U.S. patent number RE36,317 [Application Number 09/014,128] was granted by the patent office on 1999-09-28 for indicating fuse block.
Invention is credited to Jose F. Arratia.
United States Patent |
RE36,317 |
Arratia |
September 28, 1999 |
Indicating fuse block
Abstract
An indicating fuse assembly includes an electrically
non-conductive housing; an array of first and second electrically
conductive contacts supported by the housing, each pair of first
and second contacts being adapted for connecting a replaceable
fuse, the contacts being connected in a powered circuit wherein
each fuse, when connected between a respective pair of the
contacts, is electrically series-connected with a load of the
circuit; and a plurality of illuminators electrically connected
within the housing for displaying open circuit conditions of
corresponding ones of the fuses when the contacts are connected in
the powered circuit, electrical current in the illuminators being
limited to a minor fraction of a rated current of the corresponding
loads. At least some the illuminators can include bipolar pairs of
light emitting diodes for activation of the respective illuminators
without regard to polarity of the circuit. In a preferred
configuration, the assembly also includes a detector driver circuit
for sensing activation of any of the illuminators, the detector
driver circuit being adapted for .[.signalling.]. .Iadd.signaling
.Iaddend.an external circuit. The detector driver circuit can be
configured for independently sensing a voltage across each fuse for
driving the illuminators with current not flowing in the loads.
Inventors: |
Arratia; Jose F. (Moreno
Valley, CA) |
Family
ID: |
27003774 |
Appl.
No.: |
09/014,128 |
Filed: |
January 27, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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367394 |
Dec 30, 1994 |
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Reissue of: |
414332 |
Mar 30, 1995 |
05659283 |
Aug 19, 1997 |
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Current U.S.
Class: |
337/206; 337/265;
337/4; 361/626; 340/638 |
Current CPC
Class: |
H01H
85/32 (20130101); H02H 3/046 (20130101) |
Current International
Class: |
H01H
85/00 (20060101); H01H 85/32 (20060101); H02H
3/04 (20060101); H02H 3/02 (20060101); H01H
085/30 (); G08B 021/00 () |
Field of
Search: |
;337/4,5,142,198,206,241,265 ;340/635,638 ;361/103,104,626,833 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Picard; Leo P.
Assistant Examiner: Gandhi; Jayprakash N.
Attorney, Agent or Firm: Sheldon & Mak
Parent Case Text
RELATED APPLICATION
This application is a continuation-in-part of application Ser. No.
08/367,394, filed on Dec. 30, 1994, .Iadd.now abandoned,
.Iaddend.which is incorporated herein by this reference.
Claims
What is claimed is:
1. An indicating fuse assembly comprising:
(a) a housing formed of an electrically non-conductive
material;
(b) an array of first and second electrically conductive contact
members extending within the housing for support thereby, each pair
of first and second contact members being adapted for connecting a
replaceable fuse;
(c) means for connecting the contact members in a powered circuit
wherein each fuse, when connected between a respective pair of the
contact members, is electrically series-connected with a load of
the circuit, each load having a rated current, at least some of the
first contact members of the array being powered independently of
others of the first contact members;
(d) a plurality of illuminators electrically connected within the
housing for displaying open circuit conditions of corresponding
ones of the fuses when the contact members are connected in the
powered circuit, one side of each illuminator being connected to a
respective second contact member of the array;
(e) means for limiting electrical current in the illuminators to a
minor fraction of the rated current of the corresponding loads;
and
(f) a detector driver circuit for sensing activation of any of the
illuminators, the detector driver circuit being adapted for
.[.signalling.]. .Iadd.signaling .Iaddend.an external circuit, the
detector driver circuit including means for preventing false
activation of the external circuit in the event that only a subset
of the first contact members are powered.
2. The fuse assembly of claim 1, wherein at least some of the
illuminators comprise light emitting diodes.
3. The fuse assembly of claim 2, wherein the means for limiting
comprises a resistor element series-connected with each
illuminator.
