Abstract:
A support structure comprises a first portion for sliding attachment to a seat having a front, a back, and two sides, and a second portion connected to the first portion at a substantially right angle. The first portion has a hollow cross-sectional shape with an asymmetrical material distribution through the plane of the cross section, the material distribution placing more of the material comprising the first portion toward the sides of the vehicle seat. The support structure is adapted for attachment to the seat and is adapted to be activated to extend in a substantially vertical direction upwardly from the seat. The first portion has an arc shape along its length so that when the support structure is activated the second portion is supported by the first portion at a desirable angle for bracing against an impact force direction that is typical of vehicle rollover.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of Invention  
         [0002]     This invention relates to the field of reinforcing vehicles to lessen roof crush during rollover. More specifically, this invention relates to a reinforcement that can be deployed during a vehicle rollover to cooperate with the vehicle roof to lessen roof crush during the rollover.  
         [0003]     2. Background  
         [0004]     United States Federal Motor Vehicle Safety Standard (FMVSS)  216  is a requirement designed to protect vehicle occupants in the event of a rollover accident. New standards require that, by 2009, roof deformation be limited to five inches (127 mm) of crush. Under the new standard, a vehicle&#39;s roof structure will have to support 2.5 times the vehicle weight or 5,000 pounds, whichever is less (up from the previous requirement of 1.5 times the vehicle weight).  
         [0005]     Presently, most non-convertible automobiles have pillared hardtops. A pillared hardtop typically includes a framework of A-pillars, B-pillars, C-pillars, and interconnecting roof rails and headers. This framework protects vehicle occupants should a rollover condition occur, by limiting roof crush. The A-pillars are typically located on the sides of the vehicle&#39;s front windshield. The C-pillars are typically located on the sides of the vehicle&#39;s rear window. The B-pillars are typically located about midway between the A-pillars and the C-pillars. The roof rails and headers extend between the pillars longitudinally and transversely.  
         [0006]     To strengthen roof structures to meet the new requirements, there are a number of alternatives that are commonly used. The most common practice to strengthen the roof structure is to increase the strength of the A-pillar, B-pillar, and C-pillar, as well as the roof rails and headers. Strengthening these elements is most commonly achieved by increasing their size and thickness, which can increase vehicle weight and production costs. Other ways to strengthen these elements include using stronger materials, which may be prohibitively expensive to obtain or use in existing production facilities, and adding additional support elements, which also increases vehicle weight and production costs.  
         [0007]     It has been proposed, in convertible vehicles that do not have protective roof structures, to employ rollover bars that are enclosed within or otherwise attached to a vehicle&#39;s seat. The rollover bars are activated, upon sensing a rollover condition, to extend upward to protect the seat occupant during rollover. These rollover bars are disclosed to be desirable due to the lack of a protective roof structure in convertible vehicles, and are not adapted or designed to work in cooperation with a pillared hard top to reinforce the pillared hard top.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     In one embodiment, the invention is directed to a support structure comprising a first portion for sliding attachment to a seat having a front, a back, and two sides, and a second portion connected to the first portion at a substantially right angle. The first portion has a hollow cross-sectional shape with an asymmetrical material distribution through the plane of the cross section, the material distribution placing more of the material comprising the first portion toward the sides of the vehicle seat. The support structure is adapted for attachment to the seat and is adapted to be activated to extend in a substantially vertical direction upwardly from the seat.  
         [0009]     In another embodiment, the invention is directed to a support structure comprising a first portion for sliding attachment to a seat, and a second portion connected to the first portion at a substantially right angle. The first portion has an arc shape along its length so that when the support structure is activated the second portion is supported by the first portion at a desirable angle for bracing against an impact force direction that is typical of vehicle rollover. The support structure is adapted for attachment to the seat and is adapted to be activated to extend in a substantially vertical direction upwardly from the seat.  
         [0010]     In yet another embodiment, the invention is directed to a method of making a support structure. The method comprises providing a first portion, attaching a second portion at a substantially right angle to the first portion, and attaching the first portion to a vehicle seat so that it can slide vertically relative to the seat. The first portion has an arc shape along its length so that when the support structure is activated the second portion is supported by the first portion at a desirable angle for bracing against an impact force direction that is typical of vehicle rollover.  
