Vehicle seat with perimeter frame and pelvic catcher

A vehicle seat is providing including a seat bottom frame; a generally U-shaped seat back frame with an upper cross member with legs pivotally mounted with respect to the seat bottom frame, the seat back cross member being generally at least approximately 470 millimeters along a line generally parallel to the torso of a seated occupant from an H point of the seated occupant, and the cross member being concavely bowed if under approximately 525 millimeters from the H point of the seated occupant; and a deformable lower cross member having ends fixably connected to the seat back legs being concavely bowed, the cross member having a major dimension oriented generally parallel to the torso of the seated occupant, the lower cross member having an upper and a lower end, the lower cross member upper end being vertically above the H point of a seated occupant when the seat back frame is positioned in a normal seating position and where in a rear crash situation, the lower cross member deforms to pivot its lower end further away from the seat back frame legs than its top end to capture the seated occupant's pelvic region between the lower cross member and the bottom frame.

FIELD OF THE INVENTION 
The field of the present invention is that of vehicle seats, especially 
recliner vehicle seating. 
BACKGROUND OF THE INVENTION 
Most efforts in designing vehicle seats for maximum occupant protection 
have mainly been directed toward protecting the vehicle occupant in 
frontal crash situations since the vehicle operator is more likely to be 
involved in a frontal crash situation in an accident. However, lately more 
attention has been directed in the designing of seats in situations where 
the occupant's vehicle is struck from the rear. Protection of the vehicle 
occupant when struck from the rear becomes more challenging when utilizing 
a recliner seat rather than the typically stiffer, non-recliner seat which 
was popular in the past. A simple solution to providing more protection to 
the seat occupant is to increase the thickness and strength of the 
materials utilized. However, a simple strengthening of the seat is 
typically unacceptable due to the fact that increased weight diminishes 
the environmental efficiency of the vehicle. 
SUMMARY OF THE INVENTION 
The present invention provides a vehicle recliner seat which has a lower 
cross member in its seat back which is normally in an unnoticeable 
position but in a crash situation plastically deforms, directing the 
pelvic region of a seated occupant in a downward motion to capture the 
pelvic region of a seated occupant between itself and a lower bun frame of 
the vehicle seat.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1, 3A, 3B and 3C, the preferred embodiment vehicle seat 
7 of the present invention has a seat bottom frame 10. Bottom frame 10 has 
two stamped steel side frame members 16 which are connected by a front 
cross bar 12 and a rear cross member 14. The front cross member 12 and 
rear cross member 14 support between a seat suspension 18, which is 
partially shown. As is well known to those skilled in the art, the lower 
bottom frame is typically covered with padding and a seat covering 
material. Along with its suspension, the seat bottom frame 10 provides a 
platform for support of a thigh and hip, commonly referred to as the 
pelvic region, of a seated occupant. 
Selectively adjustable and pivotally mounted with respect to the seat 
bottom frame is a generally U-shaped seat back frame 20. The means of 
adjustment of the seat back frame with respect to the bottom frame 10 can 
be according to U.S. Pat. Nos. 4,781,415; 4,805,961; 4,824,172 or 
4,865,386 or other suitable alternatives. 
The seat back frame 20 has two legs 22 which pivot about a pin 15 extending 
through an aperture provided in the seat pan 10. The seat back frame 20 
also has extending between the legs a seat suspension 26, which is 
normally covered with padding and appropriate cover material. The legs 22 
will typically be in a single plane; however, the seat back legs may 
extend in two different planes in some applications. In a normal seating 
position, the upper cross member 24 will be at a vertical height 37. 
Vertical height 37 is defined by a length 41 of at least 470 millimeters 
from H point 40 (the H point is the center of gravity of the pelvic region 
of a seated occupant; as shown, it is that of a 95 percentile male) taken 
along a line 39 which intersects the H point and is generally parallel to 
line 42. Line 42 provides the angle of the torso of the seated occupant. 
