JP2000324672A - Insulating plug for cable joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compact an insulation plug being fixed to an idle terminal while ensuring the required performance, e.g. surface pressure, surely without increasing the cost. SOLUTION: The insulation plug 1 comprises a cone part 11, a shield metal 12, and a spring part 13. The spring part 13 comprises a guide member 13a and a coned disc spring 13b and the guide member 13a is inserted into the recess of the shield metal 12 and fixed in place such that the projecting length thereof can be adjusted. The coned disc springs 13b are fitted over the guide member 13a while differentiating the direction and located between the head part of the guide member 13a and the shield member. Head part of the guide member 13a is retained by means of a fixed cover and the cone part 11 is pressed against a bushing 21 by a resilient recovery force incident to compression of the coned disc springs 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating plug for a cable connecting portion used for mounting to a free terminal of a cable connecting portion.

[0002]

2. Description of the Related Art Conventionally, this type of insulating plug for a cable connecting portion (hereinafter, simply referred to as an insulating plug) is, for example, shown in FIG.
To FIG. 8 are known. This insulating plug 1 '
Of the terminal connection part (the bushing 21) and other connection parts (branch connection parts) of the device, the terminal is attached to a vacant terminal to which a cable is not connected for electrical and mechanical protection. The bushing 21 is formed of, for example, an insulating resin such as an epoxy resin, and has a central conductor 22 therein.
Are arranged. The inner surface of the bushing 21 is a tapered surface whose diameter decreases toward the center conductor 22, and the bushing 21 is attached to the device-side base plate 23 (see FIG. 6).

On the other hand, the insulating plug 1 'is, as shown in FIG. 7, a rubber cone portion 11 which is pressed against the inner surface of a bushing 21 as a connection portion, and is embedded at the rear end of the cone portion 11. A shield fitting 12 for adjusting an electric field and a spring section 15 for pressing the cone section 11 against a bushing 21 are provided.

[0004] The spring portion 15 is connected to the shield fitting 12.
(See FIG. 8), and each spring portion 15
Have shafts 15a, 15a,... Arranged to protrude rearward from the shield fitting 12 (see FIG. 7). Each of the shafts 15a penetrates a washer member 16 provided at a rear portion thereof.
Between the shield fitting 12 and the washer member 16, a coil spring 15b is provided so as to be externally inserted into each of the shafts 15a.

[0005] As shown in FIG. 6, a fixed lid 25 is attached to the bushing 21 with the insulating plug 1 'attached to the bushing 21. The fixed lid 25 is formed in a substantially cylindrical shape with one end sealed, and has a stepped portion 25 having an inner diameter reduced on its inner surface.
a is provided. The step portion 25a engages with the washer member 16 to bias the washer member 16 toward the cone portion 11 side. Therefore, the coil spring 15b is compressed to generate an elastic restoring force, and the elastic restoring force pushes the cone portion 11 toward the bushing 21 so that the cone portion 11 is pressed against the inner surface of the bushing 21. Has become. Here, in order to obtain a predetermined insulating performance, it is necessary that the pressure (surface pressure) in a direction orthogonal to the inner surface of the bushing 21 is set to a predetermined value or more by pressing the cone portion 11 with a predetermined pressing force. In order to obtain a predetermined pressing force of the cone portion 11, the wire diameter and the number of turns of the coil spring 15b are set.

[0006]

However, in the above-mentioned conventional insulating plug 1 ', since the portion protruding rearward is large (see L2 in FIG. 6), this protruding portion is made small from the viewpoint of making the equipment compact. There is a request to do it.

Therefore, in the connection part to which the cable is connected, the deflection of the coil spring is made relatively large in order to absorb the change in the pressing force of the cone part 11 due to the energization, and the movable amount of the cone part 11 is increased. However, since the amount of change in the pressing force is relatively small in the unoccupied terminals and there is no energization, the movable amount of the cone portion 11 may be relatively small. In view of this point, there is known an arrangement in which a coil spring is provided in a shield metal fitting (for example, see Japanese Patent No. 2561941). In this one,
A recess formed from the rear end surface of the shield fitting is formed, and a coil spring is inserted into the recess. As a result, the portion protruding backward is smaller than that of the conventional insulating plug.

However, in the insulating plug described in the above publication, a special coil spring having a rectangular cross section is used in order to obtain as large an elastic restoring force as possible. However, there is a disadvantage that the cost increases.