         [0011]     Further features of the present invention, as well as the structure of various embodiments of the present invention are described in detail below with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements.  
         [0013]      FIG. 1  illustrates a prior art vehicle seat having a headrest.  
         [0014]      FIG. 2  illustrates a vehicle seat including a reinforcement in accordance with the present invention.  
         [0015]      FIG. 3A  is a front view of a reinforcement in accordance with the present invention.  
         [0016]      FIG. 3B  is a side view of the reinforcement shown in  FIG. 3A , taken along line  3 A- 3 A.  
         [0017]      FIGS. 4A-4C  are alternate cross-sectional views of a portion of a reinforcement in accordance with the present invention.  
         [0018]      FIG. 5  illustrates an embodiment of an activation mechanism for a reinforcement in accordance with the present invention.  
         [0019]      FIG. 6  illustrates an embodiment of a reinforcement in accordance with the present invention, being utilized in a vehicle during a rollover simulation test.  
         [0020]      FIG. 7  illustrates exemplary forces acting on a reinforcement during a rollover simulation test.  
         [0021]      FIG. 8A  is a front view of an embodiment of a reinforcement of the present invention, with an overhanging top portion.  
         [0022]      FIG. 8B  is a side view of the reinforcement of  FIG. 8A .  
         [0023]      FIG. 8C  is a perspective view of the reinforcement of  FIG. 8A .  
         [0024]      FIG. 9  illustrates exemplary forces acting on a reinforcement of the present invention during vehicle rollover, and also illustrates exemplary deformation of a vehicle floor and roof during rollover. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     The present invention provides a roof reinforcement or support structure. An occupant safety device for an automotive vehicle lessens roof crush during vehicle rollover and comprises the roof reinforcement or support structure. The reinforcement is preferably deployed during a vehicle rollover to cooperate with the vehicle roof to limit roof crush.  
         [0026]      FIG. 1  illustrates a prior art vehicle seat  10  including a seat back portion  20  and a headrest  30 . It is known to mount headrests  30  on the seat back portion  20  via vertical supports  40 . It is most common to employ two vertical supports  40  for each headrest  30 , and to fashion the supports  40  so that the headrest  30  is vertically adjustable to a limited extent for occupant comfort. It is also known to reinforce vehicle seats in a number of ways to increase occupant safety in the event of side and rear impact collisions.  
         [0027]      FIG. 2  illustrates a vehicle seat including an embodiment of a reinforcement in accordance with the present invention. Vehicle seat  100  is situated in a vehicle having a roof portion  200 . The seat  100  includes a bottom portion  110  and a back portion  120 . The seat  100  also preferably includes a headrest  130 . Mounted within the seat  100  is a reinforcement  300  (see  FIG. 3A ) having at least one first vertical portion  310  and a second horizontal portion  320 . The reinforcement is preferably mounted within the seat back  120  so that its at least one vertical portion  310  can slide substantially vertically within the seat back  120  as shown in  FIG. 2 .  
         [0028]     As schematically illustrated in  FIG. 2 , a sensor  210  is connected to the reinforcement, preferably via an electrical line  220 . The sensor  210  is capable of sensing a condition for which roof reinforcement is desirable. Upon sensing such a condition, the sensor  210  sends a signal to the reinforcement  300  via the electrical line  220  to suitably deploy the reinforcement so that it reinforces the vehicle roof.  
         [0029]     As shown in  FIG. 2 , the seat&#39;s headrest  130  preferably covers the horizontal portion  320  of the reinforcement  300 . During normal operation of the vehicle, the reinforcement  300  is mounted within the seat back portion  120  in a lowered position (not shown) such that the headrest  130  is properly positioned for occupant comfort and safety during normal driving conditions. In a particularly preferred embodiment of the invention, the reinforcement  300  is mounted within the seat back portion  120  so that the headrest height is adjustable to a limited extent for the vehicle occupant. However, if the sensor  210  senses a condition for which roof reinforcement is desirable, the reinforcement  300  can be activated/deployed by an activation mechanism (discussed below) to extend upwardly within the seat back  120  so that it is properly positioned to reinforce the vehicle roof  200 .  
