Pivoting Seat Armrest Bushing Structure for Lateral Stability
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Solution Overview
Problem
Existing armrest structures in vehicles experience variability in axial load due to tolerance stack-up and are prone to lateral movement when laterally directed forces are applied, compromising their stability and functionality.
Innovation Solution
A seat assembly with a pivotable armrest design that incorporates a spring bushing and fixed spacer, where the spring bushing applies a radial force to both the rotating bushing and the fixed spacer, allowing for consistent pivoting motion while resisting lateral forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Belleville or wave washers are used to apply axial load on the armrest, then the armrest can be maintained in a desired position, but there is an undesirably large amount of variation in the axial load due to tolerance stack-up
Solution Approach 1:
The patent changes the parameter of load application from axial (through washers) to radial (through spring bushing), which fundamentally alters how the retaining force is applied to the armrest. This parameter change eliminates the tolerance stack-up issue because the radial spring force can be independently controlled and does not depend on the cumulative tolerances of multiple stacked components.
Solution Approach 2:
The spring bushing acts as an intermediary component between the armrest and the retaining structure. Instead of directly stacking washers to create retaining force, the spring bushing mediates the force application through its radial spring action, providing a more consistent and controllable retaining force that compensates for manufacturing variations.
2Ease of operation
If traditional armrest support structures are used, then the armrest can pivot between positions, but the armrest may undesirably move in the lateral direction when lateral forces are applied
Solution Approach 1:
The patent applies different qualities to different parts of the armrest support system. The spring bushing provides radial flexibility that allows pivoting motion, while the overall structure maintains lateral stability. This local differentiation of properties enables the armrest to pivot smoothly while resisting unwanted lateral movement.
Solution Approach 2:
The patent introduces dynamic elements through the spring bushing that allows the armrest to pivot between positions while maintaining stability. The spring mechanism provides a dynamic retaining force that accommodates motion in the pivoting direction while resisting lateral displacement, creating a balanced system that is both movable and stable.
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 design ensures a consistent and stable pivoting motion of the armrest between retracted and extended positions, effectively managing lateral forces and reducing variability in axial load, enhancing user comfort and safety.
Implementation Method 1
a spring bushing is disposed about the fixed spacer... The spring bushing applies a radial force against both the rotating bushing and the fixed spacer
Data Source
AI summary
A seat assembly includes a seat including a back and an armrest assembly. The armrest assembly includes a fastener supported on the back of the seat and that defines an axis. A fixed spacer is disposed about the fastener, and a spring bushing is disposed about the fixed spacer. An armrest includes a frame having a rotating bushing supported on the spring bushing. As a result, the frame and the armrest can pivot relative to the fastener and the back of the seat. The spring bushing applies a radial force against both the rotating bushing and the fixed spacer.