Cable rack earth metal fitting

Abstract

To provide a cable rack earth metal fitting capable of largely reducing an operation of electrically connecting a cable rack with an upper face cover and a lower face cover.SOLUTION: A cable rack earth metal fitting 1 for electrically connecting a ladder-like cable rack CR with an upper face cover TC and a lower face cover BC that are attached to the cable rack CR comprises: a first connection part 26 electrically connected with the upper face cover TC; a second connection part 27 that is provided at a position opposed to the first connection part 26 and electrically connected with the lower face cover BC; and a third connection part 28 that is provided at a connection part where the first connection part 26 is connected with the second connection part 27 and electrically connected with a side face of a master girder CR1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a grounding fitting for a cable rack for electrically connecting a cable rack and a cover of the cable rack. And a connection method using the same Regarding. [Background technology]

[0002] A ladder-type cable rack used for wiring power cables, communication cables, etc., has a ladder shape with a pair of long parent girders and multiple child girders installed between the parent girders. The cables are arranged in a storage space surrounded by the parent girders and the child girders. Multiple such cable racks are arranged along the wiring route, and the ends of the parent girders are connected to each other with joint fittings or the like.

[0003] In order to protect and ensure the safety of the installed cables, a cable rack may be fitted with either or both of a top cover that covers the upper part of the accommodation space and a bottom cover that covers the lower part of the accommodation space. The top cover and bottom cover have a shorter longitudinal dimension along the parent girder than the cable rack. Therefore, a cable rack is fitted with a larger number of top covers and bottom covers than the number of cable racks.

[0004] The cable rack, top cover, and bottom cover are made of conductive metal and have the function of dissipating leakage current in the event of a leakage current in the cable. When multiple cable racks are connected together for use, adjacent cable racks are electrically connected to each other using joint fittings or earth bond wires, and the cable rack at the end is connected to a ground electrode. Similarly to the cable racks, the top cover and bottom cover are also electrically connected to adjacent top covers and adjacent bottom covers using earth bond wires or cover earth fittings (see, for example, Patent Document 1), and the top cover and bottom cover at the end are connected to a ground electrode. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 09-163539 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, conventionally, it was necessary to electrically connect and ground the cable rack to the top cover and bottom cover, respectively. In addition, since the number of top covers and bottom covers is greater than the number of cable racks, when the cable rack path length is long, the number of operations to electrically connect adjacent covers becomes very large. Furthermore, the top cover and bottom cover are attached to the cable rack after the cable is installed along the wiring path, and then the adjacent covers are electrically connected. Therefore, when the cable rack is installed at a high place, it is necessary to move the aerial work vehicle many times depending on the length and number of covers, and to raise and lower the work platform each time to perform the operation of electrically connecting the covers.

[0007] Thus, conventionally, there has been a problem in that the task of electrically connecting the cable rack to the top cover and bottom cover is extremely time-consuming.

[0008] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an earthing fitting for a cable rack that can significantly reduce the work required to electrically connect the cable rack to an upper cover and a lower cover. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention provides a cable rack earthing fitting for use with a ladder-shaped cable rack including a pair of long parent girders and a plurality of child girders installed between the parent girders, a first cover attached to one surface of the cable rack so as to cover the space between the pair of parent girders, and a second cover attached to the other surface of the cable rack opposite to the one surface so as to cover the space between the pair of parent girders, the cable rack earthing fitting being disposed along the width direction of the parent girders perpendicular to the longitudinal direction of the parent girders and the child girders, the first cover By breaking the surface treatment film and pressing it A first connection portion electrically connected to the first A position facing the parent beam in the width direction The second cover is provided By breaking the surface treatment film and pressing it A second connection portion electrically connected to the first connection portion and a connection portion connecting the first connection portion and the second connection portion, the second connection portion being provided on a side surface of the parent beam. By breaking the surface treatment film and pressing it and a third connection portion electrically connected to the first connection portion.

[0010] The invention of claim 2 provides the cable rack grounding fitting of claim 1, wherein the first cover comprises a first cover body covering the space between the pair of parent girders and a first side edge portion formed by bending both sides of the first cover body along the width direction of the parent girders, the second cover comprises a second cover body covering the space between the pair of parent girders and a second side edge portion formed by bending both sides of the second cover body along the width direction of the parent girders, and the first connection portion is formed by bending the first side edge portion. By breaking the surface treatment film and pressing it The second connection portion is electrically connected to the first cover, and the second connection portion is connected to the second side edge portion. By breaking the surface treatment film and pressing it The present invention is characterized in that the first connection portion is electrically connected to the second cover, and the third connection portion is pressed against the side surface of the parent beam to electrically connect thereto.

[0011] The invention of claim 3 provides the cable rack grounding fitting of claim 2, wherein the first connection portion includes a first pressure-contact portion inserted between a side surface of the parent girder and the first side edge portion, a first opposing portion opposing the first pressure-contact portion on an outer surface side of the first side edge portion, a first screw hole provided in the first opposing portion, and a first bolt screwed into the first screw hole to be pressure-contacted to the first side edge portion and to pressure-contact the first pressure-contact portion to an inner surface side of the first side edge portion; and the second connection portion includes a first pressure-contact portion inserted between the side surface of the parent girder and the second side edge portion. The third connection portion comprises a second pressure contact portion to be inserted, a second opposing portion facing the second pressure contact portion on the outer surface side of the second side edge portion, a second screw hole provided in the second opposing portion, and a second bolt that screws into the second screw hole to press the second pressure contact portion against the inner surface side of the second side edge portion, and the third connection portion comprises a third opposing portion facing the side surface of the parent girder, a third screw hole provided in the third opposing portion, and a third bolt that screws into the third screw hole to press the second pressure contact portion against the side surface of the parent girder.

[0012] The invention described in claim 4 is characterized in that, in the earthing fitting for a cable rack described in claim 3, the first pressure-connecting portion has a corner that bites into the surface treatment film of the first side edge portion and breaks, and the second pressure-connecting portion has a corner that bites into the surface treatment film of the second side edge portion and breaks.

