JP2985159B2 - Grounding terminal for coaxial cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground terminal attached to a coaxial cable.

[0002]

2. Description of the Related Art In order to protect a communication device from a lightning surge or the like, a ground terminal is attached to a coaxial cable serving as an antenna feed line. FIGS. 8 and 9 show such ground terminals. FIG.
The grounding terminal 50 shown in FIG. 1 has a contact band 51 made of a plain woven copper wire and the contact band 51
And a clamp member 52 for crimping the contact band 51 on the coaxial cable 1 after stripping a part of the jacket 102 of the coaxial cable 100 over the entire circumference.
00 on the outer conductor 101, and from above the wound contact band 51, with the clamp member 52, using the coaxial cable 10.
0 to the contact strip 5 on the outer conductor 101.
1 is connected and fixed. A ground wire 54 is connected to the contact band 51 via an external connection portion 53,
Thus, the outer conductor 101 of the coaxial cable 100 is grounded. In addition, the outer periphery of the connection portion of the coaxial cable 100 to which the ground terminal 50 is attached is stripped off over the entire circumference, and it is necessary to newly provide a waterproof structure here. Therefore, in the grounding terminal 50, the grounding terminal 50 and the entire connection site are covered with a moisture-proof compound 55, and further, a butyl rubber tape 56 and an adhesive PVC tape 57 are sequentially wound on the moisture-proof compound 55 to ground. The connection part of the terminal 50 is waterproof-protected.

A ground terminal 60 shown in FIG.
02 is stripped over the entire circumference and wound around the outer conductor 101, and a clamp member 62 for tightening the coaxial cable 100 from above the contact band 61 is provided. The structure for guiding 101 to the outside is basically the same as that of FIG. This grounding terminal 60 is different from that of FIG. That is, the grounding terminal 60 is provided with a mold cover 63 surrounding the entire connecting portion, and by filling a gap between the mold cover 63 and the coaxial cable 100 with the molding resin 64, the grounding portion of the grounding terminal 60 is formed. It is designed to protect waterproof. Furthermore, just by filling the mold resin 64,
Since the waterproof structure is not complete, the connection between the outer conductor 101 and the contact band 61 and the like is prevented from being mixed with the mold resin 64 or moisture.
5 and a C cement 66 for adapting the jacket 102 of the coaxial cable 100 and the molding resin 64 are provided.

In FIG. 9, 67 is an external connection portion, 68 is a ground wire connected to the contact band 61 by the external connection portion 67, 69 is a funnel used when filling the molding resin 64, and 70 is a mold. An insulating tape provided to cover a gap between the cover 63 and the outer cover 102.

[0005]

The conventional ground terminals 50 and 60 have the following problems.

[0006] In order to wind and fix the contact strips 51 and 61 around the outer conductor 101, the jacket 1 of the coaxial cable 100 is fixed.
It is necessary to peel off a part of 02 over the entire circumference, and the work is troublesome.

In order to largely peel off the outer cover 102 over the entire circumference, the work is covered again to make it watertight (covered with a moisture-proof compound 55, wound with tapes 56 and 57, or covered with a mold cover 63). The work of filling the mold resin 64) is very troublesome.

The contact bands 51 and 61 are made of plain woven copper wires. Such plain woven copper wires are connected to the connected members (the outer conductor 101 and the clamp members 52 and 62) by point contact. In addition, since the copper wires constituting the plain woven copper wire are in point contact with each other, the contact resistance increases.

Since the tapes 56 and 57 are wound around or covered with the mold resin 64 after being covered with the moisture-proof compound 55, the structure of the grounding terminals 50 and 60 becomes large. Accordingly, it is an object of the present invention to provide a ground terminal that can be easily mounted and that can reduce the ground resistance.

[0010]

In order to achieve the above object, a ground terminal according to the present invention includes a pair of clamp members which are connected with a coaxial cable interposed therebetween, and at least one of the clamp members has at least one of the clamp members. The clamp member has a contact member that is disposed through the inner and outer ends of the clamp member and is elastically urged inward, and an adhesive surface having a shape that is in close contact with the outer conductor surface is provided at the inner end of the contact member. It is characterized in that an annular sealing member is arranged on the inner end face of the clamp member provided with the contact member and surrounding the contact member projecting opening.