4. The fuse assembly of claim 3, wherein the illuminators and the
series resistor elements are supported within the housing.
5. The fuse assembly of claim 2, wherein at least some the
illuminators comprise bipolar pairs of light emitting diodes for
activation of the respective illuminators without regard to
polarity of the circuit.
6. The fuse assembly of claim 1, wherein the means for limiting
current comprises a single resistance element in series with a
common connection to a plurality of the illuminators.
7. The fuse assembly of claim 1, wherein the detector driver
circuit is operative for activating a current source to the
external circuit for driving a current load thereof.
8. An indicating fuse assembly comprising:
(a) a housing formed of an electrically non-conductive
material;
(b) an array of first and second electrically conductive contact
members extending within the housing for support thereby, each pair
of first and second contact members being adapted for connecting a
replaceable fuse;
(c) means for connecting the contact members in a powered circuit
wherein each fuse, when connected between a respective pair of the
contact members, is electrically series-connected with a load of
the circuit, each load having a rated current;
(d) a plurality of illuminators electrically connected within the
housing for displaying open circuit conditions of corresponding
ones of the fuses when the contact members are connected in the
powered circuit;
(e) means for limiting electrical current in the illuminators to a
minor fraction of the rated current of the corresponding loads;
and
(f) .[.a detector driver circuit for sensing activation of any of
the illuminators, the detector driver circuit being adapted for
signalling an external circuit, the detector driver circuit
comprising.]. a comparator circuit for comparing a voltage of each
load with a reference voltage, activation of the corresponding
illuminator being responsive to operation of the comparator
circuit, the illuminator being driven by current not required to
flow within the load.
9. The fuse assembly of claim 8, wherein at least some of the
illuminators comprise light emitting diodes.
10. The fuse assembly of claim 9, wherein the means for limiting
comprises a resistor element series-connected with each
illuminator.
11. The fuse assembly of claim 10, wherein the illuminators and the
series resistor elements are supported within the housing.
12. The fuse assembly of claim 9, wherein at least some the
illuminators comprise bipolar pairs of light emitting diodes for
activation of the respective illuminators without regard to
polarity of the circuit.
13. The fuse assembly of claim 8, wherein the means for limiting
current comprises a single resistance element in series with a
common connection to a plurality of the illuminators.
14. The fuse assembly of claim .[.8.]. .Iadd.15.Iaddend., wherein
the detector driver circuit is operative for activating a current
source to the external circuit for driving a current load thereof.
.Iadd.
15. The fuse assembly of claim 8, further comprising a detector
driver circuit for sensing activation of any of the illuminators,
the detector driver circuit being adapted for signaling an external
circuit in response to operation of the comparator circuit.
.Iaddend.
Description
BACKGROUND
The present invention relates to electrical fuses and fuse blocks
such as are used in automobiles, trucks and in a wide variety of
electrical and electronic equipment.
Electrical fuses for many medium power applications have a
non-conductive housing, a fusible link in the housing, and a pair
of electrical contacts extending from external of the housing into
electrical contact with opposite sides of the fusible link. Typical
fuses of the prior art have the housing translucent for permitting
visual inspection of the fusible link. Other fuses have elements
that move or change color when the fuse is blown. However, in many
situations it is impractical to visually monitor the fuses, such as
when a large number of fuses are connected in different circuit
portions of a system, and when only limited ambient light is
available for inspecting the fuses.
It is also known to provide illuminated indicia of fuse failure as
disclosed, for example in U.S. Pat. Nos. 4,382,225 to Peltz and
4,875,322 to Shumway. U.S. Pat. No. 5,300,913 to Liston also
discloses light indicators being connected across ferrules of
cartridge fuses with reference to U.S. Pat. Nos. 3,432,789 and
3,457,535.
