Information
-
Patent Grant
-
6418005
-
Patent Number
6,418,005
-
Date Filed
Monday, February 7, 200024 years ago
-
Date Issued
Tuesday, July 9, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Armstrong, Westerman & Hattori, LLP.
-
CPC
-
US Classifications
Field of Search
US
- 361 247
- 361 248
- 361 261
- 361 264
- 361 266
- 361 103
- 361 104
- 337 158
- 337 159
- 337 168
- 337 169
- 337 186
- 337 208
- 337 228
- 337 401
- 337 414
- 337 170
-
International Classifications
-
Abstract
The power circuit breaker has an igniter unit disposed in a cylindrical wall formed in a main housing. A holder is disposed in the cylindrical wall so as to oppose to the igniter unit. The holder has a boss engaged with the cylindrical wall, and a fuse element is held by the holder. Each end of the fuse element is electrically connected to one of a pair of interconnection terminals disposed in the main housing. The holder is locked by a locking lance formed in the main housing when each end of the fuse element has engaged with one of the interconnection terminals. The holder rests on the locking lance when the fuse element has been released from the interconnection terminals after activation of the igniter unit. The fuse element is engaged with and stopped by an insertion hole of the holder. The interconnection terminals each are a receptacle type terminal having two resilient contact strip portions one of which is connected to one end of the fuse element and the other of which is connected to an opposing terminal of a power circuit.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power circuit breaker to cut off instantaneously a power circuit with a gas pressure generated by an igniter unit to release a fuse element from a pair of interconnection terminals.
2. Related Art
FIG. 3
shows a conventional fuse
61
for cutting off a large power circuit. The fuse
61
has a synthetic resin main housing
62
, a conductive metal fuse element
63
received in the main housing, and a synthetic resin cover
64
for covering an upper opening of the main housing
62
.
The fuse element
63
has a generally U-shaped base plate
65
, two terminals
66
each unitarily formed with the base plate
65
at one end thereof, a tin piece
67
disposed on the base plate
65
for thermal accumulation. Each terminal
66
is opposed to a resilient contact strip
68
formed separately from the fuse element
63
. The terminal
66
and resilient contact strip
68
can contact a pin terminal of a fuse box (not shown) or the like. The pin terminal is inserted from a lower opening
69
of the main housing
62
.
The base plate
65
is formed with a locking piece
70
extending diagonally outward. The locking piece
70
abuts against an inner shoulder of the main housing
62
to prevent the fuse element
63
from being released from the main housing
62
. The base plate
65
is fused by an overcurrent to cut off an associated power circuit.
FIG. 4
is a graph showing a time required for fusing of the fuse
61
. The time is a function of applied current. This fuse characteristic is obtained by a measurement devise shown in FIG.
5
.
In
FIG. 5
, denoted
61
is a fuse,
71
a busbar connected to the fuse
61
, and
72
an electrical wire connected to the busbar
71
for power supply. Two busbars
71
are fixed on a base
73
made of an insulation material. Each busbar
71
has an upward extending male terminal
74
which can be connected to the terminal
66
(
FIG. 3
) of the fuse
61
.
As illustrated in
FIG. 4
, the fusing time T of the fuse
61
(
FIG. 5
) decreases like a quadratic curve as current I increases. Particularly, where the applied current I is comparatively small, the fusing time T increases significantly, which is shown in a zone surrounded by a phantom line A. The vertical scale for the fusing time T is logarithmic.
The conventional fuse
61
, as shown in
FIG. 4
, requires a significantly long fusing time when the overcurrent is within a smaller range. Thus, it is difficult to cut off instantaneously an associated circuit against a smaller overcurrent. This happens also in case of an intermittent short circuit or a rare short circuit current. In addition, even in an abnormal vehicle state like a collision accident, a power circuit is not cut off when no sufficient excessive current is supplied. The conventional fuse has the disadvantages.
To solve these problems, there is proposed a power circuit breaker
76
shown in
FIGS. 6 and 7
.
