Fusible link unit

Details Fusible link unit Fusible link unit

2003-10-01

2004-11-30

Prasad, Chandrika (Department: 2839)

Electrical connectors

With circuit component or comprising connector which fully...

Connector includes or covers additional component

C439S620180

Reexamination Certificate

active

06824430

ABSTRACT:

The present application is based on Japanese Patent Application No. 2002-289614, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chained type large current fusible link unit with fuse circuit structures each containing terminal parts with fusible members connected thereto, which are linked in a chain manner through the fusible members.
2. Related Art
JP-A-2000-133114 discloses conventional fusible link unit for example. One of fusible link units of this type as shown in
FIGS. 14 through 16
is known. The fusible link unit designated by reference numeral
100
, as shown in
FIG. 14
, is generally composed of first and second fuse circuit structures
101
and
102
and a housing
103
into which those fuse circuit structures
101
and
102
are assembled.
The first fuse circuit structure
101
, as illustrated in
FIG. 15
, is made up of a linking plate
104
, a plurality of terminal parts
106
a
and
106
b
, which are coupled through fusible members
105
to the linking plate
104
, a battery terminal
107
extended from one end of the linking plate
104
, and a common terminal part
108
coupled through a fusible member
105
a
to the other end of the linking plate
104
. The first fuse circuit structure
101
is formed by pressing a conductive flat plate member (not shown).
The second fuse circuit structure
102
, as shown in
FIG. 16
, is made up of a linking plate
109
, a plurality of terminal parts
111
a
and
111
b
, which are coupled through fusible members
110
to the linking plate
109
, and a common terminal part
112
extended from the other end of the linking plate
109
. The first fuse circuit structure
101
is formed by pressing a conductive flat plate member (not shown).
As shown in
FIG. 14
, the housing
103
is shaped like a rectangular parallelepiped, and contains a circuit-structure accommodating chamber
114
with an opening
113
open to the upper. The housing further includes a plurality of connector housing portions
115
and a plurality of terminal supports
116
, which are located under the circuit-structure accommodating chamber
114
.
As shown in
FIG. 14
, the first and second fuse circuit structures
101
and
102
are each inserted into the circuit-structure accommodating chamber
114
, through the opening
113
of the housing
103
. In this case, an extending direction of the flat surface of each fuse circuit structure is an insertion direction, and the terminal parts (
106
a
,
106
b
,
111
a
,
111
b
) of the fuse circuit structure are first inserted as an insertion tip part.
When the first and second fuse circuit structures
101
and
102
are completely inserted into the circuit-structure accommodating chamber, the linking plates
104
and
109
of those fuse circuit structures
101
and
102
are located within the circuit-structure accommodating chamber
114
. The terminal parts
106
a
,
106
b
,
111
a
, and
111
b
are set at predetermined positions of the connector housing portions
115
and the terminal supports
116
.
Next, the common terminal parts
108
and
112
of the first and second fuse circuit structures
101
and
102
are fastened together to the housing
103
by means of a bolt
117
. The first and second fuse circuit structures
101
and
102
are electrically connected to each other to thereby form a desired fuse circuit.
The battery terminal
107
is also fastened to the housing
103
by means of a bolt
117
b
. A terminal of a battery cable (not shown) is connected to the battery terminal
107
. Connected to the terminal parts
106
a
and
111
a
in the connector housing portions
115
are the terminals of the counter connectors
118
. LA terminals
119
are connected to the terminal parts
106
b
and
111
b
of the terminal supports
116
by means of screws. The connectors of the counter connector
118
and the LA terminals
119
are connected to loads by way of cables
120
. Power source is distributed from a battery to those loads, through a fuse circuit. When shortcircuiting occurs in any of the loads and overcurrent flows into the related fusible member
105
(
110
), the fuse member burns out by heating to thereby prevent trouble by overcurrent.
In the fusible link unit
100
thus constructed, the first and second fuse circuit structures
101
and
102
, shaped like flat plates, are assembled into the housing
103
to thereby form a unit. Therefore, a fuse circuit containing a number of fusible members (fuses)
105
and
110
may be made considerably compact. In particular, as shown in
FIG. 14
, the first and second fuse circuit structures
101
and
102
may be disposed in a state that those structures are merely spaced a narrow distance W apart from each other. Accordingly, to the fuse circuit extension, what a designer has to do is to slightly increase the housing
103
in the width direction Y, not in the longitudinal direction L.
In the conventional fusible link unit, the first and second fuse circuit structures
101
and
102
are each formed with one flat plate member. Accordingly, current flows always through the linking plates
104
and
109
even if it is fed from any of the terminal parts
106
a
,
111
a
,
106
b
, and
111
b
. Accordingly, a problem arises that temperature of the linking plates
104
and
109
rises by the current flowing therethrough.
To lessen the temperature rise, all one has to do is to increase the areas of the linking plates
104
and
109
. However, to make the housing
103
compact, it is desirable to minimize the external dimensions of the first and second fuse circuit structures
101
and
102
. Accordingly, it is preferable to avoid increasing the external dimensions of the first and second fuse circuit structures
101
and
102
.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a fusible link unit which can reliably suppress the temperature rise of the fuse circuit structures with little increasing of the external dimensions of the fuse circuit structures.
According to the present invention, there is provided a fusible link unit comprising:
a fuse circuit structure including a plurality of terminal parts linked through fusible members to a linking plate, and
a housing into which the fuse circuit structure is assembled,
wherein the fuse circuit structure is formed by laminating a plurality of part plates,
a first part plate includes a first linking portion constituting the linking plate by being laminted by a second linking portion of a second part plate, and
a respective part of the plurality of terminal parts which are connected to the linking plate with a respecitve part of the fusible members are provided with the first part plate.
In the fusible link unit thus constructed, current flowing through the linking plate of the fuse circuit structure branches into plural current paths to thereby suppress heat generation by the current flow.
In a preferred embodiment of the invention, the terminal parts with the fusible members connected thereto and the terminal parts, which are shared by the part plates, are substantially equal in number.
In the embodiment having the advantage mentioned above, current branches into the linking portions of the part plates at almost equal ratios.
In another embodiment, two part plates are used.
The fusible link unit of the embodiment has advantages comparable with those mentioned above.


REFERENCES:
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patent: 4842534 (1989-06-01), Mobley et al.
patent: 5088940 (1992-02-01), Saito
patent: 5438310 (1995-08-01), Ikari
patent: 5474475 (1995-12-01), Yamaguchi
patent: 5476395 (1995-12-01), Raffles et al.
patent: 5643693 (1997-07-01), Hill et al.
patent: 5795193 (1998-08-01), Yang
patent: 5977859 (1999-11-01), Kawamura et al.
patent: 6007350 (1999-12-01), Isshiki
patent: 6178106 (2001-01-01), Umemoto et al.
patent: 6294978 (2001-09-01), Endo et al.
patent: 6322376 (2001-11-01), Jetton
patent: 6402569 (2002-06-01), Spadoni et al.
patent: 6494722 (2002-12-01), S

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