Patent attributes
A vehicle seat has a back frame, an elastic member interconnecting side supports of the back frame, a movable member on the elastic member, and a restriction on the back frame. The movable member and the restriction engage each other in a first mode when a rearward load on the elastic member is less than a given value and are released from one another in a second mode when the load on the elastic member equals or exceeds the given value. The restriction restricts a rearward movement of the movable member in the first mode to limit rearward bending of the elastic member. Rearward movement of the movable member is permitted in the second mode to release the limitation on bending of the elastic member. Thus, the vehicle seat protects an occupant's neck during a rear collision.
