FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003


COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION System For Detecting Blown Off Fuse In A Vehicle
APPLICANTS
TATA MOTORS LIMITED, an Indian company
Having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Dileep Kumar Singh and Mr. M. Javed Hussain
Both Are Indian Nationals
of TATA MOTORS LIMITED,
An Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention And the manner in which it is to be performed.


FIELD OF INVENTION
The present invention relates to the fields of fuse system in automobile. The present invention specifically relates to a system for detecting blown off fuse in a vehicle irrespective of its load connectivity.
BACKGROUND OF INVENTION
In general, a window is provided in the fuse for showing the connectivity of the fuse. When the fuse gets blown off, then the window shows no connectivity between the two legs of the fuse. In case, a fuse placed in the fuse box is blown off, then the individual or driver has to manually find out the fuse corresponding to a particular load from the diagram given on the fuse box cover. In order to check the connectivity of the fuse, either a multimeter is used or the fuse is taken out from the fuse slot and looked or taken towards the light to see the continuity of the fuse, which is burden for the driver and vehicle owner.
Moreover, such fuse box is located below the dashboard or at an area with poor approachability. Thus, the conventional method or practice of checking the blown off fuse becomes very troublesome, time taking and almost impossible if it is dark. Therefore, it is desirable to provide a system for detecting blown off fuse in a vehicle, which facilitates easy and visible indication of the blown off fuse to the driver or vehicle owner.
OBJECTS OF INVENTION
An object of the present invention is to provide a system for detecting a blown off fuse in a vehicle, which facilitates easy detection of the blown off fuse in less time.
Another object of the present invention is to provide a system for detecting a
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blown off fuse in a vehicle, which provides easy and visible indication of the blown off fuse at the dashboard.
Yet another object of the present invention is to provide a system for detecting a blown off fuse in a vehicle without switching on the loads.
SUMMARY OF INVENTION
According to one aspect, the present invention, which achieves the objectives, relates to a system for detecting a blown off fuse in a vehicle, comprising a power source for DC supply, a diode, two NPN transistors, four resistors and two LEDs, which are connected between the fuse and the second NPN transistor. The diode and the first resistor is connected between the load side of the fuse and the first NPN transistor. The base of the first NPN transistor is connected to the load side of the fuse. When the fuse gets blown off, the base voltage of the first NPN transistor is low so that the second NPN transistor is forward biased and hence it turns on both the LEDs. One of the LEDs is placed besides the fuse in the fuse box, which glows if the corresponding fuse blows off.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a circuitry diagram of a system for detecting a blown off fuse in a vehicle, in accordance with an exemplary embodiment of the present invention; and
FIG. 2 illustrates an arrangement of fuses and LEDs in a fiise box connected with loads, in accordance with an exemplary embodiment of the present invention.
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DETAILED DESCRIPTION OF INVENTION
The invention will be discussed in greater detail with reference to the accompanying Figures.
Referring to FfG. 1, a circuitry diagram of a system for detecting a blown off fuse in a vehicle is illustrated, in accordance with an exemplary embodiment of the present invention. The system comprises a power source configured for supplying DC power to the vehicle loads, a diode, two NPN transistors, four resistors, and two light emitting diodes (LED) for light indication. The diode is adapted in the electronic circuit to block the flow of reverse current if any in the circuit ahead of the second terminal (J2). The system also includes three terminals, which are named as first terminal (Jl), second terminal (J2) and third terminal (J3). The LED 1 is connected between the first terminal (Jl) of the fuse and the second NPN transistor.
The first NPN transistor is connected between the second terminal (J2) and the third terminal (J3), which is negative terminal. Similarly, the second NPN transistor is connected between the first terminal (Jl) and the third terminal (J3). The diode and the first resistor can be connected between the second terminal (J2) at the load side of the fuse and the first NPN transistor, where the base of the first NPN transistor is connected to one side of fuse where the load is connected. The second resistor is connected between the LED 1 and the second transistor. Similarly, the third resistor is connected between the first terminal (Jl) and the first NPN transistor whereas the fourth resistor is connected with the LED 2 and the second NPN transistor.