[0013] The invention described in claim 5 is characterized in that, in the earthing fitting for a cable rack described in claim 4, the first pressure contact portion and the second pressure contact portion are formed by bending a plate material having a slit-shaped notch formed along the slit direction at the notch portion, and the corner portions of the first pressure contact portion and the second pressure contact portion are formed by twisting the edges of the notch.

[0014] The invention described in claim 6 is characterized in that, in the earthing fitting for a cable rack described in claim 2, the cable rack has the child girder erected on one end side of the parent girder in the width direction, and the third connection portion is arranged in the width direction of the parent girder at the one end side where the child girder is erected.

[0015] The invention as set forth in claim 7 provides the cable rack grounding metal fitting as set forth in claim 1, further comprising a locking metal fitting used when electrically connecting the cable rack to the first cover or the second cover attached to the cable rack, the locking metal fitting being formed by bending a substantially rectangular plate material so that a cross section of the plate material is substantially L-shaped to form a first surface and a second surface, and either one of the first connection portion or the second connection portion is attached to the first surface. By bolt The cable rack is characterized in that a connecting portion is provided to connect the first and second covers to the first and second surfaces, and a locking portion is provided on the second surface to lock onto one end of the parent girder in the width direction, and when only the first cover is attached to the cable rack, the locking fitting connected to the second connection portion is locked to the parent girder, and the cable rack and the first cover are electrically connected by the first connection portion and the third connection portion, and when only the second cover is attached to the cable rack, the locking fitting connected to the first connection portion is locked to the parent girder, and the cable rack and the second cover are electrically connected by the second connection portion and the third connection portion.

[0016] The invention described in claim 8 is an earthing fitting for a cable rack used to electrically connect a ladder-shaped cable rack having a pair of long parent girders and a number of child girders erected between the parent girders, and a first cover attached to one side of the cable rack so as to cover the space between the pair of parent girders, characterized in that it comprises an earthing fitting main body arranged along the width direction of the parent girders perpendicular to the longitudinal direction of the parent girders and having a first connection portion that is electrically connected by breaking and crimping the surface treatment film of the first cover, and a third connection portion that is electrically connected by breaking and crimping the surface treatment film on the side of the parent girders, and a locking fitting connected to the earthing fitting main body and having a locking portion that is locked to one end of the parent girders in the width direction.

[0017] The invention as recited in claim 9 is the cable rack grounding fitting as recited in claim 8, characterized in that the locking fitting is formed integrally with the grounding fitting body.

[0018] The invention described in claim 10 relates to a connection method for electrically connecting a ladder-shaped cable rack including a pair of long parent girders and a plurality of child girders installed between the parent girders, a first cover attached to one surface of the cable rack so as to cover the space between the pair of parent girders, and a second cover attached to the other surface of the cable rack opposite to the one surface so as to cover the space between the pair of parent girders, using a cable rack grounding fitting, wherein the first cover includes a first cover body covering the space between the pair of parent girders and a first side edge portion formed by bending both side edges of the first cover body along the width direction of the parent girders, the second cover includes a second cover body covering the space between the pair of parent girders and a second side edge portion formed by bending both side edges of the second cover body along the width direction of the parent girders, and the cable rack grounding fitting is provided by breaking a surface treatment film of the first cover and pressing the first cover against the first cover. and a second connection part that is electrically connected by breaking a surface treatment film of the second cover and pressing the second cover against the side surface of the parent girder, the first connection part comprising a first pressure contact part that is inserted between the side surface of the parent girder and the first side edge part, and the second connection part comprising a second pressure contact part that is inserted between the side surface of the parent girder and the second side edge part, and the cable rack grounding fitting is pressed against the side surface of the parent girder in a state inclined obliquely with respect to the width direction of the parent girder so that the first pressure contact part and the second pressure contact part do not interfere with the first side edge part and the second side edge part, and then the cable rack grounding fitting is rotated about an axis in the longitudinal direction of the parent girder, so that the first pressure contact part is inserted between the side surface of the parent girder and the first side edge part and at the same time the second pressure contact part is inserted between the side surface of the parent girder and the second side edge part.

[0019] The invention described in claim 11 is characterized in that, in the connection method described in claim 10, the earthing fitting for the cable rack is provided with a third connection portion that is electrically connected by breaking the surface treatment film on the side of the parent girder and pressing it. Effect of the Invention

[0020] According to the invention described in claim 1, the cable rack can be electrically connected to the first cover and the second cover, so that the cable rack, the first cover, and the second cover can be grounded as a whole by simply connecting only the cable rack to the grounding electrode at the end. Conventionally, adjacent covers were electrically connected to each other, so that electrical connection work had to be performed for the top cover and the bottom cover separately. In contrast, according to the present invention, the top cover and the bottom cover can be electrically connected simultaneously by simply connecting one cable rack grounding metal fitting, so that the work required for electrical connection of the covers, etc. can be significantly reduced.

[0021] According to the invention described in claim 2, the first connection part, the second connection part and the third connection part of the cable rack grounding fitting are electrically connected by being pressed against the first cover, the second cover and the cable rack, respectively, so that the work can be performed more simply and quickly than a configuration in which a conductive hole or the like is provided in the cover and a bolt is inserted into this conductive hole for connection. Also, even if the surfaces of the cable rack and the cover are subjected to a non-conductive surface treatment to impart weather resistance, rust prevention, etc., the surface treatment can be broken by pressing the first connection part, etc., so that the cable rack and the first cover and the second cover can be reliably electrically connected.

[0022] According to the invention described in claim 3, the first side edge of the first cover is sandwiched between the first pressure contact portion and the first opposing portion, and the second side edge of the second cover is sandwiched between the second pressure contact portion and the second opposing portion, so that the cable rack grounding fitting can be easily and quickly attached to the side surfaces of the cable rack, the first cover, and the second cover. Also, by simply screwing and tightening the bolts into the respective screw holes provided in the first opposing portion, the second opposing portion, and the third opposing portion, the bolts can be pressed against the cable rack, the first cover, and the second cover, so that the work can be performed easily and quickly.