Referring to
FIG. 6
, the power circuit breaker
76
has a pair of terminals
77
,
78
, two multi-contact-point elastic plates
80
(
FIG. 7
) each connected to one of the terminals
77
,
78
, an electrically conductive shaft
79
slidably contacting with the plates
80
, and an igniter unit
81
disposed in one side of the shaft
79
.
The shaft
79
is joined to a drive shaft
82
at the other end thereof. The drive shaft
82
is mounted with a torsion spring
83
. The igniter unit
81
has a gas-blasting agent and a heater therein. The heater is connected to a pair of lead wires
84
. The shaft
79
and the drive shaft
82
are slidably received in a housing
85
of the power circuit breaker
76
.
In
FIG. 6
, the terminals
77
,
78
each are connected to the shaft
79
by way of one of the plates
80
. An overcurrent flown between the terminals
77
,
78
is detected by a sensor. Successively, a current is applied to the lead wires
84
, so that the heater heats up the gas blasting agent. The blasting gas pressure moves the shaft
79
in its disconnecting direction, This cuts off electrical connection between the terminals
77
,
78
. The torsion spring
83
urges the stopper
86
outward so that the stopper
86
abuts against the housing
85
, preventing a return movement of the shaft
79
.
However, the power circuit breaker
76
has disadvantages described in the following. That is, the power circuit breaker
76
has the expensive multi-contact-point elastic plates
80
connected to the terminals
77
,
78
for allowing a decreased friction force. Furthermore, the power circuit breaker
76
requires parts increased in number and in cost and is complicated in configuration, because the torsion spring
83
and the stopper
86
are applied for stopping the shaft
79
. In addition, the multi-contact-point elastic plates
80
make the terminals
77
,
78
and the shaft
79
larger for reducing an electrical resistance between the plates
80
and the shaft
79
, which tends to enlarge related parts of the power circuit breaker
76
, resulted in an enlarged breaker in overall size.
Japanese Patent Application H. 10-241524 discloses a power circuit breaker (not shown) in which a gas bursting force breaks a connection substrate to cut off a power circuit. Because of this configuration, the power circuit breaker is not reusable and is not commonly applied to various uses. Moreover, the power circuit breaker has another disadvantage that its main housing including an igniter unit requires an additional fitting work to secure it by bolting.
SUMMARY OF THE INVENTION
In view of the disadvantages of the aforementioned fuse and breakers, an object of the invention is to provide a power circuit breaker which can positively cut off a power circuit even at a smaller overcurrent. The breaker also allows a reliable cut-off of the power circuit when a sensor detects an abnormal state like an unintentional heat generation state or on a vehicle collision accident. In addition, the breaker has a simplified configuration consisting of parts reduced in number. The breaker is not expensive in cost, compact, easy in assembling, reusable, and suitable for a general-purpose.
For achieving the object, a power circuit breaker according to a first aspect of the present invention includes a main housing, an igniter unit disposed in a cylindrical wall formed in the main housing, a holder disposed in the cylindrical wall so as to oppose to the igniter unit, a boss of the holder engaging with the cylindrical wall, a fuse element held by the holder, and a pair of interconnection terminals disposed in the main housing. Each end of the fuse element is electrically connected to one of the interconnection terminals.
In a second additional aspect of the present invention, the holder is locked by a locking lance formed in the main housing when each end of the fuse element has engaged with one of the interconnection terminals.
In a third additional aspect of the present invention, an activating pressure force generated by the igniter unit is larger than the sum of the stopping force of the locking lance and the friction force of the interconnection terminals to the fuse element.
In a fourth additional aspect of the present invention, the holder rests on the locking lance when the fuse element has been released from the interconnection terminals after activation of the igniter unit.
In a fifth additional aspect of the present invention, the fuse element is engaged with and stopped by an insertion hole of the holder.
In a sixth additional aspect of the present invention, the igniter unit is pressed into to be mounted in the cylindrical wall.
In a seventh additional aspect of the present invention, the interconnection terminals each are locked in the main housing with a locking piece.
In an eighth additional aspect of the present invention, the interconnection terminals each are a receptacle type terminal having two resilient contact strip portions one of which is connected to one end of the fuse element and the other of which is connected to an opposing terminal of a power circuit.
