Patent Publication Number: US-2022212622-A1

Title: Apparatus and method for floor-mounted passenger lower leg protection

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/847,369, filed on May 14, 2019, the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     It is known to provide an inflatable vehicle occupant protection device, such as an airbag, for helping to protect an occupant of a vehicle. One particular type of airbag is a frontal airbag inflatable between an occupant of a front seat of the vehicle and an instrument panel of the vehicle. Such airbags may be driver airbags or passenger airbags. When inflated, the driver and passenger airbags help protect the occupant from impacts with parts of the vehicle such as the instrument panel and/or a steering wheel of the vehicle. 
     Passenger airbags are typically stored in a deflated condition in a housing that is mounted to the vehicle instrument panel. An airbag door is connectable with the housing and/or instrument panel to help enclose and conceal the airbag in a stored condition. Upon deployment of the passenger airbag, the airbag door opens to permit the airbag to move to an inflated condition. The airbag door opens as a result of forces exerted on the door by the inflating airbag. 
     Driver airbags are typically stored in a deflated condition in a housing that is mounted on the vehicle steering wheel. An airbag cover is connectable with the housing and/or steering wheel to help enclose and conceal the airbag in a stored condition. Upon deployment of the driver airbag, the airbag cover opens to permit the airbag to move to an inflated condition. The airbag cover opens as a result of forces exerted on the cover by the inflating driver airbag. 
     There are trends in the auto industry to make vehicles more spacious. Styling has been making the instrument panel smaller and thus farther away from the occupant. Looking further into the future, driverless, autonomous vehicles are even more spacious. Autonomous vehicles have been contemplated for some time, and now their adaption on a large scale is approaching. Autonomous vehicles can eliminate some of the structure traditionally relied upon for supporting various vehicle safety devices. 
     With these realities as a backdrop, the paradigm of occupant safety systems must shift. In the past, the necessity of a vehicle operator/driver lent to a somewhat standard vehicle passenger cabin configuration. In the U.S., the driver is a front seat, left side, forward facing occupant within reach of the vehicle controls and instrumentation (steering wheel, pedals, instrument panel, console, etc.). This driver configuration helps dictate the layout of the remainder of the vehicle—front seat, forward-facing passenger-side occupant, rear seat (second row, third row, etc.) forward-facing occupants. Accordingly, in the past, occupant safety systems were typically designed with this passenger cabin layout and the associated occupant positions and orientations in mind. 
     The autonomous vehicle eliminates the operator/driver, which eliminates the necessity of their being positioned and oriented in the conventional manner. Vehicle manufacturers are free utilize passenger cabin space as they see fit without being constrained to predetermined passenger arrangements, such as all forward-facing occupants, or vehicle structural configurations, such as steering wheel/instrument panel configurations, center console configurations, foot well pedal controls, etc. 
     This presents the challenge of not only where to locate airbag systems, but also finding a reaction surface against which to position the airbag so that it can absorb impacts. Typically, instrument panel and steering wheel mounted frontal airbags utilize those structures as a reaction surface against which the airbag rests so that it can oppose, cushion, and absorb the impact energy of an impacting occupant and provide a desired ride-down effect. In the autonomous vehicles, however, the vehicle may not have an instrument panel or steering wheel at all, and the occupants can be positioned and oriented outside the traditional manner. This can make it difficult or impossible to utilize traditional structures in the vehicle as reaction surface. 
     BACKGROUND 
     An apparatus for helping to protect occupants of a vehicle in the event of a collision includes a deployable restraint having a stored, pre-deployment condition in a vehicle floor. The restraint is deployable from the floor to restrain the feet and/or lower legs of an occupant from swinging forward and upward in response to a vehicle collision. 
     According to one aspect, the restraint can be a component of a module installed in or on the vehicle floor, and the vehicle is free from structure other than the floor and module components for providing a reaction surface for supporting the restraint. 
     According to another aspect, alone or in combination with any other aspect, the deployable restraint can include an airbag and an inflator for inflating and deploying the airbag. 
     According to another aspect, alone or in combination with any other aspect, the module can include a door that opens in response to deployment of the airbag. The door can be configured to serve as a reaction surface for the airbag. 
     According to another aspect, alone or in combination with any other aspect, the module can include a tether for limiting movement of the door so that the door can serve as a reaction surface for the airbag. 
     According to another aspect, alone or in combination with any other aspect, the deployable restraint can include a restraining panel configured to move to a deployed position extending above the vehicle floor adjacent the occupant&#39;s lower legs and feet. The restraining panel, when deployed, can engage the occupant&#39;s feet to prevent the feet and lower legs of the occupant from swinging upward and forward in response to a vehicle collision. 
     According to another aspect, alone or in combination with any other aspect, the module can include an actuator for actuating the restraining panel to pivot or otherwise move to the deployed position. 
