JPH03840Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention provides a waterproof and explosion-proof terminal processing unit for fixing a corrugated steel pipe armored cable, in which a corrugated steel pipe and an anti-corrosion layer are sequentially provided on the outer periphery of the cable core, to a terminal box. This invention relates to a corrugated steel pipe fixing part of an end treatment part.

The corrugated steel pipe fixing section of the terminal processing section has the functions of aligning the cable and the metal fittings and grounding the cable. If the alignment is incomplete, the seal in the annular elastic packing on the longitudinal side of the cable with respect to the fixing part will be insufficient and the desired seal will not be secured, so alignment must be performed with sufficient precision. . Therefore, in another previous application for utility model registration, the present applicant provided a terminal treatment section for a corrugated steel pipe armored cable that can properly align the cable regardless of the slight difference in the cable outer diameter. According to the terminal processing section, in the terminal processing section of a corrugated steel pipe armored cable in which a corrugated steel pipe and an anti-corrosion layer are sequentially provided on the outer periphery of the cable core, the cable is bent circularly so as to overlap by a predetermined amount in the circumferential direction. An annular member made of a metal plate material is fitted onto the exposed outer periphery of the corrugated steel pipe or cable core, and is capable of radially abutting the outer periphery of the annular member and pressing the annular member radially inward. A suitable tightening screw is provided on the fitting.

The purpose of the present invention is to provide an end processing section that exhibits an excellent effect regarding the grounding of the cable at the fixing section, in relation to the improvement of the terminal processing section of the previous application.

To achieve this objective, according to the present invention, the annular member located on the outer periphery of the corrugated steel pipe is made of copper material, and at least the threaded portion of the tightening screw and the contact end with the annular member are plated with silver. .

Embodiments of the present invention will be described with reference to the drawings.

In Fig. 1, the corrugated steel pipe armored cable 15
A corrugated steel pipe 17 and an anti-corrosion layer 18 covering the corrugated steel pipe 17 are sequentially provided around the outer periphery of the central cable core 16, and the cable core 16 and the corrugated steel pipe 17 are separated longitudinally by being separated at the end. A predetermined amount is exposed in each direction. The main body fitting 19 is
It has a boss part 21 having a male thread 20 formed on its outer periphery, and the boss part 21 passes through a partition wall 22 of the terminal box and is tightened with a double nut 23 from inside the terminal box. Furthermore, a circular packing 25 is arranged on the facing surface of the main body fitting 19 and the partition wall 22. On the inner periphery of the flange portion 24 of the main body fitting 19,
Recess 2 with an inner diameter larger than the outer diameter of the cable core 16
6 is provided and an annular elastic packing 27 is placed within this recess 26. The recess 26 has a female thread 28
It has a cylindrical side portion formed with a cylindrical side portion and a receiving portion 29 that receives the annular elastic packing 27 in the axial direction,
The receiving portion 29 is formed into a radius. The fixing fitting 30 has a boss portion 32 formed on the outer periphery with a male thread 31 that is screwed into the female thread 28 of the main body fitting 19.
The tip of the boss portion 32 acts as a pressing portion 34 that presses the annular elastic packing 27 toward the receiving portion 29 through the washer 33 in the axial direction. Body metal fittings 1
9 and the fixture 30, the annular elastic packing 27 is pressed against the receiving part 29 in the axial direction by the pressing part 34, and the outer peripheral surface of the annular elastic packing 27 moves along the radius of the receiving part 29. As a result, the annular elastic packing 27 is constricted, the inner peripheral edge 38 of the annular elastic packing 27 protrudes radially inward, and the annular elastic packing 27 tightly adheres to the outer periphery of the cable core 16. The seal by the annular elastic packing 27 prevents the propagation of flame in the event of an explosion within the terminal box. The fixing fitting 30 is located astride the exposed cable core 16 and the corrugated steel pipe 17, and will be described in detail later.

A male thread 39 is formed on the outer periphery of the flange portion 24 of the main body fitting 19, and the external fitting 40 has this male thread 3.
A female thread 41 is formed on the inner periphery to be screwed into the hole 9 . The O-ring 42 is arranged in an annular groove on the outer periphery of the flange portion 24 to prevent water from entering between the outer periphery of the flange portion 24 and the inner periphery of the external fitting 40, and the rotation prevention screw 43 is arranged in the annular groove on the outer periphery of the flange portion 24. It is provided near the side end to prevent rotation of the external metal fitting 40 with respect to the main body metal fitting 19. A recess 44 having an inner diameter larger than the outer diameter of the anti-corrosion layer 18 is provided on the inner periphery of the end of the external metal fitting 40 that is far from the partition wall 22, and an annular elastic packing 45 is disposed within this recess 44. recess 4
4 has a cylindrical side surface portion formed with a female thread 46 and a receiving portion 47 for receiving the annular elastic packing 45 in the axial direction, and the receiving portion 47 is formed in a radius. The fastening fitting 50 has a boss portion 52 formed on the outer periphery with a male thread 51 that is screwed into the female thread 46 of the external fitting 40, and the tip of the boss portion 52 is connected to the washer 5.
3 through the annular elastic packing 45 receiving part 47
It acts as a pressing portion 54 that presses the axial direction toward the axial direction. The tightening mode of the annular elastic packing 45 is the same as that of the annular elastic packing 27, and the annular elastic packing 45 prevents water from entering from the outside. The anti-rotation screw 55 is provided at the end of the external fitting 40 to tighten the fitting 50 against the external fitting 40.
to prevent rotation. Note that a grounding screw 57 is provided on the flange portion 56 of the fastening fitting 50.