The illuminated fuse fault indicators of the prior art exhibit one
or more of the following disadvantages:
1. They are ineffective for use with blade contact fuses and in low
voltage DC circuits and/or circuits having very low resistance
loads;
2. They are unsuitable in that they are undesirably bulky and/or
they require impractical additional wiring in many
applications;
3. They are unreliable in that they are subject to damage in
ordinary handling;
4. They are unsafe in that they have exposed conductors that are
subject to shorting; and
5. They are undesirably expensive to produce.
Thus there is a need for an illuminating fuse fault indicator that
avoids the disadvantages of the prior art.
SUMMARY
The present invention meets this need by providing a particularly
effective indicating fuse array assembly. In one aspect of the
invention, the assembly includes a housing formed of an
electrically non-conductive material; an array of first and second
electrically conductive contact members extending within the
housing for support thereby, each pair of first and second contact
members being adapted for connecting a replaceable fuse; means for
connecting the contact members in a powered circuit wherein each
fuse, when connected between a respective pair of the contact
members, is electrically series-connected with a load of the
circuit, each load having a rated current; a plurality of
illuminators electrically connected within the housing for
displaying open circuit conditions of corresponding ones of the
fuses when the contact members are connected in the powered
circuit; and means for limiting electrical current in the
illuminators to a minor fraction of the rated current of the
corresponding loads.
At least some of the illuminators can include light emitting
diodes. The means for limiting can include a resistor element
series-connected with each illuminator. The illuminators and the
series resistor elements can be supported within the housing.
Preferably at least some the illuminators include bipolar pairs of
light emitting diodes for activation of the respective illuminators
without regard to polarity of the circuit. The means for limiting
current can include a single resistance element in series with a
common connection to a plurality of the illuminators.
Preferably the fuse assembly further includes a detector driver
circuit for sensing activation of any of the illuminators, the
detector driver circuit being adapted for .[.signalling.].
.Iadd.signaling .Iaddend.an external circuit. The detector driver
circuit can be operative for activating a current source to the
external circuit for driving a current load thereof. One side of
each illuminator can be connected to a respective second contact
member of the array, at least some of the first contact members of
the array being powered independently of others of the first
contact members, the detector driver circuit including means for
preventing false activation of the external circuit in the event
that only a subset of the first contact members are powered.
Preferably the detector driver circuit includes a comparator
circuit for comparing a voltage of each load with a reference
voltage, activation of the corresponding illuminator being
responsive to operation of the comparator circuit, the illuminator
being driven by current not required to flow within the load.
DRAWINGS
These and other features, aspects, and advantages of the present
invention will become better understood with reference to the
following description, appended claims, and accompanying drawings,
where:
FIG. 1 is a pictorial circuit diagram of a power circuit
incorporating an indicating fuse block according to the present
invention;
FIG. 2 is a fragmentary sectional elevational view of the fuse
block of FIG. 1;
FIG. 3 is an oblique elevational perspective view showing internal
connections of the fuse block of FIG. 1;
FIG. 4 is a sectional elevational detail view of the fuse block of
FIG. 1 on line 4--4 of FIG. 2;
FIG. 5 is a partial circuit diagram of a gate element of the fuse
block of FIG. 1 in the circuit thereof;
FIG. 6 is a pictorial circuit diagram showing an alternative
configuration of the fuse block of FIG. 1; and
FIG. 7 is a pictorial circuit diagram showing another alternative
configuration of the fuse block of FIG. 1.
DESCRIPTION
The present invention is directed to an indicating fuse array that
is particularly advantageous for use in vehicles and a wide variety
of electrical and electronic equipment. With reference to FIGS. 1-5
of the drawings, an indicating fuse assembly 10 includes a block
unit 12 having a housing 14 that is adapted to removably receive a
plurality of fuses 16, an array of contacts including first
contacts 18A and second contacts 18B being supportively located
within the housing 14 for electrically connecting the fuses 16 in a
predefined circuit 20, the contacts being collectively designated
18. In an exemplary configuration, each fuse 16 includes a body 22,
a pair of main contact members 24, and a fusible link 26
electrically connecting the contact members 24, the contact members
24 being supported in fixed approximately parallel-spaced relation
by the body 22. The main contact members 24 project below the body
22 for plug connection to the contacts 18.