In the first aspect of the invention, the cylindrical wall can guide the boss of the holder like a cylinder-piston movement, so that the gas blasting pressure reliably forces out the holder. Thus, the breaker can rapidly cut off the power circuit even on a smaller overcurrent or on an abnormal state of the vehicle where there is no overcurrent such as collision or an unintentional heat generation in the vehicle. The igniter unit is reduced in size because of the above-mentioned construction of the holder and cylindrical wall, which makes the power circuit breaker compact. The fuse element and interconnection terminals, which are simple and not expensive, can disengage from each other to reliably cut off the power circuit because the holder retaining the fuse element is moved by the blasting pressure of the igniter unit. The power circuit breaker has more functions than the conventional large current fuse but causes no significant size increase as compared with the conventional fuse. In addition, the fuse element which is fused by a current larger than a predetermined value can cut off the power circuit on an overcurrent without ignition of the igniter unit, allowing a selective use thereof including reuse according to an application of the breaker.
In the second additional aspect of the invention, the holder is reliably retained on the housing by the locking lance while the interconnection terminals engage with the fuse element. In addition, the holder can be easily mounted on and removed from the housing.
In the third additional aspect of the invention, on ignition of the igniter unit, the locking lance positively releases the holder so that the fuse element disengages from the interconnection terminals to cut off the associated power circuit.
In the fourth additional aspect of the invention, the holder is resting on the lance when the lance has been released the holder, preventing the fuse element from unintentionally contacting the interconnection terminals to keep a cut-off state of the power circuit. The lance used for the locking and retaining of the holder is advantageous for reduction in part number and in manufacturing cost.
In the fifth additional aspect of the invention, the fuse element is S inserted into the through holes of the holder to be locked therein, allowing an easy engagement with the holder. The fuse element can be readily disengaged from the holder. The holder can be commonly used for various applications with changing the fuse element according to the associated circuit. That is, the power circuit breaker is suitable for general purpose applications, which enables standardized and reusable parts, resulted in reduction in cost of the breaker.
In the sixth additional aspect of the invention, the igniter unit is easily pushed in the cylindrical wall to be set therein. The igniter unit can be dismounted from the cylindrical wall for replacement with ease.
In the seventh additional aspect of the invention, the locking piece can readily lock the interconnection terminal in the housing. Moreover, the interconnection terminal can be removed from the housing for maintenance by releasing engagement with the locking piece.
In the eighth additional aspect of the invention, the interconnection terminals, which can electrically connect the fuse element to the lead terminals, each have the two resilient contact strip portions. The construction of the interconnection terminals is useful for reduction in part number and in manufacturing cost.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a longitudinal sectional view showing an embodiment of a power circuit breaker according to the present invention, the breaker being in a circuit connection state;
FIG. 2
is a longitudinal sectional view showing the breaker which is in circuit disconnection state;
FIG. 3
is a longitudinal sectional view showing a conventional large current fuse;
FIG. 4
is a graph showing the relationship between current and fusing time of the fuse in
FIG. 3
;
FIG. 5
is a perspective view showing a measurement devise for knowing a performance of a fuse;
FIG. 6
is a longitudinal sectional view showing a conventional power circuit breaker which is in a connection state; and
FIG. 7
is a longitudinal sectional view showing the conventional breaker which is in a circuit disconnection state.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the accompanied drawings, an embodiment of the present invention will be discussed in detail hereinafter.
FIGS. 1 and 2
show an embodiment of a power circuit breaker according to present invention.
In
FIG. 1
, a power circuit breaker
1
has an insulating, synthetic resin housing
2
, a pair of receptacle-type interconnection terminals
3
, a generally inverted-U-shaped fuse element
4
made of an electrically conductive metal, a holder
5
made of a synthetic resin, insulating material, and an igniter unit
6
. The terminals
3
,
3
each are received in a lower portion of the housing
2
. The fuse element is connected to the terminals
3
,
3
. The holder
5
supports the fuse element
4
. The holder
5
is locked in the housing
2
and located at a mid-height portion of the housing
6
. The igniter unit
6
is positioned to upwardly oppose to the holder
5
. The igniter unit
6
is located inside the pair of terminals
3
,
3
in a horizontal direction.
