US Patent 11623550 Vehicle seat with torsion bar spring

A vehicle seat includes a back frame having opposing side members and side brackets pivotally connected to the opposing side members about a pivot axis such that the back frame is pivotal between a reclined position and a folded position. A spring-assist system is configured to urge pivoting of the back frame towards the folded position. The spring-assist system including a torsion rod spring extending between the side members at a location that is radially outboard of the pivot axis to generate an off-axis moment that urges the back frame towards the folded position.