Ventilation – Electronic cabinet
Reexamination Certificate
1999-06-15
2001-09-04
Joyce, Harold (Department: 3749)
Ventilation
Electronic cabinet
C361S724000
Reexamination Certificate
active
06283850
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit board cabinet having a plurality of shelves arranged therein one above another for receiving circuit boards, and more particularly to a circuit board cabinet having heat-shielding capability.
2. Description of the Related Art
A communication apparatus for connecting a large number of communication lines is required to incorporate a large member of circuit boards in dependence on the number of the communication lines, etc. The communication apparatus of this kind is typically housed in a cabinet.
FIG. 10
is an exploded perspective view showing an outline of the construction of a conventional cabinet of a communication apparatus. The cabinet
60
has a power supply unit
62
arranged at the bottom of a frame
61
thereof. A plurality of shelves
63
(only one of the shelves
63
is shown in the figure) are arranged in the frame
61
one above another. Each of the shelves
63
has a large number of circuit boards
64
fitted therein in parallel with each other. Further, a front cover plate
65
is attached to a front end of the shelf
63
such that it can be opened and closed. Top and bottom faces of the shelf
63
are open to ensure ventilation. A heat shield unit
66
is arranged immediately above each of the shelves
63
.
FIG. 11
is a perspective view showing details of the construction of the conventional heat shield unit
66
. A housing
661
of the heat shield unit
66
has a top face
662
, a bottom face
663
, and a rear face
664
, which are all open. A front face
665
of the housing
661
is formed with lots of vent holes
665
a
for taking in air flowing toward the front face
665
. In the housing
661
, there is mounted a heat guide plate
666
which extends obliquely downward from an upper end of the rear face
664
to a lower end of the front face
665
in a manner dividing a space within the housing
661
into upper and lower portions. The air flowing into the housing
661
through the front face
665
is guided by the oblique heat guide plate
666
and discharged via the open top face
662
. On the other hand, air flowing in via the open bottom face
663
is guided by the underside of the oblique heat guide plate
666
and discharged via the open rear face
664
.
FIG. 12
illustrates streams of air flowing within the cabinet
60
in which the shelves
63
are mounted. The air flowing into each of the heat shield units
66
through the front face
665
thereof is guided upward by the heat guide plate
666
and passes through the shelf
63
immediately above the heat shield unit
66
. The air cools the shelf
63
while passing therethrough. After cooling the shelf
63
, the air is guided by the heat guide plate
666
in another heat shield unit
66
immediately above the shelf
63
and discharged backward from the cabinet
60
.
However, it is obligatory that the cabinet
60
of this kind is provided with a sufficient self-fire extinguishing capability so as to prevent a fire from spreading to other devices in case the fire occurs within the cabinet.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a circuit board cabinet which is capable of more reliably preventing flames of a fire in a shelf from causing the spread of the fire to other devices outside the shelf, without degrading cooling capability thereof.
To attain the above object, the present invention provides a circuit board cabinet having a plurality of shelves arranged therein one above another for receiving circuit boards, the circuit board cabinet comprising a plurality of heat shield blocks arranged above the shelves, respectively, each of the heat shield blocks having at least one heat shield plate formed with numerous through holes and arranged for blocking an upper opening of a corresponding one of the shelves.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with accompanying drawings which illustrate preferred embodiments of the present invention by way of example.
REFERENCES:
patent: 3730264 (1973-05-01), Krylow et al.
patent: 3874444 (1975-04-01), Perce et al.
patent: 4612979 (1986-09-01), Heitzig
patent: 5105336 (1992-04-01), Jacoby et al.
patent: 5409419 (1995-04-01), Euchner et al.
patent: 5471099 (1995-11-01), Larabell et al.
patent: 5657641 (1997-08-01), Cunningham et al.
patent: 5873407 (1999-02-01), Wang et al.
patent: 53031316 (1978-03-01), None
patent: 63266846 (1988-11-01), None
patent: 7198638 (1995-08-01), None
patent: 7262470 (1995-10-01), None
Kadoya Hiroshi
Kaetsu Mitsuo
Murayama Tetsuya
Nozu Yasuko
Toshimitsu Kenji
Boles Derek S.
Fujitsu Limited
Helfgott & Karas, PC.
Joyce Harold
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