Variable-Stiffness Seat Back Hinge for Crash Energy Absorption
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Solution Overview
Problem
In the event of a collision, existing vehicle safety mechanisms do not effectively absorb energy to reduce passenger injury, as they lack a dynamic seat system that can recline and absorb impact forces while maintaining passenger restraint.
Innovation Solution
A seat system with a rotating back support and integrated seat belt that unlocks and rotates forward when a torque threshold is exceeded, using a hinge mechanism with adjustable resistance to dissipate energy and a reinforcement plate to withstand forces, allowing the seat to move and absorb crash energy while keeping the passenger secure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the seat back support is locked in a fixed position, then structural stability is maintained, but crash energy cannot be absorbed and peak impulse is increased
Solution Approach 1:
The hinge mechanism transitions from a static locked state to a dynamic unlocked state during collision, allowing the seat back to rotate forward and absorb crash energy through controlled movement rather than rigid resistance
Solution Approach 2:
The hinge stiffness parameter is made variable through the spring mechanism, allowing it to transition from a high-stiffness locked state to a low-stiffness unlocked state, enabling the system to adapt its mechanical properties based on collision conditions
2Loss of energy
If the hinge is designed to unlock easily, then crash energy absorption is improved, but normal seat stability and passenger restraint are compromised
Solution Approach 1:
The spring mechanism is pre-loaded during normal operation to maintain the hinge in a locked state, providing stable seat restraint. During collision, the pre-loaded spring enables easy unlocking by reversing its force direction, allowing energy absorption without compromising normal reliability
3Loss of energy
If the back support is allowed to rotate freely, then crash energy absorption is maximized, but controlled rotation and passenger safety are reduced
Solution Approach 1:
The brake mechanism acts as an intermediary between the unrestricted rotation needed for energy absorption and the controlled rotation needed for passenger safety, providing regulated resistance that manages the rotation speed and extent
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 reduces passenger injury by distributing crash forces over time, maintaining restraint and reducing peak impulse, thereby minimizing injury and damage to the vehicle.
Implementation Method 1
a resilient support for the backrest
Implementation Method 2
The rotation of the back support is dampened by a brake on the hinge
Data Source
AI summary
The disclosure provides for a system that includes a seat mounted in a vehicle. The seat includes a base, a back support, a hinge, and a seat belt integrated into the seat. The back support is capable of rotating relative to the base and thereby reclining. The hinge is between the base and the back support and is configured to lock the back support in positions in relation to the base. The seat belt has a shoulder portion and a lap portion and is attached to the seat at a shoulder anchor in the back support and a base anchor in the base. When a generated torque, created from a forward force applied by the shoulder portion of the seat belt, exceeds a threshold amount of torque, the hinge is configured to unlock and back support is configured to rotate forward from a reclined position towards an upright position.