Abstract:
An impact-G-force, vector-modifying seat structure in a vehicle, which seat structure introduces, in a forward crash situation, and in a generally vertical plane, a special forward, then upward, and then rearward rotation of the base of the spine of a seated occupant. This motion tends to minimize crash injuries.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
   This invention relates to seat structure employable in a high-speed vehicle such as an aircraft, and more specifically, to a seat structure and an associated method which, upon the occurrence of an impact, such as a crash, vector-modify the impact G-force transmitted to a seat occupant in a manner which introduces a special companion/component force that has a vector direction which lies at an angle relative to that of such an introduced G-force. 
   Quite by surprise, we have discovered that, with respect to the base of the spine of a seat occupant in an aircraft during a crash, if one introduces a special kind of vector modification of G-forces that are delivered to the base of the spine, it is possible very significantly to minimize injury, and even the likelihood of fatality. The specific modification which we have discovered that accomplishes this involves a vector force modification that introduces to the base of the spine, during an impact crash, for example, vector forces that produce a kind of rotary motion of the base of the spine as viewed from the side of the spine. This special kind of rotation includes a slight forward motion, followed immediately by an upward and rearward rotational motion. 
   To implement this finding in a useful way, we have created a special seat structure that includes interactive components (also called defeatable, frictional-clamping break-away structure herein) which, effectively, break somewhat free of one another during a crash impact to promote the introduction of the injury-reducing vector-change rotary motion just briefly mentioned above. 
   A preferred and best mode embodiment of the invention are described herein below in relation to the accompanying drawings, a reading of all of which will serve to explain to those skilled in the art just how to practice this invention, and how to appreciate its contribution to significant injury minimization. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a very simplified and schematic side elevation of an aircraft passenger seat effectively anchored to the frame in the aircraft, and including mechanism which implements both the structure and the method of the present invention. 
       FIG. 2  is an enlarged, fragmentary, and still somewhat simplified close-up detail illustrating more specifically the special mechanism of this invention which is included in the seat structure pictured in FIG.  1 . 
       FIG. 3  is a fragmentary view taken generally along the line  3 — 3  in FIG.  2 . 
       FIG. 4  is a side-view, vector-force diagram which describes the vector-modifying force behavior of the present invention that induces the kind of forward, then upward, and then rearward rotary motion for the base of the spine described generally hereinabove. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings, and referring first of all to  FIG. 1 , indicated generally at  10  is a fragment of an aircraft frame to which a passenger occupant vector-modifying seat structure  12  constructed in accordance with the invention is attached. Seat structure  12  includes a base  14  which is directly and fixedly anchored to frame  10 , a seat panel structure  16  which directly underlies a seated occupant, a seatback  18 , and mechanism (also referred to herein as defeatable, frictional-clamping break-away structure) constructed in accordance with the present invention, represented generally by a bracket  20 , which effectively acts between seat structure  12  and frame  10  and more specifically between seat base  14  and seat panel structure  16 , on the occurrence of a crash impact. Mechanism  20  herein acts normally in a manner which, before an impact event, participates in defeatably anchoring seat panel structure  16  with respect to seat base  14 . The seat panel structure  16 , and the panel-support structure  18 , are determinedly non-springy structures herein. They create very little spring rebound to an impact event, and are referred to herein as lacking any appreciable spring constant. 
   Seat structure  12  is constructed in any one of a number of well-known manners to allow an occupant to adjust the fore and aft position of panel structure  16  relative to base  14 , in a lockable and releasable fashion. The details of this structure are not specifically shown herein, inasmuch as they do not form any part of the present invention. 
   As will become more fully apparent, if the aircraft possessing frame  10  and carrying seat structure  12  crashes while traveling generally in the direction of arrow  22  in  FIG. 1 , the base of the spine of an occupant of seat structure  12 , which spine base is represented generally by the cross that is labeled  24  in  FIG. 1 , is subjected to a modified vector G-force which causes the base of the spine to travel in a specialized kind of rotary upwardly and then rearwardly directed manner, as is illustrated generally by the compoundly curved arrow  26  in FIG.  4 .  FIGS. 1 and 4  are taken, generally speaking, from the same lateral point of view with respect to seat structure  12 . This modified vector force condition is characterized by plural, substantially simultaneously acting companion forces, and these forces, insofar as they are relevant to the behavior and operation of the present invention, act substantially in a common vertical plane. 