[0023] According to the invention described in claim 4, the first pressure-welding portion and the second pressure-welding portion have corners that bite into and break the surface treatment films of the first cover and the second cover, so that a reliable electrical connection can be made by applying pressure with a bolt.

[0024] According to the invention described in claim 5, the bending process for forming the first and second pressure-contact parts is used, and the edges of the notches are twisted to form the corners, so there is no need to provide protrusions by blanking or punching, as in the past, and it is possible to reduce the number of steps required to create a grounding metal fitting for a cable rack. In addition, in blanking or punching, the shape of the formed protrusion may change (such as the blunting of acute angles) due to wear of the mold, but in the present invention, the twisting during bending is used, so the effects of wear of the mold and the like can be reduced. Therefore, it is possible to stably obtain corners with little change in shape.

[0025] According to the invention described in claim 6, the third connection part is arranged in the width direction of the parent girder at one end side where the child girder is erected and has high rigidity, so that the parent girder will not be deformed by pressing the third connection part against the parent girder.

[0026] According to the invention described in claim 7, by using a locking metal fitting that can be used together with the cable rack grounding metal fitting, it is possible to electrically connect the cable rack to the first cover or the second cover attached to the cable rack. Therefore, even if the cable rack cover is one-sided, it is possible to effectively use the cable rack grounding metal fitting of the present invention without preparing a new separate grounding metal fitting. [Brief description of the drawings]

[0027] [Figure 1] 1 is a perspective view showing a state in which a cable rack grounding fitting according to an embodiment of the present invention is attached to a cable rack. FIG. [Diagram 2]FIG. 2A is a first perspective view showing the cable rack grounding fitting from the front side, and FIG. 2B is a second perspective view showing the fitting body from the rear side. [Diagram 3] 2A is a front view of the metal fitting body, (c) a cross-sectional view taken along line XX of (c), (d) a side view of the metal fitting body, and (e) a rear view of the metal fitting body 2. [Figure 4] FIG. 3(e) is a YY cross-sectional view (f) and a development view (g) of the metal fitting body. [Diagram 5] 10A to 10C are explanatory diagrams showing a procedure for attaching the cable rack grounding fitting to the cable rack. [Figure 6] 4 is a cross-sectional view showing the state in which the cable rack grounding fitting is attached to the cable rack. FIG. [Figure 7] FIG. 1 is an explanatory diagram comparing a case where linked cable racks and the like are electrically connected by a conventional method with a case where a grounding metal fitting for a cable rack is used. [Figure 8] 1 is a perspective view showing a grounding fitting for a cable rack and a locking fitting used in combination therewith. FIG. [Figure 9] 11 is a cross-sectional view showing the state in which the cable rack and the top cover are electrically connected using a cable rack grounding fitting and a locking fitting. FIG. [Figure 10] FIG. 2 is a perspective view showing the configuration of a cable rack, an upper cover, and a lower cover. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the present invention will be described based on the illustrated embodiment.

[0029] (Embodiment 1) 1 is a perspective view showing a usage form of a cable rack grounding fitting 1 according to this embodiment. The cable rack grounding fitting 1 is a fitting for electrically connecting a cable rack CR to an upper cover (first cover) TC and a lower cover (second cover) BC of the cable rack CR.

[0030] In this embodiment, the cable rack earthing fitting 1 is described as being attached to a cable rack CR that is installed in a substantially horizontal direction, however, the cable rack earthing fitting 1 of this embodiment can also be applied to a cable rack CR that is installed in a substantially vertical direction and to covers that are attached to the front and rear surfaces of this cable rack CR.

[0031] Here, the cable rack CR, the top cover TC and the bottom cover BC will be described. As shown in Fig. 10, the cable rack CR of this embodiment is a ladder-type cable rack used for wiring power cables, communication cables (not shown) and the like. The cable rack CR has a ladder shape including a pair of long parent girders CR1, CR2 and a plurality of child girders CR3 installed between the parent girders CR1, CR2. The cables are arranged in a storage space surrounded by the parent girders CR1, CR2 and the child girders CR3.

[0032] The cross section perpendicular to the longitudinal direction of the parent girders CR1 and CR2 is roughly U-shaped with the opening facing inward to increase rigidity, and the central part protrudes toward the inside of the cable rack CR. Mounting holes are provided on both ends of the parent girders CR1 and CR2 to which joint fittings are connected when connecting multiple cable racks CR.

[0033] The sub-girder CR3 is a rod-like body having a cross section perpendicular to the longitudinal direction that is substantially U-shaped. The sub-girder CR3 is installed at a predetermined interval on one end side, for example, the lower end side, of the parent girders CR1 and CR2 in the width direction perpendicular to the longitudinal direction of the parent girders CR1 and CR2 and the sub-girder CR3.

[0034] In order to protect the installed cables and ensure their safety, the cable rack CR may be fitted with either or both of a top cover TC that covers the upper part of the accommodation space and a bottom cover BC that covers the lower part of the accommodation space. The top cover TC and bottom cover BC have a shorter longitudinal dimension than the cable rack CR, which is arranged along the parent girders CR1 and CR2. Therefore, a cable rack CR is fitted with a greater number of top covers TC and bottom covers BC than the number of cable racks CR.

[0035] The top cover TC comprises an top cover body (first cover body) TC1 that covers the space between the pair of parent girders CR1, CR2, and top cover side edge portions (first side edge portions) TC2 formed by bending both sides of the top cover body TC1 along the width direction of the parent girders CR1, CR2. Similarly, the bottom cover BC comprises a bottom cover body (second cover body) BC1 that covers the space between the pair of parent girders CR1, CR2, and bottom cover side edge portions (second side edge portions) BC2 formed by bending both sides of the bottom cover body BC1 along the width direction of the parent girders CR1, CR2.

