JPH025612Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of an explosion-proof junction box used for branching multicore cables in an explosion-proof area.

[Conventional technology]

The shape of the conventionally used general explosion-proof junction box is, for example, the junction box 1, which has a rectangular housing as shown in Figure 1, and its material is aluminum alloy, which is lightweight and easy to process. Most of them were made of heavy cast iron.

The reason why cast iron is used for this type of junction box 1 is that when the junction box is installed, the bottom A of the box has a large diameter that is used as an inlet (primary conduit piping) with the required diameter and number of pieces. The hub 2 of the box is protruded, and if necessary, small diameter hubs for passing through the branch line are protruded from the upper side C of the box and the left and right sides B and D to form an outlet (secondary side conduit piping). This is due to the fact that cast iron processing, which is suitable for forming various hub protrusions, is often employed.

In addition, as shown in Japanese Utility Model Publication No. 32-6450, an opening is formed on one side of the box body, and this opening is used as a terminal that also serves as a lid that is removably fixed to the box body using a fixing device consisting of a screw. There was a terminal box that was blocked by a single mounting base plate. This terminal box has a box body that is inclined so that the depth dimension inside the box body increases sequentially from the top to the bottom, and the thickness of the bottom wall of this box body is the thickness of each wall other than the bottom wall. 1 on the bottom wall.
Two electric wire piping holes are formed.

[Problem that the invention attempts to solve]

In general, it is desirable for a junction box to be as small as possible from the viewpoint of explosion protection and cost. In reality, it depends not only on the number of terminals but also on the number of terminals attached via terminal blocks inside the box body. In other words, the size of an explosion-proof junction box is, in principle, determined by the diameter or number of hubs protruding from the upper, lower, left, or right sides of the junction box 1, and the number of terminals installed inside the junction box. This is determined by correlation, but individually, for example, even if the number of terminals is small, if the hub is large in diameter, the size of the junction box will inevitably be large, and as a result, This is leading to a significant increase in costs.

In addition, the explosion-proof junction box is located in an explosion-proof area, i.e.
Because they are installed in dangerous places such as chemical factories and nuclear power plants, and at high places on the sea, they require not only safety, but also strong waterproofing, water resistance, and corrosion resistance. A structure in which no hub is attached to the upper side surface C is required, and in this case as well, there is a problem that the overall size of the box becomes large and the cost increases.

However, in order to increase the internal volume of the box itself,
As a result, the wall thickness must be increased and the depth of the bottom part A is also increased, making it difficult to perform installation work at high places. Not only does it take time and effort to add a raised base for the terminal block to the inside of the box, but in addition, we have no choice but to use a custom-made method to meet various requests, and as a result, delivery times are becoming noticeably longer. be.

Therefore, it may be possible to apply the configuration of the conventional terminal box described above to an explosion-proof type junction box, but even if this is done, the internal volume surrounded by the box body and the lid is It can be reduced compared to the general one, and the hub provided on the box body can only be eliminated.

Therefore, the problems of conventional general explosion-proof junction boxes, such as cost, piping workability, installation branch workability, etc., cannot be satisfactorily solved.

This invention solves the above problems and improves the basic shape of the box body of the junction box in order to maintain pressure resistance by reducing the internal volume, which is one of the important points for explosion-proof performance. This makes it possible to make the entire box more compact and reduce its weight, making it possible to machine molds using corrosion-resistant aluminum alloy instead of iron castings, and making it possible to create various types of molds by simply cutting the bottom part. We can form conduit entry ports that meet orders, and the number of entry ports is
The aim is to provide an explosion-proof junction box that can be significantly increased compared to conventional ones with the same internal volume and is superior in terms of cost, delivery time, piping branching work, corrosion resistance, and safety.

[Means for solving problems]

The present invention provides an explosion-proof junction box in which an opening provided at the front of the box body is closed with a lid that is removably fixed to the box body with a fixing device. the opening of the box body is disposed above the protrusion, the depth dimension within the protrusion portion is larger than the depth dimension of the portion of the box body having the opening, and the box body The thickness of the bottom wall is larger than the thickness of each wall other than this bottom wall, and the bottom wall is provided with electrical wire piping holes for inlet and outlet at multiple locations in the depth direction. .

[Effect]

The explosion-proof junction box according to the present invention has a protrusion that protrudes toward the front only at the bottom of the box body, and an opening that is closed by the lid above this protrusion, so that the box body and the lid are connected. The enclosed internal volume, that is, the internal volume of the box, is not wasted, and this volume and the area of the lid are, of course, used in conventional general explosion-proof junction boxes.
This junction box can be made smaller than a junction box to which the structure of the terminal box described above is applied, and an explosion-proof junction box with high strength can be obtained using less material. In addition, the explosion-proof junction box according to the present invention utilizes the fact that a protrusion is provided at the bottom of the box body to increase the depth of the bottom wall, and wire piping holes are formed at multiple locations in the depth direction. The number of piping holes can be increased, and these piping holes can be used as inlets and outlets.Furthermore, only the bottom of the box body has extra volume due to the protruding parts, so the inside of the protruding parts can be used for wiring. It serves as a storage area for wires, making it easy to branch wires.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 to 9.

