Extended stroke energy attenuator

1. An energy attenuating vehicle seating system configured to attenuate shock loads imparted through a vehicle compartment to a seat occupant during a high energy impact event, the seating system comprising:

a seat configured for guided motion relative to a vehicle compartment over a stroking distance from a starting position at a first height to an ending position at a second height below the first height; and

an energy attenuating component with a first end attached to the seat, a second end configured for attachment to the vehicle compartment, and an intermediate point configured for guided motion relative to the vehicle compartment,

a first attenuation zone between the first end and the intermediate point of the energy attenuating component comprising a first deformable metal bar extending from an upper flange at the first end to an intermediate flange at the intermediate point; and

a second attenuation zone between the intermediate point and the second end of the energy attenuating component comprising a second deformable metal bar extending from the intermediate flange to a lower flange at the second end of the energy attenuating component, the first and second deformable metal bars each having a letter V shape with bends at the middle and ends of the bars and straight sections between the bends, wherein the energy attenuating component is configured to remain rigid and prevent the seat from moving as long as a magnitude of any shock load imparted to the seat through the energy attenuating component is less than a predetermined threshold value, and to deform in a progressive, predictable manner in response to a shock load exceeding the threshold value, thereby allowing the seat to stroke from the starting position toward the ending position as the energy attenuating component deforms and attenuates energy.

2. The vehicle seating system of claim 1 , further comprising a guide track configured for secure attachment to a vehicle compartment, wherein the guide track defines a seat stroke path, and wherein the seat is moveably constrained to the guide track at upper and lower sliding attachments that allow seat movement only along the stroke path.

3. The vehicle seating system of claim 2 , wherein the intermediate point of the energy attenuating component is moveably attached to the guide track between the upper and lower sliding attachments at an intermediate sliding attachment that constrains the intermediate point of the energy attenuating component to move only along the stroke path.

4. The vehicle seating system of claim 3 , wherein the guide track comprises left and right parallel bars, and the sliding attachments comprise left and right pairs of upper, lower, and intermediate bushings slidably disposed on the respective left and right parallel bars.

5. The vehicle seating system of claim 4 , wherein the energy attenuating component comprises a left and right pair of energy attenuating components, and wherein respective left and right intermediate attachments provide a moment restraint preventing the intermediate points of the left and right energy attenuating components from rotating.

6. The vehicle seating system of claim 1 , wherein the energy attenuating component comprises separate first and second energy attenuating members, and wherein the first end of the energy attenuating component is an upper end of the first energy attenuating member, the second end of the energy attenuating component is a lower end of the second energy attenuating member, and the intermediate point of the energy attenuating component is a lower end of the first energy attenuating member and an upper end of the second energy attenuating member.

7. The vehicle seating system of claim 6 , wherein a threshold load value of the first energy attenuating member is unequal to a threshold load value of the second energy attenuating member.

8. The vehicle seating system of claim 1 , wherein a threshold load value of the first attenuation zone is unequal to a threshold load value of the second attenuation zone.

9. An energy attenuating vehicle seating system configured to attenuate shock loads imparted through a vehicle compartment to a seat occupant during a high energy impact event, the seating system comprising:

a seat configured for guided motion relative to a vehicle compartment over a stroking distance from a starting position at a first height to an ending position at a second height below the first height;

an energy attenuating component comprising serially arranged first and second energy attenuating members, the first energy attenuating member comprising a first deformable metal bar with an upper end attached to the seat and a lower end constrained to move along the stroke path, and the second energy attenuating member comprising a second deformable metal bar with an upper end constrained to move along the stroke path, and a lower end configured for attachment to the vehicle compartment, the first and second deformable metal bars each having a letter V shape with bends at the middle and ends of the bars and straight sections between the bends, wherein the energy attenuating component is configured to remain rigid and prevent the seat from moving as long as a magnitude of any shock load imparted to the seat through the energy attenuating component is less than a predetermined threshold value, and to deform in a progressive, predictable manner in response to a shock load exceeding the threshold value, thereby allowing the seat to stroke from the starting position toward the ending position as one or both energy attenuating members deform.

10. The vehicle seating system of claim 9 , wherein a load threshold value of the first energy attenuating member is unequal to a load threshold value of the second energy attenuating member.

11. The vehicle seating system of claim 9 , further comprising a guide track configured for secure attachment to a vehicle compartment, wherein the guide track defines the seat stroke path, and wherein the seat is moveably constrained to the guide track at upper and lower sliding attachments that allow seat movement only along the stroke path.

12. The vehicle seating system of claim 11 , wherein the lower end of the first energy attenuating member and the upper end of the second energy attenuating member cooperatively define an intermediate point of the energy attenuating component, and are moveably attached to the guide track between the upper and lower sliding attachments with an intermediate sliding attachment that is constrained to move only along the stroke path.

13. The vehicle seating system of claim 12 , wherein the guide track comprises left and right parallel bars, and the sliding attachments comprise left and right pairs of upper, lower, and intermediate bushings slidably disposed on the respective left and right parallel bars.

14. The vehicle seating system of claim 13 , wherein the energy attenuating component comprises a left and right pair of energy attenuating components, and wherein respective left and right intermediate sliding attachments provide a moment restraint preventing the intermediate points of the left and right energy attenuating components from rotating.