VEHICLE SEAT INCLUDING AN ENERGY ABSORPTION DEVICE

1 . A vehicle seat assembly comprising:

a seat body configured for attachment to a vehicle; and

a headrest subassembly connected to the seat body, the headrest subassembly having a front surface, a backstop member, and a first cushion disposed adjacent the backstop member, the first cushion being positioned between the front surface and the backstop member;

wherein the first cushion is configured to collapse against the backstop member in response to a force applied by a human head to the headrest subassembly during a vehicle collision and wherein the first cushion remains substantially collapsed while the human head is disposed adjacent the headrest subassembly subsequent to the collision.

2 . The vehicle seat assembly of claim 1 wherein the first cushion is further configured to return to a pre-collapse condition over a predetermined period of time after the human head moves to a position that is spaced apart from the headrest.

3 . The vehicle seat assembly of claim 1 further comprising a second cushion disposed adjacent the first cushion, the second cushion being configured to collapse against the backstop member in response to force applied by a human head to the headrest subassembly during a vehicle collision and wherein the second cushion remains collapsed while the human head is disposed adjacent the headrest subassembly subsequent to the collision.

4 . The vehicle seat assembly of claim 3 wherein the cushions are disposed adjacent one another such that the first cushion and the second cushion are substantially coaxial with one another.

5 . The vehicle seat assembly of claim 4 wherein the first cushion is more resistant to collapse than the second cushion.

6 . The vehicle seat assembly of claim 4 wherein the first cushion has a thickness that differs substantially from a thickness of the second cushion.

7 . A vehicle seat assembly comprising:

a seat body configured for attachment to a vehicle; and

a headrest subassembly connected to the seat body, the headrest subassembly having a front surface, a backstop member, and a first cushion comprising memory foam disposed adjacent the backstop member, the first cushion being positioned between the front surface and the backstop member;

wherein the first cushion is configured to collapse against the backstop member in response to a force applied by a human head to the headrest subassembly during a vehicle collision and wherein the first cushion remains substantially collapsed while the human head is disposed adjacent the headrest subassembly subsequent to the collision.

8 . The vehicle seat assembly of claim 7 wherein the first cushion is further configured to return to a pre-collapse condition over a predetermined period of time after the human head moves to a position that is spaced apart from the headrest.

9 . The vehicle seat assembly of claim 7 further comprising a second cushion comprising memory foam disposed adjacent the first cushion, the second cushion being configured to collapse against the backstop member in response to a force applied by a human head to the headrest subassembly during a vehicle collision and wherein the second cushion remains collapsed while the human head is disposed adjacent the headrest subassembly subsequent to the collision.

10 . The vehicle seat assembly of claim 9 wherein the cushions are disposed adjacent one another such that the first cushion and the second cushion are substantially coaxial with one another.

11 . The vehicle seat assembly of claim 10 wherein the first cushion is more resistant to collapse than the second cushion.

12 . The vehicle seat assembly of claim 10 wherein the first cushion has a thickness that differs substantially from a thickness of the second cushion.

13 . A vehicle seat assembly comprising:

a seat body configured for attachment to a vehicle; and

a headrest subassembly connected to the seat body, the headrest subassembly having a front surface, a backstop member, a first cushion subassembly comprising a foam material substantially surrounded by a membrane, the first cushion subassembly being disposed adjacent the backstop member, the first cushion subassembly being positioned between the front surface and the backstop member;

wherein the first cushion subassembly is configured to collapse against the backstop member in response to a force applied by a human head to the headrest subassembly during a vehicle collision such that a quantity of air is ejected from the first cushion subassembly and wherein the membrane at least partially obstructs air from entering the first cushion subassembly whereby the first cushion subassembly remains substantially collapsed while the human head is disposed adjacent the headrest subassembly subsequent to the collision.

14 . The vehicle seat assembly of claim 13 wherein the first cushion subassembly further comprises a valve attached to the membrane, the valve being configured to permit air to flow out of the first cushion subassembly and to obstruct air from entering the first cushion subassembly.

15 . The vehicle seat assembly of claim 14 further comprising a plurality of the valves attached to the membrane.

16 . The vehicle seat assembly of claim 13 wherein the membrane comprises nylon.

17 . The vehicle seat assembly of claim 13 wherein the material comprises polyurethane.

18 . The vehicle seat assembly of claim 13 wherein the material comprises memory foam.

19 . The vehicle seat assembly of claim 13 wherein the first cushion subassembly is configured to return to a pre-collapse condition over a predetermined period of time after the human head moves to a position that is spaced apart from the headrest.

20 . The vehicle seat assembly of claim 13 wherein the material comprises polyurethane and memory foam.