2 is an overall perspective view, FIG. 3 is a perspective view with the lid removed, FIG. 4 is a rear view, and FIG. 5 is a partial perspective view of the bottom.

In each figure from FIG. 2 to FIG. 5, 10 is a box body of an explosion-proof junction box made of aluminum alloy AC7A, and this box body 10 has a protruding part 20 provided only at the bottom and protruding to the front side. It consists of an upper wall 30, left and right side walls 40, 50, and a rear wall 60. A standing wall 21 is formed in front of the protrusion 20 and stands up from the protruding end of the bottom wall. A protrusion upper wall 22 is formed that protrudes obliquely upward from the upper end toward the opening 70.

70 is an opening provided on the protrusion 20 on the front side of the main body 10, and this opening 70 is covered with a lid 80 made of the same alloy as the box main body 10, as shown in the second figure, and this lid 80 is used for bolts, washers, etc. It is removably fixed to the box body 10 with a fixture 90. In addition, the lid 8
In view of the characteristics of the explosion-proof type junction box, the hexagonal wrench 65 is used to strengthen the locking structure when the 0 is fixed.

6 and 7 respectively show the box body 10.
The figure shows a partially cutaway front view and a cross-sectional view taken along line A-A of the box body 10. Although it is formed to have a wall thickness that is approximately twice as thick as the wall thickness t, the thickness may be made larger or smaller depending on the purpose of the connection box, but the wall thickness T> It is necessary to make the wall thickness t. As shown in FIG. 6, an inclined surface 25 that slopes downward to the right is formed on the upper surface of the bottom wall 23, and a drain hole 24 formed at the right end of the bottom wall 23 drains condensed water generated inside the box body 10. Formed to fall from. The direction of the inclined surface 25 may be reversed from left to right, or may be inclined in the front-back direction.

As shown in FIG. The protrusion upper wall 22, which is formed upward from the upper end toward the opening 70, is formed to have an inclination angle θ of approximately 30° with respect to the horizontal plane, as shown in FIG.

As shown in FIG.
and the front part 31 of the upper wall 30, and at required locations inside the outer periphery of the opening 70 formed by surrounding the outer periphery,
An extra wall portion 32 is provided, and a lid 80 (described later) is attached to these portions.
The bolt holes 33 are provided so as not to penetrate through the extra wall portion 32 during fixation.

In Figures 3, 6, and 7, 34 is a reinforcing rib, and 35 is a reinforcing rib for the terminal block mounting base.These ribs are provided with non-penetrating screw holes, etc., as necessary. This hole is drilled and used for attaching a terminal block or a grounding terminal.

What is shown in FIG.
6. Inside surface 27 of the upper wall 22 of the protrusion, inside surface 28 of the rear wall 60, and inside surfaces 2 of the left and right side walls 40, 50.
9 and 29 form a hollow storage section 100, and the box body 10 as a whole is formed to have a generally boot-shaped longitudinal section. Further, 61 is an inclined surface formed on the inner surface of the rear wall 60, which allows a terminal block (not shown) to be located closer to the front to facilitate branching work, etc. A rib 62 of a desired shape is also provided on the outer surface of the holder 60, making use of the sloping surface thereof.

Further, on the bottom wall of the protrusion 20, a fifth
As shown in the figure, a required number of wire piping holes 20a, 20b, and 20c are formed at multiple locations in the depth direction, which can be used as an inlet and an outlet for primary or secondary wire piping of a required diameter. Ru. These piping holes 20a, 20b, and 20c do not need to be provided as hubs protruding outward from the bottom like in conventional ones, so they can be arranged in up to three rows in the depth direction depending on the diameter within explosion-proof standards. It can be formed at a desired position by cutting. Reference numeral 63 denotes a projection for fixing the main body 10 that projects from the outer periphery of the rear wall 60.

FIG. 8 is a front view of the lid 80, and FIG. 9 is a partial side view of the same. The strength of the lid corner portions is maintained by not providing through-screw holes 81 for fixing bolts in the four corner portions of the lid 80, and concave portions 82 are formed at each corner portion to improve the strength. There is. 83 is a rib formed on the inner surface of the lid 80, and 84 is a rib formed on the outer periphery of the surface of the lid 80.

This embodiment has the above-mentioned structure, and the depth width W of the protrusion 20 provided at the bottom of the box body 10 of the explosion-proof junction box is made larger than the depth width W in the portion above the protrusion 20. In addition, the wall thickness T of the bottom wall 23 is made larger than the wall thickness of each wall other than the bottom wall 23, such as the wall thickness t of the left and right side walls 40, 50, and the top wall 30. By forming the wire piping holes 20a, 20b, and 20c that can be used as the inlet and the outlet, it is no longer necessary to provide a hub that was conventionally protruded from the bottom wall by casting.
It has become possible to form molds with excellent precision.

Moreover, since the piping holes can be easily formed by cutting, the desired diameter and desired number of holes can be processed after the box body is formed, making it suitable for mass production. For example, in the past, even for large types, the maximum row of hub protrusions was
Due to the need to add extra wall thickness, the limit was two levels above and below, but since there is no need to add extra wall space at the bottom of this example, when the diameter of the pipe hole is small, it is possible to use up to three rows of pipe holes. It is now possible to form
As a result, it can now be used for various purposes,
Significant cost reductions can now be expected.

