Shock absorbing mechanism with feet protection for vehicle and aircraft seats

A device for protecting a vehicle seat occupant against vertical impacts, comprising:

• at least one cylindrical member characterized by a force-displacement curve having an elastic region and a plastic region, and comprises at least one respective helical cut along a respective axis thereof, forming at least one respective helical ribbon which is deformable under respective axial expansion;
• a mechanical linkage configured to transfer momentum from said vertical impacts into tension in said at least one helical ribbon;
• and
• attachment means for attaching a first region of said mechanical linkage to a vehicle seat, and attachment means for attaching a second region of said mechanical linkage to a vehicle body;
• wherein the at least one cylindrical member is configured to have a ratio in a range between about 4:1 and about 70:1 between expansion thereof in the plastic region and expansion thereof in the elastic region.

A method of attenuating an acceleration of a contained body due to impact upon a containing body, comprising:

• providing a cylinder;
• cutting said cylinder along a helical path to form a helical ribbon, said helical ribbon being adapted for plastic deformation in response to stresses greater than a predetermined threshold stress along an axis of said helical ribbon, wherein a force-displacement curve of said helical ribbon is characterized by an elastic region and a plastic region;
• providing attachment means at ends of said cylinder,
• controlling an ultimate displacement of said plastic deformation by varying a length and a helicity of said helical ribbon;
• controlling the predetermined threshold stress by varying a cross section and a material of said ribbon;
• and
• limiting a stress transferred by said impact to said contained body by interposing said helical ribbon between said containing body and said contained body by means of said attachment means,
• wherein said step of limiting the stress comprises stretching said ribbon to maintain a ratio between a stretch of said ribbon in said plastic region and a stretch of said ribbon in said elastic region caused by said impact is in a range between about 4:1 and about 70:1, and
• wherein said step of limiting the stress comprises deforming said helical ribbon under an axial stress in an expansion manner.

A method of protecting a seat occupant against impacts, comprising:

• providing a plurality of helical ribbons;
• said ribbons characterized, in response to tensions applied to the ribbons, by a force-displacement curve having an elastic region and a plastic region;
• providing a mechanical linkage configured to transfer momentum from said impacts into tension in said helical ribbons;
• providing first attachment means for attaching a first side of said mechanical linkage to a vehicle seat;
• providing second attachment means for attaching a second side of said mechanical linkage to a vehicle body;
• and
• absorbing impact momentum by means of mechanical deformation of said helical ribbons due to said tensions applied to said helical ribbons,
• wherein said step of absorbing impacts comprises deforming the helical ribbons under an axial stress in an expansion manner.

A method of protecting a seat occupant against impacts, comprising steps of:

• providing at least one helical ribbon having tubular ends, said at least one ribbon characterized, with response to tensions applied to the ribbons, by a force-displacement curve having an elastic region and a plastic region;
• providing a mechanism configured to transfer said impacts into expansion of said at least one helical ribbon;
• providing front attachment means for attaching a front tubular end of said at least one helical ribbon to a vehicle seat;
• providing back attachment means for attaching a back tubular end of said at least one helical ribbon to a respective vehicle body;
• and
• absorbing impacts by means of expansion of said at least one helical ribbon, wherein a force of said impacts that is transferred to said vehicle seat is determined by the force-displacement curve of said at least one helical ribbon,
• wherein said at least one helical ribbon is arranged to undergo stretch deformation to maintain a ratio between a stretch of said at least one ribbon in said plastic region and a stretch of said at least one ribbon in said elastic region caused by said impacts in a range between about 4:1 and about 70:1, and
• wherein said step of absorbing impacts comprises deforming the at least one helical ribbon under an axial stress in an expansion manner.

A vehicle device for dissipating impact energy in a vehicular system in which, upon impact, a first system component is movable relative to a second system component, the device comprising:

• a tubular member formed of a substantially plastically deformable material;
• said tubular member comprising a helical ribbon formed by a cut along a helical path upon the member;
• a first connector associated with a first end of the tubular member, for attachment to the first system component;
• and
• a second connector associated with a second end of the tube opposite the first end, for attachment to the second system component.