     According to another aspect, alone or in combination with any other aspect, the actuator can include a pyrotechnic actuator. 
     According to another aspect, alone or in combination with any other aspect, the pyrotechnic actuator can be configured to limit movement of the restraint panel after deployment so that the restraint panel can act as a reaction surface for receiving the occupant&#39;s feet and legs. 
     According to another aspect, alone or in combination with any other aspect, the vehicle can be an autonomous vehicle. 
     According to another aspect, alone or in combination with any other aspect, a safety module can include the apparatus according to any of the aforementioned aspects in addition to a housing configured to be mounted in the vehicle floor. The vehicle safety system can also include a sensor/controller for sensing the occurrence of an event for which deployment of the deployable restraint is desired. The sensor/controller can be configured to actuate the deployable restraint in response to sensing the occurrence of the event for which deployment is desired. 
     A method for helping to protect occupants of a vehicle in the event of a collision can include deploying from the vehicle floor a restraint to restrain the feet and/or lower legs of an occupant from swinging forward and upward in response to a vehicle collision. 
     The restraint can be an airbag module including an airbag and an inflator for inflating and deploying the airbag. The module can include a door that opens in response to deployment of the airbag, the door being configured to serve as a reaction surface for the airbag. The module can further include a tether for limiting movement of the door so that the door can serve as a reaction surface for the airbag. 
     According to another aspect, alone or in combination with any other aspect, the deployable restraint can be a module including a restraining panel configured to move to a deployed position extending above the vehicle floor adjacent the occupant&#39;s lower legs and feet. The restraining panel, when deployed, can engage the occupant&#39;s feet to prevent the feet and lower legs of the occupant from swinging upward and forward in response to a vehicle collision. The module can include an actuator for actuating the restraining panel to pivot or otherwise move to the deployed position. The actuator can be a pyrotechnic actuator. The pyrotechnic actuator can be configured to limit movement of the restraint panel after deployment so that the restraint panel can act as a reaction surface for receiving the occupant&#39;s feet and legs. 
    
    
     
       DRAWINGS 
         FIG. 1  is a schematic illustration of a vehicle including a vehicle occupant safety system depicting the system in a pre-deployment condition. 
         FIG. 2  is a schematic illustration of the vehicle depicting the vehicle occupant safety system in a deployed condition, according to a first configuration of the system. 
         FIG. 3  is a schematic illustration of the vehicle depicting the vehicle occupant safety system in a deployed condition, according to a second configuration of the system. 
         FIG. 4  is a schematic illustration of the vehicle depicting the vehicle occupant safety system in a deployed condition, according to a third configuration of the system. 
         FIG. 5  is a schematic illustration of the vehicle depicting the vehicle occupant safety system in a deployed condition, according to a fourth configuration of the system. 
     
    
    
     DESCRIPTION 
     One particular scenario where challenges arise due to autonomous vehicle configurations is in the area of leg protection. Referring to  FIG. 1 , an autonomous vehicle  20  includes a vehicle seat  30  upon which a vehicle occupant  40  is seated. The vehicle seat  30  includes a base  32  connected to the vehicle  20 , e.g., to the floor  22 . The seat base  32  supports a seat bottom  34 . A seatback  36  extends upward from the seat bottom  34  and has a reclined position that can be adjusted. A headrest  38  is positioned at an upper end of the seatback  36 . 
     The occupant  40  is seated on the seat  30 , with his/her torso  42  resting on the seatback  36 , head  44  positioned at or near the headrest  38 , and buttocks  46  and legs  50  (more specifically upper legs  52 ) resting on the base  32 . The occupant&#39;s lower legs  56  extend from the knee  54  downward toward the vehicle floor  22 , where the occupant&#39;s feet  58  rest. In the typical occupant position of  FIG. 1 , the occupant&#39;s arms  60  are at his/her side, with the upper arms  62  adjacent and parallel to the torso  42 , bent at the elbows  64  with the lower arms/forearms  66  and hands  70  resting on the upper legs  56 . 
     As shown in  FIG. 1 , the occupant  40  is restrained by a seatbelt  80 , which is a conventional three-point restraint including a shoulder belt portion  82  that extends across the occupant&#39;s shoulder  72 , and a lap belt portion  84  that extends across the occupant&#39;s lap, i.e., where the upper legs  50  meet the torso  42 . The seatbelt  80  is secured via a buckle  86 , which is anchored to the vehicle  20 . To simplify the drawings, the seatbelt  80  is not illustrated in  FIGS. 2-5 . In  FIGS. 2-5 , the occupant  40  is wearing a seatbelt, it just isn&#39;t shown in the figures. The occupant movements illustrated and described with reference to  FIGS. 2-5  are therefore those that would take place with normal use of the seatbelt  80  illustrated in  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , a vehicle safety system  10  helps protect the occupant  40  of the autonomous vehicle  20 . As shown in  FIGS. 1 and 2 , the system  10  includes an airbag  90  mounted in a roof  24  of the vehicle  20 . Being an autonomous vehicle  20 , the passenger compartment or cabin is without operator controls, such as a steering wheel, pedals, instrumentation, center console, etc., and thus represents an autonomous vehicle. Accordingly, the instrument panel is reduced in size and/or removed altogether in order to maximize the space in the cabin. Control interfaces for climate controls, GPS, navigation, entertainment, etc. can, for example, be provided in a center console area of the vehicle  20  located between the passengers of the front and/or rear rows. 