[0036] The cable rack CR, top cover TC, and bottom cover BC are formed of conductive metal plates. The surfaces of the cable rack CR, top cover TC, and bottom cover BC are coated with a non-conductive surface treatment film to provide weather resistance, rust prevention, etc. The top cover TC and bottom cover BC may be the same.

[0037] Next, the cable rack grounding fitting 1 will be described. Fig. 2 is a first perspective view (a) showing the cable rack grounding fitting 1 from the front side, and a second perspective view (b) showing the fitting body 2 constituting the cable rack grounding fitting 1 from the rear side. Fig. 3 is a front view (c) of the fitting body 2, an XX cross-sectional view of (c), a side view (d) of the fitting body 2, and a rear view (e) of the fitting body 2. Fig. 4 is a YY cross-sectional view (f) of Fig. 3(e) and an expanded view (g) of the fitting body 2.

[0038] The cable rack grounding fitting 1 comprises a rod-shaped fitting body 2, an upper cover bolt (first bolt) 3, a lower cover bolt (second bolt) 4, and a rack bolt (third bolt) 5 that are screwed into the fitting body 2. As shown in Fig. 1, the cable rack grounding fitting 1 is placed along the width direction of the parent girder CR1, avoiding the connection holes for connecting the parent girder CR1.

[0039] The rack bolts 5 are longer than the top cover bolts 3 and bottom cover bolts 4 in order to connect to the cable rack CR. Additionally, the top cover bolts 3, bottom cover bolts 4 and rack bolts 5 are recessed bolts with only the periphery of the tip surface protruding in an annular shape in the insertion direction. The tips of the top cover bolts 3, bottom cover bolts 4 and rack bolts 5 are pressed against the parent girder CR1, top cover TC and bottom cover BC, breaking the surface treatment film and coming into contact with the bare metal.

[0040] The metal fitting main body 2 is formed into a rod-like body having a front portion 21, left and right side portions 22, 23, and a pair of back portions 24, 25, by bending a roughly rectangular metal substrate 2A shown in Figure 4(g) along four bending lines indicated by dotted lines in the figure so that the cross section has a roughly U-shape.

[0041] The metal fitting main body 2 includes a first connection portion 26 electrically connected to the upper cover TC, a second connection portion 27 provided at a position opposite the first connection portion 26 and electrically connected to the lower cover BC, and a third connection portion 28 provided at a connecting portion connecting the first connection portion 26 and the second connection portion 27, and electrically connected to the side of the parent girder CR1.

[0042] The first connection portion 26 is pressed against the top cover side edge portion TC2 to electrically connect with the top cover TC. The second connection portion 27 is pressed against the bottom cover side edge portion BC2 to electrically connect with the bottom cover BC. The third connection portion 28 is pressed against the side surface of the parent girder CR1 to electrically connect. Note that "electrically connected by pressing" refers to breaking the surface treatment films of the cable rack CR, top cover TC, and bottom cover BC to contact the bare metal.

[0043] The first connection portion 26 includes first pressure contact portions 261, 262 inserted between the side surface of the parent girder CR1 and the top cover side edge portion TC2, a first opposing portion 263 opposing the first pressure contact portions 261, 262 on the outer surface side of the top cover side edge portion TC2, a first screw hole 264 provided in the first opposing portion 263, and a top cover bolt 3 that screws into the first screw hole 264 to press against the top cover side edge portion TC2 and presses the first pressure contact portions 261, 262 against the inner surface side of the top cover side edge portion TC2.

[0044] The first pressure contact portions 261, 262 are provided at the upper ends of the pair of back portions 24, 25 by utilizing a pair of slit-shaped notches 2A1, 2A2 provided in the metal substrate 2A. Of the first pressure contact portions 261, 262, an outer corner of one of the pressure contact portions 262 is notched obliquely to avoid interference with the top cover main body TC1 when the cable rack grounding fitting 1 is attached to the cable rack CR. This oblique notch may also be provided on the outside of the other first pressure contact portion 261.

[0045] 4(f), the base portions of the first pressure-contact portions 261, 262 are provided with blade-like corners 261a, 262a that bite into and break the surface treatment film of the top cover side edge portion TC2. These corners 261a, 262a are formed by bending the notches 2A1, 2A2 of the metal substrate 2A shown in FIG. 4(g) along the slit direction, thereby twisting the edges of the notches 2A1, 2A2.

[0046] Oval contact parts 261b, 262b protruding toward the rear side are provided on the rear parts of the first pressure contact parts 261, 262. These contact parts 261b, 262b are provided to reduce the contact area between the fixture body 2 and the side surface of the parent girder CR1 and thereby reduce friction when the cable rack grounding fixture 1 is attached to the cable rack CR.

[0047] The first opposing portion 263 is provided at the upper end portion of the front portion 21. The first screw hole 264 is disposed at approximately the center in the width direction of the first opposing portion 263. The first screw hole 264 has a female thread formed on the inner circumferential surface of a hole that has been made cylindrical by burring processing.

[0048] The second connection portion 27 includes second pressure contact portions 271, 272 inserted between the side surface of the parent girder CR1 and the lower cover side edge portion BC2, a second opposing portion 273 opposing the second pressure contact portions 271, 272 on the outer surface side of the lower cover side edge portion BC2, a second screw hole 274 provided in the second opposing portion 273, and a lower cover bolt 4 that screws into the second screw hole 274 to press against the lower cover side edge portion BC2 and presses the second pressure contact portions 271, 272 against the inner surface side of the lower cover side edge portion BC2.

[0049] The second pressure contact portions 271, 272 are provided at the lower ends of the pair of back portions 24, 25 by utilizing a pair of slit-shaped cutouts 2A3, 2A4 provided in the metal substrate 2A. Of the second pressure contact portions 271, 272, an outer corner of one of the pressure contact portions 272 is cut out obliquely to avoid interference with the bottom cover body BC1 when the cable rack grounding fitting 1 is attached to the cable rack CR. This oblique cutout may also be provided at the outer corner of the other second pressure contact portion 271.