Further, since the surface pressure depends on the taper angle of the inner surface of the bushing and the outer peripheral surface of the cone portion, etc.,
It is necessary to adjust the pressing force of the cone portion according to the taper angle. However, when a special coil spring described in the above publication is used, the pressing force is changed by changing the number of special coil springs to be provided. It is necessary to adjust the pressure by adjusting the pressure or preparing a plurality of types of special coil springs having different elastic restoring forces and replacing the coil spring itself. Therefore, there is an inconvenience that the design is complicated, and there is also an inconvenience that the fine adjustment of the pressing force becomes difficult.

The present invention has been made in view of such circumstances, and an object of the present invention is to ensure that required performance such as surface pressure is ensured in an insulating plug attached to a connection portion. Therefore, the present invention aims to reduce the size and solve inconveniences such as an increase in cost.

[0011]

In order to achieve the above object, the inventor of the present invention can solve all of the above disadvantages by using a flat spring capable of obtaining a large load with a small amount of deflection instead of a coil spring. The present invention has been completed by focusing on the points.

More specifically, the present invention is directed to an insulation plug for a cable connection portion to be attached to a cable connection portion, wherein a cone portion crimped on an inner surface of the cable connection portion, A shield provided at the rear end, and a spring protruding from the shield and pressing the cone toward the inner surface of the cable connection by being pressed by a fixed lid sealing the cable connection. It shall be assumed. The specific feature is that the spring portion has a predetermined number of flat springs and is formed in series so that the directions of the flat springs are alternately opposite. Here, as the “flat spring”, for example, a “flat spring washer” of J1S may be used. If this flat spring washer is used, it is easy to obtain, and the cost can be greatly reduced.

In this case, since the flat spring can obtain a large load with a small amount of deflection, the length required to obtain the same pressing force as compared with the case of using the coil spring is sufficiently long. It becomes possible to shorten it. As a result, the required performance such as surface pressure is ensured, and the insulation plug is made more compact.

Further, the flat spring can be easily obtained as described above, and the cost is greatly reduced as compared with the case where a special coil spring having a rectangular cross section described in the official gazette is used. Is achieved.

Further, if the number of the above-mentioned springs arranged is changed, the pressing force of the cone portion changes, so that the pressing force of the cone portion can be easily adjusted and the fine adjustment thereof can be easily performed. Further, the cost can be significantly reduced as compared with the case where a plurality of types of coil springs are prepared.

Such a spring portion is, as shown in FIG.
A shaft attached to the shield fitting like a conventional cable connection part insulating plug, and a washer member movably arranged along the shaft shall be provided, and between the shield fitting and the washer member Alternatively, the flat spring may be extrapolated and arranged on the shaft.

However, in this case, it is necessary to protrude the shaft from the back of the washer member, and accordingly, the fixing lid needs to be formed to have a shape protruding more than the length in which the flat springs are arranged. .

Therefore, the spring portion is provided with a rod-shaped guide member having a head portion whose diameter is larger than that of the intermediate portion, and the length of the guide member protruding from the shield metal can be expanded and contracted. As described above, the spring may be attached to the shield fitting, and the flat spring may be inserted between the head of the guide member and the shield member by being inserted outside the intermediate portion of the guide member. With this configuration, since the guide member is movable with respect to the shield fitting, if the fixed lid is formed so as to contact the head of the guide member, the guide member is pressed by the fixed lid. ,
Accordingly, the flat spring is compressed. For this reason, it is sufficient that the fixing lid is protruded to a length corresponding to the length in which the flat springs are arranged, and the size is further reduced.

[0019]

As described above, according to the insulating plug for the cable connection portion of the present invention, the required size of the insulating plug can be reduced while ensuring the required performance, and the cost can be reduced. Can be. Further, the adjustment of the pressing force can be easily performed.

[0020]

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

FIG. 1 shows a state in which an insulating plug 1 for cable connection (hereinafter simply referred to as an insulating plug) according to an embodiment of the present invention is mounted on a bushing 21 as a connecting portion.

The bushing 21 is formed of, for example, an insulating resin such as an epoxy resin, and has a center conductor 22 disposed therein. Also,
The inner surface of the bushing 21 is a tapered surface whose diameter decreases toward the center conductor 22.
1 is attached to the device side base plate 23.