[0011]

According to the above construction, the connection between the ground terminal and the coaxial cable is performed by pressing the adhesive surface provided on the inner end of the contact member against the outer conductor of the coaxial cable. The stripping of the jacket of the coaxial cable need only be performed at a portion where the adhesive surface of the contact member is in contact.

Further, since the sealing member is brought into close contact with the jacket of the coaxial cable due to the connection between the clamp members, the connecting portion between the contact member and the external conductor is reliably sealed from the outside by the sealing member.

Further, the contact member is elastically urged toward the coaxial cable arranged inside, and the contact surface has a shape which is in close contact with the surface of the outer conductor. The connection between is assured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a ground terminal according to a first embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of a connection portion.

The ground terminal 1 is attached to a coaxial cable 100 provided with an outer conductor 101 made of a copper pipe with a ring-shaped corrugation, and includes a pair of clamp members 2A and 2B arranged to face each other. Clamp member 2
A and 2B are integrally formed with connecting flanges 3 at both ends, and clamp members 2A and 2B are connected to these connecting flanges 3 and 3 respectively.
They are integrally connected to each other by a connection screw 4 screwed therebetween. Also, the clamp members 2A, 2
The inner end surfaces 5 and 5 of B have the same curved surface shape as the peripheral surface of the coaxial cable 100, and are almost in close contact with the coaxial cable 100.

One clamp member 2A has an insertion hole 6 formed at the center thereof. The insertion hole 6 is formed along the radial direction of the coaxial cable 100 to be clamped. A rod-shaped contact member 7 made of a conductor such as metal is penetrated through the insertion hole 6. In addition, the insertion hole 6
Is formed with a stepped portion 8 which is open to the inner end face 5 side, and a leaf spring 9 is disposed on the stepped portion 8. The contact member 7 is elastically urged toward the inner end face 5, that is, toward the coaxial cable 100 by the plate spring 9.
The inner end of the contact member 7 is the opening 1 on the inner end face 5 side of the insertion hole 6.
The contact member 7 has an adhesive surface 11 formed at the inner end thereof. The bonding surface 11 is formed with irregularities so as to be in close contact with the ring-shaped wave shape of the external conductor 101. An external connection terminal portion 13 is provided at an outer end of the contact member 7 protruding outside from the outer opening 12 of the insertion hole 6.
The external connection terminal 13 is connected to a ground wire 14. A ring gasket 15 is provided on the inner end face 5 of the clamp member 2A. The ring gasket 15 is provided so as to surround the inner end face side opening 10 of the insertion hole 6. Further, an O-ring mounting groove 16 is formed in the middle of the insertion hole 6, and this O-ring mounting groove 16 is formed.
An O-ring 17 that seals a gap formed between the contact member 7 and the clamp member 2 </ b> A in the insertion hole 6 is provided in the ring mounting groove 16.

In the figure, reference numeral 102 denotes the coaxial cable 10.
0 is a jacket, 103 is a center conductor of the coaxial cable 100, 1
Reference numeral 04 denotes an insulator provided between the center conductor 104 and the outer conductor 101.

Next, a process of attaching the ground terminal 1 to the coaxial cable 100 will be described. First, the outer jacket of the central part of the peripheral surface of the coaxial cable 100 is peeled off to a degree slightly larger than the bonding surface 11 of the contact member 7. This stripping operation is performed using the stripping tool 20 shown in FIG. That is, the stripping tool 20 is provided with a center guide pin 22 and a cutter blade 23 at the tip of a handle 21, and the handle 21 is pierced by the center guide pin 22 on the surface of the jacket 102 of the coaxial cable 100. Is rotated, and the jacket 102 is cut out by the cutter blade 23 in a circular shape.