The housing
2
has, for example, a rectangular shape similar to the housing of the conventional fuse (FIG.
3
). The housing
2
has a top opening
7
which is provided with a synthetic resin cover
8
. The cover
8
sealingly closes the opening
7
by engagement of a lock hook portion
9
formed on the cover
9
with a locking projection portion
10
formed on the housing
2
. In an upper part of the housing
2
, there is provided a hollow chamber
11
. Under the hollow chamber
11
, the holder
5
is located. An upper half of the housing
2
is swelled to be larger than the lower half in width.
The housing
2
has side walls
12
,
12
each provided with an inner, resilient locking lance
13
located at a middle height of the housing
2
. The lances
13
,
13
are symmetrically positioned to lock the holder
5
. The locking lance
13
having a root portion
15
extends straight from a tapered part
14
joining the upper half of the hosing
2
to the lower half so as to be inwardly inclined in an upper direction. The lance
13
has an inward locking projection
16
at the free end thereof. The locking projection
16
has an upper inclined guide surface
16
a
and a lower locking face
16
b
. The locking face
16
b
is slightly inclined upward to a horizontal direction. The locking face
16
b
abuts against an inclined shoulder
18
formed on an outer surface
17
of the holder
5
.
The housing
2
is unitarily formed with a cylindrical wall
19
therein at a transversely middle part thereof. The cylindrical wall
19
is rectangular or circular in cross-section and has a top opening
20
and a bottom opening
21
. From the top opening
20
, an upper space
22
of the cylindrical wall
19
receives a central boss
23
of the holder
5
such that there is no clearance between the cylindrical wall
19
and the boss
23
. The boss
23
has a shape rectangular or circular in section to meet with the cylindrical wall
19
. For easy alignment, the boss
23
and the cylindrical wall
19
each have a round or tapered leading guide surface. The cylindrical wall
19
has an upper half formed with an outer surface
24
slightly inwardly tapered in the upward direction to have a smaller thickness. The inclined outer surface
24
is a guide face for downward entering the interconnection receptacle terminal
3
into a terminal accommodation space
25
located outside the cylindrical wall
19
.
The igniter unit
6
is pressed into a mid-height portion of the cylindrical wall
19
to be secured therein under the boss
23
of the holder
5
. The cylindrical wall
19
is provided with a horizontal, inward stopper projection
26
which engages with a shoulder
28
formed in a bottom portion
27
of the igniter unit
6
for reliably supporting the igniter unit
6
. The igniter unit
6
is downwadly inserted from the upper opening
20
of the cylindrical wall
19
until the igniter unit
6
engages with the stopper projection
26
. By the simple assembling step, the igniter unit is mounted to just fit in with the cylindrical wall
19
. Between the boss
23
and the igniter unit
6
, there is provided a small clearance
22
. The igniter unit
6
can be readily removed from the cylindrical wall
19
by pushing upward the bottom
27
of the igniter unit
6
with a little stronger force for replacement of a used one.
The igniter unit
6
consists of a synthetic resin body
29
, a gas blasting agent
30
sealingly filled in the body
29
, a heating wire
31
positioned in the gas blasting agent
30
, and a pair of lead terminals
32
each connected to one end of the heating wire
31
. The terminals
32
downwardly extends from the bottom
27
of the body
29
. The body
29
is provided with a thin sealing plate
33
formed in the top thereof. The lead terminals
32
are extending in a lower inner space
34
of the cylindrical wall
19
. The inner space
34
and the lead terminals
32
compose a recess connector
35
. The recess connector
35
engages with an opposing connector (not shown) for supplying an ignition current. The cylindrical wall
19
serves as a cylinder for a piston-like movement of the boss
23
of the holder
6
.
