Vehicle seat with protection from shock loads

A vehicle seat comprising a rigid support structure, a seat proper, a seat back provided with a rigid framework carried by the support structure, and a headrest, the framework of the seat back being connected to the support structure via at least first and second couplings that are disposed at different heights and that are adapted:

• normally, to hold the seat back in an in-use position;
• and
• when the seat back is subjected to high rearward stress, greater than a predetermined limit, to enable at least a top portion of the seat back to move rearwards at least to a safety position;
• in which seat the support structure comprises a substantially vertical central beam connected to the framework of the seat back by the first and second couplings, said central beam carrying the headrest;
• in which the second coupling comprises at least one energy dissipater member which is adapted to deform plastically when the seat back of the seat is subjected to a rearward force that is greater than a first limit value at said second coupling;
• and
• in which said energy dissapator member is adapted to deform elastically when the framework of the seat back is subjected to a rearward force less than said first limit value at said second coupling, so as to filter out vibration coming from the vehicle.

A vehicle seat comprising a rigid support structure, a seat proper, a seat back provided with a rigid framework carried by the support structure, and a headrest, the framework of the seat back being connected to the support structure via at least first and second couplings that are disposed at different heights and that are adapted:

• normally, to hold the seat back in an in-use position;
• and
• when the seat back is subjected to high rearward stress, greater than a predetermined limit, to enable at least a top portion of the seat back to move rearwards at least to a safety position;
• in which seat the support structure comprises a substantially vertical central beam connected to the framework of the seat back by the first and second couplings, and central beam carrying the headrest;
• in which the first coupling is plastically deformable so as to make it possible for a bottom portion of the seat back to move rearwards when the seat back, at said first coupling, is subjected to a rearward force greater than a second predetermined limit value;
• and
• in which the first coupling is adapted to deform elastically when the seat back, at said first coupling, is subjected to a force less than said second predetermined limit value, so as to filter out vibration coming from the vehicle.