FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"REVERSE AIR-BAG SYSTEM FOR AUTOMOTIVE VEHICLE"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK - 422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PATICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF THE INVENTION
The present invention is related to the passenger safety and protection system for automotive vehicle. More particularly the present invention is related to reverse air bag system wherein two air bags are provided out of which one air bag is integrated in seatbelt assembly.
BACKGROUND OF THE INVENTION
Air-bag system in an automotive vehicle is used as a passive safety element and is increasingly getting popular in this Ultra Fast World. Air-bag system is going to be one of the mandatory compliance for an automotive vehicle as far as safety of the occupant is concerned. Driver and co-driver airbags are most commonly available in the vehicles and are placed inside the steering wheel and dash-board respectively. These air bags are triggered by a set of sensors. These sensors which are fitted in the either side of the front end module of the vehicle send a signal which excites the Sodium Azide (NaN3) and Potassium Nitrate (KN03). This further leads to a chemical reaction and results in a gas of Nitrogen and thus the Airbag is inflated.
In the current air bag system, the speed at which the Airbag inflates is very high. At times, the energy from the Airbag inflation, which hits the Occupant face directly, may even be fatal leading to serious injury / accident.
OBJECTIVES OF THE PRESENT INVENTION
The main object of the present invention is to provide reverse air-bag system in which a smaller air-bag will burst from the seat belt and act as a sandwich in between the current SRS air-bag system and occupant of the vehicle.
Another object of the present invention is to provide reverse air-bag system in which a smaller air-bag will burst in the direction of the occupant's movement after an accident.

Still another object of the present invention is to provide improved safety to the driver and co-driver of the vehicle.
STATEMENT OF INVENTION
Accordingly invention provides a reverse air-bag system for automotive vehicle comprising pair of frontal airbags placed inside the steering and dash board for driver and co-driver respectively; a pair of reverse air bags, of smaller size compared to the said frontal airbags, package to the seatbelts of said driver and co-driver respectively; an occupant detection sensor, mounted over the said co-driver sea belt, connected to a control means; a number of frontal crash sensors mounted at front side of vehicle at uniform distance to sense the crash of vehicle at any point, connected to the said control means to trigger the frontal and reverse air bags to inflate in known manner if crash sensed and the arrangement is such that co-driver air bags gets inflated if seat belt is engaged by the co-driver.
DESCRIPTION OF THE FIGURES
Figure 1 shows perspective view of the reverse air bag system on the automotive vehicle.
Figure 2 shows the schematics of reverse air bag system mounted on the
vehicle.
Figure 3 shows the working / operational flowchart of the reverse air bag system in accordance with the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION
In the present driver/co-driver safety system, the two air bags will burst in the opposite direction of the current Airbag. Hence, the system was named as 'reverse airbag system'.
Referring to figure 1 shows the motor vehicle equipped with the air bag in the steering wheel and reverse air bag provided on seat belt. The driver is saved by crash due to air bag blow due to reverse air bag hitting to the frontal air bag of steering wheel. In the absence of reverse air bag drive may have serious blow by air bag.
In the current air bag system, the speed at which the Airbag inflates is very high. At times, the energy from the Airbag inflation, which hits the Occupant face directly, may even be fatal leading to serious injury / accident. The reverse air bag system addresses this threat head on. Consider that the velocity at which the Airbag inflates towards the driver as V1. In times of frontal collision, the occupants are pushed forward in the seat due to the vehicle's momentum, consider this velocity as V2. At a moment, these two opposite moving bodies hit each other. And thus, the overall energy to the driver chest / head is very high. Hence, the better solution will be to design a smaller Airbag which inflates in the same direction as the V2 direction. This smaller Airbag will act as a sandwich between the Occupant and the conventional Airbag. Thus, it will act as a cushion and avoid the direct hitting of the occupant. This will drastically neglect the threats from Airbag.
To achieve the above concept, the Reverse Airbag has to be packaged on the . Seat Belt. This package must be done with few modifications on the current 3 point or 4 point Seat Belt. This package triggers off the Airbag and the profile moves to the upper direction as well, in order to protect the Occupant's neck from whiplash. Thus, Airbag inflates till it hits the conventional Airbag and then starts to deflate. Airbag is packaged on the Seat belt. An extra fitment, made of Carbon fiber plate is made as the base of the Reverse Airbag. This helps to fire the Airbag away from the occupant.

The back force created because of the Airbag on the occupant chest could be very high. This may be uncomfortable to humans. To neglect this, we are using a carbon fiber plate which will absorb the point load and exert a surface load on the occupant. The area of this plate could be increased till the limit of the seat belt. Also, as this Reverse Airbag is smaller in size, as compared to the conventional Airbag, the back force created is also minimal.
This Reverse Airbag system is active only if the driver / co-driver wears their corresponding seat-belt. Once, the Frontal crash sensor detects a frontal collision, the Reverse Airbag along with the conventional Airbag is inflated. By this, the maximum collision force is absorbed by the Reverse Airbag and protects the occupant.
Referring to figure 2 shows a vehicle is provided with conventional / frontal air bags in steering wheel for safety of driver and in the dash board for safety of co-driver/ occupant in side seat. A reverse air bag is packaged on seat belt for driver and co- driver. An occupant detection sensor is provided to the seatbelt of co-driver/ occupant side seat. The air bag system of co-driver is active due to the said occupant detection sensor only when co-driver seat is occupied with seat belt is worn. The vehicle is provided with number of crash sensors at front side uniformly placed so as to detect crash at any frontal side. The said crash sensor and occupant detector is connected to a control system. The said control system is having embedded software programmed to perform task as for the flow sheet shown in figure 3. The said embedded software developed as per the algorithms based on the flow diagram illustrated in figure 3.
It will drastically reduce the force at which the human face and the Airbag hits each other. Thus, protects the occupant after a collision and completely neglects the Airbag injuries.

WE CLAIM:
1. A reverse air-bag system for automotive vehicle comprising pair of frontal airbags placed inside the steering and dash board for driver and co-driver respectively; a pair of reverse air bags, of smaller size compared to the said frontal airbags, package to the seatbelts of said driver and co-driver respectively; an occupant detection sensor, mounted over the said co-driver sea belt, connected to a control means; a number of frontal crash sensors mounted at front side of vehicle at uniform distance to sense the crash of vehicle at any point, connected to the said control means to trigger the frontal and reverse air bags to inflate in known manner if crash sensed; and the arrangement is such that co-driver air bags gets inflated if seat belt is engaged by the co-driver. .2. A reverse air-bag system as claimed in claim 1 wherein the said crash sensors and occupant detector are connected to a control system provided with embedded software programmed as per the algorithms based the flow diagram illustrated herewith.
3. A reverse air-bag system as claimed in claims land 2 wherein the said reverse air bag arranged to have upper direction moving profile.
4. A reverse air-bag system as claimed in claims 1 and 2 wherein the reverse air bag having a base with an extra fitment made carbon fiber plate.