixed, and on the other trays 2. In the following description, a cable tray fixed to the ceiling 5 will be described as an example.

[0066] Figure 9 is a cross-sectional view (vertical section) of the cable tray according to this embodiment, taken in a plane perpendicular to the extension direction of the stored cables, and shows a cable tray in which elastic support members 3 are installed on multiple trays 2 in the height direction (up and down direction in Figure 9). The cable tray shown in Figure 9 has the same configuration as the cable tray shown in Figure 1, but differs in that elastic support members 3 are installed not only on tray 2A but also on tray 2B.

[0067] Of the three trays 2A, 2B, and 2C, tray 2A, which is located furthest from the part where the support member 4 is fixed (the ceiling 5 in Figure 9, which is the installation location), and tray 2B, which is located above tray 2A, have elastic support members 3 installed between them and the support member 4. In other words, trays 2A and 2B are fixed to the support member 4 via the elastic support members 3. The other tray 2C is fixed directly to the support member 4 without the elastic support members 3. The elastic support members 3 suppress vibrations of trays 2A and 2B.

[0068] In the cable tray shown in Figure 9, the support member 4, tray 2C, and the cable 1 housed in tray 2C constitute the main vibration system 12. Tray 2A, the cable 1 housed in tray 2A, and the elastic bearing member 3 installed on tray 2A constitute the first secondary vibration system 13, and tray 2B, the cable 1 housed in tray 2B, and the elastic bearing member 3 installed on tray 2B constitute the second secondary vibration system 13. The first secondary vibration system 13 and the second secondary vibration system 13 are connected in parallel to the main vibration system 12.

[0069] During an earthquake, these two secondary vibration systems 13 act as dynamic vibration absorbers, interacting with the main vibration system 12 to suppress vibrations in the main vibration system 12. Therefore, the cable tray shown in Figure 9 has a greater effect in suppressing vibrations in the main vibration system 12 and higher seismic resistance than, for example, the cable tray with one secondary vibration system 13 shown in Figure 1, and can effectively suppress vibrations in the cable tray even against stronger earthquakes.

[0070] In the above embodiments, a cable tray comprising three or six trays 2 has been described, but the cable tray according to this embodiment can comprise any number of trays 2. Furthermore, in the above embodiments, an example has been described in which the support member 4 comprises basic components (e.g., mounting portion 41), but the support member 4 may also comprise reinforcing members such as diagonal members or seismic support members. If the support member 4 comprises reinforcing members, the cable tray according to this embodiment can have higher seismic resistance.

[0071] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and the present invention is not necessarily limited to embodiments having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add configurations from other embodiments to the configuration of one embodiment. Furthermore, it is possible to delete parts of the configuration of each embodiment, or to add or replace other configurations. [Explanation of Symbols]

[0072] 1...Cable, 2, 2A~2F...Tray, 3, 3A~3D...Elastic bearing member, 4, 4A~4D...Support member, 5...Ceiling, 6...Floor, 7...Wall, 8A, 8B...Mass, 9A, 9B...Spring, 10A, 10B...Dashpot, 11...Fixing part, 12...Main vibration system, 13...Secondary vibration system, 14...Bolt, 41...Mounting part.

Claims

1. Multiple trays for storing cables, A support member that supports multiple trays and is fixed to the installation location, An elastic bearing member, which is an elastic member having rigidity, Equipped with, Of the multiple trays, at least one tray is fixed to the support member via the elastic support member, and all other trays are directly fixed to the support member. The tray fixed to the support member via the elastic support member is designated as the first tray. The tray directly fixed to the support member is designated as the second tray. The main vibration system consists of the support member, the second tray, and the cable housed in the second tray. The secondary vibration system consists of the first tray, the cable housed in the first tray, and the elastic bearing member. The elastic bearing member has rigidity such that the natural frequency of the secondary vibration system is within ±10% of the natural frequency of the main vibration system. A cable tray characterized by the following features.

2. Of the multiple trays, at least the tray furthest from the portion to which the support member is fixed is fixed to the support member via the elastic support member, and all other trays are directly fixed to the support member. The cable tray according to claim 1.

3. The elastic support member has different rigidities in a direction perpendicular to the extension direction of the cable stored in the tray and in a direction parallel to it. The cable tray according to claim 1.

4. The elastic bearing member has a rigidity set using the natural frequencies of the tray and the support member measured in the impact test. The cable tray according to claim 1.

Images