JPH0716112B2 - Airtight enclosure with safety plug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A safety plug applicable to an airtight housing such as a wireless repeater installed outdoors, for the purpose of preventing destruction of the airtight housing, A plate member having a shape larger than the opening formed in a part of the outer wall of the structure housing is covered with the nut, and a bolt having a head having a size smaller than the opening, the outer wall and When the pressure difference between the inside and the outside of the airtight housing exceeds a predetermined pressure, the plate member is deformed into a substantially bowl shape and passes through the opening together with the bolt and the nut. It is constructed so that it has a safety plug that can be pulled out.

[Industrial application field]

The present invention relates to a safety plug applicable to an airtight housing such as a wireless repeater installed outdoors.

The wireless repeater installed outdoors has a waterproof structure so that raindrops do not enter the inside, and therefore the housing has a completely airtight structure without air vent holes.

In this way, if the casing has an airtight structure, there is a possibility that the casing may be destroyed when the temperature rises in hot weather and the air expands and the internal pressure rises.

Therefore, the airtight housing is required to have a structure in consideration of the above pressure increase.

[Conventional technology]

The housing of the conventional wireless repeater has not been constructed in consideration of the damage due to the pressure increase.

[Problems to be Solved by the Invention]

Therefore, there is a risk of an accident in which the housing is destroyed due to an abnormal increase in internal pressure under hot weather, which is a safety problem.

In view of the above, it is an object of the present invention to provide an airtight housing having a safety plug that can prevent the airtight housing from being destroyed.

[Means for Solving the Problems]

The present invention provides a plate member having a shape larger than an opening formed in a part of an outer wall of an airtight housing, with the opening covered, a nut, and a bolt having a head smaller than the opening. The structure is fixed together with the outer wall, and when the pressure difference between the inside and the outside of the airtight housing exceeds a predetermined pressure, the plate member is deformed into a substantially bowl shape together with the bolt and nut. The safety plug is configured to come out through the opening.

[Action]

The structure in which the plate member is fastened together with the outer wall by the bolt and the nut does not impair the airtight structure of the housing.

The structure in which the head of the bolt is smaller than the opening enables the safety plate to be deformed into a bowl shape, and allows the safety plate, the bolt, and the nut to come out of the opening.

〔Example〕

FIG. 1 shows a wireless repeater housing 1 according to an embodiment of the present invention.

An electronic circuit unit 2 for wireless relay is built in the housing 1.

The housing 1 has an airtight structure including a box-shaped housing body 3 and a bottom cover 4 fixed by closing the opening.
Is installed outdoors in the posture shown in FIG.

The bottom cover 4 has a circular opening 5 in its center, and a safety plug 10 which is an essential part of the present invention is provided therein.

As shown in the enlarged view of FIGS. 2 to 4, the safety plug 10 is
The structure includes an annular safety plate 11, a bolt 12, and a nut 13.

The diameter d ₂ of the diameter d ₁ and the aperture 5 of the safety plate 11, the relationship d ₁ is slightly larger than d _2, that is, d _1> d _2.

The diameter d ₃ of the head 12a of the bolt 12 is set to be slightly smaller than the diameter d _{2 of the} opening 5. That is, d ₃ <d ₂ .

The relationship with the diameters d ₁ , d ₂ and d ₃ is d ₁ > d ₂ > d ₃ .

Assuming that the thickness of the safety plate is t, the diameters d ₃ and d ₂ are 2 × the diameter d _3.
It is determined that the dimension including t is approximately d ₂ .

Here, the thickness t of the safety plate 11 is determined by the pressure P ₁ set as the pressure inside the housing 2 when the safety plug 10 is removed. In this embodiment, the safety plug 10 is defined to be removed when the pressure P ₁ exceeds 1.4 atm.

The nut 13 includes a main body portion 13a fitted in the opening 5 and a flange portion 13b on the end side.

The safety plate 11 is arranged on the upper surface 4a side of the bottom cover 4, and the nut 13 fitted in the opening 5 from the lower surface 4b side of the bottom cover 4.
And the bolt 12 screwed into the nut 13 from the upper surface 4a side of the bottom cover 4 to be fastened together with the bottom cover 4 and pressed against the upper surface 4a of the bottom cover 4 and fixed in a state where the opening 5 is closed. There is.

15, 16 and 17 are seal members.

As a result, the safety plug 10 also has an airtight structure,
The housing 1 has a completely airtight structure as a whole, and raindrops do not enter the inside.

Next, the operation of the safety plug 10 will be described with reference to FIGS. 5 and 6.

When the temperature of the air in the housing 1 rises and expands under hot weather, and the pressure of the housing 1 rises, the pressure P in the direction of pushing the head 12a of the bolt 12 into the opening 5 acts.

When the pressure P exceeds 1.4 atm, the bolt head 12a functions as a punch of the press drawing machine and the bottom cover 4 functions as a die, and as shown in FIG.
The bolt head 12a sinks into the opening 5 with the upward bending indicated by reference numeral 11b (FIG. 5) (FIG. 2). Safety plate 1
1 is transformed into a bowl shape.

In this state, the safety plate 11 is pushed into the opening 5 together with the bolt head 12a, passes through the opening 5, and as shown in FIG.
Get out of the opening 5.

As a result, the inside of the housing 1 is communicated with the atmosphere through the opening 5, the pressure inside the housing 1 is released, and the damage of the housing 1 is prevented.

Further, the safety plug 10 may be provided upside down. This configuration is effective when applied in an environment in which the pressure outside the housing is abnormally higher than the pressure inside (for example, a radio buoy on the sea and when it is submerged in the sea).

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent the airtight housing from being destroyed by pressure without damaging the airtightness of the airtight housing, and to ensure safety.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an airtight housing having a safety plug according to an embodiment of the present invention, FIG. 2 is an enlarged view showing a portion of the safety plug in FIG. 1, and FIG. Fig. 4 is an exploded perspective view of the safety plug of Fig. 2, Fig. 4 is a plan view of the safety plug of Fig. 2, Fig. 5 is a diagram showing an initial state of the safety plug coming out of the opening, and Fig. 6 is a safety plug. It is a figure which shows the state which pulled out from the opening. In the figure, 1 is a radio relay casing, 2 is a radio relay electronic circuit unit, 3 is a casing main body, 4 is a bottom cover, 5 is an opening, 10 is a safety plug, 11 is a safety plate, 11a is an outer peripheral side portion, 11b. Is an outer peripheral portion bent upward, 12 is a bolt, 12a is a head, 13 is a nut, 13a is a main body, and 13b is a flange.

Claims (2)

[Claims] 1. A plate member (11) having a shape larger than an opening (5) formed in a part of an outer wall (4) of an airtight casing (1).
With the nut (13) and the bolt (12) having the head portion (12a) smaller than the opening (5) in the state where the opening (5) is covered, the nut (13) and the outer wall (4) are connected together. When the pressure difference between the inside and the outside of the airtight housing exceeds a predetermined pressure, the plate member is deformed into a substantially bowl shape (Fig. 5) and the bolts (12) and An airtight housing having a safety plug, characterized in that the safety plug is configured to come out through the opening (5) together with the nut (13). 2. The outer wall is a bottom cover (4) for closing the bottom side of the housing (1), and the safety plug (10) is provided on the bottom cover. An airtight housing having the safety plug according to 1.