Seat Back Armrest Restrictor Mechanism
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Solution Overview
Problem
Existing seat designs with movable armrests face challenges in retaining the armrest in position relative to the seat back when the seat is moved from an upright to a folded position, often requiring increased passenger effort or complex mechanisms like interference fits or mechanical latches.
Innovation Solution
A seat assembly with an armrest restrictor that includes a restrictor body attached to the seat back, featuring a block that engages a stop path to prevent armrest movement when the seat is folded, and a biasing element to return to a release position when the seat is upright, allowing armrest movement between stowed and use positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an interference fit is provided between the armrest and seat back, then the armrest is retained in position relative to the seat back, but the amount of force the passenger must apply to move the armrest increases
Solution Approach 1:
The armrest restrictor dynamically changes its retention characteristics based on seat back position. When the seat back is in the upright position, the restrictor allows free armrest movement. When the seat back is folded, the restrictor engages to prevent armrest movement, thus adapting the retention mechanism to different operational states without increasing passenger effort during normal use.
Solution Approach 2:
The restrictor body rotates between a first position (when seat back is upright) and a second position (when seat back is folded), changing the geometric parameters of the block relative to the stop path. This parameter change enables the system to provide retention only when needed, without continuously increasing the force required for armrest movement.
2Reliability
If a mechanical latch is provided to retain the armrest, then the armrest is retained in position, but the device complexity increases and the passenger must reach and interact with a release
Solution Approach 1:
The armrest restrictor is a passive mechanism that automatically engages and disengages based on the seat back position. The restrictor body rotates freely with the seat back, and the block automatically enters or exits the stop path depending on the seat back angle. This self-service mechanism eliminates the need for passenger interaction with releases or complex control systems.
Solution Approach 2:
The restrictor body serves multiple functions: it acts as a structural component attached to the seat back, a retention mechanism when engaged, and a passive follower that moves with the seat back. This multi-functionality reduces the need for separate dedicated latch components and control mechanisms.
3Ease of operation
If the armrest is allowed to move freely relative to the seat back, then the passenger can easily position the armrest, but the armrest may undesirably remain deployed when the seat back is moved upright
Solution Approach 1:
The restrictor body is pre-positioned and biased to engage the stop path before the seat back completes its folding motion. The spring bias ensures the block is already in place to prevent armrest movement, counteracting the armrest weight's tendency to cause unwanted deployment before the retention mechanism is fully engaged.
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 armrest restrictor effectively retains the armrest in position during seat movement, reducing passenger effort and eliminating the need for complex latches, while allowing easy transition between stowed and use positions.
Implementation Method 1
The armrest restrictor includes a biasing element that biases the restrictor body toward the block position
Data Source
AI summary
A seat assembly includes a seat back that is mounted on a base for relative movement between a first seat position and a second seat position. An armrest is mounted on the seat back for relative movement between a stowed position and a use position. An armrest restrictor prevents movement of the armrest relative to the seat back when the seat back is moved from the first seat position toward the second seat position and allows movement of the armrest relative to the seat back when the seat back is in the first seat position.