Since their introduction into the automotive market, airbags have saved thousands of lives every year. They have evolved from the simple airbag used forty years ago to the intricate airbag systems being manufactured today. Utilizing multiple sensors and sophisticated software algorithms, these modern systems deploy multiple airbags based on a list of variables (is the seat occupied, how much does the person weigh, are they wearing a seat belt, is a car seat being used, how fast is the car traveling, etc.). In the event of an accident, passengers rely on airbags to help protect them against serious injury.
In order to further protect passengers from injury, manufacturers sought to control how much an airbag inflated based on the variables programmed into the system. Depending on the severity of an accident, the airbag may or may not need to be completely inflated. The airbag sensing system determined how much the airbag needed to be inflated based on conditions of the accident.
It was determined that a manual reset latching solenoid was the best solution for this application. When the airbag did not need to be completely inflated, the system sent a short electrical pulse to the latching solenoid which cancelled the permanent magnet holding the solenoid in position. Once the solenoid was “de-latched” it opened a pressure relief valve to vent excess gas not needed for airbag inflation during the accident. This protected passengers from additional injury that could be caused by an overinflated airbag than was needed for the specific conditions. Since the solenoid needed to be manually reset, it would not return to the latched position accidentally during the accident. It would only be reset once the airbag system was serviced after the accident.
For applications needing quick response times and high latching force, the manual reset latching solenoid provides an excellent energy efficient solution. This design can be customized to fit a variety of applications, specific load hold capabilities and power requirements. Strokes and forces are flexible depending on solenoid size.