The coaxial cable 1 is removed by the stripping tool 20.
After stripping the jacket 102 of the coaxial cable 10
The clamp members 2A and 2B are applied to the position where the outer coat is stripped. At this time, the clamp members 2A and 2B are so arranged that the adhesive surface 11 of the contact member 7 comes into contact with the stripped portion.
Is placed. Coaxial cable 100 clamp member 2
After the contacts A and 2B, the two clamp members 2A and 2B are integrated with the connecting screw 4. Then, the contact member 7
The coaxial cable 10 is elastically biased by the leaf spring 9.
When pressed to the 0 side, the adhesive surface 11 of the contact member 7 comes into close contact with the outer conductor 101 of the coaxial cable 100, and both are electrically connected. At this time, since the elastic contact force of the contact member 7 is adjusted by the elastic repulsive force of the leaf spring 9, there is no inconvenience that the elastic contact force of the contact member 7 is too strong and the outer conductor 101 is deformed. Further, by connecting the two clamp members 2A and 2B, the ring gasket 15 comes into close contact with the jacket 101 around the stripped portion, so that the stripped portion is sealed by the ring gasket 15, and the outer portion is sealed. There is no intrusion of moisture, moisture, etc. Note that the gap between the insertion hole 6 and the contact member 7 is sealed by the O-ring 17, so that moisture, moisture, and the like do not enter from here.

The contact resistance between the ground terminal 1 attached to the coaxial cable 100 and the coaxial cable 100 in this manner, and the grounding using the conventional plain woven copper wire contact bands 51 and 61 and the clamp members 52 and 62. Table 1 shows the measurement results of the contact resistance between the terminals 50 and 60 and the coaxial cable 100.

[0021]

[Table 1]

As is apparent from this table, the grounding terminal 1 of the present invention has a contact resistance reduced by about 45% as compared with that of the conventional examples 50 and 60. This is because the connection between the plain woven copper wire and the object to be connected such as the external conductor is mainly made by point contact in the conventional example product, whereas the contact member 7 having a solid inside is replaced by the external conductor in the product of the present invention. 101, the contact member 7 and the external conductor 10
It is considered that the conduction with No. 1 was ensured.

Next, a second embodiment of the present invention will be described. As shown in FIG. 4, the coaxial cable 100 to which the ground terminal for a coaxial cable of the present invention is attached connects an antenna 111 provided at the tip of the tower 110 and a wireless repeater 112 provided at the foot of the tower 110. In such a case, a supporting bracket A for connecting and fixing the coaxial cable 100 to the steel tower 110 is required.
This embodiment is characterized in that the support fitting A and the ground terminal are integrated. The ground terminal 30 of this embodiment has the same basic structure as the ground terminal 1 of the above-described embodiment, and the same or similar parts are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, the ground terminal 30
A connecting bolt 31 is attached to the center of the crank member 2B without the contact member 7 so as to protrude radially outward. The connection bolt 31 is attached by a method such as screwing, welding, or the like.
A tightening nut 32 and a washer 33 are provided at the tip of 1. The ground terminal 30 and the coaxial cable 100 are connected to the structure B by inserting a connection bolt 31 into a connection hole (not shown) formed in the structure B such as a steel tower and tightening the connection nut 32. It is designed to be fixed.

In the ground terminal 30 thus configured, the number of parts required for installing the coaxial cable 100 can be reduced, and the ground terminal 30 is disposed on a single structure B (for example, a steel tower 110). Even if the number of coaxial cables 100 increases (the number of coaxial cables 100 for transmitting the same increases with the recent increase in the amount of transmitted information), a space for providing the ground terminal 30 is not required (connection metal fittings). As long as there is only an installation space). In addition, since the ground terminal 30 is not supported by the coaxial cable 100, the weight load on the coaxial cable 100 is reduced. Furthermore, even if the outer conductor 101 of the coaxial cable 100 and the structure B have the same potential and a lightning strike occurs on the structure B, no discharge occurs between the structure B and the coaxial cable 100.

The structure of the connection bolt 31 may be such that the outer end of the contact member 7 is extended and a male screw portion is formed at the extended end.

A modification of the second embodiment (third embodiment)
As shown in FIG. 6, there is a ground terminal member 35 formed by attaching a U-shaped holding member 34 to the tip of the connecting bolt 31 by screwing, welding or the like. U-shaped clamp 34
Is formed by forming a wedge-shaped non-slip 36 on the inner peripheral surface on the base end 34a side and attaching a tightening screw 37 to the distal end 34b side. After the U-shaped holding member 34 is fitted to the structure B, the tightening screw is formed. By tightening 37
Structure B between the clamping screw 37 and the wedge-shaped non-slip 36
Is to be clamped.

