Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – Fusible element actuated
Reexamination Certificate
2003-05-30
2004-12-07
Vortman, Anatoly (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
Fusible element actuated
C337S186000, C337S194000
Reexamination Certificate
active
06828896
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a fuse used for protecting an automotive electric circuit or the like, and more particularly to an improved fuse in which a fuse body is housed and held in a housing provided with a cover.
FIGS. 6 and 7
show a related-art fuse used for protecting an electric circuit in an automobile or the like.
A fusible link
1
is a so-called plug-in type fuse, and comprises a fuse body
2
made of a metal sheet, a housing
3
which is made of an insulative resin, and has the fuse body
2
housed and held therein (the fuse body
2
is inserted into the housing
3
through a rectangular upper opening), and a cover
4
which is made of an insulative resin, and covers the upper opening in the housing
3
.
As shown in
FIG. 7
, the fuse body
2
includes a strip-like fusible conductor
10
having a melting portion
10
a
, and a pair of female terminals
11
and
11
which are formed respectively at both ends of the fusible conductor
10
, and can be fittingly connected respectively to mating tab terminals
15
formed on a circuit provided at a fuse receiving portion
13
. This fuse body
2
is formed into an integral construction, using a metal sheet.
The cover
4
includes a lid
5
in the form of a generally rectangular plate, and a pair of locking pieces
6
extending downwardly respectively from opposite end edges of the lid
5
, and this cover
4
is molded into an integral construction, using a transparent plastic material. Retaining projections
7
are formed on and project respectively from those side walls (peripheral wall) of the housing
3
corresponding respectively to the locking pieces
6
. When the pair of elastic locking pieces
6
are retainingly engaged with the retaining projections
7
, respectively, the cover
4
is locked to the housing
3
in such a manner that this cover
4
covers the upper opening in the housing
3
.
As shown in
FIG. 7
, the fusible link
1
is mounted in the fuse receiving portion
13
formed at an electric connection box such as a relay box, and the fuse body
2
is electrically connected to the mating tab terminals
15
. A fuse guide wall
14
for supporting the housing
3
is formed at the fuse receiving portion
13
, and this fuse guide wall
14
serves to guide the mounting insertion of the fusible link
1
, and also serves to prevent the fusible link
1
from being displaced out of position after the fusible link
1
is mounted.
In recent years, electric connection boxes have increasingly been required to have a compact and lightweight design and a reduced cost, and in this connection fuses also have been required to have a compact and lightweight design.
Therefore, for example, when a fuse body
22
as well as a housing
23
has a compact design (a reduced height) as in a fusible link
21
shown in
FIG. 8
, this fusible link
21
can be much more reduced in size and weight as compared with the fusible link
1
shown in FIG.
7
.
And besides, since the fusible link
21
has the compact design and the reduced height, a cover of an electric connection box can be reduced in height, so that the compact and lightweight design of the electric connection box is also achieved.
In the fuse body
22
, secondary (subsequent) short-circuit or the like must be prevented when a fusible conductor
28
melts, and therefore it is difficult to further reduce the distance between a pair of female terminals
29
.
Therefore, horizontal dimensions and shapes of the fuse body
22
and housing
23
are substantially the same as those of the fuse body
2
and housing
3
of the fusible link
1
, and a cover
24
has the same shape as that of the cover
4
, and the cover
24
is locked to the housing
23
by locking pieces
26
retainingly engaged respectively with retaining projections
27
formed on and projecting from a peripheral wall of the housing
23
.
However, when the fusible link
21
is to be mounted in the fuse receiving portion
13
formed at the electric connection box such as a relay box, as shown in
FIG. 8
, the locking pieces
26
interfere with an upper edge of the fuse guide wall
14
, so that this fusible link
21
can not be mounted in the proper position in the fuse receiving portion
13
.
Therefore, it is necessary to take countermeasures such as the reduction of the height of the fuse guide wall
14
and the formation of notches for preventing the interference. However, such countermeasures for the fuse guide wall
14
will incur a change of a mold for molding an electric connection box body and a complicated construction of the mold, so that the cost greatly increases.
When the locking pieces
26
of the cover
24
are shortened so as to prevent the interference thereof with the upper edge of the fuse guide wall
14
, each locking piece
26
is less elastically deformed when it slides over the retaining projection
27
. Incidentally, when each retaining projection
27
is reduced in height so that the locking piece
26
can easily slide over the retaining projection
27
, a sufficient retaining force can not be obtained, and the cover
24
can be easily disengaged from the housing.
When the locking pieces
26
are shortened, and therefore are less elastically deformed, there are anxieties that the cover
24
can not be easily fitted on the housing, and that each locking piece
26
is damaged at its proximal end portion on which an excessive force acts.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a fuse having a compact and lightweight design while being provided with a cover having locking pieces which are prevented from damage.
In order to achieve the above object, according to the invention, there is provided a fuse, comprising:
a fuse body, provided with a fusible element;
a housing body, containing the fuse body therein, and formed with an opening and a retaining projection arranged in the vicinity of the opening; and
a cover body, formed with a locking piece adapted to engage with the retaining projection so that the cover body closes the opening,
wherein a rigidity-reduced portion is formed in the cover body, so that the cover body can be flexed substantially without flexing the locking piece, at least when the locking piece engages with the retaining projection.
In such a configuration, even when the locking piece is short, the cover body itself is elastically deformed at the rigidity-reduced portion so that the locking piece can be displaced in the disengaging directions respectively relative to the retaining projection.
Since an excessive force will not act on the locking piece which is displaced so as to slide over the corresponding retaining projection, damage to the locking pieces is prevented.
Therefore, there can be obtained the compact and light-weight fuse provided with the cover body having the relatively short locking piece.
Preferably, the rigidity-reduced portion is a recessed portion formed in a face of the cover body to be opposed to the opening.
In such a configuration, merely by forming the recessed portion in the cover body, the rigidity-reduced portion which enables the elastic deformation of the cover body can be easily formed. Further, by suitably determining the width and depth of the recessed portion, the retaining force of the locking piece can be arbitrarily adjusted.
Preferably, the locking piece includes a pair of locking pieces, which are arranged symmetrically with respect to the rigidity-reduced portion.
Preferably, the fusible element is exposed through the opening, in a case where the cover body does not close the opening.
REFERENCES:
patent: 2206786 (1940-07-01), Linton
patent: 3699500 (1972-10-01), Borzoni et al.
patent: 4563666 (1986-01-01), Borzoni
patent: 4608548 (1986-08-01), Borzoni
patent: 4672352 (1987-06-01), Takano
patent: 4800358 (1989-01-01), Takenouchi et al.
patent: 4830631 (1989-05-01), Hsueh
patent: 5444428 (1995-08-01), Carr et al.
patent: 5883561 (1999-03-01), Nakamura et al.
patent: 5886612 (1999-03-01), Beckert et al.
patent: 5929740 (1999-07-01), Oh et al.
patent: 6067004 (2000-05-01), Hibay
Ohashi Norihiro
Totsuka Mitsuhiko
Yamashita Takuro
Sughrue & Mion, PLLC
Vortman Anatoly
Yazaki -Corporation
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