JPS5922747Y2 - 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 at the entrance of a buried pipe such as an electric power cable.

Conventionally, in order to prevent cables from entering the cable burying pipeline through the gap between the cable embedding pipeline opening and the cable inserted therein, a cable embedding pipe that is almost the same as the pipeline opening 3 has been used, as illustrated in FIG. A cable insertion hole 2 is bored in the center of a rubber cylinder 1 with a diameter of about 100 mm, and the cable C is inserted through the cable insertion hole 2.The rubber cylinder 1 is then fitted into the pipe port 3, and the rubber cylinder 1 is inserted into the pipe opening 3. On both end faces of the body 1 are annular or other arbitrary shaped fastening fittings 4,
4, and the rubber cylinder is tightened in the axial direction from both end surfaces with the tightening fittings to exert a sealing effect against the wall surface of the pipe port and the outer peripheral surface of the cable. Are known.

In the above-mentioned known waterproof plug, the conduit port 3 is usually constructed of concrete, so the tightening force accompanying the compression of the rubber cylinder 1 acts more strongly on the cable C side, and the cable is connected to a large current As the polyethylene coating layer is heated and softened by the flow of the polyethylene, the tightening force of the rubber cylinder 1 causes it to become concave as shown by the dotted line in the figure, which may reduce the sealing effect of the rubber cylinder 1. In severe cases, this may cause insulation breakdown of the cable.

The present invention was devised in view of these drawbacks, and is based on forming the wall surface of the central portion of the known waterproof plug along the axis of the cable insertion hole into a concave curved surface.

The present invention will be described below with reference to illustrated examples. In FIGS. 2 and 3, the waterproof plug of the present invention is composed of a truncated conical rubber cylinder 11 having a cable insertion hole 12 in the center,
The rubber cylindrical body 11 has an incision 13 at an arbitrary point on its circumference along a plane passing through the central axis XX so as to be expandable.

Although the waterproof plug for burying a single cable is illustrated in the embodiments of FIGS. 2 and 3, the waterproof plug of the present invention can also be applied for burying multiple cables, and accordingly A plurality of holes 12 are formed at equal distances from the center axis XX of the rubber cylinder 11.

The rubber cylindrical body 11 also has concave portions 14 for fitting a tightening fitting on the large-diameter circular end surface 11a and the small-diameter circular end surface 11b, respectively.
and 15, and fastening fittings 16 and 1 are provided in each recess.
7 is fitted.

In the illustrated example, the fastening fitting may be formed into a two-part annular shape, or may be formed into a substantially fan shape as shown in FIG.

However, in any case, the fastening fittings 16 and 17 are
It should have a circular arc portion similar to the circular outer circumferential surface of the rubber cylinder 11 and a circular arc portion similar to the circular outer circumferential surface of the single-core or three-core cable to be inserted.

With this configuration, the tightening force applied by the tightening fittings 16 and 17 is applied equally to each cable, and a reliable sealing effect can be obtained.

Further, one of the fastening metal fittings 17 integrally formed with the fastening bolt 18 may be buried near the surface of the small-diameter inner end surface of the rubber cylinder 11.

According to the present invention, as shown in FIG.
An annular groove exhibiting a concave cross-sectional shape is formed on the wall surface of the approximately central portion along the direction - As a result, the rubber cylinder 11 is opened left and right from the incision 13, the cable C (indicated by the dotted line) is inserted into the cable insertion hole 12, and the rubber cylinder 1 is
1 into the pipe opening, and then screw the nut 19 onto the tightening bolt 18, and use the tightening fittings 16 and 17 to connect the rubber cylinder 11 to the large-diameter circular end surface 11a and the small-diameter circular end surface 11.
When tightened from point b, the rubber cylinder 11 compressed by the tightening operation is evenly crimped against the wall surface of the conduit port and the outer peripheral surface of each cable C, and exhibits a sealing effect, but the cable insertion hole As mentioned above, the central portion of the rubber tube 12 is initially formed into a concave curved surface, so as the rubber cylinder 11 is compressed, it comes into close contact with the outer circumferential surface of the cable with appropriate pressure, and the cable is closed like a conventionally known waterproof plug. Inconvenient situations such as denting the coating layer, thereby reducing the sealing effect and causing dielectric breakdown, can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional waterproof plug, FIGS. 2 and 3 are a front view and a sectional view of a waterproof plug according to an embodiment of the present invention, and FIG. 4 is a diagram of a fastening fitting used in the waterproof plug of the present invention. It is a perspective view showing an example. 11...Rubber cylinder body, 12...Cable insertion hole, 13...Cut portion, 14.15...
... Recessed part for fitting the tightening metal fitting, 16.17...
Tightening metal fittings, 18... Tightening bolts, 19...
...Natsuto.

Claims (1)

[Scope of utility model registration request] A truncated cone-shaped rubber cylinder having a cable insertion hole in a shape similar to the square shape of the cable to be inserted through 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 are each provided with a recessed part for fitting a fastening metal fitting, and is fitted into the recessed part for fitting a fastening metal fitting. In a waterproof plug for a conduit entrance for burying a cable that is configured to be tightened and compressed from both a large-diameter circular end face and a small-diameter circular end face by a tightening fitting, the cable insertion hole is formed in a large-diameter circular end face of a rubber cylinder. An annular groove having a concavely curved cross section is formed approximately in the center between the end face and the small-diameter circular end face, and the tightening fitting has a circular arc portion similar to the circular outer circumferential surface of the rubber cylinder, and a circular groove for each cable. A waterproof plug for a conduit opening for burying a cable, characterized by having a circular arc portion similar to the circular outer peripheral surface of the insertion hole.