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


COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
An improved passenger airbag deactivation indicator system
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

Prakash Rathi and Ganesh Bidkar
both 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
This invention relates to an indicator system-used for communicating the airbag activation status in an automobile and more particularly it relates to an improved passenger airbag deactivation indicator system.
BACKGROUND OF INVENTION
Automobiles are provided with airbags in steering wheel and in instrument panel in order to reduce the bodily injuries to the upper extremities of an occupant in the event of frontal crash. Airbag provided at steering wheel is called as Driver Air Bag (DAB). Airbag provided at the instrument panel for co -driver is called as Passenger Air Bag (PAB). The airbags inflate in the event of crash and provide a soft cushioning for the occupant for reducing the risk of bodily injuries. Airbag Control Unit (ACU) has been provided in the vehicle which controls and monitors the air bag inflation or firing. In case passenger seat is occupied by children, passenger Air Bag (PAB) sometimes prove to be injurious to them. Therefore the airbag firing circuitry has been provided with a switch to deactivate the passenger Air Bag (PAB) when children are occupying passenger seat. This deactivation switch is known as Passenger Airbag Deactivation switch or PAD. The said passenger airbag deactivation (PAD) has two positions known as "safe for child" and "adult only". When the said passenger airbag deactivation (PAD) is put on "safe for child" mode, the airbag control unit (ACU) does not power the airbag in the event of crash. When it is put on "adult only" mode, Electronic Control Unit (ECU) monitors and controls the firing of the airbag as programmed. The vehicle instrument cluster is provided with two indicators to communicate the Passenger Air Bag (PAB) activation status for "Adult only" or "Safe for Child". The said air bag control unit (ACU) also controls the airbag activation status indicator, the former version of said ACUs have capability to trigger only one PAB activation status indicator (safe for child) whereas the latest versions have
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capability to trigger two PAB activation status indicators (adult only & safe for child). It is quite difficult to implement newer ACUs in place of older one and also the changeover is quite expensive owing to the cost of new ACUs.
OBJECTS OF INVENTION
The main object of the present invention is to provide an improved airbag deactivation indicator system for an automobile.
Another object of the present invention is to provide an improved airbag deactivation indicator system for an automobile with ACUs that have capability to trigger only one indicator.
Another object of the invention is to provide an improved airbag deactivation indicator system for an automobile which is simple in construction and cost effective.
BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention, an airbag deactivation indicator system comprises; an Airbag control Unit (ACU) for controlling air bag firing, at least two indicators for displaying the status of PAB activation, passenger airbag deactivation (PAD) switch integrated with two micro switches. The first micro switch is connected to the said ACU and the second micro switch is connected to "Adult only" status indicator at instrument cluster through a separate circuitary. Said ACU provides electrical signal only to the "Safe for Child" indicator provided on the instrument cluster of the vehicle. The said second micro switch provided in the PAD is activated when PAD is in "Adult Only" position. The output of said second micro switch is fed to the Adult Only indicator through a separate electrical circuitry.
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BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows the schematic electrical circuit as used in prior art. Figure-02 shows PAD as used in prior art.
Figure-03 shows the schematic electrical circuit in accordance with this invention Figure-04 shows PAD in accordance with this invention
DETAILED DESCRIPTION OF INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
Now referring to figure -03 and 04 , in accordance with the present invention, an airbag deactivation indicator system comprises; an Airbag control Unit (ACU) for controlling air bag firing, at least two indicators for displaying the PAB status, passenger airbag deactivation (PAD) switch additionally been provided with second micro switch at PAB active (Adult only) knob position, wherein the first micro switch is connected to communicate the airbag activation status to the said ACU (Adult Only and Safe for Child). On receiving the trigger from the said first micro switch in the PAD, Said ACU provides electrical signal only to the "Safe for Child" PAB status indicator provided on the instrument cluster of the vehicle. The said second micro switch provided in the PAD switch is activated when PAD is in "Adult Only" position. The output of said micro switch is fed to the Adult Only indicator through a separate electrical circuitry.
With this arrangement in accordance with this invention, 2 PAB activation status indicators can be provided for with ACUs which have capability to drive only one PAB status indicator.
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The said passenger air bag (PAB) status indicator circuit consists of an airbag control unit (ACU) and a passenger air bag deactivation (PAD) switch. The said PAD switch is provided with a first micro switch at PAB passive (Safe for child) position of the knob to communicate the desired configuration of PAB i.e. active (Adult only) or passive (Safe for child). The said PAD consists of two switching positions, one for PAB active ("Adult only") and another for PAB passive ("Safe for Child"). The said PAB active and PAB passive are selected by actuation of a knob as indicated on the top cover of the said PAD switch. The said PAD has internally been provided with one micro switch and an actuating cam below the said top cover. The said cam is connected to the said knob & actuates the said micro switches when the said knob is turned. The said air bag control unit (ACU) provides two outputs for said PAB status indicators provided on the instrument panel (not shown); one for "Adult only" indicator and another for "Safe for Child" indicator. When the said PAD knob is in PAB deactivated mode (Safe for Child), i.e. micro switch not actuated, ACU switches on "Safe for Child" indicator ("Adult Only" indicator is turned off). When the said knob is in PAB activated mode, ACU the second micro switch switches on "Adult only" indicator through a separate electrical circuitary ("Safe for Child" indicator is switched off).
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 passenger airbag deactivation system for a vehicle comprising:
an airbag control unit for controlling air bag firing;
a first status position indicator and a second status position indicator;
a passenger airbag deactivation switch integrated with two micro switches, said passenger airbag deactivation switch capable of being switched to either a first status position or a second status position;
wherein said passenger airbag deactivation switch is connected to said airbag control unit to communicate the desired airbag activation status, said airbag control unit configured to provide electrical signal only to the one status indicator provided on the instrument panel of said vehicle, said micro switches are configured to be activated when said passenger airbag deactivation switch is in corresponding status positions, such that, the output of said second micro switch is fed to the second status position indicator provided on the instrument panel of said vehicle through a separate electrical circuitry.
2. The system as claimed in claim 1, wherein passenger air bag status indicator circuit consists of said airbag control unit and said passenger air bag deactivation switch..
3. The system as claimed in claim 1, wherein said passenger airbag deactivation switch is internally provided with an actuating cam below a top cover, said cam configured to actuate said micro switches.
4. The system as claimed in any one of the preceding claims, wherein said first status position indicator is an "adult only" indicator and the second status position indicator is a "safe for child" indicator.
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5. A passenger airbag deactivation system for a vehicle as hereinabove described with reference to the accompanying drawings.
Dated this 18th day of March 2009

Karuna Goleria of DePENNING & DePENNING
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