Typically, the angle of line 42 will differ from that of the legs 22 by 
only three or four degrees. If the cross member 24 is not at least 525 
millimeters above the H point along a line generally parallel to line 42, 
the cross bar 24 will be concavely bowed (bowed rearwardly with respect to 
the seat). The purpose of the bowing will be explained later. 
Extending rearwardly from the seat suspension and fixably connected to the 
legs 22 of the seat back 20 by welding or other permanent fastening means 
is the lower cross member 28. The lower cross member 28 will typically be 
a rectangular band with a major dimension of at least 25 millimeters, and 
in the embodiment illustrated, 38 millimeters, but other shapes and 
constructions are possible in this embodiment. The lower cross member 28 
has a top edge 30 and a lower edge 32. The lower cross member 28 is bowed 
and will extend at least 50 millimeters rearward of the front edge of seat 
back frame member 20 and at least 100 millimeters rearward of the H point. 
The lower cross member 28 will typically be a metal member capable of 
plastic deformation but yet strong enough to resist rupture in virtually 
any crash situation. In normal usage of the seat, lower cross member 28 
will not be noticeable to the seated occupant. 
An early horizontal or downward trajectory of the seated occupant pelvis is 
provided by a low profile seat cushion frame at the rear. Rear cross 
member 14 will be positioned rearward 140.+-.20 millimeters of the H point 
and 125.+-.20 millimeters below the H point 40. The rearward position 
allows a downward trajectory of the pelvis as cross strap 28 is deformed 
rearward until contact occurs between the pelvis and rear cross member 14. 
The engagement of load on rear cross member 14 will occur after the pelvis 
is trapped by deformation of member 28. If a low profile rear seat cushion 
frame is not used, a deformable back member will be used to deform 
rearward under pelvic loading and not to act as a stiff member which 
promotes an upward motion of the pelvis. 
Referring in more detail to FIGS. 3A, 3B and 3C, in a normal situation the 
top edge 30 of the lower cross member will be 55.+-.20 millimeters in 
vertical height 43 above the H point 40. If the vehicle is rear loaded in 
a severe crash situation, the inertia forces acting on the seat will 
thrust it forward, causing the occupant's pelvis and lower torso to move 
rearwardly relative to the seat back frame 20. The loading in the crash 
situation is far in excess of that which can ever be reasonably expected 
to be absorbed by the seat back suspension 26, and the suspension 26 will 
flex rearwardly. Since the upper cross member 24 is either bowed or above 
525 millimeters, the occupant's body will not initially load the upper 
cross member 24. Instead, the occupant's pelvic region will begin loading 
into the lower cross member 28, if a low profile seat cushion does now 
cause an early upward movement of the pelvis, initiating a ramping 
occupant motion. The thrust into the lower cross member 28 will cause the 
lower edge 32 to flex outwardly to bring the major dimension 34 of the 
lower cross member out of a line generally parallel to the torso of the 
seated occupant to pivot to approximately 20 to 30 degrees with respect to 
the seat back legs 22. The flexing and elastic deformation of the lower 
cross member absorbs energy and also traps the buttocks of the seated 
occupant between itself and the rearward cross member 14, which is 
sufficiently rearward and generally low enough so the downward motion of 
the pelvis by the action of member 28 causes pelvic loading on cross 
member 14. Loading will be additionally transferred and absorbed by the 
seat bottom frame 10, which is not part of the reclining seat back frame 
20. The lower cross member 28 will typically experience about 40 percent 
of the total kinetic energy of the seated occupant, with the remainder of 
the energy being absorbed by the rear cross member 14 of the seat bottom 
frame 10, the upper cross member 24 (after the loading of the lower cross 
member 28) and an optional head rest 44. 
Referring to FIG. 2, an alternate preferred embodiment of the present 
invention has a cross member 46 with accordion bends 48 for additional 
absorption of energy during the plastic deformation stage in a crash 
situation. 
While this invention has been described in terms of a preferred embodiment 
thereof, it will be appreciated that other forms could readily be adapted 
by one skilled in the art. Accordingly, the scope of this invention is to 
be considered limited only by the following claims.