Furthermore, the piping holes need only be formed in the bottom wall, and there is no need to protrude the hub from the other side surfaces, so it is possible to reduce the internal volume of the box body. especially,
A protrusion upper wall 22 is formed that slopes upward from a standing wall 21 in front of the protrusion 20, and this protrusion upper wall 22
A lid 80 that closes the opening 70 from above is fixed to the box body 10, and the depth width W inside the protrusion 20 of the box body 10 is
By making the width w of the box body 10 larger than the depth w in the portion of the box body 10 that has the opening 70, the box body 10
Since the internal volume of the lid 80 can be reduced to the minimum and the area of the lid 80 can be reduced, the explosion-proof performance can be significantly improved without waste.

By deforming the longitudinal section into an almost boot-shape as described above, when performing branching work in dangerous places such as high places or at sea, it is possible to always work within a shallow depth width W, making it safe. It can also be extremely effective in terms of performance and work efficiency.

Moreover, since it is almost boot-shaped, the protrusion 2
The hollow portion formed inside the wire serves as a storage portion 100 for excess wire during wiring, making branching work easy and convenient.

Furthermore, by slanting the top surface of the bottom wall 23 constituting the protrusion 20 in the left, right, or front-back direction, the condensed water generated inside the box body 10 can be quickly and accurately discharged from the outlet 24. Therefore, it is also excellent in terms of corrosion resistance.

[Effect of idea]

As explained above, the explosion-proof junction box of the present invention has a protrusion that protrudes toward the front only at the bottom of the box body, and the front surface of the box body above the protrusion is closed by a lid. An opening is provided, the depth within the protruding portion is greater than the depth within the portion having the opening, and the thickness of the bottom wall of the box body is greater than the thickness of each wall other than the bottom wall. In addition, since electric wire piping holes for the inlet and the outlet are formed at a plurality of locations in the depth direction of the bottom wall, the following effects can be obtained.

That is, since a protrusion that protrudes toward the front is provided only at the bottom of the box body, and an opening that is closed by the lid is provided above this protrusion, the internal volume surrounded by the box body and the lid, In other words, the internal volume of the box is not wasted, and this volume and the area of the lid can be made smaller than not only a conventional general explosion-proof junction box but also a junction box to which the structure of the terminal box is applied. , it is possible to obtain a strong explosion-proof junction box with less material. In addition, by making use of the fact that a protrusion was provided at the bottom of the box body to increase the depth of the bottom wall, electric wire piping holes were formed at multiple locations in the depth direction, so the number of these piping holes could be increased. The piping holes can be used as the inlet and outlet, and since the bottom of the box body has extra volume due to the protruding part, the protruding part becomes a storage area for excess wire during wiring, and the branching of the line is possible. Work can be done easily. Therefore, according to the present invention, it is possible to process molds using aluminum alloy, and it is possible to provide an explosion-proof junction box that is superior in cost, delivery time, piping branching work, corrosion resistance, and safety. effective.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional general explosion-proof junction box, Figure 2 is a perspective view of an explosion-proof junction box according to an embodiment of the present invention, and Figure 3 shows the internal structure with the lid removed. Fig. 4 is a rear view of the same as above, Fig. 5 is a perspective view showing the electric wire piping hole at the bottom, Fig. 6 is a front view with a part of the box main body in section, and Fig. 7 is the same as above. A-A sectional view, FIG. 8 is a front explanatory view of the lid,
FIG. 9 is a partial side view of the same as above. 10...Main body, 20...Protrusion, 20a, 20
b, 20c...Wire piping hole, 21...Standing wall, 2
2... Projection top wall, 23... Bottom wall, 30... Top wall, 40... Left side wall, 50... Right side wall, 60...
Rear wall, 70... opening, 80... lid, 90... fixture, 100... storage section.

Claims (1)

[Claims for Utility Model Registration] (1) An explosion-proof junction box in which an opening provided at the front of the box body is closed with a lid that is removably fixed to the box body with a fixture, A protrusion that protrudes forward is formed only at the bottom of the box body, and the opening of the box body is disposed above this protrusion, and the depth dimension within the protrusion is defined as the depth dimension within the portion of the box body that has the opening. The wall thickness of the bottom wall of the box body is larger than that of each wall other than this bottom wall, and there are electrical wire piping for the inlet and outlet at multiple locations in the depth direction of the bottom wall. An explosion-proof junction box characterized by having holes formed therein. (2) The box body has a protruding upper wall that protrudes diagonally upward from the upper end of the standing wall rising from the protruding end of the bottom wall toward the opening of the box body, and the opening is closed on the upper wall. The explosion-proof junction box according to claim 1 of the utility model registration claim, wherein the lid is fixedly fixed. (3) The explosion-proof junction box according to claim 2 of the utility model registration, wherein the box body has a lid that closes the opening fixed from above the upper wall of the protrusion to the front surface of the upper wall.