Abstract:
A motor vehicle occupant protection system features an upper panel of an armrest is maintained in an arm supporting position during normal vehicle operation, and is moved to a safety position by an actuation device upon sensing of an actual or impending impact on the side of the vehicle. In the arm supporting position, the arm support panel contributes to the structural strength of the armrest so that it is able to withstand rugged use. In the safety position, the arm support panel is positioned so that it does not present a rigid edge oriented directly toward the occupant, but rather is in a partially or completely folded position. Both mechanical and electronic actuation systems are disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an armrest located in the passenger compartment of an automotive vehicle, and specifically to such an armrest adapted for improved occupant protection during a crash. 
     2. Background 
     Automotive vehicles typically have an armrest located on the interior surface of each vehicle door. In addition to providing a surface on which the vehicle occupant seated immediately adjacent the door may rest his/her elbow and/or forearm, the armrest is often integrated with a door latch release lever and/or a grab handle used to open and close the door. Armrests must be relatively rigid and structurally strong to withstand the loads applied during everyday use of the vehicle. 
     Vehicle crash testing has indicated that a rigid armrest may increase the likelihood and/or severity of injury to an occupant during a collision in which the occupant forcefully strikes the armrest, such as when the vehicle is struck on its side by another vehicle or slides sideways into a stationary object. To reduce this possibility, it is known to construct the armrest so that it will yield or deform under the force of an impact with the occupant&#39;s body. Ideally, the armrest should deform in a manner to absorb some of the impact energy and avoid any rigid elements that project inward from the door inner surface and that could cause a concentration of the impact load on the occupant&#39;s body. It is difficult, however, to design and manufacture an armrest that is structurally strong enough to withstand the type of loads to which it may be subjected during everyday use and that is also capable of deforming so as to reduce injury in a crash. 
     SUMMARY OF INVENTION 
     The present invention provides an occupant protection system for a motor vehicle in which an upper arm support panel of an armrest is maintained in an arm-supporting position during normal vehicle operation, and is moved to a safety position by an actuation device upon sensing of an actual or impending impact on the side of the vehicle. 
     In the arm supporting position, the arm support panel contributes to the structural strength of the armrest so that it is able to withstand rugged use. In the safety position, the arm support panel is positioned so that it does not present a rigid edge oriented directly toward the occupant, but rather is in a partially or completely folded position. When in the safety position, if a side impact urges an occupant&#39;s body forcefully into contact with the armrest, the armrest is able to collapse to a position generally parallel with the interior surface of the vehicle sidewall so as to minimize injury to the occupant. 
     According to a preferred embodiment of the invention, the actuation device comprises a mechanical linkage having a contact pad disposed within the vehicle sidewall at a position where it will be urged inwardly when another vehicle strikes the subject vehicle. As the contact pad is urged inwardly, the mechanical linkage releases the arm support panel and so that it may be urged to the safety position by the mechanical linkage or by a stored energy device such as a spring. 
     According to another feature of the invention, an electronic actuation system comprises a microprocessor-based controller, a powered panel actuator, and one or more sensors for detecting or predicting a side impact. The panel actuator may be a pyrotechnic device, or may be an electromagnetically powered device such as a solenoid or an electrically actuated latch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial perspective view of a sidewall of an automotive vehicle with an active armrest according to a first embodiment of the present invention. 
     FIG. 2 is a cross-sectional view taken along line  2 — 2  or FIG. 1 showing the armrest panel in a normal, arm-supporting position. 
     FIG. 3 is a view similar to FIG. 1 showing the armrest panel in a safety position. 
     FIG. 4 is a cross-sectional view showing a second embodiment of an active armrest with the panel in a normal, arm-supporting position. 
     FIG. 5 is a view similar to FIG. 4 showing the armrest panel in a safety position. 
     FIG. 6 is a schematic block diagram of an electronic armrest panel actuation system according to the invention. 
     FIG. 7 is a cross-sectional view showing a possible embodiment of an electronic armrest panel actuation system. 
     FIG. 8 is a view similar to FIG. 7 showing the armrest panel in a safety position. 
