Vehicle seat having active head restraint system

A vehicle seat assembly comprising:

• a seatback frame and an active head restraint system operatively supported by said seatback frame, said head restraint system including a head rest, an upper armature, a lower armature and a linkage operatively interconnecting said upper and lower armatures;
• said seatback frame including a pair of side members spaced relative to one another and upper and lower cross members extending therebetween;
• said upper armature pivotally mounted relative to said seatback frame so as to be generally aligned with the thoracic area of the occupant of said seat assembly, said head rest being operatively mounted to said upper armature, said upper armature including a main support member extending in a generally transverse direction relative to said side members of said seatback frame and a pair of depending tubular legs spaced relative to one another and extending from said main support member in the general direction of said lower armature, an upper suspension mechanism extends between said depending legs of said upper armature and provides thoracic support for the occupant of said seat assembly;
• said lower armature pivotally mounted to said seatback frame in spaced relationship relative to said upper armature so as to be generally aligned with the pelvic and lumbar regions of the occupant of the seat assembly, said lower armature including a pair of upstanding tubes and a lower suspension mechanism extending between said pair of upstanding tubes for providing lumbar support to the occupant of said assembly;
• said lower armature being operative to absorb energy generated by a force exceeding a predetermined level at the pelvic and lumbar regions such that said lower armature acts on said upper armature through said linkage to cause said upper armature and said head rest to pivot upwardly and forwardly to move said head rest toward the head of the occupant of said seat assembly in an initial response to an impact exceeding a predetermined force;
• and
• said upper armature further operable to absorb energy generated by a force exceeding a predetermined level at the thoracic region such that said upper armature and said head rest pivots further upwardly and forwardly following the initial response by said lower armature to an impact that exceeds a predetermined force.