     In this open passenger cabin configuration, vehicle seats  30  can be configured, positioned, and arranged in a variety of manners, not constrained by the need to facilitate a vehicle driver/operator. For example, in  FIG. 1 , the seat  30  is a forward-facing seat, facing in the direction of forward vehicle travel indicated generally by the arrow labeled A. As shown in  FIG. 4 , the seats  18  can be arranged facing each other, with the front row FR facing rearward toward the rear row RR. 
     For the conventional, forward-facing seating arrangement of  FIG. 1 , in the event of a frontal crash, the occupants  40  is urged forward in the vehicle, as shown in  FIG. 2 . As shown in  FIG. 2 , the airbag  90  restrains the occupant  40 , particularly the head  44  and torso  42 , without restraining the arms  60  and legs  50 . As a result, it can be seen that the legs  50  become extended due to inertia, as indicated generally by the arrow labeled B. This can stress the legs  50 , such as hyperextension of the knees  54 . Non-autonomous vehicles had structure for blocking this motion, such as the instrument panel/footwell (front passengers) and seatbacks of forward seating (rear passengers). Autonomous vehicles may not include these features. 
     Referring to  FIG. 3 , the vehicle safety system  10  includes a lower leg protection device  100 . In the example configuration of  FIG. 3 , the protection device  100  includes an inflatable airbag  102  and an inflator  104  for inflating the airbag, both of which are stored in a housing  106  in the vehicle floor  22 . The inflator  104  can, for example, be operatively to the same airbag control unit (“ACU”) that causes inflation of the airbag  90  in response to a vehicle collision. The ACU can actuate the inflator  104  to inflate and deploy the airbag  102  in response to the sensed vehicle collision. 
     The airbag  102 , inflator  104 , and housing  106  are components of an airbag module  110  that also includes a door  112  that conceals the airbag in a stored condition (see  FIG. 1 ). When the airbag  102  deploys, the door  112  swings open (see arrow C). A retaining member  114 , such as a cable or strap, limits the degree to which the door  112  swings open. This can allow the door  112 , alone or in combination with the floor  22 , to act as a reaction surface for the airbag  102 . The airbag  102  can receive the occupant&#39;s legs  50  as the lower leg  56  swings (arrow B) in response to the collision. The airbag  102  can therefore cushion the lower leg  56  and foot  58 , slowing their acceleration in response to a collision, and providing a desired ride-down effect. 
     The airbag  102  can have various shapes configured to receive the occupants leg  50 . For example, the airbag can be curved so as to extend over and around the occupant&#39;s foot  58  and cushion the lower leg  56 . Alternatively, the airbag  102  can have a larger, more rounded overall shape (see,  FIG. 4 ). The shape and extent of the airbag  102  can be selected to correspond with the architecture and layout of the vehicle  20 . 
     Referring to  FIG. 4 , the vehicle has a front row FR and a rear row RR of seating in which the occupants  40  face each other. In the example configuration of  FIG. 4 , the vehicle safety system  10  includes a lower leg protection device  120 . In the example configuration of  FIG. 4 , the protection device  120  includes an inflatable airbag  122  and an inflator  124  for inflating the airbag, both of which are stored in a housing  126  in the vehicle floor  22 . The inflator  124  can, for example, be operatively to the same airbag control unit (“ACU”) that causes inflation of the airbag  90  in response to a vehicle collision. The ACU can actuate the inflator  124  to inflate and deploy the airbag  122  in response to the sensed vehicle collision. 
     The airbag  122 , inflator  124 , and housing  126  are components of an airbag module  130  that conceals the airbag in a stored condition (see  FIG. 1 ). The airbag  122  deploys from the floor, for example, through a rupturable housing closure member, e.g., a tear seam. The airbag  122  can receive the front and/or rear seat occupant&#39;s legs  50  as the lower leg  56  swings (arrow B) in response to the collision. In  FIG. 4 , it is the front seat occupant  40 , whose leg  50  is received by the airbag  122 . The airbag  122  cushions the lower leg  56  and foot  58 , slowing their acceleration in response to a collision, and providing a desired ride-down effect. 