According to the present invention, the fuse assembly 10 includes a
plurality of illuminators 28 connected between respective ones of
the first and second contacts 18A and 18B, with means for limiting
current in each of the illuminators as described herein. In an
exemplary configuration of the fuse assembly 10, the first contacts
18A are connected to one or more supply conductors, generally
designated 30, that are fed from an external source such as a
vehicle battery 32. Typically, one or more of the first contacts
18A are always powered, being connected to a primary conductor 30A
that is connected directly to the battery 32, others of the
contacts 18A being connected to a main conductor 30B, a main or
ignition switch 34 being connected between the conductors 30A and
30B for activating main portions of the circuit 20. Yet others of
the first contacts 18A can be connected to one or more secondary
conductors 30C, respective load switches 36 being connected between
the main conductor 30B and corresponding ones of the secondary
conductors 30C. The switches 34 and 36, as well as a plurality of
loads 38 that are protected by respective ones of the fuses 16, are
normally remotely located from the fuse assembly 10.
A resistor array 40 is supported within the block unit 12, the
array 40 having a bus connection 42 to the main conductor 30B and
separate resistance connections 44, the illuminators 28 being
connected between respective ones of the resistance connections 44
and corresponding ones of the second contacts 18B for providing a
visual indication of current in particular ones of the fuses 16
being interrupted by opening of the links 26 thereof as might occur
in an overload situation. Preferably each of the illuminators 28 is
physically located in association with the corresponding fuse 16
for direct identification of particular blown fuses 16.
Each illuminator 28 is preferably a light emitting diode (LED) for
high reliability activation in the event of fusing of the link 26
of the associated fuse 16. At least in some applications, the
illuminator 28 can be a bipolar LED that is effective regardless of
the polarity of either its assembly into the block unit 12 or of
power applied to the source conductor 30. Also, the bipolar
configuration permits use of the fuse assembly 10 in AC
applications. Typically, bipolar LEDs are formed by connecting a
pair of polarized LEDs back-to back. The connections between the
main conductor 30B, the illuminators 28, the resistor array 40 and
the second contacts 18B are formed within the housing 14 for
enhanced structural integrity of the fuse assembly 10, and for
avoiding exposure of conductors to inadvertent shorting to external
objects. In the configuration of FIGS. 2-4, the illuminators 28
project slightly above the housing 14, for enhanced readability of
the illuminators 28. Alternatively, the illuminators 28 can be
partially of fully enclosed within the housing 14 for enhanced
immunity from environmental factors. In the drawings, the
illuminator 28 is shown as a device having a domed body 46 and a
pair of parallel-spaced leads 48. In practice, the body 46 can have
any shape and can be spaced within or partially within the housing
14 as shown in the drawings, or the body 46 can be flush with an
outside surface of the housing 14. Moreover, the body 48 can be
formed integrally with the housing 12 by providing the illuminators
28 including the leads 48, header and chip(s), then molding the
housing 14 from a suitable transparent material so as to
encapsulate the illuminators 28.
As thus described, the fuse assembly 10 can be packaged for use
with conventional blade-contact fuses of the prior art. In one such
configuration, the main contact members 24 project from the body 22
a length l of 0.275 inch, having a width w of 0.20 inch. The body
22 has a height H of 0.48 inch, a width W of 0.75 inch, and a
thickness T of 0.2 inch, being formed of a suitable insulative
transparent material.
In typical automotive applications the fuse assembly 10 is used
with the battery 32 powered at 12 v DC nominally, the voltage
ranging upwardly to approximately 14 volts when the battery 32 is
being charged. In the event of fuse failure, one or more elements
of the resistor array 40 is required to dissipate power according
to the current needed for driving the activated illuminators 28
while suitably limiting the current. The power dissipated by one
element of the resistor array 40 is the current times the applied
voltage less the voltage drop across the one or more illuminators
28 that are activated. Typically, LEDs are formed having a
series-pair of silicon p-n junctions such that the voltage drop is
approximately 1.4 volts at currents ranging from less than 5 ma to
more than 20 ma, a preferred current being approximately 10 ma.