    
    
     DETAILED DESCRIPTION 
     As seen in FIGS. 1-3, a sidewall  10  of an automotive vehicle has an armrest  12  disposed on an interior surface thereof. Sidewall  10  is shown as comprising an interior wall  10   a  adjacent the passenger compartment of the vehicle and an exterior wall  10   b  forming the outer surface of the vehicle. The sidewall  10  is shown as including a door latch mechanism  22  such as would be present in an openable door, but it may alternatively be a fixed, non-opening side portion of the vehicle having an armrest, for example in a van where some of the rear seats are not adjacent to a door. Sidewall  10  may also comprise various components located between the inner and outer panels  10   a ,  10   b , such as a window regulator (not shown) or side crash protection beams (not shown). 
     As used in this description, the terms such as “outboard,” “outer” and “outward” indicate a direction or orientation away from or farther from a longitudinal centerline of the vehicle of which the sidewall  10  forms a part. Conversely, “inboard,” “inner” and “inward” indicate a direction or orientation toward or closer to the longitudinal centerline. Terms such as “forward,” “rearward,” “lateral,” “longitudinal,” “horizontal” and “vertical” refer to the orientation of a particular component relative to the vehicle as a whole. 
     Armrest  12  comprises an arm support panel  14  projecting inwardly from the interior wall  10   a  and a trim panel  20  secured to the sidewall  10  immediately below the arm support panel  14 . In most vehicles, arm support panel  14  is generally perpendicular to interior wall  10   a  so as to provide a surface on which an occupant of the seat adjacent the sidewall  10  may comfortably rest his/her elbow and/or forearm. Arm support panel  14  may be oriented generally horizontally, or may be inclined from the horizontal as it runs along the longitudinal axis of the vehicle, or may have two or more portions disposed at different angles, depending upon the particular installation in a vehicle. The upper surface of arm support panel  14  may be substantially flat or may be partially or completely concave or convex. All or a portion of the exposed surface of trim panel  20  may be formed separately and attached to the interior wall  10   a  as is well known in the vehicle interiors art. As seen in FIGS. 2 and 3, trim panel  20  may include energy-absorbing structures such as cone-shaped elements  24  which may be made as an integral part of the trim panel, or made of crushable foam or other appropriate material. 
     A grab hole  16  may be provided in the upper surface of the arm support panel  14  to receive an occupant&#39;s fingers and allow the occupant to pull the door to the closed position. Controls, switches, or other components, such as power window operating switches  18  or a power mirror control (not shown), may be disposed in or on arm support panel  14 . Arm support panel  14  may be manufactured from any appropriate material or materials, such as plastic, metal, or composite material. 
     The outboard edge of arm support panel  14  is attached to trim panel  20  and/or to interior wall  10   a  by one or more hinges  26 . Hinges  26  are shown as being visible for clarity, but are preferably hidden from view. Locking arms  28  project downwardly from the lower surface of arm support panel  14  and curve outwardly so that distal ends of the arms overlap respective lock tabs  34  that are secured to interior wall  10   a . Holes  30  are formed in the distal ends of locking arms  28  and are aligned with matching holes  32  formed in lock tabs  34 . 
     A mechanical linkage for actuating arm support panel  14  in the event of a side impact comprises a cable guide  38  disposed within sidewall  10  and having a first end  38   a  adjacent one locking arm  28  and a second end  38   b  adjacent the other locking arm. A cable  40  extends through the hollow interior of cable guide  38  and is axially slidable relative to the cable guide. Lock pins  36  are connected to the opposite ends of cable  40  and project through the aligned pairs of holes  30 , 32  in the locking arms  28  and lock tabs  34 , thereby preventing rotation of arm support panel  14  about hinges  26 . 
     The mechanical linkage further comprises a trigger lever  42  disposed within the sidewall  10  and pivotable about an axis  43  approximately parallel with the longitudinal axis of the vehicle. An upper end  42   a  of trigger lever engages cable  40  and a lower end  42   b  comprises a contact pad  44 . Contact pad  44  is preferably positioned at a height at which it is likely to be the initial point of impact from another vehicle striking the subject vehicle. For example, the height of contact pad  44  may match the most common bumper height of other vehicles. Contact pad  44  is shown as being located closely adjacent to the exterior wall  10   b  (see FIG.  2 ), but it may be located farther inboard within sidewall  10 . If contact pad  44  is located inboard of a window glass (not shown), a pusher block (not shown) may be provided between exterior wall  10   b  and the glass so that less deformation of the exterior wall will be required to move the contact pad. Contact pad  44  may be of any shape necessary to fit in the available space within sidewall  10  and avoid other components, and it may extend over a greater length of sidewall  10  than is shown in FIG.  1 . 