Further, as another modification (fourth embodiment) of the second embodiment, as shown in FIG. 7, the connecting flanges 3 at both ends of the clamp member 2B are extended outward. Connect the connecting bolt 41 to the extending end 3a with the bolt 42
There is a ground terminal 40 fixed by. The connection and fixing operation of the ground terminal 40 to the structure B is the same as that of the second embodiment shown in FIG. 5 except that a pair of connection bolts 41 is used, and therefore the description thereof is omitted.

[0029]

According to the first aspect of the present invention, the following effects can be obtained.

At the time of mounting the grounding terminal, it is sufficient to peel off the jacket of the coaxial cable only at the portion where the contact member comes into contact. It became easier.

In addition to the fact that the stripped portion has become smaller,
Since the stripped portion is reliably waterproofed by the annular waterproof member disposed around, there is no need to provide a separate waterproof structure, which further facilitates the work of attaching the ground terminal. Was.

Since the contact member is elastically crimped to the outer conductor, the connection between the two can be assured.
Contact resistance decreased.

By simply connecting the clamp members, the ground terminal can be attached and waterproofed, so that the structure of the ground terminal is simplified and the size is reduced.

According to the second aspect, the following effects can be obtained.

Since the grounding terminal and the connecting metal can be integrated, no new connecting metal is required, and the number of parts can be reduced accordingly.

The space for installing the connection fitting for the coaxial cable only needs to be provided, and a space for newly providing a ground terminal is not required. Therefore, the space for installing the coaxial cable can be reduced accordingly.

Since the ground terminal is not supported by the coaxial cable, the weight load on the coaxial cable is reduced, and the life of the coaxial cable is prolonged accordingly.

The outer conductor of the coaxial cable and the structure such as a steel tower on which the coaxial cable is disposed have the same potential, and even if a lightning strike occurs in the structure, discharge occurs between the structure and the coaxial cable. Therefore, damage of the coaxial cable due to such discharge can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a ground terminal according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a ground terminal connection portion of the embodiment.

FIG. 3 is a side view of a jacket stripping tool used in the embodiment.

FIG. 4 is a diagram showing a schematic configuration of a steel tower as one of the structures in which the coaxial cable having the ground terminal of the present invention is disposed.

FIG. 5 is a front view showing a configuration of a ground terminal according to a second embodiment of the present invention.

FIG. 6 is a front view showing a configuration of a ground terminal according to a third embodiment of the present invention.

FIG. 7 is a front view showing a configuration of a ground terminal according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view showing a configuration of a first conventional example.

FIG. 9 is a sectional view showing a configuration of a second conventional example.

[Explanation of symbols]

 2A, 2B Clamping member 5 Inner end surface 7 Contact member 10 Inner end side opening 11 Adhesive surface 15 Ring gasket (sealing member) 100 Coaxial cable 101 Outer conductor

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor ▲ Motai ▼ 1-7-11 Aoki, Kawaguchi City, Saitama Prefecture Inside Sanei Electric Industry Co., Ltd. (72) Akio Kusui 1, Aoki Kawaguchi City, Saitama Prefecture No. 7-11, Sanei Electric Industry Co., Ltd. (56) References JP-A-2-239576 (JP, A) JP-A 62-118356 (JP, U) JP-A 59-47971 (JP, U) Hikaru Hei 2-33529 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01R 4/64 H01R 4/48 H01R 4/70 H02G 15/00

Claims (2)

(57) [Claims] A jacket (102) for a coaxial cable (100).
And a pair of clamp members (2A, 2B) which are connected to the outer conductor (101) exposed by stripping off the coaxial cable (100). At least one of the clamp members (2A, 2B) has a contact member (7) that is disposed through the inner and outer ends of the clamp member (2A) and is elastically urged inward. At the inner end of (7), an adhesive surface (11) having a shape closely contacting the surface of the outer conductor (101) is formed, and a clamp member (2) provided with a contact member (7).
A), an inner end face (5) of the contact member has a contact member projecting opening (1).
A grounding terminal for a coaxial cable, wherein a ring-shaped sealing member (15) is disposed around the (0). 2. The ground terminal for a coaxial cable according to claim 1, wherein an external connector is provided on said clamp member or said contact member.