Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – Fusible element actuated
Reexamination Certificate
2001-03-29
2003-04-29
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
Fusible element actuated
C337S142000, C337S186000, C337S198000, C337S290000, C337S380000
Reexamination Certificate
active
06556121
ABSTRACT:
BACKGROUND OF THE INVENTION
(1). Field of the Invention
This invention relates to a fuse assembly and more specifically, to a fuse assembly that can securely halt an electric power supply to a load after a blowout of a fuse element in the fuse assembly.
(2). Description of the Related Art
In a vehicle as a mobile unit, many electric power transfer lines for transferring electric power itself or signals, such as busbars in an electric junction box such as a junction block, relay box and fuse block, and terminals of a connector for electric connection, are disposed.
In the electric power transfer lines, a fuse block, in which many fuses that can be inserted or extracted are disposed, is employed to protect electric circuits of various electrical equipments. (The fuse block may be called a relay box, junction block or electric junction box as the general term since the fuse block may have relays or busbars. In this specification, the aforementioned fuse block, relay box and junction block are hereinafter called an electric junction box as the general term.)
For example, a fuse assembly
101
shown in
FIG. 5
has been employed as a fuse for use in the electric junction box. As shown in
FIGS. 5 and 6
, the fuse assembly
101
includes a pair of terminals
102
arranged in parallel with each other, a housing
104
for receiving ends
103
of the terminals
102
, and a fuse element
105
formed integrally with a pair of the terminals
102
for connecting the terminals
102
with each other.
The terminal
102
is made of an electrically conductive metal and is formed in a blade-shape as shown in FIG.
6
. The terminal
102
is provided with a plurality of through holes
106
. Each terminal
102
shown in
FIGS. 5 and 6
has two through holes
106
. The through holes
106
are disposed in parallel with each other along the direction of the length of the terminal
102
. One through hole
106
is formed at the center
107
of the terminal
102
along the direction of the length of the terminal
102
and another through hole
102
is formed around the end
103
of the terminal
102
.
When the fuse assembly
101
is mounted in the electric junction box, each opposite end
108
of a pair of the terminals
102
is connected to respective receiving terminals of the electric junction box. An electric power is supplied to one of the receiving terminals from an electric power source or the like, while various loads are electrically connected to an opposite receiving terminal.
An electric power is supplied to one of the terminals
102
through the receiving terminal and the like, while the load is connected to another terminal
102
. Each end
103
of the terminals
102
is received into the housing
104
with each inner surface
109
of the terminals
102
facing with each other.
The housing
104
is made of insulating synthetic resin and the like. The housing
104
is formed in a box-shape. The inside of the housing
104
is a receiving space for receiving each end
103
of a pair of the terminals
102
. The housing
104
is provided with each projection (not shown in the figure) for engaging with the respective through holes
106
. When each projection is engaged with the respective through hole
106
, a pair of the terminals
102
is fixed in the housing
104
.
As shown in
FIG. 6
, the fuse element
105
connects the terminals
102
with each other. Each end of the fuse element
105
is connected to the inner surface
109
situated at the center
107
of the terminal
102
. The thickness of the fuse element
105
is about uniformly formed between one connection part
105
a
connecting with one terminal
102
and another connection part
105
b
connecting with another terminal
102
. The fuse element
105
blows out when a current of an electric power supplied from one of the terminals
102
exceeds a predetermined current value.
As to the fuse assembly
101
mounted in the electric junction box, when a current value of an electric power supplied to the one terminal
102
through the one receiving terminal or the like exceeds a predetermined current value, the fuse element
105
blows out so as to halt the power supply to the load.
As to a conventional fuse
101
shown in
FIG. 5
, the thickness of the fuse element
105
is about uniformly formed between one connection part
105
a
connecting with one terminal
102
and another connection part
105
b
connecting with another terminal
102
. The fuse element
105
tends to blow out at the thinnest portion thereof. The thinnest portion may be located at any portion of the fuse element
105
between one connection part
105
a
and another connection part
105
b
, due to a variation in the manufacturing process. That is, the thinnest portion of the fuse element
105
may be different among the fuse assemblies
101
.
Therefore, as to the conventional fuse assembly
101
, the fuse element
105
may blow out at any portion of the fuse element
105
between one connection part
105
a
and another connection part
105
b
. For example, when the fuse element
105
blows out in the vicinity of one connection part out of the connection part
105
a
and the connection part
105
b
, the fuse element
105
connected to an opposite connection part becomes in a so-called cantilever state.
At this time, due to a vibration of the vehicle during the traveling or a sudden acceleration, the fuse element
105
vibrates in the housing
104
and then, a pair of the blown-out portions of the fuse element
105
may come into contact with each other, resulting in that the blown-out fuse element
105
may electrically connect a pair of the terminals
102
with each other.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to solve the above problem and to provide a fuse assembly which can securely halt an electric power supply to a load after a blowout of a fuse element in the fuse assembly.
In order to attain the above objective, the present invention is to provide a fuse assembly comprising: a pair of terminals arranged in parallel with each other; a housing for receiving each one end of a pair of the terminals; and a fuse element for connecting a pair of the terminals with each other, wherein a thickness of the fuse element at the central part thereof situated at the center between a pair of the terminals is smaller than the thickness of the fuse element at each connection part with the terminal.
According to the fuse assembly described above, since a thickness of the fuse element at the central part thereof situated at the center between a pair of the terminals is formed smaller than a thickness of the fuse element at each connection part with the terminal, therefore the central part of the fuse element blows out.
The thickness of the fuse element continuously or gradually decreases from said each connection part to said central part of the fuse element.
According to the fuse assembly described above, the central part of the fuse element securely blows out.
The fuse element comprises: a pair of supporting parts which contains said connection parts and is connected to each end surface situated at an end of a pair of the terminals, said central part connecting a pair of the supporting parts with each other; and a fixing part for fixing each supporting part of the fuse element to the housing.
According to the fuse assembly described above, since the fixing part fixes each supporting part of the fuse element to the housing, therefore the fuse element hardly vibrates in relation to the terminals.
REFERENCES:
patent: 4056884 (1977-11-01), Williamson et al.
patent: 4224592 (1980-09-01), Urani et al.
patent: 4349804 (1982-09-01), Gaia
patent: 55-165539 (1980-12-01), None
Endo Takayoshi
Kondo Hiroki
Nakamura Goro
Sato Takahiro
Armstrong Westerman & Hattori, LLP
Gandhi Jayprakash N.
Yazaki -Corporation
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