Seat back of vehicle seat

A seat back of a vehicle seat, which has a frontal surface facing to a forward side of the seat back, said frontal surface being adapted to receive a back portion of a seat occupant to be seated in the vehicle seat, comprising:

• a foam padding provided in said seat back, said foam padding including a padding portion disposed adjacent to said frontal surface of the seat back;
• a seat back frame so formed to have a space defined inwardly thereof, said seat back frame including:
• a first bracket having a hole formed therein;
• and a second bracket having a hole formed therein, wherein said first and second brackets are disposed in a spaced-apart and opposedly-facing relationship;
• a support wire element having a rigidity, said support wire element being disposed within said space of said seat back frame in a suspended manner;
• a support plate disposed anteriorly of said support wire element within said space of said seat back frame, said support plate being attached to said support wire element and adapted to support said padding portion of said foam padding;
• said support wire element including an upper portion which projects from said support wire element in a direction upwardly of the seat back frame;
• and
• a resilient reinforcing element formed of a rigid wire having an elastic property, said resilient reinforcing element being provided to said upper portion of said support wire element and being so configured as to include:
• a) a pair of upper end portions slidably inserted in said hole of said first bracket and said hole of said second bracket, respectively;
• and
• b) a main reinforcing portion which is resiliently extensible, while being resiliently deformable in a rearward direction of said seat back frame,
• wherein said resilient reinforcing element is of such a property that, under a normal condition where a low load is applied via said padding portion and support plate towards said upper portion of said support wire element in a rearward direction of the seat back, said resilient reinforcing element withstands said low load and maintains the shape thereof, thereby preventing said upper portion of said support wire element against movement in forward and rearward directions of the seat back, upon an excessive great load being applied to said upper portion of said support wire element in the rearward direction of the seat back, said resilient reinforcing element is resiliently deformed in the rearward direction, such that said main reinforcing portion thereof is resiliently extended, while being resiliently deformed in the rearward direction of the seat back frame, whereas at the same time, said pair of upper end portions thereof are slidingly moved in said hole of said first bracket and said hole of said second bracket, respectively, in a downward direction of the seat back frame, thereby absorbing said excessive great load.