Accordingly, a resistance of (14-1.4)v/10 ma=1260 ohms dissipates
[(14-1.4)v].sup.2 /1260 =0.126 watts when feeding one of the
illuminators 28. It will be understood that in most cases only a
single one of the illuminators will be activated at a time, such
activation depending on whether the corresponding fuse 16 is blown
while the associated load circuit provides a conductive return path
to the battery 32. A commercially available array suitable for use
as the resistor array 34 is available as No. 899-3-1.2K from BI
Technologies, Fullerton, Calif. (seven elements) .Iadd.from a
variety of sources.Iaddend., being rated at 1/4 watt per element.
Thus any or all of the elements can safely drive corresponding ones
of the illuminators 28 simultaneously at 10 ma.
As further shown in FIGS. 1-3 and 5, a preferred configuration of
the fuse assembly 10 includes a detector driver 50 for driving an
external indicator 52 whenever any of the illuminators 28 is
activated. The detector driver 50 has at least one power connection
54, an exemplary configuration of the driver 50 having power
connections designated 54B and 54C in FIG. 1, input connections 56
that are associated with particular ones of the power connections
54, and an output connection 58 to the indicator 52. The power
connection 54B is to the main conductor 30B, and the power
connections 54C are to respective ones of the auxiliary conductors
30C, the input connections 56 being made to respective ones of the
second contacts 18B for the fuses 16 that are powered from
corresponding ones of the supply conductors 30, the fuses 16 that
are powered from the conductors 30A and 30B being grouped together.
The detector driver 50 includes, for each power connection 54, a
bipolar transistor having an emitter connection to the power
connection 54, a base connection through respective logic diodes 60
to corresponding ones of the input connections 56, and a common
collector connection through a current limiting resistor 62 to the
output connection 58. Thus the common collector connection is
driven toward the potential of the power connection 54B whenever
any one of the illuminators 28 is activated.
As further shown in FIGS. 2-4, the housing 14 includes an upper
housing 14A and a lower housing 14B, the illuminators 28, the
resistor array 40, and the detector driver 50 being associated with
the upper housing 14A, the contacts 18 and the supply conductors 30
being associated with the lower housing 14B. The housing portions
14A and 14B can be fixably connected by any suitable means (not
shown) including screw fasteners and adhesive bonding. Also
associated with the upper housing 14A are a plurality of network
conductors 64 between the resistance connections 44 and respective
ones of the illuminators 28, input conductors 66 between the second
contacts 18B and respective ones of the input connections 56, and
power conductors 68 between respective ones of the power
connections 54 (and the bus connection 42) and corresponding ones
of the first contacts 18A. As best shown in FIG. 3, the connections
to the resistor array 40 and the detector driver 50 are implemented
by respective double spring loops 70 that are formed for grippingly
receiving corresponding lead pins of the associated devices. The
connections to the contacts 18 are similarly implemented by single
spring loops 72 that are biasingly retained between the associated
contact 18 and the lower housing 14B. Connections to the
illuminators 28 are effected by forked formations 74 of the
respective conductors 64 and 66 that grippingly receive
corresponding leads 48 of the illuminators 28. In the configuration
of FIGS. 2-4, the resistor array 40 and the detector circuit 50
project slightly above the housing 14, for facilitating possible
replacement of the resistor array 40 and the detector driver 50.
Alternatively, either or both of these components can be partially
of fully enclosed within the housing 14 for enhanced immunity from
environmental factors.
