Deformable Pivot Stop for Seatbelt Latch Plate Torque Control
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Solution Overview
Problem
Current seatbelt systems face challenges in controlling and reducing the loads applied across the chest or lap of occupants during collisions, which can increase the risk of injury due to the lack of effective load distribution and management.
Innovation Solution
The seatbelt system incorporates a latch plate assembly with a deformable pivot stop, comprising a shear pin or deformable abutment surfaces, that allows the D-ring to pivot relative to the latch plate when a predetermined torque is exceeded, altering the path of the shoulder band to distribute loads more evenly across the upper torso, thereby reducing the risk of injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seatbelt applies loads across the chest or lap of the occupant to secure the occupant against harmful movement, then the occupant is restrained effectively, but the force applied to the upper torso increases which may increase the risk of occupant injury
Solution Approach 1:
The latch plate assembly incorporates a deformable pivot stop that allows dynamic adjustment of the shoulder band path. Under normal conditions, the pivot stop maintains a fixed position for stable restraint. During impact, when predetermined torque is exceeded, the deformable element deforms and allows the D-ring to pivot, dynamically changing the load path to reduce forces on the upper torso while maintaining restraint effectiveness
Solution Approach 2:
The system changes the geometric parameter of the shoulder band path by allowing the D-ring to pivot relative to the latch plate when impact forces are detected. This parameter change alters the engagement location from near the neck to a position removed from the neck, distributing loads more evenly across the upper torso and reducing peak forces while maintaining the restraint function
2Reliability
If a pretensioner tightens the seatbelt upon detecting an impact occurrence, then the seatbelt restraint effectiveness is improved, but the load control becomes more complex requiring additional control systems
Solution Approach 1:
The latch plate assembly employs a self-regulating mechanism where the deformable pivot stop automatically responds to impact forces without requiring external control systems. When predetermined torque is exceeded during impact, the deformable element deforms and allows pivoting of the D-ring, automatically adjusting the load path to reduce upper torso forces. This passive, self-service approach achieves load control functionality without adding complex active control systems
Solution Approach 2:
The deformable pivot stop acts as an intermediary element between the D-ring and latch plate, mediating the transmission of impact forces. This intermediate component absorbs and redistributes loads through its deformable characteristic, providing load control functionality while maintaining structural simplicity and avoiding the need for complex electronic control systems
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
This design effectively reduces the risk of injury by allowing the shoulder band to engage the shoulder at a location removed from the neck, resulting in a more even distribution of loading and a decrease in the force applied to the upper torso during impacts, thereby minimizing the risk of injury.
Implementation Method 1
The deformable element is deformable at a predetermined pivot torque between the D-ring and the plate
Data Source
AI summary
A seatbelt latch plate assembly includes a latch plate, a D-ring, and a pivot stop. The D-ring is pivotably connected to the latch plate. The pivot stop is disposed between and rotatably fixes the latch plate to the D-ring. The pivot stop includes a deformable element. The deformable element is deformable at a predetermined pivot torque between the D-ring and the plate.