         [0030]     By way of example, a reinforcement  300  in accordance with the present invention may extend upwardly from four to six inches upon deployment. This distance varies by vehicle, and can depend on the distance between the top of the seat back portion  120  and the vehicle roof  200 .  
         [0031]      FIG. 3A  is a front view of a reinforcement in accordance with the present invention. As shown, horizontal portion  320  extends between two vertical portions  310 . Although the illustrated embodiment includes two vertical portions  310 , the present invention contemplates one or more vertical portions. The horizontal portion  320  preferably extends across the top of the vertical portions  310 , and spans the width of the vertical portions  310 . In the embodiment illustrated in  FIG. 3A , a crossbar  360  extends between the vertical portions  310  to increase the structural stability of the reinforcement  300 .  
         [0032]     The vertical portions  310  preferably are slidably seated in hollow pillars  330  so that they can slide vertically within the pillars  330  a predetermined amount. The pillars  330  are preferably fixedly mounted to the vehicle seat  100 . In a preferred embodiment of the invention, an activation mechanism  340  is housed within the pillars  330  and is in direct or indirect contact with the vertical portions  310 . The activation mechanism  340  is activated to drive the vertical portions  310  to an extended position substantially upward relative to the seat  100 . Although the activation mechanism  340  shown in  FIG. 3A  is a coil spring, any known, suitable activation mechanism can be employed, including other spring systems and pyrotechnic devices (not shown).  
         [0033]     Although  FIG. 3A  discloses an activation mechanism  340  for each of the two vertical portions  310  of the reinforcement  300 , the present invention also contemplates a single activation mechanism for the reinforcement  300 , even if there is more than one vertical portion, or other suitable combinations of numbers of activation mechanisms and vertical portions.  
         [0034]      FIG. 3B  illustrates a side view of the reinforcement shown in  FIG. 3A , taken along line  3 B- 3 B. In this embodiment, the activation mechanism  340  is shown to be in direct contact with a bottom surface  350  of the vertical portion  310  that it activates.  
         [0035]     The reinforcement  300  preferably comprises a retaining mechanism that retains the support structure in its extended/deployed position. The retaining mechanism is shown to include a cutout portion  370  of the pillar  300 , into which, for example, a spring-loaded or otherwise biased protrusion (not shown) passes through the cutout portion  370 .  
         [0036]     In a preferred embodiment of the invention, a cushion is provided to protect the occupant&#39;s head when the headrest  130  has been extended to an activated position. The cushion may include, as illustrated in  FIG. 2 , a portion  140  of the seat  100  that extends from the seat back  120  to protect the occupant&#39;s head. Additionally or alternatively, the present invention contemplates a soft coating for the vertical portions  310  to protect the occupant&#39;s head, or an air bag that can be deployed with the reinforcement  300  to replace the headrest  130  upon deployment.  
         [0037]      FIGS. 4A through 4C  illustrate contemplated cross sections of the at least one vertical portion  310  of the reinforcement  300 . While three possible shapes are illustrated, the present invention contemplates a variety of suitable shapes and sizes for the vertical portion&#39;s cross section.  FIG. 4A  illustrates a modified C-shaped cross section having an outer wall  410 , two side walls  420  and two additional walls  430  that increase the structural strength of the vertical portion. In one exemplary embodiment, the cross-sectional dimensions of the vertical portion are 15 mm×50 mm, with the walls having a thickness of about 2 mm.  
         [0038]      FIG. 4B  illustrates another exemplary embodiment of a cross section of the vertical portions. This C-shaped cross section includes the outer wall  410  and side walls  420  of the modified C-shaped cross section, but does not include the additional walls  430 . In use, the outer wall  410  is preferably located at an outermost side location S (see  FIG. 3A ) of the reinforcement  300 . This arrangement of the outer wall  410  increases the structural strength of the reinforcement for the forces characteristic of vehicle rollover.  FIG. 4C  illustrates a known I-shaped cross section.  