     During normal vehicle operations, arm support panel  14  is maintained in the arm-supporting position (shown in FIGS. 1 and 2) wherein it is generally perpendicular to interior wall  10   a  as described above. When another vehicle  38  strikes the subject vehicle on or near the sidewall  10  with sufficient energy to deform exterior wall  10   b , contact pad  44  is urged inward, causing trigger lever  42  to pivot about axis  43  so that the upper end  42   a  moves outwardly. This movement pulls on cable  40 , drawing it through or along cable guide  38  so that lock pins  36  are pulled out of engagement with holes  30 , 32 . When the mechanical linkage is in this released condition shown in FIG. 3, arm support panel  14  is free to rotate downwardly (clockwise as viewed in FIGS. 2 and 3) about hinges  26  to a safety position wherein the panel is no longer perpendicular to the interior wall  10   a.  Rotation of arm support panel  14  to the safety position may be caused solely by gravity, but is preferably assisted, speeded, or ensured by one or more stored energy device such as a spring. For example, one or more of hinges  26  may include a coil spring  27  biasing arm support panel  14  downwardly. Alternatively or in addition to a stored energy device, rotation to the safety position may be assisted, speeded, or ensured by providing a mechanical connection, such as a cable, between trigger lever  42  and arm support panel  14  to pull downwardly on the arm support panel upon movement of the trigger lever. 
     To realize safety benefits, the actuation mechanism needs to rotate arm support panel  14  away from the arm-supporting position only enough so that the arm support panel is not oriented directly edge-on to the occupant. Even if the actuation mechanism rotates the panel only approximately 20°, subsequent contact between the occupant&#39;s body and the armrest  12  during a collision will cause the arm support panel  14  to rotate further until it is substantially parallel with the interior wall  10   a . It may be necessary for the distal ends of locking arms  28  to bend or otherwise deform upon contact with the inner surface of exterior wall  10   b  or other structure within sidewall in order for arm support panel  14  to rotate to a parallel position, and this deformation can also be used to absorb impact energy. 
     As an alternative to the downward rotation shown, stored energy devices and/or a mechanical connection may be used to force arm support panel  14  to rotate upwardly to the safety position. If the arm support panel rotates upwardly, the underside of the panel must be free of any protrusions that could contribute to injury. 
     The entire armrest  12  is preferably designed to absorb energy and provide cushioning during an impact. For example, cone-shaped elements  24  may be located between inner panel  10   a  and trim panel  20  so as to be crushed by the force of the occupant&#39;s body impacting the armrest  12 , thereby absorbing energy and lessening the severity of injury. Many other energy absorbing means will be apparent to a person of skill in the art. 
     Only the portion of the armrest top surface in the area where the armrest is likely to contact the occupant&#39;s body during a side impact needs to move to the safety position. Accordingly, the movable portion of arm support panel  14  need not extend along the entire length of the armrest  10 , but rather only the portion directly outboard of the occupant. 
     It may be desirable to provide points of engagement between arm support panel  14  and trim panel  20  in addition to hinges  26  in order to retain the arm support panel  14  securely in the arm supporting position. If this is the case, the actuation mechanism must serve to disengage these other points to allow arm support panel  14  to move to the safety position. For example, additional pins (not shown) may connect the inboard edge of arm support panel  14  to the trim panel  20 , and cables or other connections may be attached to the pins to extract them in response to movement of the trigger lever  42 . Trim panel,  20  could be stiffened if necessary by vertical or horizontal beads etc., if necessary to control occupant contact force. 
     In a second embodiment of the invention shown in FIGS. 4 and 5, the linkage mechanism comprises a trigger lever  50  similar to that of the embodiment of FIGS. 1-3 in that it is pivotable about an axis  51  approximately parallel with the longitudinal axis of the vehicle, and a lower end of the lever comprises a contact pad  52 . The upper end of trigger lever  50  comprises a fitting  54  that engages the arm support panel  14  adjacent its outboard or hinged edge. In the preferred embodiment, the fitting has an inboard prong  54   a  and an outboard prong  54   b  that extend upwardly adjacent the respective inner and outer faces of a flange  56  projecting downwardly from the outboard edge of arm support panel  14 . 
