The Design
During a bus frontal crash, a passenger can move forward into the seat ahead. A rigid seatback may create a hard impact surface, while excessive seat movement can compromise support. The design challenge was to manage the seatback’s motion under load.
The linkage and its travel stop
The mechanism connects the seatback to a bracket on the seat base through a rod and pinned joints. A stopper at the front of the rod meets the bracket to limit further movement.
Controlled yielding. The design intent was for the pin to deform or shear under impact, allowing limited movement and absorbing some impact energy.
Travel limit. As the linkage moves, the stopper contacts the bracket to prevent excessive deformation and help the seat retain support.
The Findings
Simulation outcome. The analysis showed the expected behavior and minimal deformation of the seat under AIS-023.