NEXON

SUPPLEMENTARY RESTRAINT SYSTEM (SRS) 1 1.1. WORKING OF RESTRAINTS A. RESTRAINTS WITHOUT AIRBAGS This restraint system falls under the category of Primary 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 occupant movement inside the vehicle during driving conditions, abrupt braking or accidents. They help in avoiding or reducing the contact severity of occupants with vehicle interiors. It is necessary to wear the seat belts by the occupants before starting to drive the vehicle. The seat belts have a retractor mechanism that ensures only the required seat belt webbing length is available for occupant usage. This reduces the risk of any loose webbing over the body of occupants. The seat belts have a locking mechanism that is 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 (inside seat belt buckle) 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 the vehicle occupant for the activation of air bags requires no action. !! WARNING Every occupant shall wear seat belts whenever they ride a vehicle. This is applicable whether a vehicle is equipped with supplementary restraints systems (SRS) or not. 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 occupants in case of medium or severe accident. There are remote sensors mounted for sensing different 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 triggers the relevant restraints components in the system. This helps in providing necessary protection to occupants. The airbags and seat belt pretensioner are triggered through ECU signal. The load limiter in the seat belts is a mechanical device which is activated when the forces on the occupant upper body region crosses a defined force threshold limit. !! WARNING Only the vehicles fitted with airbags should be fitted with RPLL seat belts. COMPONENTS 1. ECU 2. Front Remote Sensing Unit 3. Air bags  Driver air bag  Passenger air bag 4. RPLL 5. Clock spring 6. Airbag warning lamp 7. Airbag warning labels