Between the cylindrical wall
19
and the side wall
12
of the housing
2
, there are provided the terminal accommodation chambers
25
. A lower end of the cylindrical wall
19
is joined to a bottom wall
36
of the terminal accommodation chamber
25
. The bottom wall
36
is formed with insertion holes
37
for receiving pin terminals of a fuse box (not shown) or etc. The terminal chamber
25
receives the interconnection terminal
3
which is inserted downwadly from the top opening
7
, and a resilient locking piece
38
locks the interconnection terminal
3
in the housing
2
.
The interconnection terminal
3
has a pair of comparatively smaller resilient strips
40
at an upper side thereof and a comparatively larger, arc-shaped resilient strip
42
at a lower side thereof. The upper resilient strips
40
receive a tab-shaped terminal portion
39
of the fuse element
4
. The arc-shaped resilient strip
42
receives a pin terminal
41
of a fuse box (not. shown). The resilient strips
40
,
42
each are formed by inwardly turning back a base plate
43
of the interconnection terminal
3
. The lower resilient strip
42
is opposed to a vertically flat contact plate portion
59
formed by inwardly raising up the base plate
43
.
The resilient strips
40
,
42
and the base plate
43
are unitarily S formed from one plate. This unseparated construction decreases components in number and in cost as compared with the conventional fuse element (FIG.
3
).
The flat contact plate portion
59
is positioned adjacent to the side wall
12
of the housing
2
. The base plate
43
including the flat contact plate portion
59
has a lower end from which the locking piece
38
extends upward in an outward diagonal direction. The locking piece
38
has a free end which abuts against a shoulder
45
formed on an inner wall
44
of the housing
2
. The inner wall
44
is formed on an inner surface of the side wall
12
so as to vertically straight extend. The inner wall
44
has a lower end constituting the shoulder
45
inside the housing
2
. The interconnection terminal
3
is smoothly inserted along the inclined guide surface
24
the cylindrical wall
19
into the terminal receiving chamber
25
when the holder has not been mounted in the housing
2
. During the insertion, the locking piece
38
deflects inwardly to slide downward on the inner wall
44
before it is received in a space under the shoulder
45
to return outward so as to abut against the shoulder
45
. The interconnection terminal
3
is readily removed from the housing
2
by inwardly deflecting the locking piece
38
with a tool (not shown) like a flat-type driver and pushing upward a lower end of the interconnection terminal
3
.
The fuse element
4
, which is connected to the resilient contact strips
40
of the interconnection terminals
3
, has a generally inverted-U shape. The fuse element
4
has a base plate
47
including a fuse portion
46
, which composes an upper part of the fuse element
4
. The fuse element
4
also has a pair of side plates
48
each downwardly extending from one end of the fuse element
4
. Each side plate
48
has a lower end portion constituting the tab terminal
39
which is inserted between the pair of the resilient contact strips
40
. The fuse portion
46
generally positioned at the center of the base plate
47
is smaller in width than the other part of the base plate
47
. Near the fuse portion
46
, a tin piece
49
constituting a heat accumulation member and projecting upward is located. The side plate
48
is formed with a locking piece
50
rising up in a diagonal, outward direction. The locking piece
50
abuts against a shoulder
51
formed an inner surface of the side wall
17
of the holder
5
, more definitely against a horizontal stopping face of the shoulder
51
. The locking piece
50
prevents the fuse element
4
from moving out of the holder
5
.
The holder
5
has unitarily a locking wall
53
at each side of the central boss
23
of the holder
5
. The locking wall
53
is formed with a through hole
52
for downwardly passing the side plate
48
of the fuse element
4
. The locking wall
53
is joined to the boss
23
by way of a connection wall
55
having an inclined inner abutment surface
54
. The inner surface
54
abuts against the top end of the cylindrical wall
19
, which positions downwadly both the holder
2
including the boss
23
and the tab terminals
39
to rest them thereon.