With further reference to FIG. 6, an alternative configuration of
the fuse assembly, designated 10', provides independent voltage
detection for open-circuit conditions of the various fuses 16. A
counterpart of the detector driver, designated 50', includes a
separate voltage comparator 76 for each of the fuses 16, each of
the comparators 76 having a reference voltage input (+) and an
input (-) from a counterpart of the input connection, designated
56', each of the connections 56' being made to a corresponding
second contact 18B. The voltage comparators 76 are configured for
sinking current for the illuminators 28, the detector driver 50'
incorporating current limiting means 40' and corresponding
counterparts of the resistance connections, designated 44'. The
connections 44' are to respective cathodes of the illuminators 28,
the anodes thereof being connected to corresponding first contacts
18A of the fuses 16. The a reference voltage divider for the
comparators 76 that are associated with the fuses 16 on the primary
conductor 30A and the main conductor 30B are fed from the conductor
30B through the power connection 54B. However, counterpart circuits
associated with the fuses 16 on the secondary conductors 30C are
fed from the corresponding power connections 54C for preventing
false activation of the associated comparators 76 when the
corresponding load switches 36 are open. The detector driver 50'
also includes a multiple-input OR gate 78 that is responsive to
each of the comparators 76 and having current source capability for
feeding the external indicator 52 through the limiting resistor 62
whenever any of the comparators 76 are activated. The principal
advantage of this configuration of the fuse block 10' is that the
loads 38 are not required to sink the drive current of the
respective illuminators 28. The comparators 76 can have a very high
input impedance so that the presence of substantially any load
conductivity within a particular load 38 is effective for causing
illumination of the respective illuminator 28 when the
corresponding fuse 16 is open, provided only that the main switch
34 is closed (and in appropriate cases, the associated load switch
36 is also closed). Another advantage is that the function of the
resistor array 40 is incorporated within the detector driver 50',
thereby simplifying packaging of the fuse block 10'. It will be
understood that separate source current connections and reference
voltage dividers can be provided for each of the voltage
comparators 76, so that a single configuration of the detector
driver 50' having a sufficient number of the comparators 76 can be
used regardless of the number of secondary conductors 30C and fuses
16 associated therewith.
With further reference to FIG. 7, another alternative configuration
of the fuse assembly 10 has a single resistor 40" connected between
the supply conductor 30 and a limiting conductor 42', a plurality
of the illuminators 28 being connected between the limiting
conductor 42' and respective ones of the second contact 18B. In
this embodiment of the present invention, the illuminators 28 will
always be activated within the range of 5 ma to 20 ma, assuming
that there is no "current hogging" when the resistor 40" is
selected for powering a single illuminator 28 at 20 ma, as long as
the battery 32 provides 14 volts, the load circuits have
resistances that are insignificant relative to the resistance of
the resistor 40", and not more than four of the illuminators 28 are
activated at a time. Similarly, with the battery 32 supplying 12
volts, three of the illuminators 28 would be activated at
(12-1.4)v/(3)630 ohms=5.6 ma. With four of the illuminators 28
activated, the average current drops to 4.2 ma, and the resistor
40" dissipates [(14-1.4)v].sup.2 /630=0.252 watts at full voltage.
Thus the resistor 40" can be appropriately configured for a power
rating of 1/2 watt. It will be understood that in the configuration
of FIG. 6, the use of incandescent lamps or bipolar LEDs would be
inappropriate due to shorting current paths between the
illuminators 28.
Although the present invention has been described in considerable
detail with reference to certain preferred versions thereof, other
versions are possible. For example, the resistor network 40 (or the
resistor 40") can be selected for other current limitations and/or
for use in circuits having other voltages. Also, each illuminator
28 can be provided as a flashing LED for reduced power dissipation
by the resistor array 40 (or the resistor 40"), and for attracting
the attention of those monitoring the fuse assembly 10. Moreover, a
LED having an integral resistor can be substituted in the
configurations of FIGS. 1-6. An LED having an integral resistor and
suitable for the present invention is available as 2RD-xxx from
Dialight of Manasaquan, N.Y. The detector driver 50' can
incorporate low current sources for biasing the fuses 16 that are
fed from the secondary conductors 30C, for providing visual
indications of fuse failure even when the corresponding circuitry
is unpowered. In the circuit configuration of FIG. 5, the resistor
array 40 can be combined with the detector driver 50. Therefore,
the spirit and scope of the appended claims should not necessarily
be limited to the description of the preferred versions contained
herein.
* * * * *