[0050] Furthermore, blade-like corners 271a, 272a that bite into and break the surface treatment film of the lower cover side edge portion BC2 are provided at the base portions of the second pressure contact portions 271, 272. These corners 271a, 272a are formed in the same manner as the corners 261a, 262a of the first pressure contact portions 261, 262 and have the same shape, so a detailed description will be omitted.

[0051] Oval contact portions 271b, 272b protruding toward the rear side are provided on the rear portions of the second pressure contact portions 271, 272. These contact portions 271b, 272b are provided to reduce the contact area between the bracket body 2 and the side surface of the parent girder CR1 and thereby reduce friction when the cable rack grounding bracket 1 is attached to the cable rack CR.

[0052] The second opposing portion 273 is provided at the lower end portion of the front portion 21. The second screw hole 274 is disposed at approximately the center in the width direction of the second opposing portion 273. The second screw hole 274 has a female thread formed on the inner circumferential surface of a hole that has been made cylindrical by burring.

[0053] The third connection part 28 includes a third opposing part 281 that faces the side surface of the parent girder CR1, a third screw hole 282 provided in the third opposing part 281, and a rack bolt 5 that screws into the third screw hole 282 and is pressed against the side surface of the parent girder CR1. The third screw hole 282 has a female thread formed on the inner circumferential surface of a hole that has been made cylindrical by burring.

[0054] The third opposing portion 281 and the third screw hole 282 are provided on the lower side of the front portion 21 of the metal fitting main body 2. This is to prevent the parent girder CR1 from deforming and bending inward when the rack bolt 5 screwed into the third screw hole 282 abuts against and presses against the parent girder CR1. Since the child girder CR3 is arranged on the lower side of the metal fitting main body 2, i.e., on the lower end side of the parent girder CR1 in the width direction and has high rigidity, it is possible to prevent the parent girder CR1 from deforming due to the pressure of the rack bolt 5.

[0055] The metal fitting body 2, except for the third connecting portion 28, has a rotationally symmetric shape about a central axis C along the front-rear direction of the metal fitting body 2. In other words, the first connecting portion 26 and the second connecting portion 27 have the same shape.

[0056] Next, the operation of the above embodiment will be described. Fig. 5 shows the procedure for attaching the cable rack grounding fitting 1 to the cable rack CR. As shown in Fig. 5(a), the cable rack grounding fitting 1 is pressed against the side of the parent girder CR1 in an inclined state so that the first pressure contact portion 262 and the second pressure contact portion 272 do not interfere with the top cover side edge portion TC2 and the bottom cover side edge portion BC2.

[0057] Thereafter, the cable rack grounding fitting 1 is rotated in the direction of the arrow Z. As a result, as shown in Figures 5(b) and 6, the first pressure contact portions 261, 262 are inserted between the side surface of the parent girder CR1 and the top cover side edge portion TC2, and the first opposing portion 263 faces the outer surface of the top cover side edge portion TC2. Similarly, the second pressure contact portions 271, 272 are inserted between the side surface of the parent girder CR1 and the bottom cover side edge portion BC2, and the second opposing portion 273 faces the outer surface of the bottom cover side edge portion BC2.

[0058] When the top cover bolt 3 is tightened in this state, the tip of the top cover bolt 3 bites into the outer surface of the top cover side edge TC2, breaking the surface treatment film and coming into contact with the bare metal. Furthermore, tightening the top cover bolt 3 causes the first pressure contact parts 261, 262 to be pressure-contacted with the inner surface of the top cover side edge TC2, and the corners 261a, 262a break the surface treatment film and come into contact with the bare metal. This electrically connects the cable rack grounding fitting 1 and the top cover TC.

[0059] Similarly, when the bottom cover bolt 4 is tightened, the tip of the bottom cover bolt 4 bites into the outer surface of the bottom cover side edge BC2, breaking the surface treatment film and contacting the bare metal. Furthermore, when the bottom cover bolt 4 is tightened, the second pressure contact parts 271, 272 are pressure-welded to the inner surface of the bottom cover side edge BC2, and the corners 271a, 272a break the surface treatment film and contact the bare metal. This electrically connects the cable rack grounding fitting 1 and the bottom cover BC.

[0060] Furthermore, when the rack bolt 5 is tightened, the tip of the rack bolt 5 bites into the side of the parent girder CR1, breaking the surface treatment film and coming into contact with the bare metal. This electrically connects the cable rack grounding fitting 1 to the cable rack CR. Also, the cable rack CR is electrically connected to the top cover TC and bottom cover BC via the cable rack grounding fitting 1.

[0061] FIG. 7 is a schematic diagram showing a rack path consisting of a plurality of cable racks CR and a plurality of upper covers TC and lower covers BC attached to the cable racks CR. Each horizontal line indicates one cable rack CR and one upper cover TC and lower cover BC, and the black circles at both ends of each line indicate the ends of each cable rack CR and each upper cover TC and lower cover BC. In this embodiment, the length of each cable rack CR is, for example, 3 m, the length of each upper cover TC and lower cover BC is, for example, 1.5 m, and two upper covers TC and two lower covers BC are used for one cable rack CR. Six cable racks CR are connected to form a rack path with a total length of 18 m.

[0062] When installing the top cover TC and bottom cover BC by setting up a rack path as shown in Fig. 7, conventionally, adjacent top covers TC and adjacent bottom covers BC were electrically connected using earth bond wires or cover earth fittings. The connection parts are shown by dashed ellipses, and a total of 22 connection points are required. For example, if this rack path is installed at a high place that is difficult to reach, work must be done using a high-altitude work vehicle with a work platform that can be raised and lowered. In other words, conventionally, it was necessary to move the high-altitude work vehicle 11 times every 1.5 m (to the dashed ellipse position) and raise and lower the work platform each time to perform the electrical connection work of the top cover TC and bottom cover BC 22 times.