     In the vehicle of  FIG. 4 , the occupant  40  of the rear row seat  30  utilizes the airbag  120 . This is because the rear seat occupant&#39;s lower legs  56  swing in the direction of arrow B in response to the collision when travelling in the forward direction (see arrow A). The lower legs  56  of the rear row occupant  40  do not extend in response to the collision when vehicle  20  is travelling in the forward direction of arrow A. Instead, the front seat occupant  40  is pushed against the seatback  36 , and his/her legs  50  are pushed forward against the seat  30  and the vehicle floor  22 . Because of this, the front seat occupant  40  may make little or no use of the airbag  122 . 
     The airbag  122  can have various shapes configured to receive the occupants leg  50 . For example, the airbag can be curved or contoured (see, e.g.,  FIG. 2 ) so as to extend over and around the occupant&#39;s foot  58  and cushion the lower leg  56 , from either the front row or rear row seats  30 . Alternatively, the airbag  122  can have the illustrated larger, rounded overall shape. The shape and extent of the airbag  122  can be selected to correspond with the architecture and layout of the vehicle  20 . 
     The airbags  102 ,  122  can be constructed of any suitable material, such as nylon (e.g., woven nylon 6-6 yarns), and may be constructed in any suitable manner. For example, the airbag may include one or more pieces or panels of material. If more than one piece or panel is used, the pieces or panels may be interconnected by known means, such as stitching, ultrasonic welding, heat bonding, or adhesives, to form the airbag. The airbag may be uncoated, coated with a material, such as a gas impermeable urethane, or laminated with a material, such as a gas impermeable film. The airbag thus may have a gas-tight or substantially gas-tight construction. Those skilled in the art will appreciate that alternative materials, such as polyester yarn, and alternatives coatings, such as silicone, may also be used to construct the airbag. 
     Upon sensing the occurrence of an event for which inflation of the airbag is desired, such as a vehicle collision, the ACU provides signals to the inflators. Upon receiving the signals from the ACU, the inflators are actuated and provide inflation fluid to the inflatable volumes of the airbags  90 ,  102 ,  122  in a known manner. The inflating airbags exert a force on their respective housings, which causes the housings to open. This releases the airbags inflate and deploy from their stored conditions in their respective housings to their respective deployed conditions. The airbags, while inflated, help protect the vehicle occupants  40  by absorbing the impact of the occupants. This can be achieved in a variety of manners. 
     Referring to  FIG. 5 , for purposes of illustrating an example configuration, the vehicle has a single forward facing seat  30  upon which the occupant  40  is seated. In the example configuration of  FIG. 5 , the vehicle safety system  10  includes a lower leg protection device  140 . In the example configuration of  FIG. 4 , the protection device  140  includes a foot/lower leg restraint panel  142  and an actuator  144  that is actuatable to move the restraint panel  142  to the illustrated deployed position. The restraint panel  142  and actuator  144  are stored in a housing  126  in the vehicle floor  22  in a pre-deployment condition (see  FIG. 1 ). The restraint panel  142  can be a cover for the inflator and can sit flush with the vehicle floor  22 . The actuator  144  can, for example, be operatively to the same airbag control unit (“ACU”) that causes inflation of the airbag  90  in response to a vehicle collision. The ACU can actuate the actuator  144  to deploy the restraint panel  142  in response to the sensed vehicle collision. 
     The restraint panel  142 , actuator  144 , and housing  146  are components of a module  140 . The restraint panel  142  deploys from the floor  22 , for example, through a rupturable housing closure member, e.g., a tear seam. The restraint panel  142  can receive the front and/or rear seat occupant&#39;s feed  58 , which helps prevent rotation and hyperextension of the lower legs  56  due to swinging (arrow B) in response to the collision. The restraint panel  142  restricts lower leg movement toward hyperextension and slows acceleration of the foot  58  and lower leg  56  in response to a collision. 
     The actuator  144  can be of any configuration capable of deploying the restraint panel  142  in the requisite amount of time. For example, the actuator  144  can be a pyrotechnic actuator including a pyrotechnic material that undergoes a chemical reaction when actuated, e.g., via a squib, which creates pressure for moving an actuator component, such as a piston or plunger, attached to the restraint panel  142 . The actuator  144  can be configured to lock at its furthest deployed condition to prevent the restraint panel  142  from moving back toward its pre-deployment condition. 
     Upon sensing the occurrence of an event for which deployment of the restraint panel is desired, such as a vehicle collision, the ACU provides signals to the airbag inflators and to the actuator  144 . Upon receiving the signals from the ACU, the inflators are actuated and provide inflation fluid to the inflatable volumes of the airbags in a known manner. The actuator  144  is actuated to deploy the restraint panel  142 , which helps protect the occupant  40  by limiting movement of the lower legs and feet. 
     From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications to the disclosed system and methods that fall within the spirit and scope of the invention. These improvements, changes, and/or modifications are intended to be covered by the appended claims.