Dual Locking Reel Assembly for Passenger Restraint
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Solution Overview
Problem
Existing reel assemblies for passenger restraint systems lack separate locking mechanisms that can be independently triggered and released in response to different incident types, such as major and minor events, and require complex reset procedures.
Innovation Solution
A reel assembly with dual locking mechanisms, where a first mechanism is triggered by major incidents (over 100 pounds of force) and remains locked until manually reset, and a second mechanism is triggered by minor incidents (less than 100 pounds of force) and reset by counter tension, allowing for independent operation and simplified reset processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single locking mechanism is used in existing reel assemblies, then the structure is simpler, but it cannot independently trigger and release locking in response to different incident types (major vs. minor events)
Solution Approach 1:
The locking mechanism is divided into two independent subsystems: a first locking mechanism with first and second pawls for major incidents, and a second locking mechanism with third and fourth pawls for minor incidents. Each subsystem can be independently triggered and reset, allowing the system to adapt to different incident types while maintaining manageable complexity through modular design.
2Reliability
If a first locking mechanism is added for major incidents, then safety during major incidents is improved, but the device complexity increases
Solution Approach 1:
The locking system is segmented into two independent mechanisms: the first locking mechanism (with first and second pawls) handles major incidents requiring manual reset, while the second locking mechanism (with third and fourth pawls) handles minor incidents allowing automatic reset. This segmentation improves reliability for different incident types while keeping each subsystem relatively simple.
3Reliability
If manual reset is required after major incidents, then safety is ensured, but ease of operation is reduced
Solution Approach 1:
Different reset procedures are assigned to different locking mechanisms based on incident severity: the first locking mechanism requires manual button pressing for reset after major incidents, ensuring high safety, while the second locking mechanism allows automatic reset through counter-tension after minor incidents, providing ease of operation. This local differentiation optimizes both safety and usability.
4Ease of operation
If automatic reset via counter tension is allowed after minor incidents, then ease of operation is improved, but reliability may be reduced
Solution Approach 1:
The system applies different quality standards to different locking mechanisms: the second locking mechanism (third and fourth pawls) is designed with automatic reset capability via counter-tension for minor incidents, improving ease of operation, while the first locking mechanism maintains manual reset only for major incidents, ensuring higher reliability. This local quality differentiation ensures appropriate safety levels for each incident type.
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 dual locking mechanism effectively restrains occupants during both major and minor incidents while allowing for easy reset after minor incidents without manual intervention, enhancing safety and usability in various vehicle restraint systems.
Implementation Method 1
a first locking mechanism including a first pawl and a second pawl, each adapted to engage with a gear
Implementation Method 2
a second locking mechanism including a third pawl and a fourth pawl, each adapted to engage with the gear
Implementation Method 3
a spring biased to maintain the pawls in the disengaged position
Implementation Method 4
When a strap is rapidly pulled from the reel, an inertia mass turns with respect to the reel. This causes the inertia mass to move forward axially and trip a dog which locks the reel.
Data Source
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AI summary
Disclosed is an improved reel assembly for use in conjunction with an occupant restraint system. The assembly employs a dual locking arrangement whereby an occupant can be restrained during both major and minor incidents. After a major incident, the reel assembly remains locked until the occupant disengages the reel via push button. After a minor incident, the reel assembly can be conveniently unlocked, without the need for accessing the push button, by applying counter tension to the webbing.