Inflatable Plastic Beam for Vehicle Seat Submarining Prevention
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Solution Overview
Problem
During a frontal vehicle impact, vehicle occupants can experience submarining due to their momentum causing them to move forward relative to the vehicle, which conventional seat belt systems fail to prevent effectively, especially when the thighs and pelvis can slide under the dashboard.
Innovation Solution
A deployable beam module is integrated into the seat assembly, comprising an inflatable plastic beam that deploys upon impact detection, raising the seat cushion to prevent forward motion of occupants by increasing the seat ramp angle and providing resistance to forward forces through its design and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional three-point seat belt system is used, then the occupant is restrained by the lap and shoulder belts, but the occupant's thighs and pelvis can still slide forward under the dashboard during rapid deceleration
Solution Approach 1:
The deployable beam is pre-positioned in a retracted state within the seat structure, ready to deploy before impact occurs. Upon detection of a frontal collision, the beam rapidly extends forward to create a physical barrier that prevents submarining by blocking the forward motion of the occupant's thighs and pelvis, addressing the limitation of conventional seat belts that cannot prevent this specific type of forward sliding
Solution Approach 2:
The deployable beam acts as an intermediary element between the seat and the occupant's lower body. It provides additional restraint at the thigh level, complementing the existing lap and shoulder belts, and creates a multi-point restraint system that effectively prevents the occupant from sliding under the dashboard during impact
2Reliability
If the seat cushion is raised to prevent forward motion of occupants, then the seat ramp angle increases providing better restraint, but the structural complexity of the seat assembly increases
Solution Approach 1:
The seat cushion's ramp angle is made dynamic rather than static. The deployable beam can extend and retract, allowing the seat cushion to transition between a lower normal position and a raised impact position. This dynamic adjustment provides enhanced restraint during collisions while maintaining a simpler, more comfortable configuration during normal operation, thereby reducing perceived structural complexity
Solution Approach 2:
The restraint function is segmented into multiple independent components: the existing lap and shoulder belts for upper body restraint, and the deployable beam for lower body restraint. This segmentation allows each component to be optimized independently and simplifies the overall system architecture by adding functionality through a modular, space-efficient mechanism rather than redesigning the entire seat structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The deployable beam module effectively reduces the likelihood of submarining by restraining occupants more securely during frontal impacts, utilizing a plastic beam that resists deformation and pivoting forces, thus enhancing occupant safety.
Implementation Method 1
an inflatable plastic beam that deploys upon impact detection
Implementation Method 2
utilizing a plastic beam that resists deformation and pivoting forces
Data Source
AI summary
A beam module for a vehicle seat is mounted at a front of a seat, on top of a seat pan and underneath a seat cushion. The module includes a molded plastic beam. The module has a first shape substantially flush with the seat pan and a second shape projecting above the seat pan. The molded plastic beam has a mounting flange with a forward portion and a second portion. The molded plastic beam is inflatable. When inflated, the molded plastic beam assumes its second shape with the seat cushion being correspondingly displaced and deformed to raise the seat cushion when a frontal impact is detected.