   Turning attention now to  FIGS. 2 and 3  to describe one preferred manner of implementing mechanism  20 , mounted by a pair of spaced nut-and-bolt clamping assemblies  28  on seat base  14  is an elongate, generally horizontal, flat member, or slide component,  30  which includes, near its opposite ends, two elongate slots  32 , and between these two slots a plurality of outwardly facing, generally U-shaped through-passages (vertically speaking), such as those shown at  34 , passages  34  are also referred to herein as slots. Very specifically, component  30  is appropriately tightened, in its manner of fastening to seat base  14 , through a pair of low-friction frictioning plates  36  which generally underlie slots  32 , and which receive the shanks of the bolts in nut-and-bolt assemblies  28 . These same bolt shanks pass through slots  32 , with the tightening nuts, which are secured to the bolt shanks, bearing downwardly on the upper surface of member  30 . Preferably, the generally described components so far pictured and labeled in  FIGS. 2 and 3  are positioned in such a fashion that the mentioned bolt shanks extend through slots  32  near the left, or forward, ends of these slots as pictured in  FIGS. 2 and 3 . The axes of the mentioned bolt shanks are shown by dashed lines  38  in  FIG. 2 , and by a small cross (for just one of these axes) which is also given reference numeral  38  in FIG.  3 . The combination herein of assemblies  28 , component  3 , slots  32  and plate  36  is referred to as fore and aft, defeatable, frictional clamping break-away structure. Appropriately mounted on seat panel structure  16 , and very specifically on that side of this panel structure which is visible in  FIGS. 1 and 2 , is a vertically shiftable, spring-biased plunger, or slide-drive member,  40  which can be lifted and lowered, as indicated by double-headed arrow  42  in  FIG. 2 , through a lift/lower drive connection represented by fragmentary dash-dot-line  44  in FIG.  2 . This drive connection is established with the mechanism previously mentioned which operates to release seat panel structure  16  relative to base  14  at the selection of a seat occupant to position the fore and aft location of the seat panel structure relative to base  14 . In  FIG. 2  in the drawings, the plunger  40  is shown downwardly extending into one of previously mentioned slots  34 , and may be relied upon to establish, or assist in establishing, a locked, fore and aft selected position of seat panel structure  16  relative to base  14 . The interrelationship which exists between plunger  40  and a slot  34  is referred to herein as a slide-drive connection. 
   On the occurrence of a forward impact, such as an airplane crash, the plunger in mechanism  40 , acting as a slide-drive member, drives forwardly against the front side of the associated slot  34  with respect to which it is disposed, and very specifically drives (breaks away) member  30  slidably forwardly over low-frictioning plates  36  and against the tightened resistance of nut-and-bolt assemblies  28 . Member  30  thus, effectively, “breaks away” from this fixed (initially) position relative to seat base  14 , and undergoes a certain amount of immediate, limited forward sliding travel by the distance D indicated generally in FIG.  3 . It is this simple, limited-forward-motion break-away sliding action which, in relation to a forward impact crash of an aircrafl such as that which has just been suggested, introduces modified G-force vectors to the base of a seat occupant&#39;s spine to create a condition wherein the base of the spine undergoes the specialized forward, upward, and then rearward rotary motion pictured at  26  in FIG.  4 . Non-intuitive though it may seem, observations performed in test simulations have clearly demonstrated that the event of a forward crash causes the base of the spine, when it is associated with a seat possessing the mechanism of the present invention, definitively to undergo the vector-changed rotary motion described herein. And, as was mentioned earlier, simulation tests that have been performed utilizing this invention produce confirmed “injury numbers” that are significantly lower than those same kind of injury numbers which one observes in the absence of mechanism  20  of the invention. 
   Accordingly, while a preferred and best mode manner of implementing and practicing the present invention have been illustrated and described herein, it is recognized that variations and modifications may be made in the specific structural arrangements capable of creating the unique vector force conditions proposed. All such variations and modifications are deemed to come within the scope of this invention.