         [0039]     In a preferred embodiment, the reinforcement  300  comprises ultra high strength steel (UHSS). In a particularly preferred embodiment, the reinforcement  300  comprises boron.  
         [0040]     The present invention contemplates different components of the reinforcement  300  being made from different suitable materials. The materials should be suitably light and strong, and also should be economically feasible to use.  
         [0041]      FIG. 5  illustrates an embodiment of an activation mechanism for a reinforcement in accordance with the present invention. Sensor  210  is capable of sensing a crash condition for which vehicle roof reinforcement is desirable, such as a vehicle rollover. Sensor  210  is preferably connected to the activation mechanism  340  for the reinforcement  300  via an electrical line  220 . As shown in  FIG. 5 , when the activation mechanism  340  is a pre-loaded spring or other preloaded spring system, a pre-tension device  500  may be provided between the sensor  210  and the activation mechanism  340 . The pre-tensioner  500  pulls a cable  510  that slides a plate  520  extending into the pillar  330  to release the spring to activate the vertical portion  310  residing in the pillar.  
         [0042]     Upon sensing a crash condition for which vehicle roof reinforcement is desirable, the sensor  210  sends a signal to the reinforcement  300  via the electrical line  220  to activate the activation mechanism  340  and suitably deploy the reinforcement  300  so that it reinforces the vehicle roof  200 . As stated above, although the activation mechanism  340  is depicted as a coil spring, any known, suitable activation mechanism can be employed, including other spring systems and pyrotechnic devices.  
         [0043]      FIG. 6  schematically illustrates a reinforcement in accordance with the present invention, being utilized in a vehicle during a rollover simulation test. The reinforcement  300  is shown extending from a seat  100  of a vehicle. The embodiment of the reinforcement  300  illustrated in  FIG. 6  includes two crossbars  360   a  and  360   b . In the embodiment of the reinforcement shown, when employed during a rollover condition or simulated rollover condition, crossbar  360   a  is in compression and crossbar  360   b  is in tension.  
         [0044]     The simulated rollover condition is created when a simulator plate  700  impacts the vehicle with a given force. The force can be, for example, based on the calculated forces exerted during a rollover, or based on a set weight such as a multiple of the vehicle&#39;s weight. As stated above, FMVSS  216  requires that, by 2009, a vehicle&#39;s roof structure will have to support 2.5 times the vehicle weight or 5,000 pounds, whichever is less. The simulator plate  700  commonly impacts the vehicle at the junction of the sides  610  and roof  200  of the vehicle, in the area of both the A pillar (not shown) and the roof rail  620  of the vehicle.  
         [0045]     As can be seen in  FIG. 6 , the activated reinforcement  300  extends toward the roof of the vehicle and may stop just short of the roof or upon contacting the roof. Extension is stopped when the protrusion of the retaining mechanism passes through the cutout portion  370  and retains the reinforcement in its extended portion as discussed above. Upon actual or simulated rollover impact, roof crush is limited when the roof contacts the reinforcement  300  because the reinforcement provides support that limits further crush.  
         [0046]     The reinforcement  300  is preferably mounted to the vehicle seat  100 . Although vehicle seats are commonly reinforced to a limited extent in a number of ways to increase occupant safety in the event of side or rear impact collisions, the seat  100  supporting the reinforcement  300  may include additional framing to allow the seat  100  to provide a suitable support for the reinforcement  300 . The seat  100  is commonly mounted to the vehicle floor  600 . The present invention contemplates reinforcing the vehicle floor  600  so that it provides a suitable support for the seat  100  and the reinforcement  300 .  
         [0047]     With respect to the forces commonly generated during vehicle rollover, components of the vehicle that provide occupant protection during a rollover condition, such as the A-pillars, B-pillars, C-pillars, rails, and headers, are subject to bending forces during rollover due to their position relative to the forces generated during rollover. The bending forces that are generated during vehicle rollover cause deformation of these components, making them much less effective than a component positioned so that rollover forces act upon it axially. Similarly, forces applied to the vertical portions  310  of the reinforcement  300  during a vehicle rollover have both an axial component and a bending component. As a general principal, bending forces cause greater deformation of the vertical portion than do axial forces, so that the reinforcement  300 , like other structural supports, is more effective against applied axial forces.  