[0063] In FIG. 7, a rectangle extending vertically from the top cover TC to the bottom cover BC indicates the cable rack grounding fitting 1 of this embodiment. One cable rack grounding fitting 1 is attached to each top cover TC and bottom cover BC. Therefore, the rack path shown in FIG. 7 requires installation of the cable rack grounding fitting 1 at 12 locations. In addition, since the cable rack grounding fitting 1 can be attached to any position on the cover, two adjacent cable rack grounding fittings 1 can be installed at a distance that can be reached from the work platform by bringing the positions of the two cable rack grounding fittings 1 close to each other. Therefore, when using the cable rack grounding fitting 1 of this embodiment, the aerial work platform is moved 6 times every 3 m, and the work platform is raised and lowered each time to perform the installation work of the cable rack grounding fitting 1 1 times, so that the number of times the aerial work platform is moved and the number of times the cable rack grounding fitting 1 is installed can be reduced compared to the conventional method. In this way, by using the cable rack grounding fitting 1 of this embodiment, it is possible to significantly reduce the work of electrically connecting the cable rack CR to the top cover TC and bottom cover BC.

[0064] As described above, according to the cable rack grounding fitting 1 of this embodiment, the cable rack CR can be electrically connected to the top cover TC and bottom cover BC, so that at the end, it is possible to ground the entire cable rack CR, top cover TC, and bottom cover BC by simply connecting only the cable rack CR to the ground electrode. In addition, in the past, adjacent covers were electrically connected to each other, so it was necessary to perform electrical connection work on the top cover and the bottom cover separately. In contrast, according to this embodiment, the top cover and the bottom cover can be electrically connected at the same time by simply connecting one cable rack grounding fitting 1, so it is possible to significantly reduce the work required for electrical connection of covers, etc.

[0065] Furthermore, according to the cable rack grounding fitting 1 of this embodiment, the first connection portion 26, the second connection portion 27 and the third connection portion 28 are electrically connected by being pressed against the top cover TC, the bottom cover BC and the cable rack CR, respectively, so that the work can be performed more simply and quickly than a configuration in which a conductive hole or the like is provided in the cover and a bolt is inserted into this conductive hole to make the connection. Even if the surfaces of the cable rack CR, the top cover TC and the bottom cover BC are subjected to a non-conductive surface treatment to impart weather resistance, rust prevention and the like, the surface treatment can be broken by pressing the first connection portion 26 etc., so that the cable rack CR can be reliably electrically connected to the top cover TC and the bottom cover BC.

[0066] Furthermore, according to the cable rack grounding fitting 1 of this embodiment, the top cover side edge TC2 is sandwiched between the first pressure-contact parts 261, 262 and the first opposing part 263, and the bottom cover side edge BC2 is sandwiched between the second pressure-contact parts 271, 272 and the second opposing part 273, so that the cable rack grounding fitting 1 can be easily and quickly attached to the side surfaces of the cable rack CR, the top cover TC, and the bottom cover BC. Also, by simply screwing and tightening the bolts 3, 4, 5 into the screw holes 264, 274, 282 provided in the first opposing part 263, the second opposing part 273, and the third opposing part 281, respectively, the bolts 3, 4, 5 can be pressure-welded to the top cover TC, the bottom cover BC, and the cable rack CR, so that the work can be performed easily and quickly.

[0067] Furthermore, according to the cable rack earthing fitting 1 of this embodiment, the first pressure contact portions 261, 262 and the second pressure contact portions 271, 272 are provided with corners 261a, 262a, 271a, 272a that bite into the surface treatment film of the top cover TC and the bottom cover BC and break off, so that in addition to the pressure contact provided by the bolts 3, 4, 5, a reliable electrical connection can be made.

[0068] Furthermore, according to the cable rack grounding fitting 1 of this embodiment, the corners 261a, 262a, 271a, 272a are formed by twisting the edges of the slit-shaped notches 2A1, 2A2, 2A3, 2A4 using bending to form the first pressure contact parts 261, 262 and the second pressure contact parts 271, 272, so there is no need to provide protrusions by blanking or punching as in the past, and it is possible to reduce the number of steps for producing the cable rack grounding fitting 1. In addition, in blanking or punching, the shape of the formed protrusions may change (such as blunting of acute angles) due to wear of the mold, but in the present invention, the twisting during bending is used, so the effects of mold wear and the like can be reduced. Therefore, it is possible to stably obtain corners 261a, 262a, 271a, 272a with little change in shape.

[0069] Furthermore, according to the cable rack earthing fitting 1 of this embodiment, the third connection portion 28 is arranged on one end side in the width direction of the parent girders CR1, CR2 where the child girder CR3 is erected and has high rigidity, so that the parent girder CR1 will not be deformed by pressing the third connection portion 28 against the parent girder CR1.

[0070] (Embodiment 2) Next, a second embodiment of the present invention will be described. This embodiment relates to a locking fitting used together with the cable rack grounding fitting 1 when electrically connecting a cable rack CR and a top cover TC or a bottom cover BC attached to the cable rack CR.

[0071] 8, the locking fitting 6 is formed by bending a generally rectangular plate material so that its cross section is generally L-shaped, forming a first surface 61 and a second surface 62. The first surface 61 is provided with a connection hole (connection portion) 611 that is connected to either the first connection portion 26 or the second connection portion 27 of the cable rack grounding fitting 1. The second surface 62 is provided with a hook-shaped locking portion 621 that is locked to one end of the parent girder CR1 in the width direction.

[0072] The first surface 61 of the locking fitting 6 is inserted into the cable rack grounding fitting 1 so that the second surface 62 is disposed on the back side of the cable rack grounding fitting 1, and the underside cover bolt 4 of the second connecting part 27 is inserted into the connecting hole 611 to connect to the fitting body 2. The tip of the first surface 61 of the locking fitting 6 is bent to abut against the inner surface of the cable rack grounding fitting 1 inside the cable rack grounding fitting 1, and furthermore, a portion of it is cut out to avoid interference with the third connecting part 28.

