An Analytical Model of the Inertial Opening of Seat Belt Latches

A mathematical treatment of inertial release of seatbelt buckles is presented, along with an exact criterion for belt release The model balances forces on each part of the mechanism to find their accelerations These accelerations are double integrated with respect to time to get displacements, and when these displacements reach certain values, the buckle opens Sample results are given for a common type of latch, and these results are compared to experimental results.

The analysis shows that the acceleration required to inertially open a latch is an increasing function of the belt tension The shape and duration of the acceleration vs time pulse are also important.