         [0048]      FIG. 7  illustrates exemplary forces acting on a reinforcement  300  being utilized in a vehicle during a rollover simulation test. As can be seen, the simulator plate  700  presses on the vehicle, exerting a roof crush force F 1  on the vehicle roof  200 . The direction of the counter force F 2  exerted by an activated reinforcement  300  can, in part, depend on the position of the seat back  120  and is exerted at an angle α to the direction of the roof crush force F 1 . Ideally, the reinforcement  300  would be positioned such that the counter force F 2  exerted by an activated reinforcement  300  would be directly opposite to the roof crush force F 1 , as represented by force F 3 . Such a position for reinforcement  300  would cause the rollover forces F 1  to act upon the vertical portions  310  of the reinforcement  300  axially, beneficially minimizing or eliminating bending forces applied to the vertical portions  310 .  
         [0049]     In addition to positioning the reinforcement  300  as a whole such that the counter force F 2  exerted by an activated reinforcement  300  would be directly opposite to the roof crush force F 1 , the present invention contemplates the vertical portions  310  being curved (see  FIGS. 3B and 8B ) to minimize the angle α between the counter force F 2  exerted by an activated reinforcement  300  and the ideal direction F 3  for the counter force.  
         [0050]      FIGS. 8A through 8C  illustrate an embodiment of a reinforcement of the present invention. In the embodiment of  FIGS. 8A through 8C , the reinforcement  300  has an overhanging top portion  320   a . The overhanging top portion  320   a  is similar to the horizontal portion  320  of the previously-described embodiments of the reinforcement  300 . However, in addition to extending between vertical portions  310 , the overhanging top potion  320   a  also extend past the vertical portions  310  on at least one side of the reinforcement  300 .  
         [0051]     The overhanging top portion  320   a  preferably has a length and a direction of overhang that, upon actuation of the reinforcement, provides early roof engagement in the event of roof crush. This is because, based on the most common characteristics of roof crush, the overhanging top portion  320   a  extends into the crush zone and thus makes earlier contact with the roof during roof crush. This can be seen in the schematic illustration of a vehicle rollover simulation test presented in  FIG. 6 .  
         [0052]      FIG. 9  illustrates exemplary forces acting on a reinforcement  300  of the present invention during vehicle rollover, and also illustrates exemplary deformation of a vehicle floor  600  and roof  200  during rollover. The reinforcement  300  is mounted directly or indirectly to the vehicle floor  600 , and is activated when the sensor  210  (see  FIG. 2 ) senses a crash condition for which vehicle roof reinforcement is desirable. When activated, the reinforcement  300  extends to contact the vehicle roof  200  to reinforce the roof during rollover.  
         [0053]     The reinforcement  300  also cooperates with the vehicle floor  600 , via the seat  100 , to provide an amount of floor deformation upon rollover to absorb collision energy while maintaining an area of occupant headroom as well as a safe passenger space between the roof  200  and the floor  600 . In  FIG. 9 , occupant head room is generally illustrated at  810 . The safe passenger space, which includes the space necessary to prevent major injuries to an occupant, is generally illustrated at  820 .  
         [0054]     Floor deformation can increase collision energy absorption during a rollover event, which is beneficial because it can lessen the duration of the rollover by absorbing some of the energy that must be dissipated during the rollover. In most vehicles, the seat is stronger than the floor because the seat is designed to protect the occupant from front and rear impacts, allowing the floor to deform while the seat maintains its integrity and maintains a safe passenger space  820 .  
         [0055]     The present invention contemplates the reinforcement  300  being provided at any number of positions within the vehicle. For example, the reinforcement  300  may be provided only for the driver of the vehicle, or may additionally be provided for the front passenger and even rear passengers. This method and device for reinforcing a vehicle roof can beneficially maintain a lower center of gravity in vehicles, and uses a minimal amount of material to provide a desired amount of reinforcement.