[0073] 9 shows the state in which the cable rack CR and the top cover TC are electrically connected using the cable rack grounding fitting 1 and the locking fitting 6. The locking fitting 6 connected to the second connection part 27 of the cable rack grounding fitting 1 has the locking part 621 locked to the lower end part of the parent girder CR1, and the cable rack CR and the top cover TC are electrically connected by the first connection part 26 and the third connection part 28.

[0074] Although the case has been described where the cable rack CR and the top cover TC are electrically connected using the cable rack grounding fitting 1 and the locking fitting 6, it is also possible to electrically connect the cable rack CR and the bottom cover BC. In this case, the locking fitting 6 is connected to the first connection portion 26 of the cable rack grounding fitting 1. Then, the locking fitting 6 connected to the cable rack grounding fitting 1 has the locking portion 621 locked to the upper end portion of the parent girder CR1, and the cable rack CR and the bottom cover BC are electrically connected by the second connection portion 27 and the third connection portion 28.

[0075] 9, in this embodiment, the bracket body 2 and the locking fitting 6 are connected by the bottom cover bolt 4, and the cable rack CR is electrically connected by the rack bolt 5, but one bolt may serve the functions of these two bolts 4, 5. Specifically, instead of the bottom cover bolt 4, a rack bolt 5 longer than the bottom cover bolt 4 is screwed into the second screw hole 274 of the second connection part 27, and the rack bolt 5 is inserted into the connecting hole 611 of the locking fitting 6 and then pressed against the side surface of the cable rack CR. As a result, the bracket body 2 and the locking fitting 6 can be connected by one rack bolt 5, and the cable rack CR can be electrically connected, so that the number of bolts used is reduced to two, improving work efficiency.

[0076] Incidentally, when electrically connecting the cable rack CR and the bottom cover BC, the number of bolts used can be reduced in the same manner as above. Specifically, instead of the top cover bolts 3, rack bolts 5 longer than the top cover bolts 3 can be screwed into the first screw holes 264 of the first connecting parts 26, and the rack bolts 5 can be inserted into the connecting holes 611 of the locking fittings 6 and then pressed against the side surfaces of the cable rack CR.

[0077] According to this embodiment, it is possible to electrically connect the cable rack CR to the top cover TC or bottom cover BC attached to the cable rack CR by using the locking fitting 6 that can be used in combination with the cable rack grounding fitting 1. Therefore, even if the cable rack CR has a single-sided cover, it is possible to effectively use the cable rack grounding fitting 1 of this embodiment without having to prepare a new separate grounding fitting.

[0078] Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there are design changes within the scope of the present invention, they are included in the present invention. For example, in order to electrically connect the cable rack grounding fitting 1 to the top cover TC and the bottom cover BC, the corners 261a, 262a, 271a, 272a are formed on the first pressure contact parts 261, 262 and the second pressure contact parts 271, 272, but if the electrical connection by the bolts 3, 4, 5 is reliably performed, the corners 261a, 262a, 271a, 272a may be omitted.

[0079] In the above embodiment, gaps are provided between the first pressure contact portions 261, 262 and the second pressure contact portions 271, 272 in order to allow the bolts 3, 4, and 5 to be inserted through the cable rack CR1, the top cover TC, and the bottom cover BC. However, when holes through which the bolts 3, 4, and 5 can be inserted are provided on the rear side of the cable rack grounding fitting 1, the first pressure contact portions 261, 262 and the second pressure contact portions 271, 272 may be formed integrally.

[0080] Furthermore, in the above embodiment, when only one of the top cover TC and the bottom cover BC is attached to the cable rack CR1, the cable rack grounding fitting 1 and the locking fitting 6 are combined to make an electrical connection, but a dedicated grounding fitting may also be provided. Specifically, the locking fitting 6 is provided integrally with the above cable rack grounding fitting 1 instead of the first connection part 26 or the second connection part 27 on one end side. This eliminates the need to incorporate the locking fitting 6 into the cable rack grounding fitting 1, improving work efficiency.

[0081] In addition, the cable rack earthing fitting 1 and locking fitting 6 of this embodiment can be applied to cable racks having different parent girder width dimensions by adjusting the length of the fitting body 2 and the size of the locking fitting 6. [Explanation of symbols]

[0082] 1. Cable rack earth fitting 2 Bracket body 26 First Connection 261, 262 First pressure contact 261a, 262a corner 263 First opposing part 264 First screw hole 27 Second Connection 271, 272 Second pressure weld 271a, 272a corner 273 Second opposing part 274 Second screw hole 28 Third Connection 281 Third opposing part 282 3rd screw hole 3 Top cover bolt (first bolt) 4 Bottom cover bolt (second bolt) 5 Rack bolt (third bolt) 6 Locking fitting 61 First Side 611 Connection hole (connection part) 62 Second Side 621 Locking part CR Cable Rack CR1, CR2 parent digit CR3 minor digit TC Top Cover (First Cover) TC2 Top cover side edge (first side edge) BC Bottom cover (second cover) BC2 Lower cover side edge (second side edge)

Claims

1. A cable rack grounding fitting used for a ladder-shaped cable rack including a pair of long parent girders and a plurality of child girders installed between the parent girders, a first cover attached to one surface of the cable rack so as to cover the space between the pair of parent girders, and a second cover attached to the other surface of the cable rack opposite to the one surface so as to cover the space between the pair of parent girders, The main beam and the sub beam are arranged along a width direction of the main beam perpendicular to a longitudinal direction of the main beam and the sub beam, a first connection portion that is electrically connected by breaking a surface treatment film of the first cover and pressing the first cover; a second connection portion provided at a position facing the first connection portion along the width direction of the parent beam, and electrically connected by breaking a surface treatment film of the second cover and pressing the second cover; a third connection portion provided in a connection portion that connects the first connection portion and the second connection portion, and electrically connected by breaking a surface treatment film on a side surface of the parent beam and pressing the surface treatment film against the side surface of the parent beam; An earthing fixture for a cable rack comprising:

2. The first cover includes a first cover body covering the space between the pair of parent girders and a first side edge portion formed by folding both sides of the first cover body along the width direction of the parent girders, and the second cover includes a second cover body covering the space between the pair of parent girders and a second side edge portion formed by folding both sides of the second cover body along the width direction of the parent girders, the first connection portion is electrically connected to the first cover by breaking the surface treatment film of the first side edge portion and pressing the surface treatment film against the first cover, the second connection portion is electrically connected to the second cover by breaking the surface treatment film of the second side edge portion and pressing the surface treatment film against the second cover, The third connection portion is electrically connected to a side surface of the parent beam by pressure contact.