     Prior to the device being triggered by an impact on the side of the vehicle, the armrest is in the normal operating condition shown in FIG.  4 . Trigger lever  50  is positioned so that the outboard prong  54   b  contacts the flange  56  on its lower edge and/or outer face and thereby holds arm support panel  14  in the arm supporting position. When the contact pad  52  is forced inward by a collision (see FIG.  5 ), the trigger lever  50  pivots about the axis  51  so the upper end moves outward and the inboard prong  54   a  contacts the flange  56 . As trigger lever  50  continues to rotate to the released condition shown in FIG. 5, it urges flange  56  outwardly, causing arm support panel  14  to rotate downward about hinge to the safety position. The surfaces of fitting  54  and flange  56  that contact one another during this actuating motion may be angled, beveled, rounded, or otherwise contoured or shaped so that the movement of fitting  54  is effectively transferred to the flange  56  to cause arm support panel  14  to rotate to the safety position, and so that the arm support panel may rotate further downward as the trim panel  20  is crushed outwardly by contact with the occupant. 
     As with the first embodiment, there may be points of engagement between arm support panel  14  and trim panel  20  in addition to the fitting/flange engagement if necessary to hold the arm support panel  14  securely in the arm supporting position, the actuation mechanism serving to disengage these additional engagement points to allow arm support panel  14  to move to the safety position. 
     Many other possible mechanisms for achieving a movable arm support panel  14  will be apparent to those of skill in the art. 
     FIGS. 6-8 depict an embodiment of the invention utilizing an electronic panel actuation system. As shown schematically in FIG. 6, the system comprises a controller  60 , a side impact sensor  62 , and a panel actuator  64 . Controller  60  is preferably a microprocessor-based device and may comprise or be integrated with a restraints control module  66  (RCM) connected other sensors, such as a front crash sensor  67 , and controlling other occupant safety systems of the vehicle, such as airbags  68  and seatbelt pretensioners  70 , as is well known in the vehicle restraints art. Side impact sensor  62  may be disposed in, on, or adjacent to the structure of the vehicle&#39;s sidewall and may comprise any appropriate type of device, such as an inertial sensor or a contact sensor such as those known to be used to actuate side airbags. In addition or alternatively to the side impact sensor  62 , a pre-crash sensor  72  may be connected with controller  60  to provide a signal in response to a predicted impact with another vehicle. Pre-crash sensor  72  may utilize radio frequency, ultrasonic, laser, capacitive, or any other known type of non-contact detection. 
     Panel actuator  64  is operable to move or initiate movement of the arm support panel to a safety position upon receipt of a signal from the controller  60 . The actuator  64  may be any appropriate electrically actuated device, such as a pyrotechnic actuator of the type known in the automotive occupant protection field, or an electromagnetically operated device such as a solenoid or an electrically operated latch and spring device. The controller  60  may also receive inputs from sensors located elsewhere in the vehicle, such as a vehicle dynamics sensor cluster  74  and/or a satellite positioning system receiver  76 , such as a GPS unit. The vehicle dynamics sensors  74  and GPS unit  76  detect movements of the vehicle and may be used to trigger panel actuator  64  if a crash or other event causes lateral accelerations of a magnitude high enough to result in contact between the armrest and vehicle occupant. The controller  60 , panel actuator  64 , and the various sensors may be connected to a communications bus (not shown) to enable efficient and rapid communication between the devices. 
     FIGS. 7 and 8 show a possible wherein a panel actuator  64  is mounted on or adjacent to the interior wall  10   a  of a sidewall  10 . Panel actuator  64  has a vertically movable piston  80 , an upper end of which engages arm support panel  14  to retain the arm support panel in the arm supporting position (see FIG. 7) during normal operation of the vehicle. RCM  66  is electrically connected with panel actuator  64  and with one or more side impact sensors  62 . Other possible system components such as those described in relation to FIG. 6 are not shown for simplicity. When either of side impact sensors  62  detects a side impact and/or lateral acceleration, RCM  66  makes an actuation decision and sends an actuation command to panel actuator  64 . When the actuation command is received, piston  80  is driven upwardly, causing arm support panel  14  to pivot about axis  43  toward the safety position as shown in FIG.  8 . If the actuation of piston  80  does not move arm support panel  14  to a vertical or nearly vertical orientation, the engagement between the piston and arm support panel is preferably such as to permit further downward/clockwise rotation of the arm support panel. 
     Various other modifications and variations will no doubt occur to those skilled in the arts to which this invention pertains. Such variations and modifications, which generally rely on the teachings through which this disclosure has advanced the art, are properly considered within the scope of this invention. This disclosure should thus be considered illustrative, not limiting; the scope of the invention is instead defined by the following claims.