Adjacent to and outward the through hole
52
of the locking wall
53
, the locking shoulder
51
is positioned in the holder
2
. Under the shoulder
51
, there is provided a channel
56
having a larger sectional area than the through hole
52
for receiving the locking piece
50
. The locking wall
53
has an outer wall
17
of which a lower half is embossed outward as compared with the upper half so as to define the shoulder
51
. The lower half has an inclined top shoulder
18
adjacent to the upper half The inclined shoulder
18
can stop the locking lance
13
of the housing
2
. A stopping face of the shoulder
18
abuts against an engagement face
16
b
of the locking projection
16
of the lance
13
, thereby preventing the holder
5
from removing upward out of the housing
2
to be secured thereto. The outer wall
17
of the holder
5
has an outwardly tapered surface
57
at a lower end thereof.
On assembling, the holder
5
is slidingly vertically movable along both the inner walls
44
of the housing
2
. The holder
5
is inserted from the top opening
7
of the housing
2
into the space
11
to move downward along the inner walls
44
. First, the tapered surface
57
formed at the lower end of the locking wall slidingly abuts against the tapered guide face
16
a
of the locking projection
16
of the locking lance
13
, which deflects outward the lance
13
. Then, the boss
23
of the holder
5
advances into an inner space of the cylindrical wall
19
. Finally, the top of the cylindrical wall
19
abuts against the inclined surface
54
of the holder
5
, and at the same time, the locking projection
16
of the lance
18
engages with the shoulder
18
of the holder
2
. Thus, the holder
2
is assembled in the housing
2
with ease.
The fuse element
4
has been preliminarily mounted in the holder
5
. The fuse element
4
can be assembled in the holder
2
in a single step so that the tab terminals
39
of the fuse element
4
are inserted into the through holes
52
of the holder
5
until the side plates
48
of the fuse element
4
are received in the holder
2
. During the insertion, the locking piece
50
is deflecting inward in the through hole
52
. When the base plate of the fuse element
4
abuts against a top surface of the connection wall
55
of the holder
5
, the locking piece returns outward to engage with the shoulder
51
.
Next, operation of the power circuit breaker shown in
FIG. 1
will be discussed hereinafter.
In the state shown in
FIG. 1
, when an overcurrent. is applied to the pin terminals
41
, a sensor provided in a fuse box (not shown) senses the overcurrent. The sensor is enough sensitive to detect even an overcurrent only a little larger than a threshold value. According to the detection of the overcurrent, a current is applied to the lead terminals
32
of the igniter unit
6
. This heats up the heating wire so that the gas agent
30
is ignited to generate a blasting gas instantaneously. As illustrated in
FIG. 2
, the blasting gas breaks the seal plate
33
, so that the gas pressure pushes the boss
23
. As a result, the holder
5
is instantaneously moved upward into the upper hollow
11
. The fuse element
4
moves upward together with the holder
5
, so that the tab terminals
39
are released from the interconnection terminals
3
, thereby cutting off the associated power circuit.
A pushing force P exerted on the holder
5
by the blasting gas of he igniter unit
6
is determined to be larger than the sum of a stopping force P
1
of the lance
13
for the holder
5
and the friction force P
2
of the interconnection terminals
3
to the fuse element
4
. That is, P>P
1
+P
2
.
Now, advantages of the embodiment will be discussed. The igniter unit
6
is mounted in the cylindrical wall
19
, and the central boss
23
of the holder
5
is inserted to engage with the cylindrical wall
19
with no clearance therebetween. Hence, the gas pressure generated by the igniter unit
6
effectively pushes out the boss
23
from the cylindrical wall
19
. The striking force P is larger than the sum of the stopping force P
1
and the friction force P
2
, which positively releases the holder
5
from the lance
13
of the housing
2
. The arrangement of the igniter unit
6
and the boss
23
in the cylindrical wall
19
allows a smaller amount of gas blasting agent
30
(FIG.
1
), so that the igniter unit
6
may be compact.
The released holder
5
, as shown in
FIG. 2
, rests on the tops of the lances
13
within the upper hollow
11
. That is, the tapered face
16
a
of the locking projection
16
of the lance
13
abuts against the lower end tapered face
57
of the outer wall
17
. This prevents the holder
5
from moving in the reverse direction, so that the tab terminals
39
of the fuse element
4
may not contact again the interconnection terminals
3
. The lance
13
allows the locking of the holder
5
during an on-state of the circuit as shown in FIG.
