Vehicle Armrest Locking Assembly Prevents Inadvertent Deployment
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Solution Overview
Problem
Center seat armrests in motor vehicles often deploy inadvertently during frontal impacts due to lack of restraint, posing safety concerns.
Innovation Solution
A locking assembly featuring a pivoting catch member, catch wire, and retractable stop pin with a spring-loaded mechanism that engages and disengages to prevent unwanted deployment during sudden deceleration, while allowing manual deployment by a user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a friction fit between the armrest and receiver is used to keep the armrest stowed, then ease of operation is improved, but reliability deteriorates due to inadvertent deployment during impact
Solution Approach 1:
The locking mechanism is divided into separate functional components: a catch member with engagement features, a stop pin with actuating features, and a spring biasing mechanism. Each component performs a specific function - the catch member retains the armrest, the stop pin prevents accidental release, and the spring provides automatic reset capability. This segmentation allows the system to maintain reliability while preserving ease of operation.
Solution Approach 2:
The stop pin acts as an intermediary element between the catch member and the external environment. It mediates the interaction by physically blocking the catch member's movement under normal conditions, preventing inadvertent deployment. When intentional release is required, the stop pin is actuated to allow the catch member to move, thus controlling the transition between locked and unlocked states.
2Reliability
If a locking mechanism is added to prevent inadvertent deployment, then reliability is improved, but device complexity increases
Solution Approach 1:
The spring-loaded stop pin mechanism is self-actuating and automatically resets. During normal operation, the spring continuously biases the stop pin into the engaged position, preventing accidental deployment. When the armrest needs to be deployed, the user simply pulls the armrest, which automatically actuates the stop pin through the cable linkage. After deployment, the spring automatically returns the stop pin to its engaged position. This self-service capability eliminates the need for separate locking and unlocking actions, reducing operational complexity.
Solution Approach 2:
The locking mechanism transitions from a static friction-fit design to a dynamic system with movable components. The stop pin can move between engaged and disengaged positions, and the catch member can pivot to lock or unlock the armrest. This dynamic behavior allows the mechanism to respond automatically to user actions and impact forces, providing reliable retention while maintaining ease of deployment through natural motion sequences.
3Reliability
If the stop pin is spring-loaded to maintain engagement, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The spring is designed to provide excessive biasing force, ensuring that the stop pin is always firmly engaged with the catch member under normal operating conditions. This excessive action creates a large safety margin that compensates for variations in spring characteristics due to manufacturing tolerances. The spring force is sufficient to overcome typical impact forces and ensure reliable retention, while the generous force margin reduces sensitivity to precise spring calibration.
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
Effectively prevents inadvertent deployment of the armrest during vehicle deceleration events while allowing normal use, enhancing safety and convenience.
Implementation Method 1
the retractable stop pin is urged into engagement with the pivoting catch member by a spring-loaded mechanism
Data Source
AI summary
A locking assembly for a vehicle armrest includes a pivoting catch member disposed below an armrest body and a catch wire disposed on a seat back frame member. A retractable stop pin maintains engagement of the pivoting catch member and the catch wire. A release is operatively connected to the retractable stop pin, which may be urged into engagement with the pivoting catch member by a spring. Armrest and seat assemblies including the locking assembly are provided.