To explain how to assemble the terminal processing section in order, first tighten the fixing metal fitting 30 on the inner circumference of the main body metal fitting 19,
Next, tighten the external fitting 40 on the outer periphery of the main body fitting 19, and then tighten the tightening fitting 50 on the inner periphery of the outer external fitting 40.
Tighten. External fitting 40 and tightening fitting 50
The outer peripheral contour of the flange portion 56 is defined in a shape such as a regular hexagon or a regular octagon, which can be tightened with a tool.

2 and 3 show the fixing fitting 30 in an enlarged manner. The fixing fitting 30 is attached to the cable core 16
An inner peripheral portion 58 surrounding the outer periphery of the corrugated steel pipe 17
An annular groove 60, 61 is formed in the inner peripheral portions 58, 59, respectively. Tightening screws 63 and 64 are provided at locations on the flange portion 62 corresponding to the outer peripheries of the annular grooves 60 and 61, respectively. FIG. 3 shows two typical types of outer peripheral contours of the fixture 30.
All of them have a shape that allows them to be rotated using a tool. The tightening screws 63, 64 can protrude radially inward, and are provided in plural at predetermined angular intervals in the circumferential direction. Annular groove 60,6
1 are respectively arranged with annular members 69 and 70,
As shown in FIGS. 4 and 5, the annular members 69 and 70 are made of thin copper plates that are bent into circular shapes so as to overlap by a predetermined amount L in the circumferential direction.

The annular members 69 and 70 in the annular grooves 60 and 61 are fitted around the cable core 16 and the corrugated steel pipe 17, respectively. By changing the protrusion amount of the tightening screws 63, 64, the annular members 69, 70
The circumferential overlapping amount L changes and the annular members 69, 70
The inner diameters of the annular members 69 and 70 are adjusted so that the inner circumferences of the annular members 69 and 70 are in close contact with the outer circumferences of the cable core 16 and the corrugated steel pipe 17, respectively. In addition, by individually selecting the amount of protrusion of the tightening screws 63 and 64 at each location in the circumferential direction, the center of the fixing fitting 30 can be set to the center of the fixing metal fitting 30 for any outside diameter of the cable core 16 and the corrugated steel pipe 17. It can be matched to a line. The tightening screw 64 located on the side of the corrugated steel pipe 17 is plated entirely with silver, or at least the threaded portion and the radially inner end as the contact end with the annular member 70 are silver-plated, and the annular member 70 is plated with silver as already described above. Made of copper plate. As a result, the fixture 30 is in contact with the corrugated steel pipe 17 via the silver-plated tightening screw 64 and the copper annular member 70, so the conductivity between the corrugated steel pipe 17 and the fixture 30 is extremely low. It becomes expensive.

Note that one of the tightening screws 63 does not need to be silver plated, and the annular member 69 may also be omitted in some cases.

As described above, according to the present invention, an annular member made of a thin metal sheet material that is bent to overlap a predetermined amount in the circumferential direction is fitted into an exposed corrugated steel pipe, and the annular member is tightened with a tightening screw. Since the inner diameter and center of the cables are adjusted appropriately, the cables can be properly aligned regardless of slight differences in the outer diameters of the cables. Since the amount of overlap in the circumferential direction in the annular member can be adjusted over a wide range, it can be applied to corrugated steel pipes with a wide range of diameters. In addition, since the annular member completely surrounds the outer periphery of the corrugated steel pipe, no matter what position the annular member is in, the tightening screw will hit the annular member and press the annular member radially inward. be able to.

Further, according to the present invention, the annular member that fits around the outer periphery of the corrugated steel pipe is made of copper material, at least the threaded portion of the tightening screw and the contact end with the annular member are plated with silver, and the fitting and the corrugated steel pipe The resistance between the ground and the ground becomes extremely small, and excellent grounding characteristics can be obtained.

A large ground fault current may flow through the fastening screw, and conventional steel screws will be damaged in this case. If the purpose is simply to prevent damage to the screws caused by ground fault current, it is sufficient to make the screws of a highly conductive material such as copper, but screws made of copper are soft and do not have sufficient strength. In this invention, the threaded part and contact end of the tightening screw are silver-plated, so that
It is possible to prevent damage to the screw due to ground fault current while ensuring the strength of the screw.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of an embodiment of the present invention, Fig. 2 is an enlarged view of the fixing fitting shown in Fig. 1, Fig. 3 is a view taken from the direction of Fig. 2, and Fig. 4 is the annular member shown in Fig. 1. FIG. 5 is a side view showing the annular member of FIG. 4 with the upper half in cross section. 15... Corrugated steel pipe armored cable, 16... Cable core, 17... Corrugated steel pipe, 18... Corrosion protection layer, 30... Fixing metal fittings, 63, 64... Tightening screw, 69, 70... Annular member .

Claims (1)

[Scope of utility model registration request] At the end treatment part of a corrugated steel pipe armored cable in which a corrugated steel pipe and a corrosion protection layer are sequentially provided around the outer periphery of the cable core, the cable is made of a thin copper plate material that is bent into a circle so as to overlap by a predetermined amount in the circumferential direction. The annular member is fitted onto the exposed outer periphery of the corrugated steel pipe, and a tightening screw that can radially abut the outer periphery of the annular member and press the annular member radially inward is provided between the main body fitting and the cable core. A corrugated device provided on a fixing fitting that acts to press the arranged annular elastic packing in the axial direction, and characterized in that at least the threaded portion of the tightening screw and the contact end with the annular member are silver-plated. Terminal processing section of steel pipe armored cable.