1
. The lance
13
also can rest the holder
5
to keep an off-state of the circuit as shown in FIG.
2
. This enables a simplified construction and reduces parts in number for the power circuit breaker.
The holder
5
is easily returned to the locked position by downwardly moving the holder
5
against the supporting force of the lance
13
after the igniter unit
6
is replaced by a new one. The cover
8
of the housing
2
is readily removed by unlocking the lock hook
9
from the locking projection
10
.
In the power circuit breaker shown in
FIG. 1
, the ignition of the igniter unit
6
disconnects the tab terminals
39
of the fuse element
4
from the interconnection terminals
3
as shown in
FIG. 2
, even when no overcurrent is applied in the associated circuit. For example, the ignition is carried out on an abnormal state of the vehicle such as collision or an unintentional heat generation in the vehicle. The ignition is also carried out before fusing of the fuse element, when the current in the associated circuit is only a little larger than a reference value. When a sensed overcurrent is significantly larger than a reference value, the fuse element may be fused without the ignition of the igniter unit
6
. This requires only replacement of the fuse element
4
for reuse of the power circuit breaker.
The power circuit breaker
1
may be used for various types of vehicles or machines only with modifying the fuse element
4
. That is, the other parts including the holder
5
, the interconnection terminal
3
, the housing
2
, and the igniter unit
6
are commonly used for different applications. This advantage is obtained by providing the fuse element
4
and the interconnection terminals
3
which are separately constructed unlike the conventional large current fuse shown in FIG.
3
.
The power circuit breaker
1
of the embodiment is only a little larger in size than the conventional large current fuse. The power circuit breaker
1
has a simplified configuration consisting of the fuse element
4
positioned above the interconnection terminals
3
, the holder
5
retaining the fuse element
4
, and the igniter unit
6
mounted under the holder
5
. Thus, the power circuit breaker
1
, which consists of parts reduced in number and cost, is more compact than the conventional breaker described in the prior art.
Claims
- 1. A power circuit breaker comprising:a main housing having side walls, an igniter unit disposed in a cylindrical wall formed in said main housing, a holder disposed in the cylindrical wall so as to be in contact with said igniter unit, a boss of said holder engaging with the cylindrical wall, a fuse element held by said holder, and a pair of interconnection terminals disposed in said main housing, wherein each end of said fuse element is electrically connected to one of the interconnection terminals.
- 2. The breaker recited in claim 1, wherein said holder is locked by a locking lance formed in said main housing when each end of said fuse element has engaged with one of the interconnection terminals.
- 3. The breaker recited in claim 2, wherein an activating pressure force generated by said igniter unit is larger than the sum of the stopping force of said locking lance and the friction force of the interconnection terminals to said fuse element.
- 4. The breaker recited in claim 2, wherein said holder rests on said locking lance when said fuse element has been released from the interconnection terminals after activation of said igniter unit.
- 5. The breaker recited in claim 1, wherein said fuse element is engaged with and stopped by an insertion hole of said holder.
- 6. The breaker recited in claim 1, wherein said igniter unit is pressed into and mounted in said cylindrical wall.
- 7. The breaker recited in claim 1, wherein the interconnection terminals each are locked in said main housing with a locking piece.
- 8. The breaker recited in claim 1, wherein the interconnection terminals each are a receptacle type terminal having two resilient contact strip portions one of which is connected to one end of said fuse element and the other of which is connected to an opposing terminal of a power circuit.
- 9. The breaker recited in claim 1, wherein the fuse element has a fusing portion reduced in sectional area.
- 10. The breaker recited in claim 1, wherein the fuse element has a thermal accumulation piece.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-055054 |
Mar 1999 |
JP |
|
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Number |
Date |
Country |
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Dec 1993 |
JP |
7-201269 |
Aug 1995 |
JP |
10-55742 |
Feb 1998 |
JP |
10-241522 |
Sep 1998 |
JP |
10-241523 |
Sep 1998 |
JP |
10-241524 |
Sep 1998 |
JP |