Juvenile Vehicle Seat Energy Dissipation via Deforming Load-Limiter Bars
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Solution Overview
Problem
Current child restraints for vehicles lack effective energy dissipation mechanisms to minimize the impact of external forces on children during crashes, potentially leading to increased risk of injury.
Innovation Solution
The child restraint system incorporates a rigidifying truss with J-shaped stiffener beams and an energy-dissipation system featuring top and bottom load-limiter bars that deform to absorb and dissipate energy applied during impacts, coupling with the seat-back tether strap and crotch belt respectively, to reduce the load on the child.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the juvenile seat uses a rigid seat shell structure, then the structural strength is improved, but the energy dissipation capability during impact deteriorates
Solution Approach 1:
The load-limiter bar is segmented into multiple sections (first section, second section, third section) with different geometric configurations. Each section has distinct cross-sectional dimensions and wall thicknesses, allowing different parts of the same component to dissipate energy through different deformation mechanisms while maintaining overall structural integrity.
Solution Approach 2:
The load-limiter bar features varying geometric parameters along its length, including different outer diameter dimensions (D1, D2, D3), wall thicknesses (t1, t2, t3), and section lengths (L1, L2, L3). These parameter changes enable progressive energy dissipation through controlled deformation at different stages of impact loading.
2Loss of energy
If the juvenile seat incorporates energy-dissipation structures, then the impact energy absorption is improved, but the device complexity increases
Solution Approach 1:
The load-limiter bar is integrated with the seat shell structure through coupling mechanisms at its ends. The first end couples to the front surface of the seat shell while the second end couples to the rear surface, merging the energy-dissipation function with the existing seat structure rather than adding completely separate components.
Solution Approach 2:
The load-limiter bar serves multiple functions: it acts as a structural support element, an energy-dissipation component through controlled deformation, and a load-transfer mechanism between the seat shell and external anchors. This multi-functionality reduces the need for additional specialized components.
3Loss of energy
If the load-limiter bar deforms during impact, then the energy dissipation is improved, but the structural integrity deteriorates
Solution Approach 1:
The load-limiter bar is divided into multiple sections with progressively varying dimensions. The deformation is distributed across these sections rather than concentrated at a single point, preventing catastrophic failure while maximizing energy dissipation through controlled plastic deformation in each segment.
Solution Approach 2:
The load-limiter bar is pre-designed with specific geometric features and material properties that enable controlled deformation at predetermined locations and stages during impact. The varying wall thicknesses and cross-sectional dimensions create progressive collapse mechanisms that absorb energy before reaching critical failure points.
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 system effectively dissipates energy from external impacts, reducing the force transmitted to the child by deforming load-limiter bars, thereby enhancing safety and minimizing injury risk during vehicle collisions.
Implementation Method 1
The top load-limiter bar is configured to mate with a seat-back tether strap anchored to the vehicle and deform to dissipate energy applied to the juvenile seat during exposure of the vehicle to an external impact force
Implementation Method 2
deform to dissipate energy applied to the juvenile seat during exposure of the vehicle to an external impact force
Data Source
AI summary
A child restraint in accordance with the present disclosure includes a juvenile seat and a child-restraint harness coupled to the juvenile seat. The child-restraint harness includes a crotch belt. A seat-back tether strap is also included in the child restraint.