2. The earth fitting for a cable rack according to claim 1.

3. the first connection portion includes a first pressure-contact portion inserted between a side surface of the parent girder and the first side edge portion, a first opposing portion opposing the first pressure-contact portion on an outer surface side of the first side edge portion, a first screw hole provided in the first opposing portion, and a first bolt screwed into the first screw hole to be pressure-contacted to the first side edge portion and to pressure-contact the first pressure-contact portion to an inner surface side of the first side edge portion, the second connection portion includes a second pressure-contact portion inserted between a side surface of the parent girder and the second side edge portion, a second opposing portion opposing the second pressure-contact portion on an outer surface side of the second side edge portion, a second screw hole provided in the second opposing portion, and a second bolt screwed into the second screw hole to pressure-contact the second side edge portion and to pressure-contact the second pressure-contact portion against an inner surface side of the second side edge portion, the third connection portion includes a third opposing portion opposing a side surface of the parent girder, a third screw hole provided in the third opposing portion, and a third bolt screwed into the third screw hole and pressed against the side surface of the parent girder.

3. The earth fitting for a cable rack according to claim 2.

4. the first pressure-welding portion has a corner portion that bites into and breaks the surface treatment film of the first side edge portion, the second pressure-welding portion has a corner portion that bites into and breaks the surface treatment film of the second side edge portion; 4. The earth fitting for a cable rack according to claim 3.

5. the first pressure-contact portion and the second pressure-contact portion are formed by bending a plate material having a slit-shaped cutout along a slit direction at the cutout portion, The corners of the first and second pressure-welding portions are formed by twisting the edges of the notches.

5. The earth fitting for a cable rack according to claim 4.

6. The cable rack is provided with the child girder installed on one end side of the parent girder in a width direction, The third connection portion is arranged on one end side where the child girder is installed in the width direction of the parent girder.

3. The earth fitting for a cable rack according to claim 2.

7. a locking metal fitting used in combination when electrically connecting the cable rack to the first cover or the second cover attached to the cable rack, The locking fitting is formed by bending a substantially rectangular plate material so that its cross section is substantially L-shaped, and a first surface and a second surface are formed, a connecting portion is provided on the first surface which is connected to either the first connecting portion or the second connecting portion by a bolt, and a locking portion is provided on the second surface which is locked to one end of the parent girder in the width direction, When only the first cover is attached to the cable rack, the locking fitting connected to the second connection portion is locked to the parent girder, and the cable rack and the first cover are electrically connected by the first connection portion and the third connection portion; When only the second cover is attached to the cable rack, the locking fitting connected to the first connection part is locked to the parent girder, and the cable rack and the second cover are electrically connected by the second connection part and the third connection part.

2. The earth fitting for a cable rack according to claim 1.

8. An earth fitting for a cable rack used to electrically connect a ladder-shaped cable rack having a pair of long parent girders and a plurality of child girders erected between the parent girders, and a first cover attached to one side of the cable rack so as to cover the space between the pair of parent girders, an earth fitting body including a first connection part disposed along a width direction of the parent beam perpendicular to a longitudinal direction of the parent beam and the child beam, the first connection part being electrically connected by breaking and crimping a surface treatment film of the first cover, and a third connection part being electrically connected by breaking and crimping a surface treatment film on a side surface of the parent beam; A locking fitting connected to the grounding fitting body and having a locking portion that is locked to one end of the parent beam in the width direction; An earthing fixture for a cable rack comprising:

9. The locking fitting is integrally formed with the earth fitting body.

9. The earth metal fitting for a cable rack according to claim 8.

10. A connection method for electrically connecting a ladder-shaped cable rack having a pair of long parent girders and a number of child girders erected between the parent girders, a first cover attached to one side of the cable rack so as to cover the space between the pair of parent girders, and a second cover attached to the other side of the cable rack opposite the one side so as to cover the space between the pair of parent girders, using an earth fitting for a cable rack, The first cover includes a first cover body that covers a space between the pair of parent girders, and a first side edge portion in which both side edges of the first cover body are bent along a width direction of the parent girders, The second cover includes a second cover body that covers a space between the pair of parent girders, and a second side edge portion in which both side edges of the second cover body are bent along a width direction of the parent girders, the cable rack grounding metal includes a first connection portion electrically connected by breaking and crimping a surface treatment film of the first cover, and a second connection portion electrically connected by breaking and crimping a surface treatment film of the second cover, the first connection portion includes a first pressure contact portion inserted between a side surface of the parent girder and the first side edge portion, the second connection portion includes a second pressure contact portion inserted between a side surface of the parent girder and the second side edge portion, the cable rack grounding fitting is pressed against a side surface of the parent girder in a state inclined obliquely with respect to a width direction of the parent girder so that the first pressure contact portion and the second pressure contact portion do not interfere with the first side edge portion and the second side edge portion, and then the cable rack grounding fitting is rotated about an axis in the longitudinal direction of the small girder, whereby the first pressure contact portion is inserted between the side surface of the parent girder and the first side edge portion and at the same time the second pressure contact portion is inserted between the side surface of the parent girder and the second side edge portion; A connection method comprising:

11. The cable rack earth fitting has a third connection part that is electrically connected by breaking the surface treatment film on the side of the parent beam and pressing it. The connection method according to claim 10 .

Images