Furthermore, the first terminal (Jl) of the electronic circuit is interfaced with the LED 1, which is connected to supply side of the fuse i.e. the side from where power supply is coming. The second terminal (J2) of the electronic circuit is interfaced with
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the diode, which is connected to the load side of the fuse i.e. the side where load is connected. Likewise, the third terminal (J3) of the electronic circuit is interfaced and connected with the negative terminal of the power source.
In normal condition, when the fuse is working properly and ignition is "ON", then the first transistor is forward biased and conducting whereas the second transistor is not conducting. When the fuse gets blown off, the base voltage of the first transistor becomes zero so it does not conduct and the second transistor is forward biased and starts conducting to turn on the LED 1 and also glows the LED 2. The LED 2 is the master LED, which glows if any of the LEDs inside the fuse box glows. The fourth resistor is connected between the LED 2 and the negative terminal of the power source for protection of the LED 2. The LED 2 can be mounted on the vehicle dashboard or place which is in driver's range of visibility.
The electronic circuit is clubbed with the fuses inside the vehicle fuse box to provide a one to one indication of the blown off fuses. In case, any of the fuse blows off, it is very well indicated by the LED 1 besides the blown off fuse. If any fuse has blown off inside the fuse box located below the dashboard, the blown off fuse is indicated by glowing the LED 2 when the ignition is turned ON. By looking on to the glowing LED 2, the driver recognizes that one of the mses has blown off inside the fuse box. Such electronic circuit is configured in such a way that when the first transistor conducts, then the second transistor stops conducting and vice versa. When the fuse blows off, then the collector and the emitter of the first transistor acts as an open circuit and thus forward biasing the second transistor which in turns glow the LED 1 and the LED 2.
Moreover, glowing of the LEDs depends only on the condition of the fuse and it does not depend on whether the load is switched ON or not. Such system facilitates the driver to know the condition of the fuses in the fuse box by only switching the
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ignition ON without the need of switching on the connection of each and every load. Thus, the identification of the blown off condition of the fuse becomes easier, which reduces the searching time of the blown off fuses. Even if the fuse box is placed in the dark or in some difficult to approach area, the blown off fuse can easily be identified using the LEDs. The system also facilitates the visual identification and detection of the blown fuses in the electronic circuit. In case of any failure of the electronic circuit, no current flows towards the load, which provides safety to the overall circuit.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.
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WE CLAIM
1. A system for detecting blown off fuse in a vehicle, comprising:
a power source configured for supplying DC power;
a first transistor and a second transistor respectively connected between a plurality of terminals;
at least one diode connected between a load side of a fuse and said first transistor for blocking the flow of reverse current to said first transistor;
one or more light emitting diodes (LED) placed besides said fuse in a fuse box, said one or more LEDs are connected between a supply side of said fuse and said second transistor; and
a master LED mounted on a dash board for visual indication of blown off fuse to a driver, wherein if said fuse is blown off, the base voltage of said first transistor is low so that said second transistor is forward biased to turn on said one or more LEDs and said master LED.
2. The system as claimed in claim 1, further comprising:
a first resistor connected between said at least one diode and said first transistor;
a second resistor connected between said one or more LEDs and said second transistor;
a third resistor connected between said fuse and said first transistor; and
a fourth resistor connected between said master LED and a negative terminal of said power source.
3. The system as claimed in claim 1, wherein said first transistor is forward
biased and conducting while the said second transistor is in non-conducting
state, during normal operation of said fuse.
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4. The system as claimed in claim 1, wherein said first transistor acts as an open circuit, when said fuse is blown off
5. The system as claimed in claim 1, wherein said plurality of terminals is connected and interfaced with said one or more LEDs, said at least one diode and the negative terminal of said power source.
6. The system for detecting blown off fuse in a vehicle as herein described above and as illustrated in accompanying figures.

th
Dated this 11th day of February 2009

TATA MOTORS LIMITED By their Agent & Attorney

(Karuna Goleria) of DePENNING & DePENNING