As shown in FIG. 1 or FIG. 2, the insulating plug 1 includes a rubber cone 11 and a shield fitting 12 buried in the rear of the cone 11. A spring portion 13 is provided so as to project rearward from the shield fitting 12.

The cone portion 11 is formed as a tapered surface which decreases toward its tip so that the outer peripheral surface matches the shape of the inner surface of the bushing 21.

The shield fitting 12 is for adjusting an electric field, and has a predetermined shape so as to obtain the effect.

As shown in FIG. 3, the spring portions 13 are circumferentially disposed on the shield fitting 12, and each of the spring portions 13 includes a guide member 13a attached to the shield fitting 12. And a predetermined number of flat springs 13b, 13b,... Extrapolated to the guide member 13a.

The guide member 13a is provided as shown in FIG.
As shown in the figure, the head 13d is formed in a cylindrical shape, and has a head 13d whose diameter is larger than that of the intermediate portion 13g. The inner peripheral surface of the guide member 13a is configured such that the protruding end portion 13e has a larger diameter than the base end portion 13f.
Is inserted, the head of the flat screw 13c is located at the enlarged diameter portion (see FIG. 4).

On the other hand, a concave portion 12a is formed in the shield fitting 12 so as to be concave from the rear end surface thereof. A screw hole 12b having a screw groove formed in the bottom surface of the concave portion 12a.
Are formed.

Each of the above-mentioned flat springs 13b is provided in the manner shown in FIG.
As shown in FIG. 1, the plate is formed in a dish shape, and a through hole is formed in the center thereof. As such a flat spring, for example, a J1S "flat spring washer" may be used.
The springs 13b, 13b,... Are externally arranged in series so that the directions of the adjacent springs 13b, 13b are opposite to each other with respect to the intermediate portion 13g of the guide member 13a. (See FIG. 4).

The guide member 13a is inserted into the recess 12a with its base end inserted into the guide member 1a.
3 is fixed to the shield fitting 12 by fastening the flat head screw 13c inserted into the screw hole 12b. For this reason, the guide member 13a
The protrusion length from the shield fitting 12 is
It can be expanded and contracted by the depth of a. Are arranged between the rear end face of the shield fitting 12 and the head 13a of the guide member 13.

Then, as shown in FIG.
The insulating plug 1 is mounted in a bushing 21 with a metal fitting 14 having a U-shaped cross section disposed on the front side of the bushing 21. The hitting fitting 14 is used as a stopper for preventing the cone 11 from being pushed too far inward. On the other hand, a fixed lid 24 is attached to the rear end surface of the bushing 21 so that the bushing 21 is sealed. The fixed lid 24 comes into contact with the head 13d of the guide member 13a, and pushes the guide member 13a toward the cone portion 11, whereby each of the flat springs 13b is compressed and the elastic restoring force is reduced. Is to occur. As a result, a predetermined pressing force acts on the cone portion 11, and the cone portion 11 is pressed against the inner surface of the bushing 21 with a predetermined surface pressure.

Next, the operation and effect of the above embodiment will be described.

By using the flat springs 13b, 13b,... Capable of obtaining a large load with a small amount of deflection, coil springs 15b, 1 shown in FIGS.
The required surface pressure can be sufficiently obtained even if the amount of protrusion to the rear is significantly reduced as compared with the conventional insulating plug 1 'using 5b,..., And as a result, the insulating plug 1 can be made more compact. Will be able to In addition, the flat springs 13b, 13
Since b and b are easily available, the cost can be significantly reduced.

Adjusting the pressing force of the cone portion 11 can be realized by increasing or decreasing the number of the spring portions 13. For example, in this embodiment,
As shown in FIG. 3, five spring portions 13, 13,... Are arranged circumferentially, but if the number of the spring portions 13 is reduced to, for example, four or increased to six, the above-mentioned cone portion 11 is formed. The pressing force is adjusted. Further, when the amount of deflection of the spring portion 13 is changed, it can be realized by adjusting the number of superposed springs 13b, 13b,. As described above, by the combination of one kind of the flat springs 13b, the adjustment of the pressing force of the cone portion 11 and the adjustment of the deflection amount of the spring portion 13 can be performed, and the fine adjustment can be easily performed. . When such a fine adjustment is to be performed by the conventional coil spring method, for example, the arrangement of the coil spring or the 1
There is an inconvenience that a special specification product must be produced after setting the spring constant per unit, calculating the element wire diameter, the coil diameter, and the number of turns in accordance with the spring constant. On the other hand, when using a flat spring, the size and spring characteristics of the unit flat spring are standardized by JIS, and even when actually incorporating, a suitable flat spring can be selected and a commercially available product can be purchased. There are no troubles such as cumbersome calculations or specially made products.

