HEXA

SUPPLEMENTARY RESTRAINT SYSTEM (SRS) 3 24.2 WORKING OF RESTRAINTS A. RESTRAINTS WITHOUT AIRBAGS This restraint system falls under the category of Pri- mary restraint systems. PRIMARY RESTRAINT SYSTEM Seat belts are known as primary restraints systems as they provide the basic safety to occupants during driving or accidents. WORKING The basic purpose of seat belts is to control occu- pant movement inside the vehicle during driving conditions, abrupt braking or accidents. They help in avoiding or reducing the contact severity of occu- pants with vehicle interiors. It is necessary to wear the seat belts by the occu- pants before starting to drive the vehicle. The seat belts have a retractor mechanism which ensures only the required seat belt webbing length is availa- ble for occupant usage. This reduces the risk of any loose webbing over the body of occupants. The seat belts have a locking mechanism which gets activated in relevant conditions thereby preventing any loose belt webbing to come out of retractor. This phenomenon helps in controlling occupant movement inside the vehicle. COMPONENTS 1. Seat belt 2. Micro switch 3. Indicator lamp in cluster B. RESTRAINTS WITH AIRBAGS This restraint system falls under the category of Supplementary restraint system. SUPPLEMENTARY RESTRAINT SYSTEM (SRS) Air bags are the secondary restraint system as no action is required by the vehicle occupant for the activation of air bags. WARNING Seat belts shall be worn by every occupant whenev- er they ride a vehicle. This is applicable whether a vehicle is equipped with supplementary restraints systems (SRS) or not. 24.3 WORKING OF SRS Whenever there is an accident the sensor mounted remotely sends crash signal to the ECU. The type of accident and its severity, determines the time-to-fire different airbags in the system. The basic function of an airbag is to provide cushioning effect to occu- pants. There are remote sensors mounted for sensing dif- ferent frontal and side accidents. These sensors are connected to the electronic control unit (ECU) of the system. When an accident event input signal crosses a pre-defined threshold level in ECU, the ECU trig- gers the relevant restraints components in the sys- tem. This helps in providing necessary protection to occupants. The airbags and seat belt pretensioners get triggered through ECU signal. The load limiter in the seat belts is a mechanical device which gets ac- tivated when the forces on the occupant upper body region crosses a defined force threshold limit. WARNING RPLL seat belts for Driver and Passenger should be fitted only in the vehicle fitted with both frontal air- bags. COMPONENTS 1. ECU 2. Remote Sensors  Front remote sensor / Front Impact Sensor  Side remote sensor / Side Impact Sensor 3. Air bags  Driver air bag  Passenger air bag  Side air bag  Curtain air bag 4. RPLL 5. Clock spring 6. Airbag warning lamp 7. PAB deactivation switch 8. PAB indicator 9. Airbag warning labels