JPS5922746Y2 - Waterproof plug for conduit entrance for buried cables - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a waterproof plug for a conduit opening that opens into a manhole constructed in the middle of an underground conduit such as an electric power cable.

Conventionally, in order to prevent the cable from penetrating into the buried pipe through the gap between the cable opening and the electric cable inserted therein, a rubber material was used to seal the gap between the cable opening and the cable. Various cylindrical waterproof plugs have been proposed, but in many cases, these waterproof plugs do not have sufficient sealing performance, especially against the circumferential surface of the cable that is inserted, and as the diameter of the cable increases, the waterproof plug becomes larger in size. There were some inconveniences, such as not being able to move around.

The present invention was devised in view of these drawbacks, and it is an object of the present invention to provide a waterproof plug for a conduit entrance for burying cables that has good sealing properties, is relatively small, and is easy to install and operate.

Below, we will explain an illustrated example in which the present invention is applied to burying a triplex cable. In Figures 1 and 2, the waterproof plug of the present invention has three cable insertion holes centered at positions equidistant from the central axis XX. The rubber cylinder 1 consists of a truncated conical rubber cylinder 1 having 2..., and the rubber cylinder 1 has an arbitrary point on its circumference, preferably at two adjacent points in the illustrated example. An incision 3 is made along the plane at a point where a plane passing through the midpoint of the line segment connecting the centers of the cable insertion holes and the center X of the rubber cylinder 1 intersects with the circumferential surface.

The center portion of the rubber cylinder 1 is formed as a trifurcated removable portion 4.

The rubber cylinder 1 also has a circular arc portion 5 a along the circumference of the rubber cylinder 1 and a circular arc portion 5 along the circumference of the cable insertion hole 2 on each of the large-diameter circular end surface 1 a and the small-diameter circular end surface 1 b.
It is provided with three substantially sector-shaped recesses 5 having a diameter of 1.b, and the recesses are formed in a tapered shape toward the bottom surface.

Reference numeral 6 designates a tightening bolt insertion hole which is drilled from the bottom of the substantially fan-shaped recess 5 on the large-diameter circular end face 1a side to the bottom face of the substantially fan-shaped recess 5 on the small-diameter circular end face 1b side.

The rubber cylindrical body 1 is further provided with a substantially fan-shaped fastening fitting 7 formed in a shape slightly larger than or similar to each of the substantially fan-shaped recesses 5 to be fitted into each of the substantially fan-shaped recesses 5, as shown in FIG. As referenced, the substantially sector-shaped fastening fitting 7 to be fitted into the substantially sector-shaped recess 5 on the side of the small-diameter circular end face 1b has a tightening bolt 8 integrally formed on its bottom surface.

In order to attach the waterproof plug of the present invention constructed as described above to the conduit entrance when burying the cable, the trifurcated removable portion 4 is removed from the rubber cylinder 1, and the portion is attached to each line of the triplex cable (not shown). Then, the rubber cylinder 1 is expanded from the incision 3 in the circumferential direction as shown by arrows 9 and 10, and the triplex cable is inserted through the expanded incision. Each wire cable is placed in the cable insertion hole 2.

Prior to the above-mentioned cable insertion and fixing operation, each tightening fitting 7 is normally temporarily installed in each recessed portion 5, but in the conventionally known similar type of waterproof plug, the tightening fitting 7 is a circle of the rubber cylindrical body 1. A two-part ring type fitting that is fitted along the circumference is used, and half of the ring type fastening fitting is attached to the rubber cylinder body 1 in advance.
Since it is fitted into the fitting groove along the circumference of the rubber tube 1, the opening and expansion operation of the rubber cylinder 1 for inserting the cable is obstructed as described above.

However, the tightening fittings 7 of the waterproof plug according to the present invention are formed into a substantially fan shape, and are disposed on the left and right sides of the incision line 3 of the rubber cylinder 1, so that the opening and expansion operation of the rubber cylinder 1 is obstructed. It has the advantage that it does not.

Rubber cylinder 1 with triplex cable inserted and fixed
Next, the tip of the tightening bolt 8 of the tightening fitting 7 is press-fitted into the conduit opening shown by the dotted line in FIG. is inserted into the through hole 11 of the fastening fitting 7 fitted into the substantially fan-shaped recess 5 on the side of the large-diameter circular end surface 1a and tightened with the nut 12. The elastic body is crimped against the wall of the conduit port and the outer peripheral surface of the cable to provide a sealing effect.

At this time, since the tightening fitting 7 of the waterproof plug of the present invention is formed into a substantially fan shape having a circular arc portion 5a along the circumference of the rubber cylinder 1 and a circular arc portion 5b along the circumference of the cable insertion hole 2, A perfect waterproof sealing effect is achieved by applying an even pressing force to the entire circumference of the circular wall surface of the conduit entrance and the entire circumference of the circumferential surface of the cable.

Furthermore, in the case of the conventional two-part ring-type clamp, the area of the cable insertion hole 2 is limited by the inner diameter of the ring-type clamp, so if the cable diameter becomes larger, the rubber cylinder 1 The diameter of the waterproof plug must be made larger accordingly, whereas the tightening fitting of the proposed waterproof plug is fitted into the substantially fan-shaped part between the adjacent cable insertion holes 2, so the cable diameter has to be made larger accordingly. Even so, it is not necessarily necessary to increase the diameter of the rubber cylinder, and it is sufficient to reduce the dimensions of the substantially fan-shaped fastening fitting accordingly, and it is possible to omit increasing the size of the waterproof plug.

As described above, the present invention provides a waterproof plug for a conduit opening for burying cables that has a good waterproof sealing effect, is relatively small, and is easy to install and operate.

[Brief explanation of the drawing]

Figure 1 is a front view of the proposed waterproof plug, viewed from the small diameter circular end side;
FIG. 2 is a sectional view taken along line A--A in FIG. 1...Rubber cylinder body, 2...Cable insertion hole, 3...Cut portion, 4...Trifurcated removable part, 5...・・・Approximately fan-shaped recessed part, 6...
...Tightening bolt insertion hole, 7...Approximately sector-shaped tightening fitting, 8...Tightening bolt.

Claims (1)

[Scope of utility model registration request] A truncated cone-shaped rubber cylinder having a cable insertion hole with a similar shape to the outer shape of the cable to be inserted in the central part, and the rubber cylinder has a central axis line at an arbitrary point on its circumference. The large-diameter circular end face and the small-diameter circular end face each have a circular arc portion corresponding to the circular outer peripheral surface of the cylindrical body and a circular shape of each cable insertion hole. A plurality of substantially sector-shaped recesses each having an outer circumferential surface and a corresponding arcuate portion, and a shape corresponding to each recess,
A waterproof plug for a conduit opening for burying a cable, comprising a plurality of substantially fan-shaped fastening fittings that are fitted and fixed into the recess.