In addition, by forming the spring portion so as to protrude from the shield fitting 12, a predetermined space is created between the shield fitting 12 and the fixed lid 24. Moreover, since the spring portions 13, 13,... Are stacked in series such that the directions of the adjacent flat springs 13b, 13b,... Are opposite to each other, a relatively large amount of deflection can be obtained. For this reason, even when the cone portion 11 expands when a temperature change or the like occurs, the amount of change in the pressing force can be sufficiently absorbed, and the cone portion 11 always receives the optimum pressing force. Will be able to do that. As a result, the performance required for the insulating plug 1 can be stably obtained.

Further, a guide member 13 having a protruding length that can be extended and contracted with respect to a shield fitting 12 is used as compared with a conventional insulating plug 1 'having a shaft 15a and a washer member 16 shown in FIG. Therefore, the portion protruding rearward can be further reduced, and the size can be further reduced. Here, as shown in FIG. 6, in the conventional insulating plug 1 ',
When the length L2 from the rear end of the bushing 21 to the fixed lid 25 is 75 mm, the flat springs 13b, 13
1, the length L1 from the rear end of the bushing 21 to the fixed lid 24 is 1 as shown in FIG.
The size may be set to 5 mm, and the size can be significantly reduced. <Other Embodiments> Note that the present invention is not limited to the above-described embodiments, but includes various other embodiments. That is, in the above-described embodiment, the insulating plug 1 is attached to the terminal end of the device. However, the present invention is not limited to this. For example, the insulating plug 1 may be used for an empty terminal of a T-type bushing. Further, the insulating plug 1 may be used for an empty terminal of an intermediate branch connection box provided in the middle of the cable line. Even in this case, it is possible to form the device compactly while ensuring required performance such as surface pressure.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a state in which an insulating plug for a cable connecting portion according to an embodiment of the present invention is mounted on an empty terminal.

FIG. 2 is a half sectional explanatory view showing an insulating plug for a cable connecting portion.

FIG. 3 is a right side view showing an insulating plug for a cable connection portion.

FIG. 4 is an enlarged sectional explanatory view showing a spring portion of the insulating plug for a cable connection portion.

FIG. 5 is a longitudinal sectional view showing a guide member.

FIG. 6 is a view corresponding to FIG. 1, showing a state in which a conventional insulating plug for a cable connecting portion is attached to an empty terminal.

FIG. 7 is a diagram corresponding to FIG. 2 showing a conventional insulating plug for a cable connecting portion.

FIG. 8 is a view corresponding to FIG. 3 showing a conventional insulating plug for a cable connection portion.

[Explanation of symbols]

 1, 1 'Insulation plug for cable connection part 11 Cone part 12 Shield fitting 13, 15 Spring part 21 Bushing (cable connection part) 24, 25 Fixed lid 13a Guide member 13b Flat spring 13d Head 13g Middle part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor, Katsunori Funano 8 Nishinocho, Higashimukaijima, Amagasaki City, Hyogo Prefecture F-term (reference) 5G375 AA02 BA15 BB05 BB26 CB05 CB25 CB42 DB04 EA15

Claims (2)

[Claims] 1. An insulating plug for a cable connection portion mounted on a cable connection portion, comprising: a cone portion crimped on an inner surface of the cable connection portion; and a shield fitting provided at a rear end of the cone portion; A spring portion protruding from the shield metal fitting and being pressed by a fixed lid for sealing the cable connection portion, thereby pressing the cone portion toward the inner surface of the cable connection portion. An insulated plug for a cable connecting portion, comprising a spring and being formed in series so that the directions of the flat springs are alternately reversed. 2. The spring portion according to claim 1, wherein the spring portion includes a rod-shaped guide member having a head portion whose diameter is larger than that of an intermediate portion thereof, and wherein the guide member has a projecting length extending from a shield metal. The shield spring is attached to the shield fitting so as to be possible, and the flat spring is inserted between the head of the guide member and the shield member by being externally inserted into an intermediate portion of the guide member. Insulation plug for cable connection.